Solid-pseudopapillary neoplasms are rare, but are distinctive pancreatic tumors of low-malignant potential. While the histogenesis of these tumors is unclear, they are often associated with gain-of-function mutations in the catenin (cadherin-associated protein), beta 1 (88 kDa), or CTNNB1 gene, resulting in nuclear accumulation of CTNNB1. CTNNB1 is a central component of the Wnt signaling pathway and mediates gene expression through the lymphoid enhancer-binding factor 1 (LEF1) /T-cell factor transcription complex. Although LEF1 has a pivotal role in the transactivation of Wnt/CTNNB1 responsive genes, the status of LEF1 in solid-pseudopapillary neoplasms and other pancreatic tumors has not been examined. We analyzed both LEF1 and CTNNB1 in a large cohort of pancreatic tumors (n=155). In all cases of solid-pseudopapillary neoplasms including surgical resections (n=27) and cytologic samples (n=8) had strong and diffuse nuclear labeling for both LEF1 and CTNNB1. The surrounding uninvolved pancreatic parenchyma was devoid of any LEF1 staining. All resection and cytologic specimens from well-differentiated pancreatic neuroendocrine tumors (n=44; n=29, respectively), high-grade pancreatic neuroendocrine carcinomas (n=2; n=1), pancreatic ductal adenocarcinomas (n=25; n=12), and acinar cell carcinomas (n=9; n=2) studied were negative for both nuclear LEF1 and CTNNB1. However, nuclear LEF1 and CTNNB1 were detected in all four resected pancreatoblastomas (no cytologic specimens were available for immunolabeling), but primarily centered around and within squamoid corpuscles. In summary, abnormal CTNNB1 accumulation was accompanied by nuclear LEF1 overexpression in both solid-pseudopapillary neoplasms and pancreatoblastomas. But, in contrast to pancreatoblastomas, a diffuse, nuclear labeling was observed in solid-pseudopapillary neoplasms and further implicates the CTNNB1/ LEF1 transcriptional complex in the development of solid-pseudopapillary neoplasms. In addition, as part of an immunohistochemical panel, LEF1 can be a useful ancillary stain in the diagnosis of solid-pseudopapillary neoplasms.
CTNNB1; LEF1; pancreas; pancreatoblastoma; solid-pseudopapillary neoplasms
Myxoid and round-cell liposarcoma is a frequently encountered liposarcoma subtype. The mainstay of treatment remains surgical excision with or without chemoradiation. However, treatment options are limited in the setting of metastatic disease. Cancer-testis antigens are immunogenic antigens with the expression largely restricted to testicular germ cells and various malignancies, making them attractive targets for cancer immunotherapy. Gene expression studies have reported the expression of various cancer-testis antigens in liposarcoma, with mRNA expression of CTAG1B, CTAG2, MAGEA9, and PRAME described specifically in myxoid and round-cell liposarcoma. Herein, we further explore the expression of the cancer-testis antigens MAGEA1, ACRBP, PRAME, and SSX2 in myxoid and round-cell liposarcoma by immunohistochemistry in addition to determining mRNA levels of CTAG2 (LAGE-1), PRAME, and MAGEA3 by quantitative real-time PCR. Samples in formalin-fixed paraffin-embedded blocks (n=37) and frozen tissue (n=8) were obtained for immunohistochemistry and quantitative real-time PCR, respectively. Full sections were stained with antibodies to MAGEA1, ACRBP, PRAME, and SSX2 and staining was assessed for intensity (1–2+) and percent tumor positivity. The gene expression levels of CTAG2, PRAME, and MAGEA3 were measured by quantitative real-time PCR. In total, 37/37 (100%) of the samples showed predominantly strong, homogenous immunoreactivity for PRAME. There was a variable, focal expression of MAGEA1 (11%) and SSX2 (16%) and no expression of ACRBP. Quantitative real-time PCR demonstrated PRAME and CTAG2 transcripts in all eight samples: six tumors with high mRNA levels; two tumors with low mRNA levels. The gene expression of MAGEA3 was not detected in the majority of cases. In conclusion, myxoid and round-cell liposarcomas consistently express PRAME by immunohistochemistry as well as CTAG2 and PRAME by qualitative real-time PCR. This supports the use of cancer-testis antigen-targeted immunotherapy in the treatment of this malignancy.
cancer-testis antigens; immunotherapeutics; myxoid and round-cell liposarcoma
Rare, sporadic uterine leiomyomas arise in the setting of severe metabolic aberration due to somatic fumarate hydratase mutation. Germline mutations account for the Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome, which predisposes for cutaneous and uterine leiomyomas and aggressive renal cell carcinomas. Altered fumarate hydratase leads to fumarate accumulates in affected cells with formation of S-(2-succino)-cysteine, which can be detected with polyclonal antibody. High levels of these modified cysteine residues are found characteristically in fumarate hydratase-deficient cells, but not in normal tissues or tumors unassociated with Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome. We hypothesized that S-(2-succino)-cysteine-positive leiomyomas, indicating fumarate hydratase aberration, have morphologic features that differ from those without S-(2-succino)-cysteine positivity. Hematoxylin and eosin-stained slides of uterine smooth muscle tumors were prospectively analyzed for features suggesting Hereditary Leiomyomatosis and Renal Cell Carcinoma Syndrome, such as prominent eosinophilic macronucleoli with perinucleolar halos, yielding 9 cases. Germline genetic testing for fumarate hydratase mutations was performed in 3 cases. A detailed morphological analysis was undertaken, and S-(2-succino)-cysteine immunohistochemistry was performed with controls from a tissue microarray [leiomyomas (19), leiomyosarcomas (29), and endometrial stromal tumors (15)]. Of the 9 study cases, 4 had multiple uterine smooth muscle tumors. All cases had increased cellularity, staghorn vasculature, and fibrillary cytoplasm with pink globules. All cases had inclusion-like nucleoli with perinuclear halos (7 diffuse, 1 focal). All showed diffuse granular cytoplasmic labeling with the S-(2-succino)-cysteine antibody. Two of 3 tested patients had germline fumarate hydratase mutations. Only 1 leiomyoma from the tissue microarray controls was immunohistochemically positive, and it showed features similar to other immunohistochemically positive cases. Smooth muscle tumors with fumarate hydratase aberration demonstrate morphological reproducibility across cases and S-(2-succino)-cysteine immuno-positivity. Although the features described are not specific for germline fumarate hydratase mutation or the Hereditary Leiomyomatosis and Renal Cell Carcinoma syndrome, their presence should suggest fumarate hydratase aberration. Identifying these cases is an important step in the diagnostic workup of patients with possible Hereditary Leiomyomatosis and Renal Cell Carcinoma.
uterine leiomyomas; fumarate hydratase; HLRCC (hereditary leiomyomatosis and renal cell carcinoma syndrome); S-(2-succino)-cysteine; succination
DNA methylation is the most well studied epigenetic modification in cancer biology. 5-hydroxymethylcytosine is an epigenetic mark that can be converted from 5-methylcytosine by the ten-eleven translocation gene family. We recently reported the loss of 5-hydroxymethylcytosine in melanoma compared to benign nevi and suggested that loss of this epigenetic marker is correlated with tumor virulence based on its association with a worse prognosis. In this study we further characterize the immunoreactivity patterns of 5-hydroxymethylcytosine in the full spectrum of melanocytic lesions to further validate the potential practical application of this epigenetic marker. 175 cases were evaluated: 18 benign nevi, 20 dysplastic nevi (10 low-grade and 10 high-grade lesions), 10 atypical Spitz nevi, 20 borderline tumors, 5 melanomas arising within nevi, and 102 primary melanomas. Progressive loss of 5-hydroxymethylcytosine from benign dermal nevi to high-grade dysplastic nevi to borderline melanocytic neoplasms to melanoma was observed. In addition, an analysis of the relationship of nuclear diameter to 5-hydroxymethylcytosine staining intensity within lesional cells revealed a significant correlation between larger nuclear diameter and decreased levels of 5-hydroxymethylcytosine. Furthermore, borderline lesions uniquely exhibited a diverse spectrum of staining of each individual case. This study further substantiates the association of 5-hydroxymethylcytosine loss with dysplastic cytomorphologic features and tumor progression and supports the classification of borderline lesions as a biologically distinct category of melanocytic lesions.
5-hydroxymethylcytosine; DNA methylation; melanocytic lesion; dysplastic nevus; melanoma
We analyzed the in situ molecular correlates of infection from cancer patients treated with reovirus. Melanoma, colorectal, and ovarian cancer samples from such patients showed variable infection of the cancer cells but not the intermingled benign cells. RT in situ PCR showed most cancer cells contained the viral genome with threefold less having productive viral infection as documented by either tubulin or reoviral protein co-expression. Productive infection in the cancer cells was strongly correlated with co-expression of p38 and caspase-3 as well as apoptosis-related death (P<0.001). The cancer cell apoptotic death was due to a marked viral-induced inhibition of microRNA-let-7d that, in turn, upregulated caspase-3 activity. In summary, reovirus shows a striking tropism to cancer cells in clinical samples. A rate-limiting factor of reovirus-induced cancer cell death is productive viral infection that operates via the marked reduction of microRNA-let-7d and concomitant elevated caspase-3 expression.
apoptosis; caspase-3; microRNA-let-7d; PKR; Ras; reovirus
Although the cure rate for cutaneous squamous cell carcinoma is high, the diverse spectrum of squamous cell carcinoma has made it difficult for early diagnosis, particularly the aggressive tumors that are highly associated with mortality. Therefore, molecular markers are needed as an adjunct to current staging methods for diagnosing high-risk lesions, and stratifying those patients with aggressive tumors. To identify such biomarkers, we have examined a comprehensive set of 200 histologically defined squamous cell carcinoma and normal skin samples by using a combination of microarray, QRT-PCR and immunohistochemistry analyses. A characteristic and distinguishable profile including matrix metalloproteinase (MMP) as well as other degradome components was differentially expressed in squamous cell carcinoma compared with normal skin samples. The expression levels of some of these genes including matrix metallopeptidase 1 (MMP1), matrix metallopeptidase 10 (MMP10), parathyroid hormone-like hormone (PTHLH), cyclin-dependent kinase inhibitor 2A (CDKN2A), A disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1), FBJ osteosarcoma oncogene (FOS), interleukin 6 (IL6) and reversion-inducing-cysteine-rich protein with kazal motifs (RECK) were significantly differentially expressed (P≤0.02) in squamous cell carcinoma compared with normal skin. Furthermore, based on receiver operating characteristic analyses, the mRNA and protein levels of MMP1 are significantly higher in aggressive tumors compared with non-aggressive tumors. Given that MMPs represent the most prominent family of proteinases associated with tumorigenesis, we believe that they may have an important role in modulating the tumor microenvironment of squamous cell carcinoma.
cutaneous squamous cell carcinoma; degradome; gene expression
The distinction between chondrosarcoma and chordoma of the skull base/head and neck is prognostically important; however, both have sufficient morphologic overlap to make distinction difficult. As a result of gene expression studies, additional candidate markers have been proposed to help in this distinction. Hence, we sought to evaluate the performance of new markers: brachyury, SOX-9, and podoplanin alongside the more traditional markers glial fibrillary acid protein, carcinoembryonic antigen, CD24 and epithelial membrane antigen. Paraffin blocks from 103 skull base/head and neck chondroid tumors from 70 patients were retrieved (1969-2007). Diagnoses were made based on morphology and/or whole section immunohistochemistry for cytokeratin and S100 protein yielding 79 chordomas (comprising 45 chondroid chordomas and 34 conventional chordomas), and 24 chondrosarcomas. A tissue microarray containing 0.6 mm cores of each tumor in triplicate was constructed using a manual array (MTA-1, Beecher Instruments). For visualization of staining, the ImmPRESS detection system (Vector Laboratories) with 2 - diaminobenzidine substrate was used. Sensitivities and specificities were calculated for each marker. Core loss from the microarray ranged from 25-29% yielding 66-78 viable cases per stain. The classic marker, cytokeratin, still has the best performance characteristics. When combined with brachyury, accuracy improves slightly (sensitivity and specificity for detection of chordoma 98% and 100%, respectively). Positivity for both epithelial membrane antigen and AE1/AE3 had a sensitivity of 90% and a specificity of 100% for detecting chordoma in this study. SOX-9 is apparently common to both notochordal and cartilaginous differentiation, and is not useful in the chordoma-chondrosarcoma differential diagnosis. Glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen did not outperform other markers, and are less useful in the diagnosis of chordoma versus chondrosarcoma. Podoplanin still remains the only positive marker for chondrosarcoma, though its accuracy is less than previously reported.
chordoma; chondrosarcoma; D2-40; SOX-9; cytokeratin; brachyury; CD24
Although tumor deposits have been associated with poor prognosis in colorectal carcinoma, the prevalence and clinical significance of tumor deposits in rectal adenocarcinoma following neoadjuvant chemoradiation are relatively unexplored. The aims of this study are to assess the clinical significance of tumor deposits in rectal adenocarcinoma patients, including those receiving neoadjuvant therapy. Pathology slides and medical records from 205 consecutive patients who underwent resection for rectal adenocarcinoma between 1990 and 2010 at a single tertiary care center were reviewed. Patients with tumor deposits had higher tumor grade (P=0.006) and worse tumor stage (P<0.001) at presentation than patients without tumor deposits. Among 110 patients who underwent neoadjuvant chemoradiation, tumor deposits were associated with higher rates of lymph node involvement (P=0.035) and distant metastases (P=0.006), and decreased survival (P=0.027). These patients had a trend toward lower treatment response scores (P=0.285) and higher local recurrence (P=0.092). Of 52 patients with tumor deposits, those who underwent neoadjuvant chemoradiation had significantly worse pretreatment stage by endoscopic ultrasound (P=0.001) but interestingly had significantly lower rates of lymphovascular invasion on resection (P<0.001) compared with those who had not received neoadjuvant chemoradiation. Despite treatment with neoadjuvant chemoradiation, tumor deposits were present in over one-fifth of rectal adenocarcinoma patients. Overall, the outcome of patients with tumor deposits in treated and untreated patients were similar, however the association of tumor deposits with deeply invasive tumors and less tumor regression when comparing with treated patients without tumor deposits raises the possibility that these tumors could have a more aggressive biology, possibly explaining the association of tumor deposits with higher rates of recurrence and lower survival after neoadjuvant chemoradiation. Overall, tumor deposits appear to be a poor prognostic marker among rectal adenocarcinoma patients following neoadjuvant chemoradiation and may identify a subset of patients who require aggressive adjuvant therapy to prevent recurrence.
neoadjuvant treatment; rectal carcinoma; tumor deposits
Our objective was to explore alteration of the epidermal growth factor receptor signaling pathway in ampullary carcinoma. Immunohistochemical studies were employed to evaluate expression of amphiregulin as well as expression and activation of epidermal growth factor receptor. A lab developed assay was used to identify mutations in the epidermal growth factor receptor pathway genes, including KRAS, BRAF, PIK3CA, PTEN and AKT1. Fifty two ampullary carcinomas were identified, including 25 intestinal-type and 24 pancreatobiliary-type tumors with the intestinal type being associated with a younger age at diagnosis (p=0.03) and a better prognosis (p<0.01). Expression of amphiregulin correlated the better differentiation (p<0.01), but no difference was observed between two major histologic types. Expression and activation of epidermal growth factor receptor was more commonly seen in the pancreatobiliary type (p<0.01). Mutations were detected in 50% of the pancreatobiliary type and 60% of the intestinal type. KRAS was the most common gene mutated in the pancreatobiliary type (42%) as well as the intestinal type (52%). Other mutations detected included PIK3CA, and SMAD4 and BRAF. KRAS mutations at codons 12 and 13 did not impact adversely on overall survival. In conclusion, epidermal growth factor receptor expression and activation were different between intestinal- and pancreatobiliary-type ampullary carcinoma. KRAS mutation was common in both histologic types; however, the incidence appeared to be lower in the pancreatobiliary type compared to its pancreatic counterpart, pancreatic ductal adenocarcinoma. Mutational analysis of the epidermal growth factor receptor pathway genes may provide important insights into personalized treatment for patients with ampullary carcinoma.
Epidermal growth factor receptor pathway; Ampullary carcinoma
Mismatch repair (MMR) deficient breast cancers may be identified in Lynch syndrome mutation carriers, and have clinicopathological features in common with MMR deficient colorectal and endometrial cancers such as tumour infiltrating lymphocytes and poor differentiation. MMR deficient colorectal cancers frequently show mucinous differentiation associated with upregulation of chromosome 11 mucins. The aim of this study was to compare the protein expression of these mucins in MMR deficient and MMR proficient breast cancers.
Cases of breast cancer (n = 100) were identified from families where 1) both breast and colon cancer co-occurred, 2) families met either modified Amsterdam criteria, or had at least one early onset (<50 years) colorectal cancer, and 3) biospecimens were available for MMR protein expression, microsatellite instability (MSI) status, and MMR gene mutation testing. Tumour sections were stained for the epithelial mucins MUC2, MUC5AC, MUC5B, and MUC6, and the homeobox protein CDX2, a regulator of MUC2 expression.
Sixteen MMR deficient Lynch syndrome breast cancers and 84 non-Lynch breast cancers were assessed for altered mucin expression. No significant difference in the expression of MUC2, MUC5AC or MUC6 was observed between the MMR deficient and MMR proficient breast cancers, however, there was a trend for MMR deficient tumours to express high levels of MUC5B less frequently (p = 0.07, OR = 0.2 [0.0 – 1.0]. Co-expression of two or more gel-forming mucins was common. Ectopic expression of CDX2 was associated with expression of MUC2 (p = 0.035, OR = 8.7 [1.3 – 58.4]).
MMR deficient breast cancers do not show differential expression of the mucins genes on chromosome 11 when compared to MMR proficient breast cancers, contrasting with MMR deficient colorectal and endometrial cancers which frequently have increased mucin protein expression when compared to their MMR proficient counterparts. In addition, ectopic CDX2 expression is positively associated with de novo MUC2 expression.
Breast cancer; microsatellite instability; mucin; Lynch syndrome
PCA3 is a prostate-specific non-coding RNA, with utility as urine based early detection biomarker. Here, we report the evaluation of tissue PCA3 expression by RNA in-situ hybridization in a cohort of 41 mapped prostatectomy specimens. We compared tissue PCA3 expression with tissue level ERG expression and matched pre-prostatectomy urine PCA3 and TMPRSS2-ERG levels. Across 136 slides containing 138 foci of prostate cancer, PCA3 was expressed in 55% of cancer foci and 71% of high grade prostatic intraepithelial neoplasia foci. Overall, the specificity of tissue PCA3 was >90% for prostate cancer and high grade prostatic intraepithelial neoplasia combined. Tissue PCA3 cancer expression was not significantly associated with urine PCA3 expression. PCA3 and ERG positivity in cancer foci were positively associated (p<0.01). We report the first comprehensive assessment of PCA3 expression in prostatectomy specimens, and find limited correlation between tissue PCA3 and matched urine in prostate cancer.
PCA3; RNA in-situ hybridization; Prostate cancer
We previously demonstrated a high specificity of immunohistochemistry using epidermal growth factor receptor (EGFR) mutation-specific antibodies in lung adenocarcinoma and correlation with EGFR mutation analysis. In this study, we assessed EGFR mutation status by immunohistochemistry in a variety of extrapulmonary malignancies, especially those that frequently show EGFR overexpression. Tissue microarrays containing triplicate cores of breast carcinomas (n = 300), colorectal carcinomas (n = 65), pancreatic adenocarcinoma (n = 145), and uterine carcinosarcoma or malignant mixed müllerian tumors (n = 25) were included in the study. Tissue microarray of lung adenocarcinoma with known EGFR mutation status was used as reference. Immunohistochemistry was performed using antibodies specific for the E746-A750del and L858R mutations. In pulmonary adenocarcinoma, a staining intensity of 2+ or 3+ correlates with mutation status and is therefore considered as positive. Out of 300 breast carcinomas, 293 (98%) scored 0, 5 (2%) had 1+ staining, 2 (1%) were 2+ for the L858R antibody. All breast carcinomas scored 0 with the E746-A750 antibody. All the colorectal, pancreatic carcinomas and malignant mixed müllerian tumors were negative (0) for both antibodies. Molecular analysis of the breast carcinomas that scored 2+ for L858R showed no mutation. Our results show that EGFR mutation-specific antibodies could be an additional tool distinguishing primary versus metastatic carcinomas in the lung. False-positivity can be seen in breast carcinoma but is extremely rare (1%).
epidermal growth factor receptor; immunohistochemistry; mutation-specific antibody; triple-negative; breast cancer
KRAS codon 12 mutations are present in about 90% of ductal adenocarcinomas and in undifferentiated carcinomas of the pancreas. The role of KRAS copy number changes and resulting KRAS mutant allele-specific imbalance (MASI) in ductal adenocarcinoma (n=94), and its progression into undifferentiated carcinoma of the pancreas (n=25) was studied by direct sequencing and KRAS fluorescence in situ hybridization (FISH). Semi-quantitative evaluation of sequencing electropherograms showed KRAS MASI (ie, mutant allele peak higher than or equal to the wild-type allele peak) in 22 (18.4%) cases. KRAS FISH (performed on 45 cases) revealed a trend for more frequent KRAS amplification among cases with KRAS MASI (7/20, 35% vs 3/25, 12%, P=0.08). KRAS amplification by FISH was seen only in undifferentiated carcinomas (10/24, 42% vs 0/21 pancreatic ductal adenocarcinoma, 0%, P=0.0007). In 6 of 11 cases with both undifferentiated and well-differentiated components, transition to undifferentiated carcinoma was associated with an increase in KRAS copy number, due to amplification and/or chromosome 12 hyperploidy. Pancreatic carcinomas with KRAS MASI (compared to those without MASI) were predominantly undifferentiated (16/22, 73% vs 9/97, 9%, P<0.001), more likely to present at clinical stage IV (5/22, 23% vs 7/97, 7%, P=0.009), and were associated with shorter overall survival (9 months, 95% confidence interval, 5–13, vs 22 months, 95% confidence interval, 17–27; P=0.015) and shorter disease-free survival (5 months, 95% confidence interval, 2–8 vs 13 months, 95% confidence interval, 10–16; P=0.02). Our findings suggest that in a subset of ductal adenocarcinomas, KRAS MASI correlates with the progression to undifferentiated carcinoma of the pancreas.
fluorescence in situ hybridization; KRAS; mutant allele-specific imbalance; pancreatic cancer; undifferentiated carcinoma
The role of immunohistochemistry in the assessment of KIT status in melanomas, especially acral lentiginous/mucosal, is not well established. Although the reported prevalence of KIT mutations in acral lentiginous/ mucosal melanomas is relatively low, detection of mutations in KIT can have profound therapeutic implications. We evaluated the efficacy of immunohistochemistry to predict mutations in KIT. One hundred seventy-three tumors, comprising primary and metastatic melanomas (141 acral lentiginous/mucosal, 5 nodular, 4 lentigo maligna, 3 superficial spreading, 2 uveal, 1 melanoma of soft parts, 8 metastases from unclassified primaries, and 9 metastases from unknown primaries) were studied. Immunohistochemical expression of KIT using an anti-CD117 antibody and KIT mutational analysis by gene sequencing of exons 11, 13, and 17 were performed. Eighty-one percent of acral lentiginous/mucosal melanomas, primary and metastatic, showed KIT expression by at least 5% of the tumor cells. The overall frequency of activating KIT gene mutations in acral lentiginous/ mucosal melanomas was 15% (14 out of 91 cases), being the L576P mutation in exon 11 the most frequently detected (4 of 14 cases). Cases showing less than 10% positive tumor cells were negative for KIT mutations. Eighty-two percent (12 of 14) of cases positive for KIT mutation showed KIT expression in more than 50% of the cells. An association between immunohistochemical expression of KIT and mutation status was found (P= 0.007). Immunohistochemical expression of KIT in less than 10% of the cells of the invasive component of acral lentiginous/mucosal melanomas appears to be a strong negative predictor of KIT mutation and therefore can potentially be used to triage cases for additional KIT genotyping.
melanoma; acral lentiginous; mucosal; KIT; immunohistochemistry; mutation
TP53 mutation (and associated p53 protein overexpression) is probably a negative prognostic marker in endometrial cancers, but its relevance in the rarer histologic subtypes, including clear cell carcinomas, has not been delineated. Preclinical studies suggest functional interactions between p53 and the BAF250a protein, the product of a tumor suppressor gene ARID1A that is frequently mutated in ovarian clear cell carcinoma. In this study, we evaluated the significance of p53 and BAF250a expression, as assessed by immunohistochemistry, in a group of 50 endometrial clear cell carcinomas. Seventeen of 50 cases (34%) were p53 positive; the remaining 33 cases had a p53 wild-type (p53-wt) immunophenotype. Of the 11 relapses/recurrences in the entire dataset, 73% were in the p53[+] group (p=0.008). On univariate analyses, the median overall survival for the p53-wt patients (83 mo) was longer than the p53[+] patients (63 mo) (p=0.07), and the median progression-free survival for the p53-wt group (88 mo) was significantly longer than the p53[+] group (56 mo) (p=0.01). On multivariate analyses, p53 expression was not associated with reduced overall or progression-free survival. Additionally, p53 status was not significantly associated with pathologic stage or morphologic patterns. Ten of the 50 cases (20%) showed a complete loss of BAF250a expression. There was no significant correlation between p53 and BAF250a expression. The p53+/BAF250a−, p53+/BAF250a+, p53-wt/BAF250a+, and p53-wt/BAF250a− composite immunophenotypes were identified in 8%, 26%, 54% and 12% of cases respectively, and neither loss of BAF250a expression nor composite p53/BAF250a expression patterns were associated with reduced overall or progression-free survival. In conclusion, a significant subset of CCC express p53, and these cases are apparently not definable by their morphologic features. p53 expression may be a negative prognostic factor in this histotype, and warrants additional studies. Loss of BAF250a expression has no prognostic significance in endometrial clear cell carcinomas.
Lung metastases from primary pancreatic adenocarcinomas often have mucinous features, which makes them difficult to distinguish from the primary lung adenocarcinoma. We explored the potential utility of KRAS mutational status and immunohistochemical studies in the evaluation of adenocarcinomas in the lungs of patients with known pancreatic cancer. Metastatic pancreatic cancer cases had fewer solitary lung lesions (5 (15%) versus 37 (95%) for lung primaries; P=0.0001), more tumors with pure (100%) mucinous morphology (16 (50%) versus 9 (23%) for lung primaries; P=0.0037), and more frequent KRAS mutations (24 (75%) versus 18 (46%) for lung primaries; P=0.0093). Presence of the KRAS G12C mutation had 96% specificity and positive predictive value for lung adenocarcinoma, whereas G12R was 99% specific for pancreatic cancer with a positive predictive value of 86%. Of the 18 KRAS mutated mucinous lung tumors, only 3 (16%) occurred in nonsmokers. Conversely, of the 19 KRAS mutated pancreatic cancer metastases, 11 (58%) occurred in nonsmokers. The median overall survival was significantly shorter for patients with metastatic tumors when compared with patients with primary mucinous tumors (19 months, 95% confidence interval, 10–28 months versus 55 months, 95% confidence interval, 39–70 months, P=0.005). CK20 and CDX2 positivity supported metastatic pancreatic cancer, whereas TTF-1 positivity supported primary lung adenocarcinoma. In summary, KRAS G12C mutations, TTF-1, and napsin A were associated with primary lung adenocarcinoma, whereas KRAS G12R mutations, CK20, and CDX2 favored pancreatic adenocarcinoma. We showed survival differences for patients whose pancreatic metastases were synchronous versus metachronous to their primary tumors, and for patients with mucinous pancreatic cancer metastases versus primary mucinous lung adenocarcinomas. Differences in KRAS mutations reflect differences in exposure to tobacco smoking and highlight biological differences between two KRAS oncogene-driven cancers.
KRAS; lung cancer; mucinous adenocarcinoma; pancreatic cancer
Alterations in methylation of CpG dinucleotides at the 5 position of deoxycytidine residues (5mC) are a hallmark of cancer cells, including testicular germ cell tumors. Virtually all testicular germ cell tumors are believed to be derived from intratubular germ cell neoplasia unclassified (IGCNU), which is thought to arise from primordial germ cells. Prior studies revealed that seminomas contain reduced levels of global DNA methylation as compared with nonseminomatous germ cell tumors. Smiraglia et al have proposed a model whereby seminomas arise from IGCNU cells derived from primordial germ cells that have undergone 5mC erasure, and nonseminomas arise from IGCNU cells derived from primordial germ cells that have already undergone de novo methylation after the original erasure of methylation and contain normal 5mC levels. Yet the methylation status of IGCNU has not been determined previously. We used immunohistochemical staining against 5mC to evaluate global methylation in IGCNU and associated invasive testicular germ cell tumors. Strikingly, staining for 5mC was undetectable (or markedly reduced) in the majority of IGCNU and seminomas, yet there was robust staining in nonseminomatous germ cell tumors. The lack of staining for 5mC in IGCNU and seminomas was also found in mixed germ cell tumors containing both seminomatous and nonseminomatous components. Lack of 5mC staining was not related to a lack of the maintenance methyltransferase (DNA methyltransferase 1) protein. We conclude that testicular germ cell tumors are derived in most cases from IGCNU cells that have undergone developmentally programmed 5mC erasure and that the degree of subsequent de novo methylation is most closely related to the differentiation state of the neoplastic cells. That is, IGCNU cells and seminoma cells remain unmethylated, whereas all other histological types appear to arise after de novo methylation.
seminoma; nonseminomatous germ cell tumors; IGCNU; global methylation
Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant pleural mesothelioma in which only staging is prognostic for survival. In this study of epithelioid diffuse malignant pleural mesothelioma, we investigate the prognostic utility of nuclear features. The slides of 232 epithelioid diffuse malignant pleural mesothelioma patients (14 stage I, 54 stage II, 130 stage III, and 34 stage IV) from a single institution were reviewed for the following seven nuclear features: nuclear atypia, nuclear/cytoplasmic ratio, chromatin pattern, intranuclear inclusions, prominence of nucleoli, mitotic count, and atypical mitoses. MIB-1 immunohistochemistry was performed using tissue microarray, and MIB-1 labeling index was recorded as the percentage of positive tumor cells. Median overall survival of all patients was 16 months and correlated with nuclear atypia (P<0.001), chromatin pattern (P=0.031), prominence of nucleoli (P<0.001), mitotic count (P<0.001), and atypical mitoses (P<0.001) by univariate analysis. Multivariate analysis revealed nuclear atypia (P=0.012) and mitotic count (P<0.001) as independent prognostic factors, and these two factors were utilized to create a three-tier nuclear grade score. The resulting nuclear grade stratified patients into three distinct prognostic groups: grade I (n=107, median overall survival = 28 months), grade II (n=91, 14 months), and grade III (n=34, 5 months). Not only was nuclear grade an independent predictor of overall survival (P<0.001), but it was also a stronger discriminator of survival than all currently available factors. Furthermore, nuclear grade was associated with time to recurrence (P=0.004) in patients who underwent complete surgical resection (n=159). MIB-1 labeling index correlated with mitotic count (P<0.001) and nuclear atypia (P=0.037) and stratified overall survival (P<0.001) and time to recurrence (P=0.048), confirming the prognostic value of the nuclear grade. Nuclear grading in epithelioid mesothelioma provides a simple, practical, and cost-effective prognostic tool that better stratifies clinical outcome and time to recurrence than currently available clinicopathologic factors.
epithelioid mesothelioma; MIB-1; mitosis; nuclear atypia; nuclear grade; survival
Recent studies have shown two distinct non-CIMP methylation clusters in colorectal cancer, raising the possibility that DNA methylation, involving non-CIMP genes, may play a role in the conventional adenoma–carcinoma pathway. A total of 135 adenomas (65 left colon and 70 right colon) were profiled for epigenome-wide DNA methylation using the Illumina HumanMethylation450 BeadChip. A principal components analysis was performed to examine the association between variability in DNA methylation and adenoma location. Linear regression and linear mixed effects models were used to identify locus-specific differential DNA methylation in adenomas of right and left colon. A significant association was present between the first principal component and adenoma location (P = 0.007), even after adjustment for subject age and gender (P = 0.009). A total of 168 CpG sites were differentially methylated between right- and left-colon adenomas and these loci demonstrated enrichment of homeobox genes (P = 3.0 × 10−12). None of the 168 probes were associated with CIMP genes. Among CpG loci with the largest difference in methylation between right- and left-colon adenomas, probes associated with PRAC(prostate cancer susceptibility candidate) gene showed hypermethylation in right-colon adenomas whereas those associated with CDX2(caudal type homeobox transcription factor 2) showed hypermethylation in left-colon adenomas. A subgroup of left-colon adenomas enriched for current smokers (OR = 6.1, P = 0.004) exhibited a methylation profile similar to right-colon adenomas. In summary, our results indicate distinct patterns of DNA methylation, independent of CIMP genes, in adenomas of the right and left colon.
colon polyps; colorectal cancer; CpG island methylator phenotype; epigenetics
Claudin proteins are a major component of the tight junctions. Dysregulation of claudin protein expression has been described in a number of malignancies. Gene expression profiling has stratified breast cancers into distinct molecular subtypes: luminal, HER2+ and basal-like. Recently, a novel claudin-low molecular subtype has been described. In this study we correlated the expression patterns of claudins with the molecular subtypes of breast cancer. On the basis of immunohistochemical expression 226 grade 3 invasive ductal carcinomas were stratified into 65 luminal (ER+), 65 HER2 positive (HER2+), 86 basal-like, including 14 metaplastic carcinomas (ER−, HER2−, CK5/6 and /or EGFR+), and 10 unclassified. Tissue microarrays were analyzed for expression of claudins 1, 3, 4, 7 and 8 by immunohistochemistry and scored semiquantitatively. High levels of expression were detected in 17% of all cases for claudin 1, 32% claudin 3, 41% claudin 4, 44% claudin 7, and 40% claudin 8. Luminal cancers exhibited increased claudins 7 and 8; basal-like tumors demonstrated increased claudins 1 and 4 expression. Low expression of all five claudins was detected in 30 of 226 cases (13%) and this group was designated “claudin-low”. The majority of the claudin-low subgroup were basal-like cancers (23 of 30, 77%). In contrast, only 1 of 30 (3%) claudin-low tumors were of the luminal phenotype and 6 of 30 cases (20%) were HER2+ (P<0.001). Within the basal-like subgroup, 64% of the metaplastic and 19% of the non-metaplastic tumors were claudin-low. The claudin-low group was strongly associated with disease recurrence (P=0.0093). In conclusion, this study is the first to comprehensively examine the differential expression of claudins 1, 3, 4, 7 and 8 in the molecular subtypes of high grade breast cancer. Claudin-low subtype is a frequent phenomenon in metaplastic and basal-like breast cancer and appears to be a strong predictor of disease recurrence.
Breast; Carcinoma; Claudin
Hepatocellular carcinomas exhibit heterogeneous morphologies by routine light microscopy. Although some morphologies represent insignificant variations in growth patterns, others may represent unrecognized subtypes of hepatocellular carcinoma. Identification of these subtypes could lead to separation of hepatocellular carcinomas into discrete groups with unique underlying genetic changes, prognosis, or therapeutic responses. In order to identify potential subtypes, two pathologists independently screened a cohort of 219 unselected hepatocellular carcinoma resection specimens and divided cases into potential subtypes. One of these promising candidate subtypes was further evaluated using histological and molecular techniques. This subtype was characterized by a unique and consistent set of histological features: smooth chromophobic cytoplasm, abrupt focal nuclear anaplasia (small clusters of tumor cells with marked nuclear anaplasia in a background of tumor cells with bland nuclear cytology), and scattered microscopic pseudocysts—we designate this variant as ‘chromophobe hepatocellular carcinoma with abrupt anaplasia’. Thirteen cases were identified (6% of all hepatocellular carcinomas), including 6 men and 7 women with an average age of 61 years. Six cases occurred in cirrhotic livers. Serum AFP was elevated in 6 out of 10 cases. There were a variety of underlying liver diseases, but cases were enrichment for chronic hepatitis B, P = 0.006. Interestingly, at the molecular level, this variant was strongly associated with the alternative lengthening of telomere (ALT) phenotype by telomere FISH. ALT is a telomerase-independent mechanism of telomere maintenance and is found in approximately 8% of unselected hepatocellular carcinomas. In contrast, 11/12 (92%) of the cases of chromophobe hepatocellular carcinoma with abrupt anaplasia were ALT-positive. In summary, we propose that chromophobe hepatocellular carcinoma with abrupt anaplasia represents a new subtype of hepatocellular carcinoma with unique morphological and molecular features.
ALT; hepatocellular carcinoma; telomere
Loss of PTEN (phosphatase and tensin homolog) expression and microsatellite instability are two of the more common molecular alterations in endometrial carcinoma. From the published literature, it is controversial as to whether there is a relationship between these different molecular mechanisms. Therefore, a cohort of 187 pure endometrioid and non-endometrioid endometrial carcinomas, carefully characterized as to clinical and pathological features, was examined for PTEN sequence abnormalities and the immunohistochemical expression of PTEN and the DNA mismatch repair proteins MLH1, MSH2, MSH6 and PMS2. MLH1 methylation analysis was performed when tumors had loss of MLH1 protein. Mismatch repair protein loss was more frequent in endometrioid carcinomas compared to non-endometrioid carcinomas, a difference primarily attributable to the presence of MLH1 methylation in a greater proportion of endometrioid tumors. Among the non-endometrioid group, mixed endometrioid/non-endometrioid carcinomas were the histotype that most commonly had loss of a mismatch repair protein. In endometrioid tumors, the frequency of PTEN loss measured by immunohistochemistry and mutation did not differ significantly between the mismatch repair protein intact or mismatch repair protein loss groups, suggesting that PTEN loss is independent of mismatch protein repair status in this group. However, in non-endometrioid carcinomas, both intact positive PTEN immunohistochemical expression and PTEN wild type were highly associated with retained positive expression of mismatch repair proteins in the tumor. Relevant to screening endometrial cancers for Lynch Syndrome, an initial PTEN immunohistochemistry determination may be able to replace the use of four mismatch repair immunohistochemical markers in 63% of patients with non-endometrioid endometrial carcinoma. Therefore, PTEN immunohistochemistry, in combination with tumor histotype, is a useful adjunct in the clinical evaluation of endometrial carcinomas for Lynch Syndrome.
KRAS mutations define a clinically-distinct subgroup of lung adenocarcinoma patients, characterized by smoking history, resistance to EGFR-targeted therapies, and adverse prognosis. Whether KRAS- mutated lung adenocarcinomas also have distinct histopathologic features is not well established. We tested 180 resected lung adenocarcinomas for KRAS and EGFR mutations by high-sensitivity mass spectrometry-based genotyping (Sequenom) and PCR-based sizing assays. All tumors were assessed for the proportion of standard histologic patterns (lepidic, acinar, papillary, micropapillary, solid and mucinous), several other histologic and clinical parameters, and TTF-1 expression by immunohistochemistry. Among 180 carcinomas, 63 (35%) had KRAS mutations (KRAS+), 35 (19%) had EGFR mutations (EGFR+), and 82 (46%) had neither mutation (KRAS-/EGFR-). Solid growth pattern was significantly over-represented in KRAS+ carcinomas: the mean ± standard deviation for the amount of solid pattern in KRAS+ carcinomas was 27 ± 34% compared to 3 ± 10% in EGFR+ (P<0.001) and 15 ± 27% in KRAS-/EGFR- (P=0.033) tumors. Furthermore, at least focal (>20%) solid component was more common in KRAS+ (28/63; 44%) compared to EGFR+ (2/35; 6%; P<0.001) and KRAS-/EGFR- (21/82; 26%; P=0.012) carcinomas. KRAS mutations were also over-represented in mucinous carcinomas, and were significantly associated with the presence of tumor-infiltrating leukocytes and heavier smoking history. EGFR mutations were associated with non-mucinous non-solid patterns, particularly lepidic and papillary, lack of necrosis, lack of cytologic atypia, hobnail cytology, TTF-1 expression, and never/light smoking history. In conclusion, extended molecular and clinicopathologic analysis of lung adenocarcinomas reveals a novel association of KRAS mutations with solid histology and tumor-infiltrating inflammatory cells, and expands on several previously recognized morphologic and clinical associations of KRAS and EGFR mutations. Solid growth pattern was recently shown to be a strong predictor of aggressive behavior in lung adenocarcinomas, which may underlie the unfavorable prognosis associated with KRAS mutations in these tumors.
KRAS; EGFR; lung; adenocarcinoma; TTF-1
Borderline ovarian tumors represent an understudied subset of ovarian tumors. Most studies investigating aberrations in borderline tumors have focused on KRAS/BRAF mutations. In this study we conducted an extensive analysis of mutations and single nucleotide polymorphisms in borderline ovarian tumors.
Using the Sequenom MassARRAY platform we investigated 160 mutations/polymorphisms in 33 genes involved in cell signalling, apoptosis, angiogenesis, cell cycle regulation, and cellular senescence.
Of 52 tumors analysed, 33 were serous, 18 mucinous and 1 endometrioid. KRAS c.35G>A p.Gly12Asp mutations were detected in 8 tumors (6 serous and 2 mucinous), BRAF V600E mutations in 2 serous tumors, and PIK3CA H1047Y and PIK3CA E542K mutations in a serous and an endometrioid BOT respectively. CTNNB1 mutation was detected in a serous tumor. Potentially functional polymorphisms were found in VEGF, ABCB1, FGFR2 and PHLPP2. VEGF polymorphisms were the most common and detected at 4 loci. PHLPP2 polymorphisms were more frequent in mucinous as compared to serous tumors (p=0.04), with allelic imbalance in one case.
This study represents the largest and most comprehensive analysis of mutations and functional single nucleotide polymorphisms in borderline ovarian tumors to date. At least 25% of borderline ovarian tumors harbour somatic mutations associated with potential response to targeted therapeutics.
Borderline; Ovarian; Sequenom; Tumours