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1.  Loss of CDX2 expression is associated with poor prognosis in colorectal cancer patients 
AIM: To investigate the clinicopathologic characteristics and prognostic implications associated with loss of CDX2 expression in colorectal cancers (CRCs).
METHODS: We immunohistochemically evaluated CDX2 expression in 713 CRCs and paired our findings to clinicopathologic and molecular characteristics of each individual. Endpoints included cytokeratin 7 and CK20 expression, microsatellite instability, CpG island methylator phenotype, and KRAS and BRAF mutation statuses. Univariate and multivariate survival analysis was performed to reveal the prognostic value of CDX2 downregulation.
RESULTS: CDX2 expression was lost in 42 (5.9%) patients. Moreover, loss of CDX2 expression was associated with proximal location, infiltrative growth, advanced T, N, M and overall stage. On microscopic examination, loss of CDX2 expression was associated with poor differentiation, increased number of tumor-infiltrating lymphocytes, luminal serration and mucin production. Loss of CDX2 expression was also associated with increased CK7 expression, decreased CK20 expression, CpG island methylator phenotype, microsatellite instability and BRAF mutation. In a univariate survival analysis, patients with loss of CDX2 expression showed worse overall survival (P < 0.001) and progression-free survival (P < 0.001). In a multivariate survival analysis, loss of CDX2 expression was an independent poor prognostic factor of overall survival [hazard ratio (HR) = 1.72, 95%CI: 1.04-2.85, P = 0.034] and progression-free survival (HR = 1.94, 95%CI: 1.22-3.07, P = 0.005).
CONCLUSION: Loss of CDX2 expression is associated with aggressive clinical behavior and can be used as a prognostic marker in CRCs.
PMCID: PMC4316088  PMID: 25663765
CDX2; CpG island methylator phenotype; Microsatellite instability; Colorectal cancer; Survival
2.  RNA editing in RHOQ promotes invasion potential in colorectal cancer 
Novel A-to-I RNA editing in the coding sequence of RHOQ leads to an amino acid substitution that promotes invasion in colorectal cancer.
RNA editing can increase RNA sequence variation without altering the DNA sequence. By comparing whole-genome and transcriptome sequence data of a rectal cancer, we found novel tumor-associated increase of RNA editing in ras homologue family member Q (RHOQ) transcripts. The adenosine-to-inosine (A-to-I) editing results in substitution of asparagine with serine at residue 136. We observed a higher level of the RHOQ RNA editing in tumor compared with normal tissue in colorectal cancer (CRC). The degree of RNA editing was associated with RhoQ protein activity in CRC cancer cell lines. RhoQ N136S amino acid substitution increased RhoQ activity, actin cytoskeletal reorganization, and invasion potential. KRAS mutation further increased the invasion potential of RhoQ N136S in vitro. Among CRC patients, recurrence was more frequently observed in patients with tumors having edited RHOQ transcripts and mutations in the KRAS gene. In summary, we show that RNA editing is another mechanism of sequence alteration that contributes to CRC progression.
PMCID: PMC3978269  PMID: 24663214
3.  CD24 expression predicts distant metastasis in extrahepatic bile duct cancer 
AIM: To evaluate the prognostic significance of CD24 expression in patients undergoing adjuvant chemoradiotherapy for extrahepatic bile duct (EHBD) cancer.
METHODS: Eighty-four patients with EHBD cancer who underwent curative resection followed by adjuvant chemoradiotherapy were enrolled in this study. Postoperative radiotherapy was delivered to the tumor bed and regional lymph nodes up to a median of 40 Gy (range: 40-56 Gy). All patients also received fluoropyrimidine chemotherapy for radiosensitization during radiotherapy. CD24 expression was assessed with immunohistochemical staining on tissue microarray. Clinicopathologic factors as well as CD24 expression were evaluated in multivariate analysis for clinical outcomes including loco-regional recurrence, distant metastasis-free and overall survival.
RESULTS: CD24 was expressed in 36 patients (42.9%). CD24 expression was associated with distant metastasis, but not with loco-regional recurrence nor with overall survival. The 5-year distant metastasis-free survival rates were 55.1% and 29.0% in patients with negative and positive expression, respectively (P = 0.0100). On multivariate analysis incorporating N stage, histologic differentiation and CD24 expression, N stage was the only significant factor predicting distant metastasis-free survival (P = 0.0089), while CD24 expression had borderline significance (P = 0.0733). In subgroup analysis, CD24 expression was significantly associated with 5-year distant metastasis-free survival in node-positive patients (38.4% with negative expression vs 0% with positive expression, P = 0.0110), but not in node-negative patients (62.0% with negative expression vs 64.0% with positive expression, P = 0.8599).
CONCLUSION: CD24 expression was a significant predictor of distant metastasis for patients undergoing curative resection followed by adjuvant chemoradiotherapy especially for node-positive EHBD cancer.
PMCID: PMC3602503  PMID: 23539485
CD24; Tissue microarray; Extrahepatic bile duct cancer; Adjuvant chemoradiotherapy; Distant metastasis
4.  Open-label, Randomized Comparison of the Efficacy of Intravenous Dolasetron Mesylate and Ondansetron in the Prevention of Acute and Delayed Cisplatin-induced Emesis in Cancer Patients 
The aim of this study is to compare the antiemetic efficacy and tolerability of intravenous dolasetron mesylate and ondansetron in the prevention of acute and delayed emesis.
Material and Methods
From April 2002 through October 2002, a total of 112 patients receiving cisplatin- based combination chemotherapy were randomized to receive a single i.v. dose of dolasetron 100 mg or ondansetron 8 mg, 30 minutes before the initiation of chemotherapy. In the ondansetron group, two additional doses of ondansetron 8 mg were given at intervals of 2 to 4 hours. To prevent delayed emesis, dolasetron 200 mg p.o. daily or ondansetron 8 mg p.o. bid was administered from the 2nd days to a maximum of 5 days. The primary end point was the proportion of patients that experienced no emetic episodes and required no rescue medication (complete response, CR) during the 24 hours (acute period) and during Day 2 to Day 5±2 days (delayed period), after chemotherapy. The secondary end points included the incidence and severity of emesis.
105 patients were evaluable for efficacy. CR rates during the acute period were 36.0% for a single dose of dolasetron 100 mg, and 43.6% for three doses of ondansetron 8 mg. CR rates during the delayed period were 8.0% and 10.9%, respectively. There was no significant difference in the efficacy between the two groups. Adverse effects were mostly mild to moderate and not related to study medication.
A single i.v. dose of dolasetron 100 mg is as effective as three i.v. doses of ondansetron 8 mg in preventing acute and delayed emesis after cisplatin-based chemotherapy, with a comparable safety profile.
PMCID: PMC2843880  PMID: 20368831
Dolasetron mesylate; 5-HT3 receptor antagonist; Antiemetics; Nausea; Vomiting; Ondansetron
5.  TGF-β Suppresses COX-2 Expression by Tristetraprolin-Mediated RNA Destabilization in A549 Human Lung Cancer Cells 
Overexpression of cyclooxygenase 2 (COX-2) is thought to promote survival of transformed cells. Transforming growth factor β (TGF-β) exerts anti-proliferative effects on a broad range of epithelial cells. In the current study, we investigated whether TGF-β can regulate COX-2 expression in A549 human lung adenocarcinoma cells, which are TGF-β-responsive and overexpress COX-2.
Materials and Methods
Western blotting, Northern blotting, and mRNA stability assays were performed to demonstrate that COX-2 protein and mRNA expression were suppressed by TGF-β. We also evaluated the effects of tristetraprolin (TTP) on COX-2 mRNA using RNA interference.
We demonstrated that COX-2 mRNA and protein expression were both significantly suppressed by TGF-β. An actinomycin D chase experiment demonstrated that COX-2 mRNA was more rapidly degraded in the presence of TGF-β, suggesting that TGF-β–induced inhibition of COX-2 expression is achieved via decreased mRNA stability. We also found that TGF-β rapidly and transiently induced the expression of TTP, a well-known mRNA destabilizing factor, before suppression of COX-2 mRNA expression was observed. Using RNA interference, we confirmed that increased TTP levels play a pivotal role in the destabilization of COX-2 mRNA by TGF-β. Furthermore, we showed that Smad3 is essential to TTP-dependent down-regulation of COX-2 expression in response to TGF-β.
The results of this study show that TGF-β down-regulated COX-2 expression via mRNA destabilization mediated by Smad3/TTP in A549 cells.
PMCID: PMC4296860  PMID: 25544576
Cyclooxygenase 2; Transforming growth factor beta; Tristetraprolin; RNA stability; Smad3
6.  Impact of Multimodality Approach for Patients with Leptomeningeal Metastases from Solid Tumors 
Journal of Korean Medical Science  2014;29(8):1094-1101.
The purpose of this study was to evaluate treatment patterns, outcome and prognosticators for patients with leptomeningeal metastases from solid tumor. Medical records of 80 patients from January 1, 2004 to May 31, 2011 were retrospectively reviewed. Most frequent site of origin was the lung (59%) followed by the breast (25%). Most patients were treated with intrathecal chemotherapy (90%) and/or whole brain radiotherapy (67.5%). Systemic therapy was offered to 27 patients (33.8%). Percentage of patients treated with single, dual, and triple modality were 32.5%, 43.8%, and 23.8%, respectively. Median survival was 2.7 months and 1 yr survival rate was 11.3%. Multivariate analysis showed that negative cerebrospinal fluid cytology, fewer chemotherapy regimen prior to leptomeningeal metastases, whole brain radiotherapy, systemic therapy, and combined modality treatment (median survival; single 1.4 vs. dual 2.8 vs. triple 8.3 months, P<0.001) had statistical significance on survival. Subgroup analysis of non-small cell lung cancer (NSCLC) patients showed that targeted therapy had significant independent impact on survival (median survival; 10.5 vs. 3.0 months, P=0.008). Unlike previous reports, survival of patients with NSCLC primary was comparable to breast primary. Furthermore, combined modality treatment for all patients and additionally targeted therapy for NSCLC patients should be considered in the treatment of leptomeningeal metastases from solid tumor.
Graphical Abstract
PMCID: PMC4129201  PMID: 25120319
Leptomeningeal Metastases; Prognostic Factor; Solid Tumor
7.  A New Isolated Mediastinal Lymph Node or Small Pulmonary Nodule Arising during Breast Cancer Surveillance Following Curative Surgery: Clinical Factors That Differentiate Malignant from Benign Lesions 
A newly isolated mediastinal lymph node (LN) or a small pulmonary nodule, which appears during breast cancer surveillance, may pose a diagnostic dilemma with regard to malignancy. We conducted this study to determine which clinical factors were useful for the differentiation of malignant lesions from benign lesions under these circumstances.
Materials and Methods
We enrolled breast cancer patients who were presented with a new isolated mediastinal LN or small pulmonary nodule that arose during surveillance, and whose lesions were pathologically confirmed. Tissue diagnosis was made by mediastinoscopy, video-assisted thoracic surgery or thoracotomy.
A total of 43 patients were enrolled (mediastinal LN, 13 patients; pulmonary nodule, 30 patients). Eighteen patients (41.9%) were pathologically confirmed to have a benign lesion (benign group), and 25 patients (58.1%) were confirmed to have malignant lesion (malignant group). Between the two groups, the initial tumor size (p=0.096) and N stage (p=0.749) were similar. Hormone receptor negativity was more prevalent in the malignant group (59.1% vs. 40.9%, p=0.048). The mean lesion size was larger in the malignant group than in the benign group (20.8 mm vs. 14.4 mm, p=0.024). Metastatic lesions had a significantly higher value of maximal standardized uptake (mSUV) than that of benign lesions (6.4 vs. 3.4, p=0.021).
Hormone receptor status, lesion size, and mSUV on positron emission tomography are helpful in the differentiation of malignant lesions from benign lesions in breast cancer patients who were presented with a new isolated mediastinal LN or small pulmonary nodule during surveillance.
PMCID: PMC4132446  PMID: 25038763
Breast neoplasms; Pulmonary nodule; Mediastinal lymph node; Neoplasm metastasis; Benign
8.  The influence of the treatment response on the impact of resection margin status after preoperative chemoradiotherapy in locally advanced rectal cancer 
BMC Cancer  2013;13:576.
Circumferential resection margin (CRM) and distal resection margin (DRM) have different impact on clinical outcomes after preoperative chemoradiotherapy (CRT) followed by surgery. Effect and adequate length of resection margin as well as impact of treatment response after preoperative CRT was evaluated.
Total of 403 patients with rectal cancer underwent preoperative CRT followed by total mesorectal excision between January 2004 and December 2010. After applying the criterion of margin less than 0.5 cm for CRM or less than 1 cm for DRM, 151 cases with locally advanced rectal cancer were included as a study cohort. All patients underwent conventionally fractionated radiation with radiation dose over 50 Gy and concurrent chemotherapy with 5-fluorouracil or capecitabine. Postoperative chemotherapy was administered to 142 patients (94.0%). Median follow-up duration was 43.1 months.
The 5-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS) rates, and locoregional control rates (LRC) were 84.5%, 72.8%, 74.2%, and 86.3%, respectively. CRM of 1.5 mm and DRM of 7 mm were cutting points showing maximal difference in a maximally selected rank method. In univariate analysis, CRM of 1.5 mm was significantly related with worse clinical outcomes, whereas DRM of 7 mm was not. In multivariate analysis, CRM of 1.5 mm, and ypN were prognosticators for all studied endpoints. However, CRM was not a significant prognostic factor for good responders, defined as patients with near total regression or T down-staging, which was found in 16.5% and 40.5% among studied patients, respectively. In contrast, poor responders demonstrated a significant difference according to the CRM status for all studied end-points.
Close CRM, defined as 1.5 mm, was a significant prognosticator, but the impact was only prominent for poor responders in subgroup analysis. Postoperative treatment strategy may be individualized based on this finding. However, findings from this study need to be validated with larger cohort.
PMCID: PMC3938897  PMID: 24304825
Rectal cancer; Preoperative chemoradiotherapy; Resection margin; Treatment response
9.  Clinical Implications of VEGF, TGF-β1, and IL-1β in Patients with Advanced Non-small Cell Lung Cancer 
Vascular endothelial growth factor (VEGF)-A, VEGF165b, interleukin (IL)-1β, and transforming growth factor (TGF)-β1 are known to influence tumor angiogenesis. Clinical implications of these cytokines need to be elucidated.
Materials and Methods
Using clinical data and baseline serum samples of 140 consecutive patients with advanced non-small cell lung cancer who received platinum-based combination chemotherapy, we investigated the association among serum cytokine levels, treatment outcomes, as well as leukocyte and platelet counts.
The median age of patients was 64 years (range, 26 to 86 years). The male to female ratio was 104:36. High TGF-β1 and IL-1β levels were associated with shorter progression-free survival, and high VEGF-A and IL-1β levels were associated with shorter overall survival in the univariate analysis. VEGF165b was not related to the treatment outcomes. Leukocytosis and thrombocytosis were associated with shorter overall survival. The multivariate analysis demonstrated that VEGF-A, IL-1β, and leukocytosis were significant prognostic factors (p=0.0497, p=0.047, and p<0.001, respectively). Leukocytosis was not associated with recent pneumonia (p=0.937) and correlated with VEGF-A (p<0.001) and TGF-β1 (p=0.020) levels.
Serum VEGF-A, TGF-1β, and IL-1β levels, in addition to leukocyte and platelet counts, are shown to be associated with clinical outcomes. Leukocyte and platelet counts are correlated with serum VEGF-A and TGF-β1 levels.
PMCID: PMC3893330  PMID: 24454005
Vascular endothelial growth factor; Interleukin-1beta; Transforming growth factor beta1; Leukocytes; Blood platelets; Non-small cell lung carcinoma
10.  Expression of Immunohistochemical Markers before and after Neoadjuvant Chemotherapy in Breast Carcinoma, and Their Use as Predictors of Response 
Journal of Breast Cancer  2013;16(4):395-403.
For patients with breast carcinoma, immunohistochemical markers are important factors in determining the breast cancer subtype and for establishing a therapeutic plan, including the use of neoadjuvant chemotherapy (NACT). However, it is not clear whether the expression of certain markers changes after NACT.
We assessed estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki-67, p53, and Bcl-2 expression in specimens from 345 breast cancer cases before and after NACT. We analyzed the association between response to NACT and the expression of the markers in pre-NACT specimens. We also compared the expression between pre- and post-NACT specimens.
ER and PR expression was negatively associated with pathological complete response (pCR). HER2 was associated with pCR in all cases, but the association was lost when the cases were subdivided according to hormone receptor status. The pre-NACT tumor size of cases with pCR after NACT was smaller than that of cases with residual disease. HER2-enriched and triple-negative breast cancers were more likely to achieve pCR than luminal A type cancers. PR expression and the Ki-67 index decreased after NACT. A decrease in the Ki-67 index was also demonstrated in hormone receptor positive and HER2-enriched subtypes, but no similar tendency was observed in the triple-negative subtype.
A patient with breast cancer scheduled for NACT should be assessed for the breast cancer subtype, as this will influence the treatment plans for the patient. The expression of PR and Ki-67 after NACT should be interpreted carefully because NACT tends to reduce the expression of these molecules.
PMCID: PMC3893341  PMID: 24454461
Breast neoplasms; Drug therapy; Immunohistochemistry; Ki-67 antigen; Progesterone receptors
11.  Phosphoproteomic analysis identifies activated MET-axis PI3K/AKT and MAPK/ERK in lapatinib-resistant cancer cell line 
Lapatinib, a dual inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) tyrosine kinases, has shown promising results as a growth inhibitor of HER2-positive cancer cells in vitro. However, similar to other EGFR-targeting drugs, acquired resistance to lapatinib by HER2-positive cancer cells remains a major clinical challenge. To elucidate resistance mechanisms to EGFR/HER2-targeting agents, we performed a systematic quantitative comparison of the phosphoproteome of lapatinib-resistant (LR) human gastric cancer cells (SNU216-LR) versus parental cells (SNU216) using a titanium dioxide (TiO2) phosphopeptide enrichment method and analysis with a Q-Exactive hybrid quadrupole-Orbitrap mass spectrometer. Biological network analysis of differentially expressed phosphoproteins revealed apparent constitutive activation of the MET-axis phosphatidylinositide 3-kinase (PI3K)/α-serine/threonine-protein kinase (AKT) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathways in SNU216-LR. Inhibition of the PI3K/AKT and MAPK/ERK signaling pathways in SNU216-LR also leads to cell cycle arrest, confirming the biological network analysis. Lapatinib sensitivity was restored when cells were treated with several molecular targeting agents in combination with lapatinib. Thus, by integrating phosphoproteomic data, protein networks and effects of signaling pathway modulation on cell proliferation, we found that SNU216-LR maintains constitutive activation of the PI3K/AKT and MAPK/ERK pathways in a MET-dependent manner. These findings suggest that pathway activation is a key compensatory intracellular phospho-signaling event that may govern gastric cancer cell resistance to drug treatment.
PMCID: PMC3849569  PMID: 24263233
drug resistance; HER2-positive gastric cancer; lapatinib; phosphoproteins; Q-Exactive; therapeutic targets
12.  Targeted Sequencing of Cancer-Related Genes in Colorectal Cancer Using Next-Generation Sequencing 
PLoS ONE  2013;8(5):e64271.
Recent advance in sequencing technology has enabled comprehensive profiling of genetic alterations in cancer. We have established a targeted sequencing platform using next-generation sequencing (NGS) technology for clinical use, which can provide mutation and copy number variation data. NGS was performed with paired-end library enriched with exons of 183 cancer-related genes. Normal and tumor tissue pairs of 60 colorectal adenocarcinomas were used to test feasibility. Somatic mutation and copy number alteration were analyzed. A total of 526 somatic non-synonymous sequence variations were found in 113 genes. Among these, 278 single nucleotide variations were 232 different somatic point mutations. 216 SNV were 79 known single nucleotide polymorphisms in the dbSNP. 32 indels were 28 different indel mutations. Median number of mutated gene per tumor was 4 (range 0–23). Copy number gain (>X2 fold) was found in 65 genes in 40 patients, whereas copy number loss (
PMCID: PMC3660257  PMID: 23700467
Journal of Breast Cancer  2013;16(1):66-71.
Exemestane has shown good efficacy and tolerability in postmenopausal women with hormone receptor-positive metastatic breast cancer. However, clinical outcomes in Korean patients have not yet been reported.
Data on 112 postmenopausal women with metastatic breast cancer were obtained retrospectively. Clinicopathological characteristics and treatment history were extracted from medical records. All patients received 25 mg exemestane daily until objective disease progression. Progression-free survival (PFS) was the primary endpoint, and secondary endpoints were overall survival (OS), objective response rate (ORR), and clinical benefit rate (CBR=complete response+partial response+stable disease for 6 months).
The median age of the subjects was 55 years (range, 28-76 years). Exemestane treatment resulted in a median PFS of 5.7 months (95% confidence interval [CI], 4.4-7.0 months) and median OS of 21.9 months (95% CI, 13.6-30.3 months). ORR was 6.4% and CBR was 46.4% for the 110 patients with evaluable lesions. Symptomatic visceral disease was independently associated with shorter PFS (hazard ratio, 3.611; 95% CI, 1.904-6.848; p<0.001), compared with bone-dominant disease in a multivariate analysis of PFS after adjusting for age, hormone receptor, human epidermal growth factor receptor 2, Ki-67 status, dominant metastasis site, and sensitivity to nonsteroidal aromatase inhibitor (AI) treatment. Sensitivity to previous nonsteroidal AI treatment was not associated with PFS, suggesting no cross-resistance between exemestane and nonsteroidal AIs.
Exemestane was effective in postmenopausal Korean women with hormone receptor-positive metastatic breast cancer who failed previous nonsteroidal AI treatment.
PMCID: PMC3625772  PMID: 23593084
Aromatase inhibitors; Breast neoplasms; Exemestane; Neoplasm metastasis
Journal of Breast Cancer  2012;15(4):427-433.
The effects of body mass index on pathologic complete response and survival have not been reported in Korean patients with breast cancer. The purpose of this study was to evaluate the predictive or prognostic value of obesity in breast cancer receiving neoadjuvant chemotherapy.
A total of 438 stage II or III breast cancer patients treated with neoadjuvant chemotherapy were enrolled and analyzed retrospectively.
In the study, 319 patients (72.8%) were normal weight, 100 patients (22.8%) were overweight, and 19 patients (4.3%) were obese. Baseline clinicopathologic characteristics were not different among the groups, except for age. There were no differences in pathologic complete response rate between the groups (9.7% in normal weight, 10.0% in overweight, 5.3% in obese; p=0.804). Neither overweight nor obese patients showed a significant difference in relapse-free survival compared to normal weight patients (p=0.523 and p=0.931, respectively). Also, no significant difference in overall survival (p=0.520 and p=0.864, respectively) was observed.
Obesity or higher body mass index was not significantly associated with pathologic complete response and survival in Korean patients with breast cancer who received neoadjuvant chemotherapy. Our results suggest that the prognostic impact of body mass index is different from that of Western patients.
PMCID: PMC3542851  PMID: 23346172
Breast neoplasms; Neoadjuvant therapy; Obesity; Prognosis
BMC Cancer  2012;12:322.
To evaluate efficacy in patients with brain metastasis (BM) on entry into the lapatinib expanded access program (LEAP).
LEAP is a worldwide, single-arm, open-label study. HER2-positive, locally-advanced or metastatic breast cancer patients with progression after an anthracycline, taxane, and trastuzumab were eligible. Patients received capecitabine 2000 mg/m2 daily in two divided doses, days 1–14, every 21 days and lapatinib 1250 mg once daily.
Among 186 patients enrolled in 6 Korean centers, 58 had BM. Progression-free survival (PFS) was 18.7 weeks in patients with BM and 19.4 weeks without BM (P = 0.88). In patients with BM, brain response was synchronized with systemic responses (P = 0.0001). Overall survival (OS) was 48.9 weeks in patients with BM and 64.6 weeks without BM (P = 0.23). Multivariable analysis found hormone receptor positivity (P = 0.003) and clinical benefit rate (CBR) of combined systemic and brain disease (P < 0.0001) significantly associated with prolonged brain PFS, and CBR of combined systemic and brain disease (P = 0.03) and longer trastuzumab use (P = 0.047) associated with prolonged OS in patients with BM; prior capecitabine did not affect PFS or OS in patients with BM.
Lapatinib plus capecitabine is equally effective in patients with or without BM.
Trial registration (NCT00338247)
PMCID: PMC3480888  PMID: 22839200
Brain Metastasis; HER2-positive Metastatic Breast Cancer; Lapatinib and Capecitabine Therapy; LEAP
PLoS ONE  2012;7(7):e39943.
Lapatinib plus capecitabine is an effective treatment option for trastuzumab-refractory HER2-positive metastatic breast cancer. We have investigated the correlation between quantitative measures of HER2, p95HER2, and HER3 and treatment outcomes using lapatinib and capecitabine.
Total HER2 (H2T), p95HER2 (p95), and total HER3 (H3T) expression were quantified in formalin-fixed paraffin-embedded samples using the VeraTag assays. Patients received lapatinib and capecitabine treatment following trastuzumab failure according to the Lapatinib Expanded Access Program. The association between the protein expression levels and clinical outcomes was analyzed.
A total of 52 patients were evaluable. H2T level was significantly higher in responders (median 93.49 in partial response, 47.66 in stable disease, and 17.27 in progressive disease; p = 0.020). Longer time-to-progression (TTP) was observed in patients with high H2T [p = 0.018, median 5.2 months in high (>14.95) vs. 1.8 in low (<14.95)] and high H3T [p = 0.017, median 5.0 months in high (>0.605) vs. 2.2 in low (<0.605)]. Patients having both high H2T and high H3T had significantly longer TTP [adjusted hazard ratio (HR) 0.38 (95% CI 0.20–0.73), p = 0.004] and overall survival [adjusted HR 0.46 (95% CI 0.24–0.89), p = 0.020]. No significant association between p95 and response or survival was observed.
These data suggest a correlation between high HER2 and high HER3 expression and treatment outcome, while no significant difference was observed between clinical outcome and p95 expression level in this cohort of HER2-positive, trastuzumab-refractory metastatic breast cancer patients treated with lapatinib and capecitabine.
PMCID: PMC3407213  PMID: 22848366
Breast Cancer Research : BCR  2012;14(4):R102.
Anti-estrogen therapy has been shown to reduce mammographic breast density (MD). We hypothesized that a short-term change in breast density may be a surrogate biomarker predicting response to adjuvant endocrine therapy (ET) in breast cancer.
We analyzed data for 1,065 estrogen receptor (ER)-positive breast cancer patients who underwent surgery between 2003 and 2006 and received at least 2 years of ET, including tamoxifen and aromatase inhibitors. MD was measured using Cumulus software 4.0 and expressed as a percentage. MD reduction (MDR) was defined as the absolute difference in MD of mammograms taken preoperatively and 8-20 months after the start of ET.
At a median follow-up of 68.8 months, the overall breast cancer recurrence rate was 7.5% (80/1065). Mean MDR was 5.9% (range, -17.2% to 36.9%). Logistic regression analysis showed that age < 50 years, high preoperative MD, and long interval between start of ET to follow-up mammogram were significantly associated with larger MDR (p < 0.05). In a survival analysis, tumor size, lymph node positivity, high Ki-67 (≥ 10%), and low MDR were independent factors significantly associated with recurrence-free survival (p < 0.05). Compared with the group showing the greatest MDR (≥ 10%), the hazard ratios for MDRs of 5-10%, 0-5%, and < 0% were 1.33, 1.92, and 2.26, respectively.
MD change during short-term use of adjuvant ET was a significant predictor of long-term recurrence in women with ER-positive breast cancer. Effective treatment strategies are urgently needed in patients with low MDR despite about 1 year of ET.
PMCID: PMC3680951  PMID: 22770227
PLoS ONE  2012;7(5):e37414.
The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells.
PMCID: PMC3355131  PMID: 22616001
PLoS ONE  2012;7(3):e33322.
Identification of predictive biomarkers is essential for the successful development of targeted therapy. Insulin-like growth factor 1 receptor (IGF1R) has been examined as a potential therapeutic target for various cancers. However, recent clinical trials showed that anti-IGF1R antibody and chemotherapy are not effective for treating lung cancer.
Methodology/Principal Findings
In order to define biomarkers for predicting successful IGF1R targeted therapy, we evaluated the anti-proliferation effect of figitumumab (CP-751,871), a humanized anti-IGF1R antibody, against nine gastric and eight hepatocellular cancer cell lines. Out of 17 cancer cell lines, figitumumab effectively inhibited the growth of three cell lines (SNU719, HepG2, and SNU368), decreased p-AKT and p-STAT3 levels, and induced G 1 arrest in a dose-dependent manner. Interestingly, these cells showed co-overexpression and altered mobility of the IGF1R and insulin receptor (IR). Immunoprecipitaion (IP) assays and ELISA confirmed the presence of IGF1R/IR heterodimeric receptors in figitumumab-sensitive cells. Treatment with figitumumab led to the dissociation of IGF1-dependent heterodimeric receptors and inhibited tumor growth with decreased levels of heterodimeric receptors in a mouse xenograft model. We next found that both IGF1R and IR were N-linked glyosylated in figitumumab-sensitive cells. In particular, mass spectrometry showed that IGF1R had N-linked glycans at N913 in three figitumumab-sensitive cell lines. We observed that an absence of N-linked glycosylation at N913 led to a lack of membranous localization of IGF1R and figitumumab insensitivity.
Conclusion and Significance
The data suggest that the level of N-linked glycosylated IGF1R/IR heterodimeric receptor is highly associated with sensitivity to anti-IGF1R antibody in cancer cells.
PMCID: PMC3306383  PMID: 22438913
International Journal of Oncology  2011;40(4):1259-1266.
Aberrations of Phosphoinositide 3-kinase (PI3K)/AKT signaling are frequently observed in many types of cancer, promoting its emergence as a promising target for cancer treatment. PI3K can become activated by various pathways, one of which includes RAS. RAS can not only directly activate the PI3K/AKT pathway via binding to p110 of PI3K, but also regulates mTOR via ERK or RSK independently of the PI3K/AKT pathway. Thus, actively mutated RAS can constitutively activate PI3K signaling. Additionally, in RAS tumorigenic transformation, signal transducer and activator of transcription 3 (STAT3) has been known also to be required. In this study, we examined the efficacy of NVP-BKM120, a pan-class I PI3K inhibitor in human gastric cancer cells and hypothesized that the combined inhibition of PI3K and STAT3 would be synergistic in KRAS mutant gastric cancer cells. NVP-BKM120 demonstrated anti-proliferative activity in 11 human gastric cancer cell lines by decreasing mTOR downstream signaling. But NVP-BKM120 treatment increased p-AKT by subsequent abrogation of feedback inhibition by stabilizing insulin receptor substrate-1. In KRAS mutant gastric cancer cells, either p-ERK or p-STAT3 was also increased upon treatment of NVP-BKM120. The synergistic efficacy study demonstrated that dual PI3K and STAT3 blockade showed a synergism in cells harboring mutated KRAS by inducing apoptosis. The synergistic effect was not seen in KRAS wild-type cells. Together, these findings suggest for the first time that the dual inhibition of PI3K and STAT3 signaling may be an effective therapeutic strategy for KRAS mutant gastric cancer patients.
PMCID: PMC3584651  PMID: 22159814
BKM120; phosphoinositide 3-kinase; STAT3; KRAS; gastric cancer
BMC Medical Genomics  2011;4:82.
Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult.
We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay) in combination with a genome analyzer and a new normalization algorithm.
We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs), transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those in the HOX and histone gene families. We also discovered long-range epigenetic silencing (LRES) regions in gastric cancer tissue and identified several hypermethylated genes (MDM2, DYRK2, and LYZ) within these regions. The methylation status of CGIs and gene annotation elements in metastatic lymph nodes was intermediate between normal and cancerous tissue, indicating that methylation of specific genes is gradually increased in cancerous tissue.
Our findings will provide valuable data for future analysis of CpG methylation patterns, useful markers for the diagnosis of stomach cancer, as well as a new analysis method for clinical epigenomics investigations.
PMCID: PMC3273443  PMID: 22133303
BMC Cancer  2011;11:452.
This study was aimed 1) to investigate the predictive value of FDG PET/CT (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography) for histopathologic response and 2) to explore the results of FDG PET/CT by molecular phenotypes of breast cancer patients who received neoadjuvant chemotherapy.
Seventy-eight stage II or III breast cancer patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were enrolled in this study. FDG PET/CTs were acquired before chemotherapy and after the first cycle of chemotherapy for evaluating early metabolic response.
The mean pre- and post-chemotherapy standard uptake value (SUV) were 7.5 and 3.9, respectively. The early metabolic response provided by FDG PET/CT after one cycle of neoadjuvant chemotherapy was correlated with the histopathologic response after completion of neoadjuvant chemotherapy (P = 0.002). Sensitivity and negative predictive value were 85.7% and 95.1%, respectively. The estrogen receptor negative phenotype had a higher pre-chemotherapy SUV (8.6 vs. 6.4, P = 0.047) and percent change in SUV (48% vs. 30%, P = 0.038). In triple negative breast cancer (TNBC), the pre-chemotherapy SUV was higher than in non-TNBC (9.8 vs. 6.4, P = 0.008).
The early metabolic response using FDG PET/CT could have a predictive value for the assessment of histopathologic non-response of stage II/III breast cancer treated with neoadjuvant chemotherapy. Our findings suggest that the initial SUV and the decline in SUV differed based on the molecular phenotype.
Trial Registration NCT01396655
PMCID: PMC3224348  PMID: 22011459
FDG PET; breast cancer; neoadjuvant chemotherapy; molecular phenotype
Numerous studies have attempted to identify gene expression profiles which can be utilized to predict responses to neoadjuvant chemotherapy (NAC), but their findings are not clinically applicable at present. In the present study, we sought to determine DNA copy number alterations (CNAs) in breast cancer tissues which are associated with the response to NAC. Frozen tumor tissues from 63 breast cancer patients were obtained using core needle biopsy prior to NAC (3 cycles of docetaxel plus adriamycin) and were microdissected. Array comparative genomic hybridization (array CGH) with 4,045 bacterial artificial chromosome (BAC) probes was performed to identify the CNAs. Changes in tumor size in response to NAC were measured via magnetic resonance imaging. Fluorescence in situ hybridization (FISH) was conducted to verify array CGH results and for independent validation studies. CNAs at eight chromosomal loci encompassing 24 clones were correlated with changes in tumor size after NAC (p<0.05; t-test). Two CNAs were selected, 17p12 deletion and 17q21.32-33 gain, which were significantly associated with a smaller reduction in tumor size following NAC, via prioritization of the regions containing the candidate genes. In an independent validation set of samples from 39 patients, FISH assay further showed that the 17p12 deletion was markedly associated with smaller changes in tumor size (p=0.006), while the 17q21.32-33 gain was not significant (p=0.309). In conclusion, we successfully identified a 17p12 deletion in breast cancer tissue which can be applied in predicting tumor resistance to NAC.
PMCID: PMC3440692  PMID: 22977578
breast neoplasms; comparative genomic hybridization; copy number; microarray; neoadjuvant chemotherapy; predictive marker
BMC Cancer  2011;11:188.
Because of the late clinical presentation of biliary tract cancer (BTC), only 10% of patients are eligible for curative surgery. Even among those patients who have undergone curative surgery, most patients develop recurrent cancer. This study is to determine the clinical role of 18F-FDG PET/CT during post-operative surveillance of suspected recurrent BTC based on symptoms, laboratory findings and contrast-enhanced CT (ceCT) findings.
We consecutively enrolled 50 patients with BTC who underwent curative surgery. An 18F-FDG PET/CT was obtained for assessment of recurrence based on clinical suspicion during post-operative surveillance. The final confirmation of recurrence was determined pathologically or clinically. When a pathologic confirmation was impossible or inconclusive, a clinical confirmation was used by radiologic correlation with subsequent follow-up ceCT at a minimum of 3-month intervals. Diagnostic efficacy was evaluated by comparing the results of ceCT and 18F-FDG PET/CT with the final diagnosis.
Among the 50 patients, 34(68%) were confirmed to have a recurrence. PET/CT showed higher sensitivity (88% vs. 76%, p = 0.16) and accuracy (82% vs. 66%, p = 0.11) for recurrence compared to ceCT, even though the difference was not significant. The positive (86% vs. 74%, p = 0.72) and negative predictive values for recurrence (73% vs. 47%, p = 0.55) were not significantly different between PET/CT and ceCT. However, an additional PET/CT on ceCT significantly improved the sensitivity than did a ceCT alone (94% [32/34] for PET/CT on ceCT vs. 76% [26/34] for ceCT alone, p = 0.03) without increasing the specificity, positive predictive value, and negative predictive value.
18F-FDG PET/CT alone is not more sensitive or specific than ceCT in the detection of recurrent BTC after curative surgery. These results do not reach statistical significance, probably due to the low number of patients. However, an additional 18F-FDG PET/CT on ceCT significantly improves the sensitivity of detecting recurrences.
PMCID: PMC3120804  PMID: 21599995
18F-FDG PET/CT; biliary tract cancer; surveillance; recurrence

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