Immunohistochemistry (IHC) is an important auxiliary method for pathologists in routine diagnostic work as well as in basic and clinical research including exploration of biomarkers, as IHC allows confirmation of target molecule expressions in the context of microenvironment. Although there has been a considerable progress in automation and standardization of IHC, there are still many things to be considered in proper optimization and appropriate interpretation. In this review, we aim to provide possible pitfalls and useful tips for practicing pathologists and residents in pathology training. First, general procedure of IHC is summarized, followed by pitfalls and tips in each step and a summary of troubleshooting. Second, ways to an accurate interpretation of IHC are discussed, with introduction to general quantification and analysis methods. This review is not intended to provide complete information on IHC, but to be used as a basic reference for practice and publication.
Immmunohistochemistry; Antigen-antibody reactions; Immunostain; Auxiliary test
CD99 is a cell surface transmembrane glycoprotein expressed in various tissues. CD99 is differentially expressed between subpopulations of each tissue and is highly expressed in certain hematopoietic and precursor cells. However, there has been no comprehensive study of CD99 expression in normal skin. We evaluated CD99 expression in normal human skin and developing fetal skin.
Seventy-five adult skin samples containing normal skin and eight fetal skin samples of different gestational ages were collected. CD99 immunohistochemical staining was performed to evaluate expression pattern in adult and fetal skin samples. CD99 and CD34 expression were compared by double immunofluorescence.
In normal adult skin, CD99 was strongly expressed in the membrane of epidermal basal keratinocytes, hair follicle bulges and outer root sheaths, and inner secretory cells of eccrine sweat glands. In fetal skin, CD99 was not expressed on the periderm at 16 weeks of gestation but was expressed in basal cells of fetal skin at around 19 weeks of gestation. CD99 expression became comparable to that of the adult skin after 20 weeks of gestation. CD99 and CD34 were co-expressed in hair follicle outer root sheaths, as seen by double immunofluorescence study.
This is the first study examining CD99 expression pattern in normal adult and fetal skin. CD99 tends to be expressed in the basal/precursor cells of epidermis and in hair follicles. These results provide a basis for future investigation on functions of CD99 in the skin and provide a novel potential target for the treatment of dermatologic lesions.
CD99 protein; Skin; Immunohistochemistry
CD99 signaling is crucial to a diverse range of biological functions including survival and proliferation. CD99 engagement is reported to augment activator protein-1 (AP-1) activity through mitogen-activated protein (MAP) kinase pathways in a T-lymphoblastic lymphoma cell line Jurkat and in breast cancer cell lines. In this study, we report that CD99 differentially regulated AP-1 activity in the human myeloma cell line RPMI8226. CD99 was highly expressed and the CD99 engagement led to activation of the MAP kinases, but suppressed AP-1 activity by inducing the expression of basic leucine zipper transcription factor, ATF-like (BATF), a negative regulator of AP-1 in RPMI8226 cells. By contrast, engagement of CD99 enhanced AP-1 activity and did not change the BATF expression in Jurkat cells. CD99 engagement reduced the proliferation of RPMI8226 cells and expression of cyclin 1 and 3. Overall, these results suggest novel CD99 functions in RPMI8226 cells.
CD99; BATF; AP-1; Proliferation; MAP kinase
Multiple myeloma (MM) is a heterogeneous and ultimately fatal disease. Risk stratification using prognostic biomarkers is crucial to individualize treatments. We sought to investigate the role of CD99, a transmembrane protein highly expressed in many hematopoietic cells including subpopulations of normal and neoplastic plasma cells, for MM risk stratification.
CD99 expression was measured in paraffin samples of bone marrow and extramedullary biopsies of 170 patients with MM. Patients were divided into those with high score (moderately and strongly positive) and low score (negative and weakly positive), with all staining being cytoplasmic and/or membranous.
High anti-CD99 immunostaining was observed in 72 of 136 (52.9%) bone marrow biopsies and 24 of 87 (27.6%) extramedullary biopsies in MM. High CD99 expression of extramedullary specimens was associated with significantly longer overall survival (OS; p=.016). High CD99 expression of extramedullary specimens was also associated with better prognosis in the nonautologous stem cell transplantation group of MM patients (p=.044). In multivariate analysis, International Staging System stage was an independent prognostic factor, whereas CD99 expression was no longer statistically significant.
Expression of CD99 in extramedullary specimens was correlated with longer OS, suggesting that CD99 may be a helpful immunohistochemical marker for risk stratification.
CD99; Multiple myeloma; Immunostaining; Autologous stem cell transplantation
The survival and growth of melanocytes are controlled by the binding of stem cell factor to its cell surface receptor c-kit+ (CD117). We have observed that c-kit+ melanocytes existed in some lesions of vitiligo, while Melan A+ cells were absent.
To verify possible relation between c-kit+ expression and treatment response in non-segmental vitiligo lesions
Skin biopsies were done from the center of the 47 lesions from the 47 patients with non-segmental vitiligo. Expression of c-kit+ and Melan A, and amounts of melanin in the epidermis were assessed in each lesion, and treatment responses to excimer laser were evaluated.
Thirty-five of the 47 lesions (74.5%) had c-kit+ phenotypes. There was significant difference of c-kit staining value between good responders in 3 months of excimer laser treatment (average of 24 sessions) and the others.
c-Kit expression in vitiliginous epidermis may be related to better treatment responses to excimer laser.
c-Kit receptor; Excimer laser; Vitiligo
Here we report a case of a 76-year-old man with diffuse large B-cell lymphoma (DLBCL) with simultaneous involvement of the right breast and left testicle. The patient underwent complete resection of the involved testis, followed by immunochemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) and prophylactic radiotherapy to the contralateral testis. Following this multimodal therapy, he achieved a complete response. This is a rare case of DLBCL involving both the breast and the testis in a male patient.
Diffuse large B-cell lymphoma; Breast; Testis; Male
By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the CD31+ endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-1+ fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.
Ly110; SLC46A2; stem cell; thymic epithelial cell; TSCOT; tumor suppressor
Migration of plasma cells to the bone marrow is critical factor to humoral immunity and controlled by chemokines. Regulator of G protein signaling 1 (RGS1) is a GTPase-activating protein that controls various crucial functions such as migration. Here, we show that RGS1 controls the chemotactic migration of RPMI 8226 human plasmacytoma cells and human plasmablasts. LPS strongly increased RGS1 expression and retarded the migration of RPMI 8226 cells by suppressing CXCL12-mediated AKT activation. RGS1 knockdown by siRNA abolished the retardation of migration and AKT suppression by LPS. RGS1-dependent regulation of migration via AKT is also observed in cultured plasmablasts. We propose novel functions of RGS1 that suppress AKT activation and the migration of RPMI 8226 cells and plasmablasts in CXCL12-mediated chemotaxis.
Multicentric Castleman's disease (CD) is commonly associated with poor prognosis, and well-known prognostic factors are scarce. We performed a retrospective analysis to define the clinical features and prognostic factors for patients with multicentric CD.
Between 1990 and 2013, 32 patients with multicentric CD were identified from the database of the Asan Medical Center, Seoul, Korea. Clinicopathologic data were collected by reviewing the medical records. With the exclusion of 4 patients because of unknown human immunodeficiency virus infection status, 28 human immunodeficiency virus-negative patients with multicentric CD were included in this analysis.
Most of the patients were male (76%) and had a median age of 54 years. Hyaline vascular variant was the most common subtype (N=11, 39%). Hepatosplenomegaly (61%), fever (39%), edema (29%), and ascites (18%) were the most frequently reported symptoms and signs at diagnosis. With a median follow-up of 67 months, the 5-year overall survival (OS) was 77%. Patients with extravascular fluid accumulation (i.e., peripheral edema, ascites, and/or pleural effusions) were significantly associated with a poor survival rate (5-year OS, 94% vs. 56%; P=0.04). The extent of disease involvement was also a significant prognostic factor (5-year OS, 91% for involvement on a single side vs. 73% on both sides of the diaphragm; P=0.03). Other clinicopathologic factors were not significantly associated with patient survival.
Our findings suggest that the hyaline vascular variant is not a rare subtype of multicentric CD. Extravascular fluid accumulation and disseminated disease involvement seem to be significant prognostic factors.
Multicentric Castleman's disease; Giant lymph node hyperplasia; Angiofollicular lymphoid hyperplasia; Prognosis; HIV
Primary testicular diffuse large B-cell lymphoma (DLBCL) is a rare but aggressive extranodal lymphoma, and its relapse in the central nervous system (CNS) is a major concern during treatment. Despite this, the role of intrathecal prophylaxis in primary testicular DLBCL remains controversial.
We retrospectively reviewed the medical records of 14 patients with primary testicular DLBCL diagnosed between November 2000 and June 2012, and analyzed the CNS relapse rate in patients treated without intrathecal prophylaxis. Survival curves were estimated using the Kaplan-Meier method.
The median age at diagnosis was 57 years (range, 41-79 years). Unilateral testicular involvement was observed in 13 patients. Nine patients had stage I, 1 had stage II, and 4 had stage IV disease. The international prognostic index was low or low-intermediate risk in 12 patients and high-intermediate risk in 2 patients. Thirteen patients underwent orchiectomy. All the patients received systemic chemotherapy without intrathecal prophylaxis, and prophylactic radiotherapy was administered to the contralateral testis in 12 patients. The median follow-up period of surviving patients was 39 months (range, 10-139 months). Median overall survival was not reached and the median progression-free survival was 3.8 years. Four patients experienced relapse, but CNS relapse was observed in only one patient (7.1%) with stage IV disease, 27 months after a complete response.
Even without intrathecal prophylaxis, the rate of relapse in the CNS was lower in the Korean patients with primary testicular DLBCL compared to prior reports.
Diffuse large B cell lymphoma; Intrathecal prophylaxis; Primary testicular lymphoma
Abbreviated chemotherapy followed by radiotherapy or full cycles of chemotherapy is recommended as a standard treatment for limited-stage (LS) diffuse large B-cell lymphoma (DLBCL). After complete resection of tumors, however, Burkitt and childhood B-cell Non-Hodgkin lymphoma show favorable outcomes, even after abbreviated chemotherapy of only 2 or 3 cycles. We investigated the effectiveness of abbreviated chemotherapy in patients with LS DLBCL after complete tumor resection.
We retrospectively reviewed 18 patients with LS DLBCL who underwent complete tumor resection followed by either 3 or 4 cycles of chemotherapy between March 2002 and May 2010.
With a median follow-up period of 57.9 months (range, 31.8-130.2 months), no patients experienced disease relapse or progression; however, 1 patient experienced secondary acute myeloid leukemia during follow-up. The 5-year progression-free survival rate and overall survival rate were 93.3% and 94.1%, respectively.
These results warrant further investigation into abbreviated chemotherapy as an alternative treatment for patients who have undergone complete resection of LS DLBCL.
Diffuse large B-cell lymphoma; Limited Stage; Resection; Abbreviated chemotherapy
Previously, cutaneous lymphomas were classified according to either the European Organization for the Research and Treatment of Cancer (EORTC) or the World Health Organization (WHO) classification paradigms. The aim of this study was to determine the relative frequency of Korean cutaneous lymphoma according to the new WHO-EORTC classification system.
A total of 517 patients were recruited during a recent 5 year-period (2006-2010) from 21 institutes and classified according to the WHO-EORTC criteria.
The patients included 298 males and 219 females, and the mean age at diagnosis was 49 years. The lesions preferentially affected the trunk area (40.2%). The most frequent subtypes in order of decreasing prevalence were mycosis fungoides (22.2%), peripheral T-cell lymphoma (17.2%), CD30+ T-cell lymphoproliferative disorder (13.7%), and extranodal natural killer/T (NK/T) cell lymphoma, nasal type (12.0%). Diffuse large B-cell lymphoma accounted for 11.2% of cases, half of which were secondary cutaneous involvement; other types of B-cell lymphoma accounted for less than 1% of cases.
In comparison with data from Western countries, this study revealed relatively lower rates of mycosis fungoides and B-cell lymphoma in Korean patients, as well as higher rates of subcutaneous panniculitis-like T-cell lymphoma and NK/T cell lymphoma.
Cutaneous lymphoma; World Health Organization; EORTC; Classification
Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of non-Hodgkin lymphoma, which has no consensus for its ideal treatment or prognosis.
We reviewed the clinicopathologic features and clinical outcomes of 25 PMBL cases diagnosed at a single institution between 1993 and 2009 and compared them with 588 cases of non-mediastinal, diffuse large B-cell lymphoma (DLBCL, control group) diagnosed during the same period.
Thirteen (52.0%) PMBL patients had Ann Arbor stage III or IV disease, and 10 (40.0%) had B symptoms. Thirteen (52%) PMBL patients were classified as high-intermediate/high-risk according to the International Prognostic Index. There was a significant prevalence of young (median: 31 years; range, 15-78 years; P<0.001), female (68%; P=0.014) patients in the PMBL group compared to the control group (median: 56 years; range, 15-85 years; 43.2% female). Bulky disease and elevated levels of lactate dehydrogenase (LDH) were more frequent in the PMBL group (P<0.001 and P=0.003, respectively). Nineteen (76%) PBML patients achieved complete remission, and 18 were alive at the last follow-up (median: 43 months; range, 1-92 months). There was no difference in the 3-year, overall survival rate (72%, 95% confidence interval [CI]: 54.0-83.0 versus 70.1%, 95% CI, 109.0-126.0; P=0.686) between PMBL and control patients, respectively.
Compared to patients with non-mediastinal DLBCL, Korean patients with PMBL are predominantly young women with bulky disease and high LDH levels but with no significant difference in survival.
Lymphoma; B cell; PMBL; Prognosis; Treatment
Recent studies have reported the prognostic value of tissue-associated magrophages (TAMs) in classical Hodgkin lymphoma (cHL). In addition, TAMs are implicated in the tumor angiogenesis. In this study, we examined the prognostic relevance of TAMs in relation to vascular endothelial growth factor (VEGF) expression and angiogenesis in uniformly treated cases of cHL.
Diagnostic tissue from 116 patients with ABVD-treated cHL was evaluated retrospectively by immunohistochemical analysis for CD68, CD163 and VEGF expression and for CD31 expression as a measure of microvessel density (MVD).
High CD163 expression (≥35% of cellularity) correlated with VEGF expression (Pearson’s Chi-square test, P = 0.008) and MVD (Spearman correlation coefficient 0.310, P<0.001). High CD163 expression was associated with inferior event-free survival (EFS, P = 0.005) and overall survival (OS, P<0.001) in univariate analysis. In multivariate analysis, high CD163 expression was strongly associated with inferior EFS (P = 0.043) and OS (P = 0.008). Patients with high MVD had a lower OS than those with low MVD, but the difference was not significant (P = 0.071, respectively). While high expression of CD68 was also associated with inferior EFS (P = 0.007), it showed no correlation with VEGF or MVD.
Our data confirms that CD163 expression provides independent prognostic information in cHL. The correlation of CD163 with VEGF expression and MVD suggests the role of CD163-positive cells in tumor angiogenesis of cHL.
The gastrointestinal tract is the most common primary extranodal site for diffuse large B-cell lymphoma (DLBCL). However, there is no consensus on the most appropriate staging system for intestinal DLBCL. We evaluated the utility of the modified Ann Arbor system, the Lugano system, and the Paris staging system (a modification of the Tumor, Node, Metastases [TNM] staging for epithelial tumors) in 66 cases of resected intestinal DLBCL. The cases were treated with surgery, plus either cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) chemotherapy alone (n=26) or with the addition of rituximab immunotherapy (n=40). Median follow-up time was 40.4 months (range, 2.1-171.6 months). Fifty-six patients (84.8%) achieved complete remission. The overall 5-yr survival rate was 86.4% (57/66). Of the stage categories defined for each staging system, only the T stage of the Paris classification showed prognostic significance for overall survival by univariate analysis. However, none of the stage parameters was significantly correlated with patient survival on multivariate analysis. In conclusion, the results suggest that the T stage of the Paris classification system may be a prognostic indicator in intestinal DLBCL. The results also imply that in surgically resected intestinal DLBCL, the addition of rituximab to the CHOP regimen does not confer significant survival advantage.
Lymphoma, Large B-Cell, Diffuse; Intestines; Stage; Rituximab
Absolute lymphocyte count (ALC) in peripheral blood has recently been reported to be an independent prognostic factor in multiple myeloma (MM). Previous studies indicated that the absolute monocyte count (AMC) in peripheral blood reflects the state of the tumor microenvironment in lymphomas. Neither the utility of the AMC nor its relationship with ALC has been studied in MM.
The prognostic value of ALC, AMC, and the ALC/AMC ratio at the time of diagnosis was retrospectively examined in 189 patients with MM.
On univariate analysis, low ALC (<1,400 cells/µL), high AMC (≥490 cells/µL), and low ALC/AMC ratio (<2.9) were correlated with worse overall survival (OS) (p=.002, p=.038, and p=.001, respectively). On multivariate analysis, the ALC/AMC ratio was an independent prognostic factor (p=.047), whereas ALC and AMC were no longer statistical significant. Low ALC, high AMC, and low ALC/AMC ratio were associated with poor prognostic factors such as high International Staging System stage, plasmablastic morphology, hypoalbuminemia, and high β2-microglobulin.
Univariate analysis demonstrated that changes in ALC, AMC, and the ALC/AMC ratio are associated with patient survival in MM. Multivariate analysis showed that, of these factors, the ALC/AMC ratio was an independent prognostic factor for OS.
Multiple myeloma; Lymphocytes; Monocytes; Lymphocyte/monocyte ratio; Prognosis
Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous clinicopathological entity, and its molecular classification into germinal center B cell-like (GCB) and activated B cell-like (ABC) subtypes using gene expression profile analysis has been shown to have prognostic significance. Recent attempts have been made to find an association between immunohistochemical findings and molecular subgroup, although the clinical utility of immunohistochemical classification remains uncertain.
The clinicopathological features and follow-up data of 68 cases of surgically resected gastrointestinal DLBCL were analyzed. Using the immunohistochemical findings on tissue microarray, the cases were categorized into GCB and non-GCB subtypes according to the algorithms proposed by Hans, Muris, Choi, and Tally.
The median patient age was 56 years (range, 26-77 years). Of the 68 cases included, 39.7% (27/68) involved the stomach, and 60.3% (41/68) involved the intestines. The GCB and non-GCB groups sorted according to Hans, Choi, and Tally algorithms, but not the Muris algorithm, were closely concordant (Hans vs. Choi, κ=0.775, P<0.001; Hans vs. Tally, κ=0.724, P<0.001; Choi vs. Tally, κ=0.528, P<0.001). However, there was no prognostic difference between the GCB and non-GCB subtypes, regardless of the algorithm used. On univariate survival analyses, international prognostic index risk group and depth of tumor invasion both had prognostic significance.
The Hans, Choi, and Tally algorithms might represent identical DLBCL subgroups, but this grouping did not correlate with prognosis. Further studies may delineate the association between immunohistochemical subgroups and prognosis.
Diffuse large B-cell lymphoma; Gastrointestinal tract; Immunohistochemistry; Prognosis
Radioimmunotherapy agents have a highly significant role in autologous stem cell transplantation as they improve tolerability and increase the efficacy of the conditioning regimen.
We retrospectively analyzed the efficacy and toxicity of yttrium-90 ibritumomab tiuxetan (Zevalin) combined with intravenous busulfan, cyclophosphamide, and etoposide (Z-BuCyE) compared with those of BuCyE alone followed by autologous stem cell transplantation in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (NHL). The efficacy, toxicity, and engraftment characteristics were compared between 19 patients who received Z-BuCyE and 19 historical controls who received BuCyE.
The 2 treatment groups shared similar baseline characteristics. The median time to platelet engraftment (>20×109/L) and neutrophil engraftment (>0.5×109/L) did not significantly differ between the Z-BuCyE group (12 days and 10 days, respectively) and the BuCyE group (12 days and 10 days, respectively). No significant differences were observed between the groups with respect to toxicities and treatment-related mortality. The median follow-up period was 30.4 months, and median event-free survival was generally better in the Z-BuCyE group (12.5 months) vs. the BuCyE group (6.2 months, P=0.236). No significant difference in overall survival between the groups was noted.
Adding ibritumomab tiuxetan to BuCyE high-dose chemotherapy may benefit patients with relapsed or refractory B-cell NHL with no risk of additional toxicity.
Yttrium-90 ibritumomab tiuxetan; BuCyE; Autologous stem cell transplantation; Non-Hodgkin lymphoma
Bortezomib targets molecular dysregulation of nuclear factor-κB activation and cell cycle control, which are characteristic features of diffuse large B-cell lymphoma (DLBCL). We evaluated the safety and efficacy of bortezomib treatment with dose-dense cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) every 2 weeks (CHOP-14).
Untreated DLBCL patients were enrolled. A phase I dose-escalation study with 1.0, 1.3, and 1.6 mg/m2 bortezomib administration on day 1 and 4 in addition to the CHOP-14 regimen was performed to determine the maximum tolerated dose (MTD) and the dose-limiting toxicity (DLT). Lenograstim 5 µg/kg/d was administered on day 4-13. The bortezomib dose from the phase I study was used in the phase II study.
Nine and 37 patients were enrolled in the phase I and phase II studies, respectively. The analysis of the phase II results (40 patients) included data of the 3 patients in the last MTD dose cohort of the phase I trial. During the phase I trial, no DLT was observed at any bortezomib dose; therefore, the recommended dose was 1.6 mg/m2. In phase II, the overall response rate was 95% (complete response: 80%; partial response: 15%). Nine out of the 40 patients showed grade 3 sensory neuropathy, and 22 required at least 1 dose reduction. Three patients could not complete the intended 6 cycles of treatment because of severe neuropathy.
Bortezomib plus CHOP-14 was highly effective for the treatment of untreated DLBCL patients, but in many cases, dose or schedule modification was required to reduce neurotoxicity.
Bortezomib; CHOP-14; Diffuse large B-cell lymphoma