Calretinin expression in high-grade invasive ductal carcinoma of the breast is associated with basal-like subtype and unfavorable prognosis

The Diagnostic Utility of IDH2 R172 Immunohistochemistry in Tall Cell Carcinoma With Reversed Polarity of the Breast

Tall cell carcinoma with reversed polarity (TCCRP) is a rare histologic type of low-grade breast cancer, consisting of tall columnar cells with reversed nuclear polarity and characterized by frequent IDH2 mutations. We herein report 3 cases of TCCRP with sequencing analyses of the IDH2 gene and immunohistochemical examination using monoclonal antibodies (11C8B1) against IDH2 R172. IDH2 R172 mutations were detected in all 3 resected tumors (R172S in 2 tumors and R172T in 1 tumor), and the presence of these mutations was confirmed by IDH2 R172 immunohistochemistry. Tumor cells of TCCRP showed strong and diffuse staining for the antibody against IDH2 R172. In 1 case, tumor tissue from 2 core needle biopsy samples collected on different days were also immunohistochemically positive for IDH2 R172. These results indicate that IDH2 R172 immunohistochemistry is suitable for the detection of TCCRP in both resection and biopsy samples. In addition, a literature review revealed that R172S and R172T account for 76% of IDH2 mutations in TCCRP, suggesting that 11C8B1, which reacts with R172S and R172T, was likely most sensitive for IDH2-mutated TCCRP among many available antibodies for IDH2 R172. Furthermore, the combination of 2 or more antibodies against IDH2 R172 could be more effective for detecting TCCRP mutation. However, it is important to note that IDH2 R172 immunohistochemistry is not absolute, because IDH2 wild type is found in a small proportion (10%) of cases, and a few cases of IDH2-mutated TCCRP may harbor rare subtypes of R172 that are not covered by available antibodies.

Expression of Calretinin, Marker of Mesothelial Differentiation, in Pancreatic Ductal Adenocarcinoma: A Potential Diagnostic Pitfall

OBJECTIVE

Pancreatic ductal adenocarcinoma is one of the most common causes of "peritoneal carcinomatosis" and has an insidious growth pattern. Thus, it falls into the differential diagnosis of other peritoneal malignancies including malignant mesothelioma. Recently, we have encountered an undifferentiated pancreatic carcinoma presenting with peritoneal disease and exhibiting immunoreactivity to calretinin, mimicking mesothelioma. In this study, we explored the incidence of calretinin expression in pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Calretinin immunohistochemical staining was performed on the tissue microarrays (TMAs), which were created using three 0.6 mm diameter punches per tumor (n=113). Distribution and intensity of expression were evaluated.

RESULTS

The TMAs contained 86 well/moderately differentiated and 27 poorly differentiated/undifferentiated carcinomas. Calretinin was positive in nine tumors (8%); six with diffuse and strong staining, three with focal and/or weak staining. The incidence of calretinin expression was 15% in poorly differentiated/undifferentiated carcinomas (vs. 6% in well/moderately differentiated carcinomas, p=0.03).

CONCLUSIONS

Pancreatic ductal adenocarcinomas, especially when poorly differentiated/undifferentiated, may be diffusely and strongly positive for calretinin creating a potential diagnostic challenge with malignant mesothelioma. Therefore, caution should be exercised when using this marker to explore a diagnosis of malignant mesothelioma. Tumors expressing calretinin without other mesothelial markers should prompt a careful evaluation of the morphologic and immunohistochemical features to exclude other malignancies. If the diagnosis of pancreatic ductal adenocarcinoma is considered, ductal differentiation can be demonstrated by using additional immunohistochemical markers such as mucin-related glycoproteins (MUC1, MUC5AC) and/or oncoproteins (CEA, B72.3, CA125).

Microdissected pancreatic cancer proteomes reveal tumor heterogeneity and therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a relative paucity of cancer cells that are surrounded by an abundance of nontumor cells and extracellular matrix, known as stroma. The interaction between stroma and cancer cells contributes to poor outcome, but how proteins from these individual compartments drive aggressive tumor behavior is not known. Here, we report the proteomic analysis of laser-capture microdissected (LCM) PDAC samples. We isolated stroma, tumor, and bulk samples from a cohort with long- and short-term survivors. Compartment-specific proteins were measured by mass spectrometry, yielding what we believe to be the largest PDAC proteome landscape to date. These analyses revealed that, in bulk analysis, tumor-derived proteins were typically masked and that LCM was required to reveal biology and prognostic markers. We validated tumor CALB2 and stromal COL11A1 expression as compartment-specific prognostic markers. We identified and functionally addressed the contributions of the tumor cell receptor EPHA2 to tumor cell viability and motility, underscoring the value of compartment-specific protein analysis in PDAC.

Upregulation of mesothelial genes in ovarian carcinoma cells is associated with an unfavorable clinical outcome and the promotion of cancer cell adhesion

A hallmark of ovarian high‐grade serous carcinoma (HGSC) is its early and massive peritoneal dissemination via the peritoneal fluid. It is generally believed that tumor cells must breach the mesothelium of peritoneal organs to adhere to the underlying extracellular matrix (ECM) and initiate metastatic growth. However, the molecular mechanisms underlying these processes are only partially understood. Here, we have analyzed 52 matched samples of spheroids and solid tumor masses (suspected primary lesions and metastases) from 10 patients by targeted sequencing of 21 loci previously proposed as targets of HGSC driver mutations. This analysis revealed very similar patterns of genetic alterations in all samples. One exception was FAT3 with a strong enrichment of mutations in metastases compared with presumed primary lesions in two cases. FAT3 is a putative tumor suppressor gene that codes for an atypical cadherin, pointing a potential role in peritoneal dissemination in a subgroup of HGSC patients. By contrast, transcriptome data revealed clear and consistent differences between tumor cell spheroids from ascites and metastatic lesions, which were mirrored by the in vitro adherence of ascites‐derived spheroids. The adhesion‐induced transcriptional alterations in metastases and adherent cells resembled epithelial–mesenchymal transition, but surprisingly also included the upregulation of a specific subset of mesothelial genes, such as calretinin (CALB2) and podoplanin (PDPN). Consistent with this finding, calretinin staining was also observed in subsets of tumor cells in HGSC metastases, particularly at the invasive tumor edges. Intriguingly, a high expression of either CALB2 or PDPN was strongly associated with a poor clinical outcome. siRNA‐mediated CALB2 silencing triggered the detachment of adherent HGSC cells in vitro and inhibited the adhesion of detached HGSC cells to collagen type I. Our data suggest that the acquisition of a mesenchymal–mesothelial phenotype contributes to cancer cell adhesion to the ECM of peritoneal organs and HGSC progression.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Calretinin-expressing lung adenocarcinoma: Distinct characteristics of advanced stages, smoker-type features, and rare expression of other mesothelial markers are useful to differentiate epithelioid mesothelioma

Calretinin, a mesothelioma marker, is sometimes expressed in lung cancer, which may complicate the differential diagnosis of mesothelioma. Here, the clinicopathological and immunohistochemical characteristics of calretinin-positive lung cancer were examined to reduce confusion with malignant mesothelioma. Calretinin expression in 307 consecutive cases of lung cancer was evaluated immunohistochemically. Survival was analyzed using the Kaplan-Meier method and log-rank test. Calretinin expression was identified in 67 (22%) tumors, including those with partial and weak expression [15% (37/250) of adenocarcinomas, 54% (25/46) of squamous cell carcinomas, 75% (3/4) of adenosquamous carcinomas, and 29% (2/7) of sarcomatoid carcinomas]. In calretinin-positive adenocarcinoma (n = 37), expression percentages of Wilms tumor-1, podoplanin, thyroid transcription factor-1, and claudin-4 were 6, 3, 52, 82%, respectively, whereas in calretinin-positive squamous cell carcinoma (n = 25) the percentages were 8, 12, 12, 68%, respectively, indicating that other mesothelial markers were only rarely expressed and that claudin-4 expression was common. Although not an independent marker, calretinin expression was associated with a poor prognosis for stage I tumors of adenocarcinoma (p < 0.001) and of all histological subtypes (p < 0.001). In conclusion, calretinin-positive lung tumors share characteristics with those of smokers and advanced stages and can be differentiated from mesothelioma with the use of other mesothelial and epithelial markers.

Serum calretinin as an independent predictor for platinum resistance and prognosis in ovarian cancer

Calretinin (CRT) is a calcium-binding protein that controls intracellular calcium signaling. Besides its prominent expression in neurons, serum CRT (sCRT) has recently been suggested as blood-based biomarker for prediagnostic mesothelioma detection. CRT is expressed in ovarian cancer tissues in up to 40% of cases; however, its clinical relevance as blood-based biomarker for ovarian cancer is unknown. sCRT was determined by calretinin enzyme-linked immunoabsorbent assay (Calretinin-ELISA, DLD Diagnostika GmbH, Hamburg, Germany) in a total of 515 serum samples from 116 healthy controls and 134 ovarian cancer patients (thereof 86% with Fédération Internationale de Gynécologie et d'Obstétrique [FIGO] III/IV), including samples at primary diagnosis and at four longitudinal follow-up time points in the course of treatment and at recurrence. sCRT level was significantly increased in ovarian cancer patients compared to healthy controls (estimated difference = 0.3 ng/ml, p < 0.001), was mostly independent from CA125 (r ≤ 0.388) and enabled accurate discrimination between cases and controls (area under the curve = 0.85). Higher sCRT level at primary diagnosis predicted suboptimal debulking (p < 0.001) and was associated with advanced FIGO-stage (p < 0.001) and increased amount of ascites (p < 0.001). sCRT levels at primary diagnosis and its dynamics in the course of chemotherapy were independent predictors for poor progression-free survival (hazard ratio [HR] = 1.99, confidence interval [CI] = [1.13-3.52], p = 0.0181) and overall survival (HR = 15.4, CI = [1.92-124], p = 0.0099). Furthermore, sCRT at primary diagnosis or a relative sCRT increase in the time interval between surgery and the onset of chemotherapy were both independent predictors of platinum resistance (OR = 4.99, CI = [3.50-16,001], p = 0.0016; OR = 2.41, CI = [1.37-6,026], p = 0.0271, respectively). This is the first study that suggests sCRT as liquid biopsy marker for independent prediction of platinum resistance and prognosis.

Morphological and pathological features of basal-like breast cancer

Basal-like breast cancer (BLBC) is characterized by high grade, high mitotic indices, presence of central necrotic or fibrotic zones, and lymphocytic infiltrate. Patients presenting with BLBC have a poor prognosis and a short-term disease-free and overall survival. BLBCs may include different histological types of breast cancers but the most common histological type is represented by invasive ductal carcinomas of no special type (IDC-NST). Typical immunohistochemical markers for these tumors are basal-type cytokeratin markers such as CK5/6, CK14, CK17, but several BLBCs also express luminal-type CKs, such as CK8/18, CK19. Different molecular alterations, including BRCA1 dysfunction, p53 mutations, up-regulation of EGFR, inactivation of PTEN and the aberrant expression of many non-coding RNAs molecules are detected in BLBC cells suggesting the possibility of defining new targeted therapeutic strategies for this tumor type.

Solid papillary carcinoma with reverse polarity of the breast harbors specific morphologic, immunohistochemical and molecular profile in comparison with other benign or malignant papillary lesions of the breast: a comparative study of 9 additional cases

Solid papillary carcinoma with reverse polarity is a rare breast cancer of favorable prognosis that can be difficult to diagnose. We report here nine additional cases of this tumor, and we describe its morphologic, immunohistochemical and molecular profile in comparison to other types of papillary and micropapillary lesions of the breast that are intraductal papilloma with usual ductal hyperplasia, encapsulated papillary carcinoma, solid papillary carcinoma and invasive micropapillary carcinoma. We studied nine cases of this special papillary tumor and six of each other types mentioned above. We found that solid papillary carcinoma with reverse polarity harbor specific morphologic features as cuboid or tall cells with abundant eosinophilic cytoplasms located at the basal pole giving the impression of reverse nuclear polarity. Nuclei were sometimes grooved. Immunohistochemistry demonstrated the lack of myoepithelial cells, as in encapsulated papillary carcinoma and solid papillary carcinoma, questioning their invasive nature. Seven of nine solid papillary carcinoma with reverse polarity showed a low Ki67 proliferative index (Ki67 <5%). They showed expression of CK5/6 as in intraductal papilloma with usual ductal hyperplasia. They showed expression of calretinin and a low or lack of hormonal receptor (HR) expression that were not observed in other breast tumors studied. By whole-exome analysis, seven of nine solid papillary carcinomas with reverse polarity (78%) harbored a hotspot mutation in IDH2 (R172) that was totally absent in other groups. Six of nine tumors (67%) also harbored PRUNE2 mutation, including the two IDH2 wild-type cases. We also demonstrated for the first time in this breast tumor, immunostaining with a specific antibody IDH1/2 mutant R132/R172 (7/9) that can highlight IDH2 mutation. Moreover, transcriptomic analysis showed that proteoglycan pathway was significantly enriched. Our findings support the fact that solid papillary carcinoma with reverse polarity is a singular breast neoplasm that can be distinguished from other papillary breast tumors.

How to assess the best immunohistochemical panel in the diagnosis of malignant pleural mesothelioma in a pathology lab

BACKGROUND

malignant pleural mesothelioma (MPM) is a rare tumor with a challenging diagnosis. Even if, clinical data are mandatory to suspect the diagnosis, the positive diagnosis is based on microscopic features. Morphologic features are still the port of call of the diagnosis but their non specific character and the multiplicity of differential diagnoses made the immunohistochemical markers mandatory for the diagnosis. Many antibodies with a positive diagnostic value including claretinin, mesothelin, WT1 and antibodies with a negative diagnostic value including TTF1, EMA, CD15 are recommended by the scientific societies. This is due to the diagnostic limits of every antibody which necessitate the association of multiple antibodies. In the diagnostic demarch, pathologists deal with different antibodies and clones. Even if many recommendations are available, every pathology lab has to experiment its own antibodies in order to optimize the routine diagnostic demarch especially in low-income country. Our aim was to assess the diagnostic value of different antibodies available in our lab and to recommend a decisional flowchart.

PATIENTS AND METHODS

we conducted a retrospective study about 30 MPM diagnosed over a 20-year-period. The different techniques were realized manually. The different antibodies used were anti-calretinin, anti-Epithelial Membrane Antigen (EMA), anti-mesothelin, anti-Thyroid Transcription Factor 1 (TTF1), anti-ACE, anti-cytokeratin, anti-vimentin, anti-CD15, anti-cytokeratin 5/6, anti-bcl2, and anti-CD99 and anti-CD34 antibodies. The sensitivity and specificity of these antibodies were assessed.

RESULTS

the microscopic exam concluded to an epithelioid mesothelioma (EM) in 17 cases, sarcomatoid mesothelioma (SM) in four cases and biphasic mesothelioma (BM) in nine cases. The immunohistochemical study was performed in all cases. A mean of eight antibodies was used in every case, average 4 to 20 antibodies. The immunohistochemical study was repeated from 2 to 5 times in 15 cases and concerned a mean of 3 antibodies per case. In EM and BM, the antibodies with positive predictive value and highest sensitivity were calretinin, EMA, cytokeratin, and vimentin reaching respectively a sensitivity of 86.2%, 89.7%, 92.9% and 89.3%. The most valuable antibodies with negative predictive value were TTF1, CD15 and ACE that presented a specificity reaching respectively 100%. In sarcomatoid mesothelima, the most sensitive antibody was the cytokeratin antibody.

CONCLUSION

these results yielded to a diagnostic flowchart that we can use in routine practice and that is in accordance with the literature findings. Many diagnostic and technical pitfalls have to be known by pathologists when dealing with MPM.

Guidelines for Pathologic Diagnosis of Malignant Mesothelioma 2017 Update of the Consensus Statement From the International Mesothelioma Interest Group

CONTEXT

- Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.

OBJECTIVE

- To provide updated, practical guidelines for the pathologic diagnosis of MM.

DATA SOURCES

- Pathologists involved in the International Mesothelioma Interest Group and others with an interest and expertise in the field contributed to this update. Reference material included up-to-date, peer-reviewed publications and textbooks.

CONCLUSIONS

- There was discussion and consensus opinion regarding guidelines for (1) distinguishing benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) recognition of the key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiating epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid MM, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels employed is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Depending on the morphology, immunohistochemical panels should contain both positive and negative markers for mesothelial differentiation and for lesions considered in the differential diagnosis. Immunohistochemical markers should have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic and membranous markers). Selected molecular markers are now being used to distinguish benign from malignant mesothelial proliferations. These guidelines are meant to be a practical diagnostic reference for the pathologist; however, some new pathologic predictors of prognosis and response to therapy are also included.

Mesothelin Expression in Gastric Adenocarcinoma and Its Relation to Clinical Outcomes

Background

Although surgical resection with chemotherapy is considered effective for patients with advanced gastric cancer, it remains the third leading cause of cancer-related death in South Korea. Several studies have reported that mesothelial markers including mesothelin, calretinin, and Wilms tumor protein 1 (WT1) were positive in variable carcinomas, associated with prognosis, and were evaluated as potential markers for targeted therapy. The aim of this study was to assess the immunohistochemical expression of mesothelial markers (mesothelin, calretinin, and WT1) in gastric adenocarcinoma and their relations to clinocopathological features and prognosis.

Methods

We evaluated calretinin, WT1, and mesothelin expression by immunohistochemical staining in 117 gastric adenocarcinomas.

Results

Mesothelin was positively stained in 30 cases (25.6%). Mesothelin expression was related to increased depth of invasion (p = .002), lymph node metastasis (p = .013), and presence of lymphovascular (p = .015) and perineural invasion (p = .004). Patients with mesothelin expression had significantly worse disease-free survival rate compared with that of nonmesothelin expression group (p = .024). Univariate analysis showed that mesothelin expression is related to short-term survival. None of the 117 gastric adenocarcinomas stained for calretinin or WT1.

Conclusions

Mesothelin expression was associated with poor prognosis. Our results suggest that mesothelin-targeted therapy should be considered as an important therapeutic alternative for gastric adenocarcinoma patients with mesothelin expression.

Immunohistochemical characteristics of basal-like breast cancer

Basal-like breast cancer (BLBC) occurs mainly in young patients. It is characterized by an aggressive clinical outcome, presence of distant metastases, particularly within the first five years of the disease, bad prognosis and relatively high mortality. Recently greater interest of scientists in this subtype of breast cancer has been observed. Despite such many well-known potential biomarkers of BLBC, currently there is no official international panel of antigens dedicated to diagnosis of this subtype of breast cancer. The most commonly used set in this case contains four antibodies – estrogen receptor (ER), epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) and cytokeratins (CK) 5/6 – although it cannot provide one hundred percent detectability of these lesions. Incorporation of additional biomarkers into a panel can increase specificity, at the potential cost of sensitivity. Many biomarkers have been associated with the basal-like phenotype, and those with high sensitivity and/or specificity could improve the performance of immunohistochemical surrogate panels. Work on detection of the best of them is constantly being performed.

Aberrant Expression of Calretinin, D2-40 and Mesothelin in Mucinous and Non-Mucinous Colorectal Carcinomas and Relation to Clinicopathological Features and Prognosis

CRC is a heterogeneous disease in terms of morphology, invasive behavior, metastatic capacity, and clinical outcome. Recently, many so-called mesothelial markers, including calretinin, D2-40, WT1, thrombomodulin, mesothelin, and others, have been certified. The aim of this study was to assess the immunohistochemical expression of calretinin and other mesothelial markers (D2-40 and mesothelin) in colorectal mucinous adenocarcinoma (MA) and non mucinous adenocarcinoma (NMA) specimens and relation to clinicopathological features and prognosis using manual tissue microarray technique. We studied tumor tissue specimens from 150 patients with colorectal MA and NMA who underwent radical surgery from January 2007 to January 2012. High-density manual tissue microarrays were constructed using a modified mechanical pencil tip technique, and paraffin sections were submitted for immunohistochemistry using Calretinin, D2-40 and mesothelin expressions. We found that NMA showed significantly more calretinin and D2-40 expression than MA In contrast, no statistically significant difference between NMA and MA was detected in mesothelin expression. There were no statistically significant relations between any of the clinicopathological or histological parameters and any of the three markers. In a univariate analysis, neither calretinin nor D2-40 expressions showed any significant relations to DFS or OS. However, mesothelin luminal expression was significantly associated with worse DFS. Multivariate Cox regression analysis proved that luminal mesothelin expression was an independent negative prognostic factor in NMA. In conclusion, Calretinin, D2-40 and mesothelin are aberrantly expressed in a proportion of CRC cases with more expression in NMA than MA. Aberrant expression of these mesothelial markers was not associated with clinicopathological or histological features of CRCs. Only mesothelin expression appears to be a strong predictor of adverse prognosis.

Clinicopathologic features of breast carcinomas classified by biomarkers and correlation with microvessel density and VEGF expression: a study from Thailand

BACKGROUND

To correlate breast cancer subtypes with prognostic factors, microvessel density (MVD), vascular endothelial growth factor (VEGF) expression and clinical features.

MATERIALS AND METHODS

One hundred cases of primary breast carcinoma were classified using biomarkers on tissue microarray as: luminal A [estrogen receptor (ER) +, HER2-, Ki-67≤14%], luminal B [ER+, HER2+ or ER+, HER2-, Ki-67>14%], HER2, triple negative basal-like (TNB) [any basal cytokeratins (CKs, 5, 14, 17) and/or endothelial growth factor receptor (EGFR) expression], and TN without such markers [TNN, null], and assessed for p53, vimentin, VEGF and CD31 immunoperoxidase.

RESULTS

Of the 100 cases (mean age, 51 years; mean tumor size, 3.2cm; 56% with nodal metastasis; 89 invasive ductal carcinomas, not otherwise specified, 4 invasive lobular carcinomas, 3 metaplastic carcinomas, and 4 other types) there were 39 luminal A, 18 luminal B, 18 HER2, 15 TNB and 10 TNN. The positivities of basal-like markers in the basal-like subtype were 78.3% for CK5, 40% for CK14, 20% for CK17, 46.7% for EGFR. There was no significant difference in age distribution, tumor size, degree of tubular formation, pleomorphism, lymphovascular invasion, nodal metastasis, MVD, VEGF expression and survival among subgroups. TNs demonstrated significantly higher tumor grade, mitotic count, Ki-67 index, p53 and vimentin and decreased overall survival compared with nonTN.

CONCLUSIONS

The distribution of breast cancer subtypes in this study was similar to other Asian countries with a high prevalence of TN. The high grade character of TN was confirmed and CK5 expression was found to be common in our basal-like subtype. No significant elevation of MVD or VEGF expression was apparent.

Metaplastic carcinoma of the breast: an immunohistochemical study

Background

Metaplastic breast carcinoma is a rare entity of breast cancer expressing epithelial and/or mesenchymal tissue within the same tumor. The aim of this study is to evaluate the clinicopathological features of metaplastic breast carcinoma and to confirm the triple negative, basal-like and/or luminal phenotype of this type of tumor by using immunohistochemical staining.

Methods

Seven cases of MBC were evaluated for clinico-pathological features including follow up data. Cases were studied immunohistochemically by CK-Pan, Vimentin, ER, PR, HER2, basal markers (CK5/6, p63, EGFR, SMA and S-100), luminal cytokeratins (CK8, CK18 and CK19), markers for syncytial cells (β-HCG and PLAP), as well as prognostic markers (p53, ki-67 and calretinin).

Results

The mean age of the patients was 36 years. Three cases showed choriocarcinomatous features. All of our cases were negative for ER, PR and HER2. Six out of the 7 cases showed basal-like differentiation by demonstrating positivity with at least one of the basal/myoepithelial markers. Also 6 out of the 7 cases expressed luminal type cytokeratins (CK8, CK18 and/or CK19). P53 was positive in 3 cases, ki-67 was strongly expressed in only one case, while calretinin was expressed in 6 cases.

Conclusion

Metaplastic breast carcinoma presents in our population at a younger age group than other international studies. All cases are categorized immunohistochemically under the triple negative group of breast cancer and 86% of them exhibited basal-like and luminal phenotype. Majority of cases developed local recurrence and distant metastasis in a relatively short period of time.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1101289295115804