Breast-specific expression of MGB1/mammaglobin: an examination of 480 tumors from various organs and clinicopathological analysis of MGB1-positive breast cancers

Immunohistochemical Characterization of a Large Cohort of Triple Negative Breast Cancer

Introduction. Triple negative breast carcinomas are characterized by a lack of hormone receptor and HER2 expression and inconsistent expression of breast-specific immunohistochemical markers. The expression of many site-specific markers in these tumors is largely unknown. The objective of the study was to examine the expression of widely used immunohistochemical markers on a large cohort of triple negative breast cancer. Methods. Sections from tissue microarrays were stained with 47 markers using routine protocols. Most markers were scored using a modified Allred method. ATRX, BAP1, SMAD4, e-cadherin, and beta-catenin were scored as retained or lost. Mammaglobin was considered positive if there was at least moderate intensity staining in any tumor cells. P16 was scored as overexpressed or not overexpressed; p53 was scored as wildtype, overexpressed, null, or cytoplasmic. Results. The cohort consisted of 639 tumors including 601 primary and 32 metastases. Overall, 96% expressed GATA3, mammaglobin, and/or SOX10 while 97% of no special type tumors expressed this panel. Carcinoma of apocrine differentiation demonstrated an AR positive, SOX10 negative, K5 negative/focal immunophenotype. PAX8 (SP348), WT1, Napsin A, and TTF1 (8G7G3/1) were never or rarely expressed while CA9, CDX2, NKX3.1, SATB2 (SATBA410), synaptophysin, and vimentin were variably expressed. Conclusions. Almost all TNBC express at least 1 of the 3 IHC markers: GATA3, mammaglobin, and/or SOX10. Carcinoma of apocrine differentiation is characterized by an AR positive, SOX10 negative, K5 negative or focal immunophenotype. Cautious interpretation of so-called site-specific markers, with knowledge of antibody clones, is required in excluding the diagnosis of triple negative breast cancer.

Clinicopathological analysis of 18 cases of secretory carcinoma of the salivary glands

Background/purpose

Secretory carcinoma (SC) is a rare salivary gland tumor that featured by ETV6::NTRK3 gene fusion, and was included in the WHO Classification of Head and Neck Tumors since 2017. Nevertheless, the description of SCs by WHO is still vague. This study examined 18 SC cases by using both histomorphology and molecular pathology for diagnostic determination, especially immunohistochemical features of SCs.

Materials and methods

Based on WHO characteristics, 18 patients with SC admitted between 2001 and 2022 were included in this study. Main histomorphological patterns, FISH analyses of the ETV6::NTRK3 gene fusion, and immunohistochemical analyses of S100, mammaglobin, DOG1, ADFP, CA6 and Ki-67 were performed.

Results

Among the 18 SC patients, the median age of onset was 39.22 years. Grossly, the average tumor size in 2.96 cm with various texture from soft to tough. The majority patients were positive for S100, mammaglobin, and negative for DOG1, except for one patient negative for S100 (Case 18). All patients were positive for ADFP, and the majority patients were negative for CA6, except for Case 9. Two cases were found recurrence, and the tumor were found both in parotid gland with local invasion.

Conclusion

Combined with the results of previous studies, we proposed that the combination of all five markers, S100, mammaglobin, DOG1, ADFP and CA6, could contribute more to differential diagnosis of SCs with other salivary carcinomas, especially with AciCC. The prognosis of SCs is optimistic in most cases, but larger patient cohort and long-term follow-up are still needed.

TRPS1, a New Promising Marker for Assessment of Distant Metastatic Breast Cancer

This article reviewed the identification of breast cancer in the distant metastatic setting through traditional immunohistochemical markers, such as mammaglobin and GATA3, compared with the novel immunohistochemical stain, Trichorhinophalangeal syndrome-1 (TRPS1). We review previous studies evaluating TRPS1 staining, which were conducted using cytology specimens, as well as our recently conducted study evaluating this stain using surgical tissue samples, both from primary and distant metastatic invasive breast carcinoma. In summary, although no immunohistochemical stain is 100% specific or sensitive, in the metastatic setting where tissue available for ancillary studies is limited, TRPS1 was a reliable and even a standalone marker for breast origin, particularly in cases of triple-negative breast cancer.

Breast cancer vaccination: Latest advances with an analytical focus on clinical trials

Breast cancer (BC) is one of the main causes of cancer-related death worldwide. The heterogenicity of breast tumors and the presence of tumor resistance, metastasis, and disease recurrence make BC a challenging malignancy. A new age in cancer treatment is being ushered in by the enormous success of cancer immunotherapy, and therapeutic cancer vaccination is one such area of research. Nevertheless, it has been shown that the application of cancer vaccines in BC as monotherapy could not induce satisfying anti-tumor immunity. Indeed, the application of various vaccine platforms as well as combination therapies like immunotherapy could influence the clinical benefits of BC treatment. We analyzed the clinical trials of BC vaccination and revealed that the majority of trials were in phase I and II meaning that the BC vaccine studies lack favorable outcomes or they need more development. Furthermore, peptide- and cell-based vaccines are the major platforms utilized in clinical trials according to our analysis. Besides, some studies showed satisfying outcomes regarding carbohydrate-based vaccines in BC treatment. Recent advancements in therapeutic vaccines for breast cancer were promising strategies that could be accessible in the near future.

Immunohistochemistry in the Diagnosis and Classification of Breast Tumors

CONTEXT.—

In the clinical practice of breast pathology, immunohistochemistry (IHC) of different markers is widely used for the diagnosis and classification of breast lesions.

OBJECTIVE.—

To provide an overview of currently used and recently identified IHC stains that have been implemented in the field of diagnostic breast pathology.

DATA SOURCES.—

Data were obtained from literature review and clinical experience of the authors as breast pathologists.

CONCLUSIONS.—

In the current review, we summarize the common uses of IHC stains for diagnosing different types of breast lesions, especially invasive and noninvasive breast lesions, and benign and malignant spindle cell lesions. In addition, the cutting-edge knowledge of diagnostic carcinoma markers will lead us to further understand the different types of breast carcinoma and differentiate breast carcinomas from other carcinomas of similar morphology. Knowing the strengths and limitations of these markers is essential to the clinical practice of breast pathology.

Utility of Wnt family member 9b (Wnt9b) immunohistochemistry in the cytologic diagnosis of metastatic breast carcinoma

Wnt family member 9b (Wnt9b) has been demonstrated as a valuable marker for breast cancer diagnosis in surgical pathology. In this study, we examined the utility of Wnt9b in diagnosing metastatic breast carcinoma in cytology samples. Cell blocks from fine needle aspirations (FNA) and fluid specimens of 96 metastatic breast carcinomas and 123 primary and metastatic non-breast neoplasms from various organ systems were evaluated by Wnt9b and GATA3 immunohistochemistry (IHC). Wnt9b and GATA3 were positive in 81.3% and 92.7% of metastatic breast carcinomas, respectively. Conversely, 93.5% and 90.0% of non-breast, non-urothelial carcinomas were negative for Wnt9b and GATA3, respectively. Wnt9b expression was positive in rare gastrointestinal, gynecological, lung, pancreas, and salivary gland tumors. All twenty-eight urothelial carcinomas were negative for Wnt9b, while twenty-six (92.9%) were positive for GATA3. Wnt9b was slightly less sensitive but more specific than GATA3 in diagnosing metastatic breast cancer in cytology samples. Particularly, Wnt9b shows higher specificity in differentiating breast and urothelial primaries. The combined use of Wnt9b and GATA3 may increase diagnostic accuracy.

[Breast-like cancer of unknow primary : Implications for radiological diagnostics]

BACKGROUND

Cancer of unknown primary (CUP) is defined by the presence of metastatic disease with an undetectable primary tumor at the time of presentation despite standard-of-care imaging. Although the prognosis of most CUP patients is poor, certain subgroups with more favorable prognosis have been defined.

DIAGNOSTICS

Women with isolated axillary lymph node metastases and confirmed histologic adenocarcinoma or poorly differentiated subtype, no other distant metastases, and no evidence of a primary cancer including primary breast carcinoma evaluated by clinical examination, computed tomography of thorax and abdomen, mammography, breast ultrasound, and breast magnetic resonance imaging (MRI) represent a potentially curable subgroup of patients with CUP. Breast MRI is the most important radiological modality in the diagnostic workup of breast-like CUP to exclude a primary cancer in the breast.

THERAPY

Breast-like CUP patients are treated according to guidelines for patients with node-positive breast cancer. Standard-of-care adjuvant systemic therapy should be given. Axillary lymph node dissection (ALND) is indicated. If no primary cancer in the breast is detected, surgery of the ipsilateral breast should not be performed. Radiotherapy of the ipsilateral breast and supra-/infraclavicular lymph nodes should be discussed.

Mammaglobin-A Expression Is Highly Specific for Tumors Derived from the Breast, the Female Genital Tract, and the Salivary Gland

Human mammaglobin-A (SCGB2A2) is a secretory protein with an unknown function that is used as a diagnostic marker for breast cancer. However, other tumors can also express mammaglobin-A. To comprehensively study patterns of mammaglobin-A expression, a tissue microarray containing 16,328 samples from 128 different tumor types as well as 608 samples of 76 different normal tissue types was analyzed using immunohistochemistry. Mammaglobin-A positivity was found in only a few normal tissues, including luminal cells of the breast as well as endocervical and endometrial glands. In tumor tissues, 37 of 128 tumor categories showed mamma-globin-A staining, 32 of which were derived from one of four organs: breast (6 tumor categories), endometrium (5 tumor categories), ovary (5 tumor categories), and salivary glands (16 tumor categories). Only five additional tumor types showed occasional weak mammaglobin positivity, including medullary thyroid cancer, teratoma of the testis, squamous cell carcinoma of the skin and pharynx, and prostatic adenocarcinoma. Among 1139 evaluable invasive breast carcinomas of no special type, low mammaglobin-A immunostaining was linked to high BRE grade (p = 0.0011), loss of estrogen and progesterone receptor expression (p < 0.0001 each), and triple-negative status (p < 0.0001) but not to patient survival. In endometrial cancer, mammaglobin-A loss was linked to an advanced tumor stage (p = 0.0198). Our data characterize mammaglobin-A as a highly specific marker for tumors derived from either the breast, female genitals, or salivary gland.

Comparison of GATA3, GCDFP15, Mammaglobin and SOX10 Immunocytochemistry in Aspirates of Metastatic Breast Cancer

Introduction: Metastatic cancers are frequently detected on fine-needle aspiration (FNA) cytology, and confirmation of metastatic breast cancer often requires immunocytochemistry. Tissue provisioning for FNA specimens is important. In this study, GATA3, gross cystic disease fluid protein-15 (GCDFP15), mammaglobin (MMG), and SOX10 were performed on cell block preparations from aspirates of histologically confirmed metastatic breast cancers. The diagnostic performance of single markers and combinations of these markers were investigated with the aim to construct a tissue-efficient immunopanel. Methodology: Aspirates of metastatic breast cancer with corresponding histology and biomarker (estrogen receptor (ER), progesterone receptor (PR), HER2 and ki67) profile were retrieved. ER, GATA3, GCDFP15, MMG and SOX10 immunostains were performed on cell block sections and their expressions were assessed and compared. Results: Immunostaining was performed on a total of 115 aspirates. GATA3 showed the highest expression, followed by MMG, GCDFP15 and SOX10. Twenty-three, five and five cases expressed GATA3, MMG and SOX10 only. The five cases expressing SOX10 only were ER negative, and SOX10 expression was negatively associated with ER (p = 0.001), MMG (p = 0.001), GCDFP15 (p = 0.010) and GATA3 (p = 0.002), whereas GATA3 expression showed positive correlation with ER positivity (p < 0.001). MMG and GCDFP15 showed association with high Ki67 (p < 0.05), and no correlations were found with HER2 expression. Conclusion: In this cohort, GATA3 was the most sensitive single marker. The addition of MMG and SOX10 increases the sensitivity for detection of ER positive and ER negative breast cancers, respectively. These findings support the use of a combination of GATA3/MMG/SOX10 for confirmation of metastatic breast cancer.

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.

Breast Cancer Vaccines: Disappointing or Promising?

Breast cancer has become the most commonly diagnosed cancer globally. The relapse and metastasis of breast cancer remain a great challenge despite advances in chemotherapy, endocrine therapy, and HER2 targeted therapy in the past decades. Innovative therapeutic strategies are still critically in need. Cancer vaccine is an attractive option as it aims to induce a durable immunologic response to eradicate tumor cells. Different types of breast cancer vaccines have been evaluated in clinical trials, but none has led to significant benefits. Despite the disappointing results at present, new promise from the latest study indicates the possibility of applying vaccines in combination with anti-HER2 monoclonal antibodies or immune checkpoint blockade. This review summarizes the principles and mechanisms underlying breast cancer vaccines, recapitulates the type and administration routes of vaccine, reviews the current results of relevant clinical trials, and addresses the potential reasons for the setbacks and future directions to explore.

Wnt Family Member 9b (Wnt9b) Is a New Sensitive and Specific Marker for Breast Cancer

Confirming the tumor origin is often a diagnostic challenge in pathology and carries significant therapeutic impacts. Cytokeratin 7, estrogen receptor, and GATA binding protein 3 (GATA3) are well-established diagnostic markers frequently used to support a tumor's breast origin. However, their specificities still have room to improve. Many nonbreast tumors express cytokeratin 7 and estrogen receptor, and urothelial tumors frequently express GATA3. There is a practical need for a new breast lineage marker that is sensitive and specific. Wnt family member proteins play critical roles in embryo development, tissue homeostasis and tumor development through β-catenin dependent and independent pathways. The current study evaluated Wnt9b and GATA3 expression in 163 primary breast cancers, 63 metastatic breast cancers, and 525 nonbreast epithelial tumors. The positive rates of Wnt9b and GATA3 in primary breast cancer were both 98.7%. The positive rates in metastatic breast cancer were 87.3% for Wnt9b and 96.8% for GATA3. For nonbreast tumors, including 64 cases of urothelial carcinoma, Wnt9b was negative in all except salivary gland carcinomas. The study demonstrated that Wnt9b is a breast cancer marker with similar sensitivity as GATA3 but with greater specificity than GATA3 and may ultimately become a useful diagnostic tool in routine surgical pathology practice.

Mammaglobin protein localization and gene expression in the salivary glands

PURPOSE

This study aims to delve deeper into the hypothesis that normal salivary gland tissue expresses both protein and mRNA of mammaglobin (MGB).

METHODS

Formalin-fixed paraffin-embedded samples of submandibular (10), parotid (5), palatal (5) and labial glands (30) salivary glands were immunohistochemically investigated. The labial samples were used to examine the MGB positive ratio (MGB-PR), and localize MGB by double immunofluorescence staining and quantitative mRNA gene expression. Mann-Whitney U and Kruskal Wallis rank-sum test for group comparison, and Spearman's rank correlation coefficient for correlation analysis were used.

RESULTS

The distribution of MGB-positive cells was variable throughout samples with significantly higher MGB-PR of acini than ducts (P = 0.00376), and there was no difference when compared based on age (P = 0.0646) and gender (P = 0.245). Besides acinar cells, a number of myoepithelial cells and ductal cells also demonstrated strong MGB reactivity with varying MGB mRNA expression levels in 6 of the 7 samples (with MGB-PR > 20%) tested.

CONCLUSION

This novel study shows that unlike aberrant protein expression in some carcinomas, MGB expression in salivary gland neoplasms represents the nature of original cells, giving a better insight into the neoplasms expressing MGB.

Immunohistochemically detectable thyroglobulin expression in extrathyroidal cancer is 100% specific for thyroidal tumor origin

Thyroglobulin is a secreted 660 kDa glycoprotein produced by thyroid follicular cells used in diagnostic pathology to secure or exclude a thyroidal origin of metastases of unknown primary tumors. This study was performed to estimate specificity of thyroglobulin immunohistochemistry. 9974 tumor samples from 109 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Thyroglobulin was strongly expressed in all normal thyroid samples but not in any other normal tissues. Thyroglobulin immunostaining was detected in 99.1% of 106 thyroid adenomas, 98.1% of 364 papillary, 95.2% of 147 follicular, and 7.5% of 40 anaplastic thyroid cancers. Twelve of 15 thyroid samples that were thyroglobulin negative on TMAs showed at least a weak focal thyroglobulin positivity in corresponding large sections, suggesting higher sensitivity of large section analysis. Thyroglobulin positivity in one diffuse large B-cell lymphoma of the thyroid, one chondrosarcoma metastasis to the thyroid, and 42.4% of 92 medullary thyroid cancers was considered to be caused by diffusion of thyroidal colloid from destroyed or even intact adjacent follicles. Thyroglobulin positivity was, however, not seen in 6403 extrathyroidal tumors from 104 different tumor types and subtypes. Our data demonstrate a complete specificity of positive thyroglobulin immunostaining for thyroid origin in tumor tissues obtained from extrathyroidal locations. However, for all tumors located within the thyroid, false positivity can occur as a result of tissue contamination by thyroglobulin rich thyroid colloid from adjacent normal tissue.

SOX10, GATA3, GCDFP15, Androgen Receptor, and Mammaglobin for the Differential Diagnosis Between Triple-negative Breast Cancer and TTF1-negative Lung Adenocarcinoma

Triple-negative breast cancer (TNBC) patients have an increased risk of developing visceral metastases and other primary nonbreast cancers, particularly lung cancer. The differential diagnosis of TNBC metastases and primary cancers from other organs can be difficult due to lack of a TNBC standard immunoprofile. We analyzed the diagnostic value of estrogen receptor, progesterone receptor, human epidermal growth factor receptor, thyroid transcription factor-1 (TTF1), Napsin A, mammaglobin, gross cystic disease fluid protein 15 (GCDFP15), Sry-related HMg-Box gene 10 (SOX10), GATA-binding protein 3 (GATA3), and androgen receptor in a series of 207 TNBC and 152 primary lung adenocarcinomas (LA). All tested TNBCs were TTF1 and Napsin A-negative. When comparing TNBC and TTF1-positive or negative LA, SOX10 had the best sensitivity (62.3%) and specificity (100%) as a marker in favor of TNBC compared with LA, irrespective of TTF1 status (P<0.0001). GATA3 had moderate sensitivity (30.4%) and excellent specificity (98.7%) and misclassified only 2/152 LA (1.3%). GCDFP15 had a moderate sensitivity (20.8%) and excellent specificity (98%) and misclassified only 3/152 (2%) LA. Mammaglobin and androgen receptor had moderate sensitivities (38.2% and 30%), good specificities (81.6% and 86%), and misclassified 28/152 and 21/152 LAs, respectively. In multivariate analysis, the best markers, enabling the distinction between SOX10-negative TNBC and TTF1 and Napsin A-negative LA were GATA3 (odds ratio=33.5; 95% confidence interval, 7.3-153.5; P<0.0001) and GCDFP15 (odds ratio=31.7; 95% confidence interval, 6.9-145.6; P<0.0001). Only 13/207 (6.3%) TNBC cases did not express any aforementioned marker. On the basis of our results, the best sequential immunohistochemical analysis to differentiate TNBC from TTF1-negative LA is first SOX10 followed by GATA3, and finally GCDFP15. This order is important in the diagnostic workup of small biopsies from lung nodules in women with a previous history of TNBC.

Immunotherapy in HER2-positive breast cancer: state of the art and future perspectives

Breast cancer (BC) is a complex disease with primary or acquired incurability characteristics in a significant part of patients. Immunotherapeutical agents represent an emerging option for breast cancer treatment, including the human epidermal growth factor 2 positive (HER2+) subtype. The immune system holds the ability to spontaneously implement a defensive response against HER2+ BC cells through complex mechanisms which can be exploited to modulate this response for obtaining a clinical benefit. Initial immune system modulating strategies consisted mostly in vaccine therapies, which are still being investigated and improved. However, the entrance of trastuzumab into the scenery of HER2+ BC treatment was the real game changing event, which embodied a dominant immune-mediated mechanism. More recently, the advent of the immune checkpoint inhibitors has caused a new paradigm shift for immuno-oncology, with promising initial results also for HER2+ BC. Breast cancer has been traditionally considered poorly immunogenic, being characterized by relatively low tumor mutation burden (TMB). Nevertheless, recent evidence has revealed high tumor infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PD-L1) expression in a considerable proportion of HER2+ BC patients. This may translate into a higher potential to elicit anti-cancer response and, therefore, wider possibilities for the use and implementation of immunotherapy in this subset of BC patients. We are herein presenting and critically discussing the most representative evidence concerning immunotherapy in HER2+ BC cancer, both singularly and in combination with therapeutic agents acting throughout HER2-block, immune checkpoint inhibition and anti-cancer vaccines. The reader will be also provided with hints concerning potential future projection of the most promising immutherapeutic agents and approaches for the disease of interest.

Immunohistochemistry for diagnosis and prognosis of breast cancer: a review

Breast cancer is the most prevalent malignant tumor and main oncologic cause of mortality in women. Although most diagnosis of breast pathology is accomplished using hematoxylin and eosin stained sections, some cases require immunohistochemistry for proper evaluation. We investigated the latter cases including distinctions between ductal and lobular carcinoma, in situ and invasive carcinoma, typical ductal hyperplasia and atypical ductal hyperplasia/ductal carcinoma in situ, papillary and spindle cell lesion assessment, metastasis evaluation, and assessment of prognostic and therapy markers. E-cadherin is used to differentiate ductal and lobular carcinoma; 34βE12, CK8, p120 catenin and β-catenin also produce consistent results. Myoepithelial cell (MEC) stains are used to evaluate in situ and invasive carcinoma; calponin, smooth muscle myosin heavy chain and p63 are sensitive/specific markers. 34βE12 and CK5/6 are positive in ductal hyperplasia, which enables its differentiation from atypical ductal hyperplasia and ductal carcinoma in situ. CK 5/6, ER and MEC markers are consistent options for evaluating papillary lesions. Spindle cell lesions can be assessed using β-catenin, SMA, CD34, p63, CKs and hormone receptors. It is important to differentiate primary carcinomas from metastases; the most commonly used markers to identify breast origin include mammaglobin, GCDFP-15, GATA3 and ER, although none of these is completely sensitive or specific. Immunohistochemistry can be used to evaluate central prognostic and predictive factors including molecular subtypes, HER2, hormone receptors, proliferation markers (Ki-67) and lymph-vascular invasion markers including ERG, CD31, CD34, factor VIII and podoplanin. Owing to the complexity of mammary lesions, diagnosis also depends on each particular situation, evaluation of cytological characteristics revealed by immunochemistry and correlation with histological findings.

Immunohistochemical expression of mammaglobin in salivary duct carcinomas de novo and salivary duct carcinoma ex pleomorphic adenoma

Mammaglobin is expressed in breast and salivary gland secretory carcinomas; however, its expression in salivary duct carcinomas (SDCs) still not well established. Therefore, the aim of this study was to investigate the presence and distribution of mammaglobin immunoexpression in SDC ex-PA in different phases of the adenoma to carcinoma sequence evaluating its possible involvement in carcinogenesis and tumor progression, as well as to determine its expression in SDC de novo. Mammaglobin immunohistochemistry was performed in 84 SG tumors, including 41 pleomorphic adenomas (PA) without malignant transformation, 13 intracapsular SDC ex-PA, 5 frankly invasive SDC ex-PA, 25 SDC de novo and 10 secretory carcinomas. The reactions were qualitatively analyzed and digitally scored. Positive immunostaining for mammaglobin was observed in 37 out of 84 SG tumors evaluated (44.1%), but strong staining was consistently seen only in secretory carcinomas, SDC de novo and frankly invasive SDC ex-PA, while it was weaker in intracapsular SDC ex-PA and PA. In PA, mammaglobin expression was significantly associated with recurrence. This study has confirmed that the mammaglobin is commonly expressed in SDC de novo and secretory carcinomas. Its expression was higher in SDC ex-PA than in PA, suggesting that mammaglobin may play a role in its malignant transformation.

Gene Expression Profiling for Diagnosis of Triple-Negative Breast Cancer: A Multicenter, Retrospective Cohort Study

Background: Triple-negative breast cancer (TNBC) accounts for 12–20% of all breast cancers. Diagnosis of TNBC is sometimes quite difficult based on morphological assessment and immunohistochemistry alone, particularly in the metastatic setting with no prior history of breast cancer.

Methods: Molecular profiling is a promising diagnostic approach that has the potential to provide an objective classification of metastatic tumors with unknown primary. In this study, performance of a novel 90-gene expression signature for determination of the site of tumor origin was evaluated in 115 TNBC samples. For each specimen, expression profiles of the 90 tumor-specific genes were analyzed, and similarity scores were obtained for each of the 21 tumor types on the test panel. Predicted tumor type was compared to the reference diagnosis to calculate accuracy. Furthermore, rank product analysis was performed to identify genes that were differentially expressed between TNBC and other tumor types.

Results: Analysis of the 90-gene expression signature resulted in an overall 97.4% (112/115, 95% CI: 0.92–0.99) agreement with the reference diagnosis. Among all specimens, the signature correctly classified 97.6% of TNBC from the primary site (41/42) and lymph node metastasis (41/42) and 96.8% of distant metastatic tumors (30/31). Furthermore, a list of genes, including AZGP1, KRT19, and PIGR, was identified as differentially expressed between TNBC and other tumor types, suggesting their potential use as discriminatory markers.

Conclusion: Our results demonstrate excellent performance of a 90-gene expression signature for identification of tumor origin in a cohort of both primary and metastatic TNBC samples. These findings show promise for use of this novel molecular assay to aid in differential diagnosis of TNBC, particularly in the metastatic setting.

Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer

Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.

Prognostic role of plasma mammaglobin A expression in breast carcinoma patients: a meta-analysis

Mammaglobin A expression in peripheral blood (PB) of breast carcinoma patients has been evaluated by various studies, but the findings have been inconsistent. This meta-analysis aimed to clarify the prognostic value of mammaglobin A in the PB of breast carcinoma patients and define its relationships with clinicopathological features. PubMed, EMBASE, and the Cochrane Library databases were systematically searched for eligible studies through September 26, 2017. A total of 20 studies involving 2,323 patients were analyzed, and the data were independently extracted by two researchers. The combined hazard ratios (HRs) with 95% CI was used to assess the association between survival data and plasma mammaglobin A expression, and odds ratios (ORs) and 95% CIs were used to assess the associations between clinicopathological parameters and plasma mammaglobin A expression. The results indicated that plasma mammaglobin A expression was a predictor of poor prognosis for breast carcinoma patients, with an HR of 2.08 (95% CI=1.48–2.91; P<0.0001) for overall survival. Moreover, plasma mammaglobin A was significantly associated with lymph node metastasis (OR=2.00; 95% CI=1.17–3.45; P=0.01) and advanced tumor stage (OR=3.01; 95% CI=1.57–5.77; P=0.0009) in breast carcinoma patients. However, the results revealed that plasma mammaglobin A was not significantly associated with tumor size (OR=1.29; 95% CI=0.46–3.66; P=0.63), tumor differentiation (OR=0.99; 95% CI=0.63–1.57; P=0.97), menopausal status (OR=0.75; 95% CI=0.48–1.18; P=0.22), estrogen receptor status (OR=0.78; 95% CI=0.44–1.36; P=0.38), progesterone receptor status (OR=0.76; 95% CI=0.57–1.02; P=0.07), or human epidermal growth factor receptor 2 status (OR=1.12; 95% CI=0.78–1.59; P=0.54). In conclusion, the results demonstrate that positive plasma mammaglobin A expression might serve as a biomarker of poor prognosis for breast carcinoma patients.

The screening and electron microscopy observation of mammary analogue secretory carcinoma in Chinese

Mammary analogue secretory carcinoma of salivary gland (MASC) is a tumor with histopathologic and immunophenotypic features mimicking secretory carcinoma of the breast harboring the ETV6 split. The expression of mammaglobin, S-100, Ki-67, P63 and ETV6 split were detected in twelve cases of acinar cell carcinoma and fourteen cases of mammary analogue secretory carcinoma of salivary gland by immunohistochemistry and fluorescence in situ hybridization respectively. The expression of ETV6 gene split was detected in fourteen mammary analogue secretory carcinomas of salivary gland with positive expression of mammaglobin. Eight of mammary analogue secretory carcinomas of salivary gland also tested positive for the ETV6 gene split via fluorescence in-situ hybridization (FISH). The concordance rate of the immunohistochemistry and FISH was 72.3%. Mammaglobin and ETV6 gene split detection could help to distinguish mammary analogue secretory carcinoma of salivary gland. The mammary analogue secretory carcinoma of salivary gland specimens were also examined under transmission electron microscope. And apical junctional complexes were observed in the loosely connected tumor cells.

Gata3 Immunohistochemical Staining is A Useful Marker for Metastatic Breast Carcinoma in Fine Needle Aspiration Specimens

Aims

The utility of GATA3 immunohistochemistry (IHC) as an aid to the cytological diagnosis of metastatic breast carcinoma in fine needle aspiration (FNA) specimens was investigated.

Materials and Methods

Cell block sections from 111 FNA cases of metastatic malignancy were stained for GATA3, including metastases from 43 breast and 44 nonmammary adenocarcinomas, 19 melanomas, 4 urothelial carcinomas, and 1 thyroid medullary carcinoma. Sites sampled included lymph nodes (87), bone (8), liver (5), lung (6), superficial masses (4), and pelvic mass (1).

Results

Ninety-one percent (39/43) of metastatic breast carcinoma cases were positive for GATA3. All estrogen receptor (ER)-positive were also GATA3 positive cases. The majority (9/14; 64%) of ER-negative and 37% (3/8) of triple-negative cases were positive for GATA3. All nonmammary adenocarcinoma cases were negative with the exception of one case of metastatic pancreatic adenocarcinoma. Metastatic melanoma cases were all negative but 75% (3/4) urothelial carcinomas expressed GATA3.

Conclusions

GATA3 IHC staining is a useful addition to IHC panels for FNA samples in specific settings such as distinguishing metastatic breast from lung carcinoma or melanoma.

Immunohistochemical Analysis of the Expression of Breast Markers in Basal-like Breast Carcinomas Defined as Triple Negative Cancers Expressing Keratin 5

Estrogen and progesterone receptors are possible markers for suggesting a mammary origin of metastatic carcinoma, but are useless in cases of triple negative breast cancers (TNBC). Five other potential markers of breast origin were investigated on tissue microarrays in a series of TNBCs showing keratin 5 expression, consistent with a basal-like phenotype. GATA-3 staining was observed in 82 of 115 triple negative cases (71.3%) including 23 cases with >5% staining. Mammaglobin staining was detected in 30 cases (26.0%) including 12 with >5% staining. GCDFP-15 was seen in 23 cases (20.0%) including 9 with >5% staining. NY-BR-1 positivity was present in 7 cases (6.0%) including 3 patients with >5% staining. BCA-225 staining was observed in 74 cases (64.3%); however this latter marker lacks also specificity owing to the reported widespread staining in other malignancies. GATA-3, mammaglobin and GCDFP-15 coexpression was seen in one case (0.9%), whereas GATA-3 and mammaglobin or mammaglobin and GCDFP-15 coexpression was present in 2 and 2 cases (1.7%), respectively. Using at least 5% staining as cut-off, the expression of any of the last 4 markers was 34.7%. The expression of GATA-3, mammaglobin, GCDFP-15 and NY-BR-1 is lower in TNBC-s than in breast carcinomas in general, and this may be even lower in basal-like carcinomas. Although these markers are not fully specific, by using them, a subset of basal-like TNBC-s can be identified as of mammary origin. However, a substantial proportion will not show any staining with any of these markers.

Immunohistochemistry, carcinomas of unknown primary, and incidence rates

Pathologists use immunohistochemistry is their day-to-day practices to assist in distinguishing site of origin of metastatic carcinomas. Here, the work-up is discussed neuroendocrine carcinomas, squamous cell carcinomas and adenocarcinomas with particular attention to tumor incident rates and predictive values of the best-performing immunohistochemical markers.

Efficient and simple approach to in vitro culture of primary epithelial cancer cells

Primary breast and prostate epithelial cancer cells may be efficiently cultured in vitro using simple and easily validatable approach–plates coated with a mixture of extracellular matrix components and tissue-specific primary cell medium.

Primary cancer cells constitute a favourable testing platform for in vitro research in oncology field as they reflect tumour state more accurately than the most commonly employed stable cell lines. Unfortunately, due to limited availability of material and difficulties with protocols validation, primary models are rarely implemented into laboratory practice.

We have compared protocols for primary cultures, differing in media components and plate coatings. In terms of culture establishment, application of Geltrex® coating demonstrated equal efficiency to feeder layer (83% compared with 72% successfully established breast and 80% compared with 80% prostate tumour specimens), yet it was substantially less complicated and easier to validate. Both Geltrex® coating and tissue-specific primary cell medium were permanently required to successfully maintain primary epithelial prostate cancer cells (PEPCs) in culture. In case of primary epithelial breast cancer cells (PEBCs), collagen I coating enabled to obtain comparable number of passages to Geltrex® coating (P=0.438). Commercial primary cell media demonstrated lower efficiency than tissue-specific ones (PEPCs–5 compared with 8 and PEBCs–6 compared with 9 passages). Interestingly, both analysed tumour types were unsusceptible to induction of culture lifespan extension when transduced with SV40LT, BMI-1 or hEST2 genes, commonly applied as potential immortalizing agents.

In conclusion, the approach based on extracellular matrix reconstitution and tissue-specific primary cell media is easy to validate and provides in vitro expansion sufficient for analytical purposes (approximately 8 passages). Therefore, it may facilitate implementation of hardly available experimental models for a variety of analyses.

Markers of metastatic carcinoma of breast origin

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging. GATA3 is a nuclear transcription factor that shows superior sensitivity to GCDFP-15 and mammaglobin. However, the specificity of GATA3 can pose challenges, inasmuch as carcinomas of the bladder and other sites can show significant levels of positivity. Determination of the optimal panel of antibodies employed in a given clinical setting will thus depend on the non-breast tumours included in the differential diagnosis.

Cytokeratin 7: a re-evaluation of the 'tried and true' in triple-negative breast cancers

AIMS

Triple-negative breast cancers (TNBCs) are often poorly differentiated tumours that can present clinically as metastases of an unknown primary. Immunohistochemical panels are frequently used to determine the likelihood of a breast primary, but in this tumour subset cytokeratin (CK)7 may be the only positive finding. In this study we aimed to evaluate a commonly employed immunohistochemical panel using a large group of TNBCs (both basal-like and unclassified), and to analyse the CK7 staining patterns.

METHODS AND RESULTS

Tissue microarrays containing 138 TNBCs were stained with antibodies against CK7, CK20, gross cystic disease fluid protein 15 (GCDFP-15), and mammaglobin. CK5/6 staining was used to identify basal-like tumours. CK7 staining was notably heterogeneous, with 14.5% of all cases demonstrating ≤20% tumour cell staining. A greater proportion of basal-like TNBCs than of unclassified TNBCs showed focal staining. GCDFP-15 and mammaglobin were not expressed in the majority of TNBCs, and were less frequently positive in basal-like than in unclassified TNBCs.

CONCLUSION

TNBCs are commonly negative for most immunomarkers indicative of breast origin, with the exception of CK7. As about one in five TNBCs showed only focal CK7 positivity, use of this marker must be interpreted with caution, especially in small samples, so that the possibility of a breast primary is not overlooked.

Immunolocalization of MMP9 and MMP2 in osteolytic metastasis originating from MDA-MB-231 human breast cancer cells

The aim of the present study was to investigate the expression of matrix metalloproteinase (MMP)9 and MMP2, and their potential roles in bone metastasis nests using a well-standardized model of breast cancer bone metastasis in nude mice. BALB/c nu/nu mice (5-week-old; n=10) were subjected to intracardiac injection of MDA-MB-231 human breast cancer cells. After 4 weeks, the mice exhibiting radiolucent lesions in tibiae were sacrificed, and the tibiae were removed for histochemical analysis. The gene expression of MMP2 and MMP9 in the tumor cells, metaphysis and diaphysis of normal BALB/c nu/nu mice were determined using reverse transcription-polymerase chain reaction analysis. The metastatic tumor tissue occupied almost the entire bone marrow cavity. Numerous tartrate-resistant acid phosphatase-positive osteoclasts were found in the metastasized lesions. The invaded tumor cells positive for mammaglobin 1 exhibited different proliferation activities and apoptosis between the metaphysis and diaphysis. Proliferating cell nuclear antigen was expressed at high levels in the metaphyseal area, whereas TdT-mediated dUTP nick-end labeling (TUNEL)-positive cells were more evident in the diaphysis area. Of note, MMP9 was expressed predominantly in the proliferating cell nuclear antigen-positive area, whereas the expression of MMP2 was observed predominantly in the diaphysis, which had more TUNEL-positive cells. Taken together, the results suggested that MMP9 and MMP2 may have their own importance in extracellular matrix degradation and trabecular bone damage in different zones of bone metastasis, including the metaphysis and diaphysis.

Anti-hMAM monoclonal antibodies evaluated in breast and non-breast tissues for differential diagnosis implication

PURPOSE

Human mammaglobin (hMAM) is a breast tissue-specific marker that may have potency for the diagnosis of breast cancer. However, there is a lack of commercialization of anti-hMAM antibody made in China.

METHODS

Immunoreactivities of 2 self-made monoclonal anti-hMAM antibodies, MEF521 and MDA822, were evaluated by immunohistochemistry staining and compared with imported monoclonal antibody ab81611. A total of 48 cases of primary breast cancers, 36 cases of benign or normal breast tissues, 52 cases of lymph nodes or organ metastases from breast cancer, and 90 cases of non-breast primary carcinoma tissues were analyzed.

RESULTS

All 3 anti-hMAM antibodies showed high positive expression of hMAM in primary breast cancers, benign, and normal breast tissues. The positive ratio for MEF521 (33.3%) or MDA822 (44.4%) was much higher than that of ab81611 (16.7%) in lymph node metastasis from breast cancer (p = 0.038). There was no correlation between hMAM expression and clinicopathologic features of breast cancer in the 3 groups of antibodies. In 90 cases of non-breast primary carcinoma tissues, no hMAM-positive ones were observed in the MEF521 or MDA822 group, but 48 (53.3%) in the ab81611 group were positive, indicating that breast tissue specificity of the 2 self-made anti-hMAM monoclonal antibodies much higher than that of ab81611 (p&lt;0.001).

CONCLUSIONS

Our results showed that MDA822 and MEF521 are more specific to breast cancer as measured by means of immunohistochemistry. Therefore, the 2 self-made anti-hMAM antibodies may have good prospects for clinical application in the differential diagnosis of breast tumor and breast cancer metastases.

Differential diagnosis between primary lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma

Differentiation between lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma is clinically important because the prognoses and therapeutic options are considerably different. However, the clinical, pathological, and immunohistochemical diagnostic methods have not yet been fully established. Although various molecular methods have been developed, they have not yet been practically applied. A combined approach involving molecular and immunohistochemical analysis, such as one that uses antibodies selected on the basis of comprehensive genetic analysis results, may be effective. We suggest a new diagnostic criteria using the clinical characteristics and the result of immunohistochemical analysis. However, there are two underlying problems in the development of new diagnostic methods: tumor heterogeneity and determination of the diagnostic accuracy.

Practical Applications in Immunohistochemistry: Carcinomas of Unknown Primary Site

CONTEXT

-Identification of the site of origin of carcinoma of unknown primary using immunohistochemistry is a frequent requirement of anatomic pathologists. Diagnostic accuracy is crucial, particularly in the current era of targeted therapies and smaller sample sizes.

OBJECTIVES

-To provide practical guidance and suggestions for classifying carcinoma of unknown primary using both proven and new antibodies, as well as targeting panels based on integration of morphologic and clinical features.

DATA SOURCES

-Literature review, the authors' practice experience, and authors' research.

CONCLUSIONS

-With well-performed and interpreted immunohistochemistry panels, anatomic pathologists can successfully identify the site of origin of carcinoma of unknown primary. It is crucial to understand not only the diagnostic uses of the many available antibodies but also the potential limits and pitfalls.

Evaluating the utility of trefoil factor 1 as a mammary-specific immunostain compared and in conjunction with GATA-3 and mammaglobin in the distinction between carcinoma of breast and lung

OBJECTIVES

The distinction between metastatic breast carcinomas (BCs) and primary lung carcinomas (PLCs) can be difficult. This study tested the utility of trefoil factor 1 (TFF1) for this purpose and compared it with mammaglobin and GATA protein binding 3 (GATA-3).

METHODS

Tissue microarrays containing 365 BCs and 338 PLCs were stained with TFF1, mammaglobin, and GATA-3, and an H-score was calculated. Sensitivity, specificity, and accuracy were calculated, and logistical regression analysis was performed.

RESULTS

Accuracy of correctly classifying the tumor type was 81.9%, 71.3%, and 64.0% for GATA-3, mammaglobin, and TFF1, respectively. Odds ratios for selecting BCs were 25.69, 93.15, and 4.17, respectively, with P values less than .001. With a single exception, the best immunopanel included GATA-3 and mammaglobin in all comparisons.

CONCLUSIONS

TFF1 demonstrated breast specificity but was inferior to mammaglobin and GATA-3. Therefore, its routine clinical use may not be justified. TFF1 showed little benefit when added to an immunopanel.

GATA-binding protein 3 enhances the utility of gross cystic disease fluid protein-15 and mammaglobin A in triple-negative breast cancer by immunohistochemistry

AIMS

We have demonstrated previously that gross cystic disease fluid protein-15 (GCDFP-15) and mammaglobin A (MAM) are of limited utility in triple-negative breast cancer (TNBC). GATA-binding protein 3 (GATA-3) is an emerging breast-associated immunohistochemical (IHC) marker with limited data in TNBC. Here, we examined GATA-3 expression in TNBC in comparison with GCDFP-15 and MAM.

METHODS AND RESULTS

We studied GATA-3, GCDFP-15 and MAM IHC expression in 62 primary and 68 metastatic TNBCs. In primary TNBCs, GATA-3 staining was observed in 25 cases (40%), including 16 cases that were negative for GCDFP-15 and MAM. In metastatic TNBCs, GATA-3 staining was observed in 30 cases (44%), including 16 cases that were negative for GCDFP-15 and MAM. The expression frequency of any of the markers was 56% in primary and 62% in metastatic TNBCs. However, when focal staining was excluded, the expression frequency of any marker dropped to 31% and 44%, respectively.

CONCLUSION

GATA-3 is expressed at a higher frequency by IHC in TNBC compared to GCDFP-15 and MAM, although the tissue specificity of the latter markers may be superior. When evaluating a triple-negative tumour, including GATA-3 in a panel of markers may increase the diagnostic accuracy for tissue origin in the appropriate clinical setting.

Safety and preliminary evidence of biologic efficacy of a mammaglobin-a DNA vaccine in patients with stable metastatic breast cancer

PURPOSE

Mammaglobin-A (MAM-A) is overexpressed in 40% to 80% of primary breast cancers. We initiated a phase I clinical trial of a MAM-A DNA vaccine to evaluate its safety and biologic efficacy.

EXPERIMENTAL DESIGN

Patients with breast cancer with stable metastatic disease were eligible for enrollment. Safety was monitored with clinical and laboratory assessments. The CD8 T-cell response was measured by ELISPOT, flow cytometry, and cytotoxicity assays. Progression-free survival (PFS) was described using the Kaplan-Meier product limit estimator.

RESULTS

Fourteen subjects have been treated with the MAM-A DNA vaccine and no significant adverse events have been observed. Eight of 14 subjects were HLA-A2(+), and the CD8 T-cell response to vaccination was studied in detail. Flow cytometry demonstrated a significant increase in the frequency of MAM-A-specific CD8 T cells after vaccination (0.9% ± 0.5% vs. 3.8% ± 1.2%; P < 0.001), and ELISPOT analysis demonstrated an increase in the number of MAM-A-specific IFNγ-secreting T cells (41 ± 32 vs. 215 ± 67 spm; P < 0.001). Although this study was not powered to evaluate progression-free survival (PFS), preliminary evidence suggests that subjects treated with the MAM-A DNA vaccine had improved PFS compared with subjects who met all eligibility criteria, were enrolled in the trial, but were not vaccinated because of HLA phenotype.

CONCLUSION

The MAM-A DNA vaccine is safe, capable of eliciting MAM-A-specific CD8 T-cell responses, and preliminary evidence suggests improved PFS. Additional studies are required to define the potential of the MAM-A DNA vaccine for breast cancer prevention and/or therapy.

Metastatic carcinoma of unknown primary: diagnostic approach using immunohistochemistry

Carcinoma of unknown primary origin (CUP) is one of the 10 most prevalent malignancies. CUP patients in whom a site of origin can be ascribed have better outcomes than those in which the primary tumor remains unidentified. Among the tools available to pathologists in approaching these lesions, immunohistochemistry is a reliable, inexpensive, and widely available resource. New markers continue to emerge, which, in combination with other historically useful antibodies, allow rapid and accurate identification of primary site in an increasing number of cases. This review discusses the approach to the diagnosis of CUP using immunohistochemistry and outlines some of the most useful markers with a particular focus on the utility of lineage-restricted transcription factors, including CDX2, NKX3-1, PAX8, SATB2, TTF-1, and SF1.

Carcinoma ex-pleomorphic adenoma of the parotid gland consisting of high-grade salivary duct carcinoma and keratinizing squamous cell carcinoma

Carcinoma ex-pleomorphic adenoma (CXPA) is a rare salivary gland malignancy that presents diagnostic difficulties partly because of its wide range of histologic presentations. We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks. Magnetic resonance imaging revealed an infiltrative mass in the parotid gland, and the fine-needle aspiration (FNA) biopsy result was highly suspicious for carcinoma. Subsequent excision of the tumor demonstrated a poorly differentiated epithelial neoplasm consisting of keratinizing squamous cell carcinoma (SCC) and adenocarcinoma with regions of both ductal carcinoma in situ and invasive salivary duct carcinoma (SDC). Only focal areas exhibited a benign pleomorphic adenoma component. To our knowledge, this is the first case of a CXPA that consists of both a high-grade SDC and a keratinizing SCC in the parotid gland.

Morphology in conjunction with immunohistochemistry is sufficient for the diagnosis of mammary analogue secretory carcinoma

The recently described mammary analogue secretory carcinoma (MASC) is a low-grade salivary gland malignancy that harbors the recurrent cytogenetic abnormality t(12;15) (p13;q25) ETV6-NTRK3. Confirmation of this is currently considered the gold standard for diagnosis. Some have postulated that morphology together with supporting immunohistochemistry is sufficient to diagnose MASC. In this study we retrospectively review a series of 19 MASCs diagnosed based on histology in conjunction with immunohistochemistry; subsequently we performed in situ hybridization using an ETV6 break-apart probe. Immunohistochemistry for S100 protein and mammaglobin as well as fluorescence in situ hybridization using the Vysis ETV6 Dual Color Break-Apart FISH Probe Kit were performed on all cases. The 19 cases were from 12 females and 7 males with ages ranging from 16 to 76 years (mean = 45 years). Sixteen cases were from the parotid gland, 1 case was from a periparotid lymph node and 2 cases were from the submandibular gland. All 19 cases demonstrated moderate to strong expression of S100 protein. Eighteen cases demonstrated strong, diffuse expression of mammaglobin, while one case had only rare tumor cells that strongly expressed mammaglobin. Eighteen of 19 cases (95 %) demonstrated the ETV6 rearrangement by fluorescence in situ hybridization. Given that morphology together with immunohistochemistry is highly correlated with the ETV6 gene rearrangement, we conclude that molecular confirmation is not required to diagnose MASC.

Diagnostic utility and sensitivities of GATA3 antibodies in triple-negative breast cancer

GATA3 is implicated in mammary epithelial development and breast cancer progression and is an evolving immunohistochemical marker in breast cancer. Often associated with estrogen receptor (ER) signaling, GATA3 expression has been reported in ER-negative breast cancers, but systematic evaluation of GATA3 expression in a large set of triple-negative breast cancers (TNBC) is lacking. Given low sensitivities of mammaglobin (MGB) and GCDFP15 in metastatic TNBC, additional markers for site of origin identification would be useful in this context. We examined immunohistochemical expression of GATA3 in a large group of treatment-naive TNBC (n = 111) and ER-positive (n = 39) and HER2-positive (n = 31) breast cancers with commonly used antibody clones, HG3-31 (GATA3-H) and L50-823 (GATA3-L), and compared GATA3, MGB, and GCDFP15. Respectively, GATA3-L and GATA3-H were positive in 66% and 44% of TNBC (P = .002), 93% and 79% of ER-/HER2+ tumors (P = .596), and 100% of ER+/HER2- and ER+/HER2+ tumors (P = 1.00 each). GATA3-L was technically and diagnostically more sensitive than GATA3-H in TNBC and was technically more sensitive in other subtypes. MGB (26%) and GCDFP15 (16%) were less sensitive for TNBC than other subtypes (P < .001). Notably, 56% and 36% of MGB-/GCDFP15- TNBC were positive with GATA3-L and GATA3-H, respectively (P = .027). Seventy percent of TNBC were positive for GATA3-L, MGB, or GCDFP15 compared with 49% using GATA3-H in the panel. GATA3 is a diagnostically useful marker for TNBC and is more sensitive than MGB and GCDFP15 combined. GATA3-L is more sensitive for TNBC than GATA3-H, and an immunopanel of GATA3-L, MGB, and GCDFP15 provides optimal diagnostic sensitivity for TNBC.

Diagnostic utility of immunohistochemistry in distinguishing between epithelioid pleural mesotheliomas and breast carcinomas: a comparative study

Epithelioid mesotheliomas and breast carcinomas can present a variety of morphologic patterns. Because of this, breast carcinomas that metastasize to the pleura and lung may be confused with mesotheliomas. The aim of the present study is to compare the immunohistochemical markers currently available for the diagnosis of these 2 malignancies and to determine the best panel of markers that can be used to assist in discriminating between them. Sixty epithelioid mesotheliomas and 80 breast carcinomas (40 triple negative and 40 estrogen receptor positive) were investigated for expression of the positive mesothelioma markers calretinin, keratin 5/6, mesothelin, podoplanin, thrombomodulin, and WT1; the positive carcinoma marker claudin 4; and the breast-associated markers gross cystic disease fluid protein 15 (GCDFP-15), mammaglobin, and GATA3. All of the epithelioid mesotheliomas reacted for calretinin and keratin 5/6, 93% for WT1; 88% for podoplanin; 77% for thrombomodulin; 23% for GATA3; and 0% for claudin 4, GCDFP-15, and mammaglobin, respectively. Of the triple-negative breast carcinomas, 100% expressed claudin 4; 5%, keratin 5/6; 30%, GATA3; 18%, mammaglobin; 15%, GCDFP-15; 56%, mesothelin; 38%, calretinin; 18%, thrombomodulin; 5%, WT1; and 3%, podoplanin. Among the estrogen receptor-positive breast carcinomas, 100% were claudin 4 and GATA3 positive; 70% expressed GCDFP-15; 63%, mammaglobin; 13%, calretinin; 13%, thrombomodulin; 8%, WT1; 5%, keratin 5/6; 3%, mesothelin; and 0%, podoplanin. It is concluded that podoplanin and WT1 are the best positive mesothelioma markers for differentiating epithelioid mesotheliomas from breast carcinomas. An accurate differential diagnosis can be reached with the use of these two markers in combination with the breast-associated markers GCDFP-15, mammaglobin, and GATA3.

GATA3: a promising marker for metastatic breast carcinoma in serous effusion specimens

BACKGROUND

The usefulness of GATA3 (GATA-binding protein 3 to DNA sequence [A/T]GATA[A/G]) as a marker for metastatic breast carcinoma in serous effusion specimens was investigated.

METHODS

Cell block sections from 74 serous effusion specimens (32 ascitic, 2 pericardial, and 40 pleural fluids) were stained with an anti-GATA3 murine monoclonal antibody. The specimens included 62 confirmed metastatic carcinomas from the breast (30 specimens), female genital tract (13 specimens), gastrointestinal tract (7 specimens), lung adenocarcinoma (9 specimens), pancreas (1 specimen), kidney (1 specimen), and bladder (1 specimen). The breast carcinoma cases included 15 ductal carcinomas and 8 lobular carcinomas; the histology subtype was not available for 7 specimens. Twelve cases containing florid reactive mesothelial cells were also stained. The breast carcinoma cases were also stained for mammaglobin and gross cystic disease fluid protein of 15 kilodaltons (GCDFP-15) to compare their sensitivity with GATA3.

RESULTS

Positive nuclear staining for GATA3 was found to be present in 90% of metastatic breast carcinoma specimens (27 of 30 specimens). All nonbreast metastatic carcinomas tested were negative with the exception of the single case of metastatic urothelial carcinoma. No staining was observed in any of the benign reactive cases or in benign mesothelial cells present in the malignant cell block preparations. Two cases demonstrated weak positivity of benign lymphoid cells. Staining results were unambiguous because all positive cases demonstrated intense nuclear staining in > 50% of tumor cells. Mammaglobin (57% staining; 17 of 30 cases) and GCDFP-15 (33% staining; 10 of 30 cases) were found to be less sensitive markers of breast carcinoma. If used in a panel, mammaglobin and GCFP-15 staining would have identified only 1 additional case compared with those stained with GATA3.

CONCLUSIONS

GATA3 may be a useful addition to immunostaining panels for serous effusion specimens when metastatic breast carcinoma is a consideration.

Cutaneous and mammary apocrine carcinomas have different immunoprofiles

Often the distinction of cutaneous apocrine carcinoma from metastatic mammary apocrine carcinoma to the skin can be a diagnostic dilemma because both tumors share similar histologic features and have overlapping immunohistochemical profile. We compared the expression of adipophilin, cytokeratin 5/6, p63, GATA3, mammaglobin, androgen receptor, estrogen receptor, progesterone receptor, and HER2 by immunohistochemistry in 14 cutaneous apocrine carcinomas (11 primary tumors, 3 metastases) and 26 primary apocrine carcinomas of the breast. Whereas focal adipophilin staining was seen in 36% (5/14) of cutaneous apocrine carcinoma, strong and diffuse adipophilin staining was seen in 88% (22/25) of mammary apocrine carcinoma (P = .0013). Differences in estrogen receptor and progesterone receptor expression were also statistically significant (P = .018 and .043). Androgen receptor was strongly positive in all cutaneous and mammary cases. Although there was no significant difference in the frequency of expression of cytokeratin 5/6, p63, HER2, GATA3, and mammaglobin in cutaneous apocrine carcinoma versus mammary apocrine carcinoma, strong and diffuse cytokeratin 5/6 and/or mammaglobin expression were seen only in cutaneous apocrine carcinoma. In conclusion, cutaneous apocrine carcinoma is likely adipophilin- ER+ PR+/- HER2- and can exhibit strong and diffuse cytokeratin 5/6 and/or mammaglobin expression. On the contrary, a mammary apocrine carcinoma is likely adipophilin+ ER- PR- and often exhibit 3+ HER2 with corresponding HER2 gene amplification. A panel of adipophilin, ER, PR, HER2, cytokeratin 5/6, and mammaglobin may be helpful in distinguishing cutaneous apocrine carcinoma from mammary apocrine carcinoma.

Upregulation of human mammaglobin reduces migration and invasion of breast cancer cells

Little is known about the biological role of human mammaglobin (hMAM) that is considered as a promising marker for breast cancer. Here, we investigated hMAM's role related to migration and invasion of human breast cancer cells (hBCC). Compared to normal cells, hBCC have high MAM mRNA expression levels. Of the hBCC tested, MAM mRNA expression levels were higher in noninvasive than in invasive cells. Overexpression of hMAM in breast cancer cells decreased migration and invasion, whereas knockdown of hMAM increased both. Taken together, these results suggest that metastasis of hBCC could be controlled by hMAM expression levels.