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Immunotherapy for the treatment of programmed death-ligand 1 (PD-L1) positive locally advanced or metastatic triple negative breast cancer may benefit patients with metaplastic breast cancer (MpBC). Previous study of PD-L1 in MpBC scored tumor cells (TCs), different from Food and Drug Administration-approved scoring methods. We sought to define PD-L1 expression in MpBCs and to evaluate concordance of 3 PD-L1 assays. Primary, treatment naive MpBC treated at our Center from 1998 to 2019 were identified. PD-L1 expression was assessed using SP142, E1L3n, and 73-10. We evaluated PD-L1 expression on tumor infiltrating immune cells (IC) and also in TCs. For each assay, we scored PD-L1 expression using ≥1% IC expression according to the IMpassion130 trial criteria and using combined positive score (CPS) ≥10 according to the KEYNOTE-355 trial cutoff. A total of 42 MpBCs were identified. Most MpBC had PD-L1 positivity in ≥1% IC with all 3 assays (95%, 95%, 86%) in contrast to a maximum 71% with a CPS ≥10. PD-L1 IC expression was comparable between the SP142 and 73-10 assays and was lowest with E1L3n. PD-L1 TC expression was lowest using SP142. The overall concordance for IC scoring was 88% while 62% had concordant CPS. For each assay, the results of the 2 scoring algorithms were not interchangeable. The SP142 assay showed distinct expression patterns between IC (granular, dot-like) and TC (membranous) while 73-10 and E1L3n showed membranous and/or cytoplasmic expression in both IC and TC. Most MpBC in our cohort were positive for PD-L1 indicating eligibility for anti-PD-L1/programmed death-1 immunotherapy., Competing Interests: Conflicts of Interest and Source of Funding: Supported by a National Institutes of Health/National Cancer Institute Cancer Center Support Grant (P30CA008748). B.W. is supported in part by the Breast Cancer Research Foundation and Cycle for Survival grants. H.Y.W. received honorarium from Merck in 2020. T.T. has received research support and honoraria from Roche Tissue Diagnostics and honoraria from Merck. J.S.R.-F. is an ad hoc member of the scientific advisory board of Roche Tissue Diagnostics. For the remaining authors none were declared., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Aims: Breast adenomyoepitheliomas (AMEs) are uncommon tumours. Most oestrogen receptor (ER)-positive AMEs have mutations in phosphoinositide 3-kinase (PI3K) pathway genes, whereas ER-negative AMEs usually harbour concurrent mutations affecting the HRAS Q61 hotspot and PI3K pathway genes. Here, we sought to determine the sensitivity and specificity of RAS Q61R immunohistochemical (IHC) analysis for detection of HRAS Q61R mutations in AMEs., Methods and Results: Twenty-six AMEs (14 ER-positive; 12 ER-negative) previously subjected to massively parallel sequencing (n = 21) or Sanger sequencing (n = 5) of the HRAS Q61 hotspot locus were included in this study. All AMEs were subjected to IHC analysis with a monoclonal (SP174) RAS Q61R-specific antibody, in addition to detailed histopathological analysis. Nine ER-negative AMEs harboured HRAS mutations, including Q61R (n = 7) and Q61K (n = 2) mutations. Five of seven (71%) AMEs with HRAS Q61R mutations were immunohistochemically positive, whereas none of the AMEs lacking HRAS Q61R mutations (n = 17) were immunoreactive. RAS Q61R immunoreactivity was restricted to the myoepithelium in 80% (4/5) of cases, whereas one case showed immunoreactivity in both the epithelial component and the myoepithelial component. RAS Q61R immunohistochemically positive AMEs were associated with infiltrative borders (P < 0.001), necrosis (P < 0.01) and mitotic index in the epithelial (P < 0.05) and myoepithelial (P < 0.01) components. RAS Q61R IHC assessment did not reveal Q61K mutations (0/2)., Conclusions: IHC analysis of RAS Q61R shows high specificity (100%) and moderate sensitivity (71%) for detection of HRAS Q61R mutations in breast AMEs, and appears not to detect HRAS Q61K mutations. IHC analysis of RAS Q61R may constitute a useful technique in the diagnostic workup of ER-negative AMEs., (© 2020 The Authors. Histopathology published by John Wiley & Sons Ltd.)

Amplification of 11q13 is found in approximately 15% of breast cancers. Cyclin D1 (CCND1) has been reported to be the 'driver' of this amplicon, however, multiple genes map to the smallest region of amplification of 11q13. Out of these genes, cortactin (CTTN) has been shown to be consistently overexpressed at the mRNA level in tumours harbouring 11q13 amplification. The aims of this study are to define whether CTTN is consistently co-amplified with the main core of the 11q13 amplicon, whether it is consistently overexpressed when amplified and to determine correlations between CTTN amplification and overexpression with clinicopathological features of breast cancers and survival of breast cancer patients. CTTN and CCND1 chromogenic in situ hybridisation (CISH) probes and a validated monoclonal antibody against CTTN were applied to a tissue microarray of a cohort of breast cancers from patients treated with anthracycline-based chemotherapy. CTTN and CCND1 amplifications were found in 12.3 and 12.4% of cases, respectively. All cases harbouring CTTN amplification also displayed CCND1 amplification. High expression of CTTN was found in 10.8% of cases and was associated with CTTN amplification, expression of 'basal' markers and topoisomerase IIα. Exploratory subgroup analysis of tumours devoid of 11q13 amplification revealed that high expression of CTTN in the absence of CTTN gene amplification was associated with lymph node negative disease, lack of hormone receptors and FOXA1, expression of 'basal' markers, high Ki-67 indices, p53 nuclear expression, and basal-like and triple negative phenotypes. CTTN expression and CTTN gene amplification were not associated with disease-, metastasis-free and overall survival. In conclusion, CTTN is consistently co-amplified with CCND1 and expressed at higher levels in breast cancers harbouring 11q13 amplification, suggesting that CTTN may also constitute one of the drivers of this amplicon. CTTN expression is not associated with the outcome of breast cancer patients treated with anthracycline-based chemotherapy.

Background: The aims of this study were to define the distribution of caveolin 2 (CAV2) in frozen and formalin fixed, paraffin embedded (FFPE) normal breast samples and the significance of CAV2 expression in breast cancer., Methods: Caveolin 2 distribution in frozen and paraffin-embedded whole tissue sections of normal breast was evaluated using immunohistochemistry and immunofluorescence, in conjunction with antibodies to define luminal epithelial cells (oestrogen receptor and cytokeratin 8/18) and myoepithelial/ basal cells (cytokeratins 14 and 5/6, p63 and smooth muscle actin). CAV2 expression was also immunohistochemically analysed in two independent cohorts of invasive breast carcinomas (n = 245 and n = 418)., Results: In normal breast, CAV2 was expressed in myoepithelial cells, endothelial cells, fibroblasts and adipocytes. Luminal epithelial cells showed no or only negligible staining. CAV2 expression was observed in 9.6% of all breast cancers and was strongly correlated with high histological grade, lack of oestrogen receptor, progesterone receptor and cyclin D1 expression, and positivity for epidermal growth factor receptor, basal markers, p53 expression, and high proliferation index. Furthermore, CAV2 expression was significantly associated with basal-like immunophenotype and proved to be a prognostic factor for breast cancer-specific survival on univariate analysis., Conclusion: Our results demonstrate that CAV2 is preferentially expressed in basal-like cancers and is associated with poor prognosis. Further in vitro studies are required to determine whether CAV2 has oncogenic properties or is only a surrogate marker of basal-like carcinomas.

Purpose: The distribution and significance of caveolin 1 (CAV1) expression in different breast cell types and role in breast carcinogenesis remain poorly understood. Both tumor-suppressive and oncogenic roles have been proposed for this protein. The aims of this study were to characterize the distribution of CAV1 in normal breast, benign breast lesions, breast cancer precursors, and metaplastic breast carcinomas; to assess the prognostic significance of CAV1 expression in invasive breast carcinomas; and to define whether CAV1 gene amplification is the underlying genetic mechanism driving CAV1 overexpression in breast carcinomas., Experimental Design: CAV1 distribution in frozen and paraffin-embedded whole tissue sections of normal breast was evaluated using immunohistochemistry, immunofluorescence, and immunoelectron microscopy. CAV1 expression was immunohistochemically analyzed in benign lesions, breast cancer precursors, and metaplastic breast carcinomas and in a cohort of 245 invasive breast carcinomas from patients treated with surgery followed by anthracycline-based chemotherapy. In 25 cases, CAV1 gene amplification was assessed by chromogenic in situ hybridization., Results: In normal breast, CAV1 was expressed in myoepithelial cells, endothelial cells, and a subset of fibroblasts. Luminal epithelial cells showed negligible staining. CAV1 was expressed in 90% of 39 metaplastic breast carcinomas and in 9.4% of 245 invasive breast cancers. In the later cohort, CAV1 expression was significantly associated with 'basal-like' immunophenotype and with shorter disease-free and overall survival on univariate analysis. CAV1 gene amplification was found in 13% of cases with strong CAV1 expression., Conclusions: The concurrent CAV1 amplification and overexpression call into question its tumor-suppressive effects in basal-like breast carcinomas.

Conflicting results on the prevalence of cyclin D1 ovexpression and its correlation with CCND1 amplification and outcome of breast cancer patients have been reported. Owing to limited sensitivity and specificity of most antibodies against cyclin D1, evaluation of cyclin D1 immunoexpression is reported to be problematic. The aims of this study were to assess the prevalence of cyclin D1 expression in breast carcinomas using the SP4 rabbit monoclonal antibody; to correlate cyclin D1 expression with amplification, assessed using chromogenic in situ hybridisation (CISH); and to analyse the relationship between CCND1 amplification and overexpression with clinicopathological parameters and outcome in a tissue microarray containing replicate tumour samples from 245 breast cancer patients. Immunohistochemistry for cyclin D1 was performed using the SP4 and the results were scored according to the Allred scoring system. CISH was carried out using the Zymed CCND1 SpotLight probe. CISH signals were counted in 60 morphologically unequivocal neoplastic cells. Amplification was defined as >5 signals per nucleus in more than 50% of cancer cells, or when large gene copy clusters were seen. Strong cyclin D1 expression and CCND1 amplification were found in 67.4 and 14.5% of the cases, respectively. A strong correlation between cyclin D1 overexpression and CCND1 amplification was demonstrated (P<0.0001). Cyclin D1 expression showed a positive correlation with hormone receptor expression (both ER and PgR, P<0.0001). An inverse correlation was observed between an immunohistochemical panel of 'basal-like' markers and both cyclin D1 overexpression (P<0.0001) and CCND1 amplification (P<0.0001). On univariate analysis cyclin D1 expression showed a correlation with longer overall survival (OS). Neither cyclin D1 nor CCND1 were independent prognostic factors for disease-free survival or OS. The results of this study confirm the association between cyclin D1 overexpression and positivity for hormone receptors and the lack of CCND1 amplification in basal-like breast carcinomas.

Tall cell carcinoma with reverse polarity is a rare subtype of breast carcinoma with solid and papillary growth and nuclear features reminiscent of those of the tall cell variant of papillary thyroid carcinoma. These tumors harbor recurrent IDH2 R172 hotspot mutations or TET2 mutations, co-occurring with mutations in PI3K pathway genes. Diagnosis of tall cell carcinomas with reverse polarity is challenging in view of their rarity and the range of differential diagnosis. We sought to determine the sensitivity and specificity of IDH2 R172 immunohistochemistry for the detection of IDH2 R172 hotspot mutations in this entity. We evaluated 14 tall cell carcinomas with reverse polarity (ten excision and five core needle biopsy specimens), 13 intraductal papillomas, 16 solid papillary carcinomas, and 5 encapsulated papillary carcinomas by Sanger sequencing of the IDH2 R172 hotspot locus and of exons 9 and 20 of PIK3CA, and by immunohistochemistry using monoclonal antibodies (11C8B1) to the IDH2 R172S mutation. The 14 tall cell carcinomas with reverse polarity studied harbored IDH2 R172 hotspot mutations, which co-occurred with PIK3CA hotspot mutations in 50% of cases. None of the other papillary neoplasms analyzed displayed IDH2 R172 mutations, however PIK3CA hotspot mutations were detected in 54% of intraductal papillomas, 6% of solid papillary carcinomas, and 20% of encapsulated papillary carcinomas tested. Immunohistochemical analysis with anti-IDH2 R172S antibodies (11C8B1) detected IDH2 R172 mutated protein in 93% (14/15) of tall cell carcinomas with reverse polarity samples including excision (n = 9/10) and core needle biopsy specimens (n = 5), whereas the remaining papillary neoplasms (n = 34) were negative. Our findings demonstrate that immunohistochemical analysis of IDH2 R172 is highly sensitive and specific for the detection of IDH2 R172 hotspot mutations, and likely suitable as a diagnostic tool in the evaluation of excision and core needle biopsy material of tall cell carcinomas with reverse polarity.

Polymorphous low-grade adenocarcinoma (PLGA) is the second most frequent type of malignant tumor of the minor salivary glands. We identified PRKD1 hotspot mutations encoding p.Glu710Asp in 72.9% of PLGAs but not in other salivary gland tumors. Functional studies demonstrated that this kinase-activating alteration likely constitutes a driver of PLGA.

Triple-negative breast cancer (TNBC) accounts for approximately 12% to 17% of all breast cancers and has an aggressive clinical behavior. Increased tumor-infiltrating lymphocyte counts are prognostic for survival in TNBC, making this disease a potential target for cancer immunotherapy. Research on immunophenotyping of tumor-infiltrating lymphocytes is revealing molecular and structural organization in the tumor microenvironment that may predict patient prognosis. The anti-programmed death-ligand 1 (PD-L1) antibody atezolizumab plus nab-paclitaxel was the first cancer immunotherapy combination to demonstrate progression-free survival benefit and clinically meaningful overall survival benefit in the first-line treatment of metastatic TNBC (mTNBC) in patients with PD-L1-expressing tumor-infiltrating immune cells in 1% or more of the tumor area. This led to its United States and European Union approval for mTNBC and US approval of the VENTANA PD-L1 (SP142) assay as a companion diagnostic immunohistochemistry assay. Subsequently, the anti-programmed death-1 (PD-1 ) antibody pembrolizumab plus chemotherapy was approved by the US Food and Drug Administration for mTNBC based on progression-free survival benefit in patients with a combined positive score of at least 10 by its concurrently approved 22C3 companion diagnostic assay. Treatment guidelines now recommend PD-L1 testing for patients with mTNBC, and the testing landscape will likely become increasingly complex as new anti-PD-L1 and anti-PD-1 agents and diagnostics are approved for TNBC. Integrating PD-L1 testing into current diagnostic workflows for mTNBC may provide more treatment options for these patients. Therefore, it is critical for medical oncologists and pathologists to understand the available assays and their relevance to therapeutic options to develop an appropriate workflow for immunohistochemistry testing. [ABSTRACT FROM AUTHOR]

Background: Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) guide the clinical management of breast cancer metastases. Decalcification of bone core needle biopsies (CNBs) can affect IHC. In the current study, the authors sought to define whether fine‐needle aspiration (FNA) would be a better alternative to CNB for reliable IHC. Methods: Patients with breast cancer metastases to bone that were sampled by both CNB and FNA were selected. ER, PR, and HER2 were performed in FNA cell blocks (FNA‐CBs) and concurrent decalcified CNBs. Discrepancies were classified as minor when there was a difference of up to 30% nuclear staining in IHC for ER and PR between paired samples and as major when a clinically relevant change was observed (ie, positive vs negative). Quantitative reverse transcriptase–polymerase chain reaction of ESR1 messenger RNA levels was performed on FNA/CNB pairs with discrepancies for ER IHC. IHC status of the primary breast carcinoma was recorded. Results: Concordance rates for ER, PR, and HER2 were 89%, 67%, and 93%, respectively, between FNA‐CB and CNB pairs from 27 patients. Major discrepancies were noted in approximately 11% of FNA/CNB pairs for ER IHC and in 33% of FNA/CNB pairs for PR. ESR1 messenger RNA levels of FNA/CNB matched samples were similar and did not explain the differences in ER IHC expression in the majority of cases. Two of 27 FNA/CNB pairs had different results for HER2 IHC that changed from negative on CNB to equivocal (2+) on FNA‐CB. Both cases had prior HER2 amplification by fluorescence in situ hybridization. Conclusions: FNA‐CB and CNB appear to constitute acceptable methods for the assessment of ER, PR, and HER2 for clinical decision making. Both fine‐needle aspiration (FNA) and core needle biopsy (CNB) constitute acceptable methods for the assessment of estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2 (HER2) for clinical decision making. In the current study, approximately 50% of all ER‐positive concordant FNA/CNB pairs are found to demonstrate stronger staining and a higher percentage of staining for ER in the FNA cell block samples when compared with the paired CNB. [ABSTRACT FROM AUTHOR]

Aims Low-grade ovarian endometrioid carcinomas may be associated with high-grade components. Whether the latter are clonally related to and originate from the low-grade endometrioid carcinoma remains unclear. The aim of this study was to use massively parallel sequencing to characterize the genomic landscape and clonal relatedness of an ovarian endometrioid carcinoma containing low-grade and high-grade components. Methods and results DNA samples extracted from each tumour component (low-grade endometrioid, high-grade anaplastic and high-grade squamous) and matched normal tissue were subjected to targeted massively parallel sequencing with the 410-gene Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets ( MSK- IMPACT) sequencing assay. Somatic single nucleotide variants, small insertions and deletions, and copy number alterations were detected with state-of-the-art bioinformatics algorithms, and validated with orthogonal methods. The endometrioid carcinoma and the associated high-grade components shared copy number alterations and four clonal mutations, including SMARCA4 mutations, which resulted in loss of BRG1 protein expression. Subclonal mutations and mutations restricted to single components were also identified, such as distinct TP53 mutations restricted to each histological component. Conclusions Histologically distinct components of ovarian endometrioid carcinomas may show intratumour genetic heterogeneity but be clonally related, harbouring a complex clonal composition. In the present case, SMARCA4 mutations were probably early events, whereas TP53 somatic mutations were acquired later in evolution. [ABSTRACT FROM AUTHOR]

Synchronous early-stage endometrioid endometrial carcinomas (EECs) and endometrioid ovarian carcinomas (EOCs) are associated with a favorable prognosis and have been suggested to represent independent primary tumors rather than metastatic disease. We subjected sporadic synchronous EECs/EOCs from five patients to whole-exome massively parallel sequencing, which revealed that the EEC and EOC of each case displayed strikingly similar repertoires of somatic mutations and gene copy number alterations. Despite the presence of mutations restricted to the EEC or EOC in each case, we observed that the mutational processes that shaped their respective genomes were consistent. High-depth targeted massively parallel sequencing of sporadic synchronous EECs/EOCs from 17 additional patients confirmed that these lesions are clonally related. In an additional Lynch Syndrome case, however, the EEC and EOC were found to constitute independent cancers lacking somatic mutations in common. Taken together, sporadic synchronous EECs/EOCs are clonally related and likely constitute dissemination from one site to the other. [ABSTRACT FROM AUTHOR]

Aims Infiltrating epitheliosis is a rare complex sclerosing lesion (CSL) of the breast, characterized by infiltrating ducts immersed in a scleroelastotic stroma and filled with cells having architectural and cytological patterns reminiscent of those of usual ductal hyperplasia. In this study we sought to define the molecular characteristics of infiltrating epitheliosis. Methods and results Eight infiltrating epitheliosis, adjacent breast lesions (one usual ductal hyperplasia, one papilloma, one micropapillary ductal carcinoma in situ and one low-grade adenosquamous carcinoma), and corresponding normal breast tissue from each case were microdissected and subjected to massively parallel sequencing analysis targeting all coding regions of 254 genes mutated recurrently in breast cancer and/or related to DNA repair. Mutations in components of the PI3K pathway were found in all infiltrating epitheliosis samples, seven of which harboured PIK3 CA hotspot mutations, while the remaining case displayed a PIK3R1 somatic mutation. Conclusions Somatic mutations affecting PI3K pathway genes were found to be highly prevalent in infiltrating epitheliosis, suggesting that these lesions may be neoplastic rather than hyperplastic. The landscape of somatic genetic alterations found in infiltrating epitheliosis is similar to that of radial scars/CSLs, suggesting that infiltrating epitheliosis may represent one end of this spectrum of lesions. [ABSTRACT FROM AUTHOR]

Aims: The aims of this study were to perform a whole-exome sequencing analysis of a breast cylindroma and to investigate the role of molecular analyses in the differentiation between breast cylindroma, a benign tumour that displays MYB expression, and CYLD gene mutations, and its main differential diagnosis, the breast solid-basaloid adenoid cystic carcinoma, a malignant tumour that is characterized by the presence of the MYB-NFIB fusion gene and MYB overexpression. Methods and results: A 66-year-old female underwent quadrantectomy after an irregular dense shadow was discovered in the right breast at the screening mammogram. Histologically, the tumour displayed features suggestive of a solid-basaloid variant of adenoid cystic carcinoma with a differential diagnosis of cylindroma. Fluorescence in situ hybridization, reverse transcription- polymerase chain reaction, immunohistochemistry and whole-exome sequencing revealed absence of the MYB-NFIB fusion gene, low levels of MYB protein expression and a clonal somatic CYLD splice site mutation associated with loss of heterozygosity of the wild-type allele. Conclusions: The results of the histological, immunohistochemical and molecular analyses were consistent with a diagnosis of breast cylindroma, providing a proof-of-principle that the integration of histopathological and molecular approaches can help to differentiate between a low-malignant potential and a benign breast tumour of triple-negative phenotype. [ABSTRACT FROM AUTHOR]

Acinic cell carcinoma ( ACC) of the breast is a rare form of triple-negative (that is, oestrogen receptor-negative, progesterone receptor-negative, HER2-negative) salivary gland-type tumour displaying serous acinar differentiation. Despite its triple-negative phenotype, breast ACCs are reported to have an indolent clinical behaviour. Here, we sought to define whether ACCs have a mutational repertoire distinct from that of other triple-negative breast cancers ( TNBCs). DNA was extracted from microdissected formalin-fixed, paraffin-embedded sections of tumour and normal tissue from two pure and six mixed breast ACCs. Each tumour component of the mixed cases was microdissected separately. Tumour and normal samples were subjected to targeted capture massively parallel sequencing targeting all exons of 254 genes, including genes most frequently mutated in breast cancer and related to DNA repair. Selected somatic mutations were validated by targeted amplicon resequencing and Sanger sequencing. Akin to other forms of TNBC, the most frequently mutated gene found in breast ACCs was TP53 (one pure and six mixed cases). Additional somatic mutations affecting breast cancer-related genes found in ACCs included PIK3CA, MTOR, CTNNB1, BRCA1, ERBB4, ERBB3, INPP4B, and FGFR2. Copy number alteration analysis revealed complex patterns of gains and losses similar to those of common forms of TNBCs. Of the mixed cases analysed, identical somatic mutations were found in the acinic and the high-grade non-acinic components in two out of four cases analysed, providing evidence of their clonal relatedness. In conclusion, breast ACCs display the hallmark somatic genetic alterations found in high-grade forms of TNBC, including complex patterns of gene copy number alterations and recurrent TP53 mutations. Furthermore, we provide circumstantial genetic evidence to suggest that ACCs may constitute the substrate for the development of more aggressive forms of triple-negative disease. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aims Acinic cell carcinomas (AcCC) of the breast have been reported to constitute the breast counterpart of salivary gland AcCCs, based on the similarities of their histological and immunohistochemical features. Breast AcCC is a vanishingly rare form of triple-negative breast cancer (TNBC). Recent studies have demonstrated that in TNBCs, the two driver genes most frequently mutated are TP53 (82%) and PIK3CA (10%). We sought to define whether breast AcCCs would harbour TP53 and PIK3CA somatic mutations, and if so, whether these would be present in salivary gland AcCCs. Methods and results Sanger sequencing of the entire coding region of TP53 and of PIK3CA hotspot mutation sites of 10 breast and 20 salivary gland microdissected AcCCs revealed eight TP53 (80%) and one PIK3CA (10%) somatic mutations in breast AcCCs. No somatic mutations affecting these genes were found in the 20 salivary gland AcCCs analysed. Conclusions Our findings demonstrate that breast AcCCs display TP53 and PIK3CA mutations at frequencies similar to those of common types of TNBCs, whereas these genes appear not to be altered in salivary gland AcCCs, suggesting that despite their similar histological appearances, AcCCs of the breast and salivary glands probably constitute unrelated diseases. [ABSTRACT FROM AUTHOR]

Geyer F C, Lacroix-Triki M, Colombo P-E, Patani N, Gauthier A, Natrajan R, Lambros M B K, Khalifeh I, Albarracin C, Orru S, Marchiò C, Sapino A, Mackay A, Weigelt B, Schmitt F C, Wesseling J, Sneige N & Reis-Filho J S (2012) Histopathology 60, E115-E130 Molecular evidence in support of the neoplastic and precursor nature of microglandular adenosis Aims: Microglandular adenosis (MGA) is a proliferative breast lesion, which has been proposed to be a potential precursor of triple-negative breast cancers. The aims of this study were to determine whether MGAs harbour genetic alterations and if any such genetic aberrations found in MGAs are similar to those found in matched invasive carcinomas. Methods and results: Twelve cases of MGA and/or atypical MGA (AMGA), 10 of which were associated with invasive carcinoma, were evaluated. Immunohistochemical profiling revealed that all invasive carcinomas were of triple-negative phenotype and expressed S100, cytokeratins 8/18 and 'basal' markers. The morphologically distinct components of each case (MGA, AMGA and/or invasive carcinoma) were microdissected and subjected to microarray comparative genomic hybridization. Apart from three typical MGAs, all samples harboured genetic alterations. The percentage of the genome affected by copy number aberrations in MGA/AMGA ranged from 0.5 to 61.9%, indicating varying levels of genetic instability. In three cases, MGA/AMGA displayed copy number aberrations similar to those found in matched invasive components, providing strong circumstantial evidence that MGA may constitute the substrate for the invasive carcinoma development. Conclusions: Our results support the contention that MGA can be a clonal lesion and non-obligate precursor of triple-negative breast cancer. [ABSTRACT FROM AUTHOR]

Summary: Oncocytic breast carcinomas are tumors composed of no fewer than 70% of oncocytic cells (World Health Organization). The purpose of this study was to determine the frequency, morphologic, immunohistochemical, and clinical features of invasive oncocytic carcinoma in a large series. Twenty-eight cases of putative oncocytic breast carcinoma (selected cases group) and 76 consecutive cases of invasive breast carcinoma (consecutive cases group) were analyzed. Immunohistochemistry for mitochondria, gross cystic disease fluid protein 15, chromogranin, estrogen receptor, progesterone receptor, androgen receptor, HER2/Neu, cytokeratin 7, cytokeratin 14, epithelial membrane antigen, and differentiation cluster 68 was performed. Score for mitochondria was based on intensity and percentage of immunopositive cells. Classes were as follows: (1) oncocytic carcinoma: at least 70%, 3+; (2) mitochondrion-rich carcinoma: 50% to 70%, 3+, or more than 50%, 2+; and (3) all the other cases were referred to as invasive breast carcinoma. Ultrastructural examination was available for 6 cases of oncocytic carcinoma. Morphologic and immunohistochemical features of the 3 groups were compared using Fisher exact test (P < .05). For overall survival analysis, Kaplan-Maier curves were compared using log-rank and Wilcoxon tests (P < .05). Our results suggest that oncocytic breast carcinoma is a morphologic entity with distinctive histologic and ultrastructural features. Mitochondrion-rich carcinomas are histologically similar to oncocytic carcinomas and constitute 19.7% of all invasive carcinomas, indicating that cytoplasmic eosinophilia in breast cancer cells is often due to accumulation of mitochondria. Oncocytic carcinomas and mitochondrion-rich carcinomas are more often grade III tumors and show human epidermal growth factor receptor 2 overexpression. Clinical features and overall survival of oncocytic carcinomas are not distinctive because they are similar to those of the other cases when matched for grade and stage. [Copyright &y& Elsevier]

Background: Investigating the expression of candidate genes in tissue samples usually involves either immunohistochemical labelling of formalin-fixed paraffin-embedded (FFPE) sections or immunofluorescence labelling of cryosections. Although both of these methods provide essential data, both have important limitations as research tools. Consequently, there is a demand in the research community to be able to perform routine, high quality immunofluorescence labelling of FFPE tissues. Results: We present here a robust optimised method for high resolution immunofluorescence labelling of FFPE tissues, which involves the combination of antigen retrieval, indirect immunofluorescence and confocal laser scanning microscopy. We demonstrate the utility of this method with examples of immunofluorescence labelling of human kidney, human breast and a tissue microarray of invasive human breast cancers. Finally, we demonstrate that stained slides can be stored in the short term at 4°C or in the longer term at -20°C prior to images being collected. This approach has the potential to unlock a large in vivo database for immunofluorescence investigations and has the major advantages over immunohistochemistry in that it provides higher resolution imaging of antigen localization and the ability to label multiple antigens simultaneously. Conclusion: This method provides a link between the cell biology and pathology communities. For the cell biologist, it will enable them to utilise the vast archive of pathology specimens to advance their in vitro data into in vivo samples, in particular archival material and tissue microarrays. For the pathologist, it will enable them to utilise multiple antibodies on a single section to characterise particular cell populations or to test multiple biomarkers in limited samples and define with greater accuracy cellular heterogeneity in tissue samples. [ABSTRACT FROM AUTHOR]

Objectives: The c-met tyrosine-kinase receptor and its ligand hepatocyte growth factor are involved in cell survival, proliferation, motility, and invasion. Experimental data have suggested a putative role in melanomagenesis and progression of cutaneous malignant melanoma (CMM). We sought to evaluate c-met expression in a cohort of 62 primary CMM patients diagnosed and primarily treated at the same institution. Methods: Sixty-two cases of CMM were retrospectively retrieved from the archives of the Department of Pathology, Hospital São João, Porto, Portugal. All classical clinicopathological features were reviewed. Only those patients in whom representative paraffin blocks were available and the diagnosis of primary CMM was confirmed, and who were followed up after the primary diagnosis were included in the study. Immunohistochemistry for c-met was performed in 59 cases, and semiquantitatively and qualitatively (membranous and cytoplasmic, M+C, or cytoplasmic) evaluated. Statistical analysis was performed using χ[sup 2] , ANOVA and Kaplan-Meier/log-rank tests. Results: M+C pattern of c-met expression was significantly associated with presence of vertical growth phase (p = 0.0198), thick tumors (p = 0.0006), ulceration (p = 0.0386), high mitotic index (p = 0.0008), lymphatic (p = 0.0086) and vascular (p = 0.0080) invasion, and nodal (p = 0.0422) and combined (nodal and/or visceral) metastases (p = 0.0234). M+C pattern of c-met expression also proved to be a significant prognostic factor for overall survival in univariate analysis (p = 0.0125). Conclusions: Our findings suggest that the pattern of c-met expression is a relevant prognostic factor for overall survival and is associated with more aggressive behavior of primary CMMs.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Discusses a case study of a 53-year-old man diagnosed with pleomorphic hyalinizing angiectatic tumor of the soft tissues. Pathologic examination results; Immunohistochemical evaluation; Differential diagnosis.

* Context.--The Ventana programmed death ligand-1 (PDL1) SP142 immunohistochemical assay (IHC) is approved by the US Food and Drug Administration as the companion diagnostic assay to identify patients with locally advanced or metastatic triple-negative breast cancer for immunotherapy with atezolizumab, a monoclonal antibody targeting PD-L1. Objective.--To determine interobserver variability in PD-L1 SP142 IHC interpretation in invasive breast carcinoma. Design.--The pathology database was interrogated for all patients diagnosed with primary invasive, locally recurrent, or metastatic breast carcinoma on which PDL1 SP142 IHC was performed from November 2018 to June 2019 at our institution. A subset of cases was selected using a computerized random-number generator. PD-L1 IHC was evaluated in stromal tumor-infiltrating immune cells using the IMpassion130 trial criteria, with positive cases defined as immunoreactivity in immune cells in 1% or more of the tumor area. IHC was interpreted on whole slide images by staff pathologists with breast pathology expertise. Interobserver variability was calculated using unweighted κ. Results.--A total of 79 cases were assessed by 8 pathologists. Interobserver agreement was substantial (κ = 0.727). There was complete agreement among all 8 pathologists in 62% (49 of 79) of cases, 7 pathologists or more in 84% (66 of 79) of cases, and 6 pathologists or more in 92% (73 of 79) of cases. In 4% (3 of 79) of cases, all of which were small biopsies, pathologists' interpretations were evenly split between scores of positive and negative. Conclusions.--The findings show substantial agreement in PD-L1 SP142 IHC assessment of breast carcinoma cases among 8 pathologists at a single institution. Further study is warranted to define the basis for discrepant results. [ABSTRACT FROM AUTHOR]

Background Endometrial carcinoma comprises a group of tumours with distinct histologic and molecular features and clinical behaviour. Here, we sought to define the biological processes that govern the clinical behaviour of endometrial cancers. Methods Sixteen prototype genes representative of different biological processes that would likely play a role in endometrial and other hormone-driven cancers were defined. RNA-sequencing gene expression data from 323 endometrial cancers from The Cancer Genome Atlas (TCGA) were used to determine the transcription module of each prototype gene. The expression of prototype genes and modules and their association with outcome was assessed in univariate and multivariate survival analyses. The association of MSH6 expression with outcome was validated in an independent cohort of 243 primary endometrial cancers using immunohistochemistry. Results We observed that the clinical behaviour of endometrial cancers as a group was associated with hormone receptor signalling, PI3K pathway signalling and DNA mismatch repair processes. When analysed separately, in endometrioid carcinomas, hormone receptor, PI3K and DNA mismatch repair modules were significantly associated with outcome in univariate analysis, whereas the clinical behaviour of serous cancers was likely governed by apoptosis and Wnt signalling. Multivariate survival analysis revealed that MSH6 gene expression was associated with outcome of endometrial cancer patients independently from traditional prognostic clinicopathologic parameters, which was confirmed in an independent cohort at the protein level. Conclusion Endometrioid and serous endometrial cancers are underpinned by distinct molecular pathways. MSH6 expression levels may be associated with outcome in endometrial cancers as a group. [ABSTRACT FROM AUTHOR]