Comprehensive Molecular Portraits of Invasive Lobular Breast Cancer.

Invasive lobular carcinoma (ILC) is the second most prevalent histologic subtype of invasive breast cancer. Here, we comprehensively profiled 817 breast tumors, including 127 ILC, 490 ductal (IDC), and 88 mixed IDC/ILC. Besides E-cadherin loss, the best known ILC genetic hallmark, we identified mutations targeting PTEN, TBX3, and FOXA1 as ILC enriched features. PTEN loss associated with increased AKT phosphorylation, which was highest in ILC among all breast cancer subtypes. Spatially clustered FOXA1 mutations correlated with increased FOXA1 expression and activity. Conversely, GATA3 mutations and high expression characterized luminal A IDC, suggesting differential modulation of ER activity in ILC and IDC. Proliferation and immune-related signatures determined three ILC transcriptional subtypes associated with survival differences. Mixed IDC/ILC cases were molecularly classified as ILC-like and IDC-like revealing no true hybrid features. This multidimensional molecular atlas sheds new light on the genetic bases of ILC and provides potential clinical options.

Is prostatic adenocarcinoma detectable by urine cytology-A multicenter retrospective review.

INTRODUCTION: Urine cytology is robust for the diagnosis of urothelial lesions, but data on the detection rates of prostatic adenocarcinoma in urine cytology is limited. In this study, a multicenter review was performed to define the clinical role of urine cytology in diagnosis of prostatic adenocarcinoma. METHODS: Cytologic diagnoses of lower tract urine cytology specimens with histology-proven prostatic adenocarcinoma from three institutions, from a period of over two decades, were reviewed. Clinicopathological parameters-tumor grade, stage, histologic features, and preanalytical factors-prostate-specific antigen (PSA) level and lesion size, were retrieved and compared with cytologic diagnoses. RESULTS: In total, 2115 urine cytology specimens from 1119 patients were retrieved. The atypia (or above/C3+) and suspicious (or above/C4+) rates were 19.48% and 3.36%. Bilobar and extracapsular involvement, lymphovascular invasion, Gleason score, and International Society of Urological Pathology grade were associated with a positive urine diagnosis (p < 0.05). The atypia (C3+) and suspicious (C4+) rates of urine cytology in patients with a PSA level of ≤4.0 ng/mL was paradoxically higher (p < 0.01), but PSA levels correlated positively with urine diagnosis at higher cutoffs (>10, >20, >50, >100 ng/mL). All these factors remained significant on multivariate analysis (p < 0.05), including a negative correlation with low-PSA (≤4.0 ng/mL, p = 0.001) and positive correlation with high-PSA (>20 ng/mL, p = 0.020). Lesion size and multifocality were not associated with urine cytology diagnosis (p > 0.05). CONCLUSION: Urine cytology showed low sensitivity in detection of prostatic adenocarcinoma. Detection rates were largely positively correlated with PSA levels but not for lesion size nor multifocality, limiting its clinical utility.

Spatial Distribution and Densities of CD103+ and FoxP3+ Tumor Infiltrating Lymphocytes by Digital Analysis for Outcome Prediction in Breast Cancer.

BACKGROUND: The evaluation of tumor-infiltrating lymphocytes (TILs) for breast cancer prognosis is now established. However, the clinical value for their spatial distributions of specific immune subsets, namely CD103+ tissue-resident memory T cells FoxP3+ regulatory T ells, have not been thoroughly examined. METHOD: Representative whole sections of breast cancers were subjected to CD103 and FoxP3 double staining. Their density, ratio, and spatial features were analyzed in tumor area and tumor-stromal interface. Their associations with clinicopathological parameters and patient's prognosis were analyzed. RESULTS: CD103 TILs were closer to tumor nests than FoxP3 TILs in the tumor-stromal interface. Their densities were associated with high-grade disease, TNBC, and stromal TILs. High stromal FoxP3 (sFoxP3) TILs and close proximity of sCD103 TILs to tumor were independently associated with better survival at multivariate analysis. Subgroup analysis showed the high FoxP3 TILs density associated better survival was seen in HER2-OE and TNBC subtypes while the proximity of CD103 TILs to tumor nests associated better survival was seen in luminal cancers. CONCLUSION: The prognostic impact of CD103 and FoxP3 TILs in breast cancer depends on their spatial localization. High sFoxP3 TIL density and the lower distance of CD103 TILs from the tumor nests had independent favorable prognostic values.

Evaluation of breast-specific marker expression in metastatic breast cancers: Correlation with subtype switch.

AIMS: This study evaluates the utility of breast specific markers in identifying breast cancer subtypes within metastatic settings. The subtype alteration in metastatic disease and its consequent impact on breast-specific marker expression is also examined. MATERIALS AND METHODS: GATA-binding protein 3 (GATA3), mammaglobin (MMG), transcriptional repressor GATA binding 1 (TRSP1) and SRY-box transcription factor 10 (SOX10) expression were assessed in a large cohort of metastatic breast cancer (MBC) cases and correlated with the characteristics of both MBC and primary breast cancer (PBC). RESULTS: GATA3 was the most sensitive in MBC (83.1%), followed by TRPS1 (77.0%), MMG (58.5%) and SOX10 (7.1%). This trend was consistent in hormonal receptor (HR)+ and HR- MBC. Combining GATA3/TRPS1 yielded the highest detection rates in the overall cohort (90.1%) and HR+ MBC (97.1%), while TRSP1/MMG was most effective in HR- (76.2%) and TN (71.1%) MBC. Marker expression did not correlate with metastatic site, except SOX10 in lung metastases (P = 0.031). Subtype discordance between MBC and PBC occurred in 43 cases (24.4%), with GATA3 expression in HR- MBC significantly linked to subtype discordance (P = 0.005). Conversely, SOX10 expression was significantly associated with subtype concordance in HR- and TNBC (P ≤ 0.003). Despite a higher expression of GATA3 in all HR- cases, TRSP1 outperformed GATA3 in detecting concordant HR- cases (64.0% versus 38.5%). TRPS1 and SOX10 were expressed in more than 50% of concordant TNBC cases. CONCLUSIONS: The expression of breast-specific markers is mainly determined by the PBC subtype. GATA3 retains high sensitivity in HR+ cancers, even after HR loss during metastasis. TRPS1 and SOX10 are identified as valuable markers in TNBC metastasis.

TRPS1 is a promising marker for all subtypes of breast cancer.

AIMS: Trichorhinophalangeal syndrome-1 (TRPS1) has been proposed as a novel breast marker with equally high expression in breast cancer (BC) subtypes, making it a useful diagnostic tool. Here, its expression was evaluated alongside other commonly used markers [GATA3, GCDFP15, mammaglobin (MGB) and SOX10] in a large cohort of BCs (n = 1852) and their corresponding nodal metastases. Its usefulness as a diagnostic tool and its correlation with clinicopathological features were assessed. METHODS AND RESULTS: TRPS1 was expressed at 75.8% overall in the BC cohort, with at least 58% expression among BC subtypes. It was less sensitive than GATA3 for luminal and HER2-overexpressing (HER2-OE) cancers (luminal A: 82 versus 97%; luminal B: 80 versus 95%; HER2-OE: 62 versus 76%), but it was the most sensitive for TNBC (60 versus ≤ 41%). It showed a stable expression in nodal metastases (primary tumour 76 versus nodal metastasis 78%), unlike a reduced nodal expression for GATA3 (86 versus 77%). TRPS1 outperformed GATA3 in detecting non-luminal cancers when paired with other breast markers. TRPS1 and GCDFP15 was the most sensitive combination in TNBC detection, with a 76% detection rate. For TRPS1-negative and GCDFP15-negative TNBCs, SOX10 was more sensitive than GATA3 (29 versus 24%). CONCLUSIONS: TRPS1 is a highly sensitive marker for all breast cancer subtypes, outperforming GATA3 in non-luminal cancers and displaying the highest sensitivity for TNBC detection when combined with GCDFP15. It is a valuable addition to the breast marker panel for accurate identification of BC.

Neutrophil-lymphocyte ratio reflects tumour-infiltrating lymphocytes and tumour-associated macrophages and independently predicts poor outcome in breast cancers with neoadjuvant chemotherapy.

AIMS: The neutrophil-lymphocyte ratio (NLR) is a systemic reflection of cancer-associated inflammation and a prognostic marker for breast cancer. For the local tumour microenvironment, tumour-infiltrating lymphocytes (TILs) and tumour-associated macrophages (TAMs) are also highly correlated with breast cancer survival. This study aimed to explore the relationship between the circulating and local immune microenvironment, and to further delineate the prognostic role of NLR in breast cancer patients receiving neoadjuvant chemotherapy (NAC). METHODS: A cohort of breast cancer patients receiving NAC with subsequent surgery was retrieved. Clinical data were reviewed. Histological slides and CD8 immunohistochemistry from biopsy (pre-chemotherapy) and excision (postchemotherapy) specimens were assessed for TILs and TAMs. RESULTS: A total of 146 patients were included. There was a significant positive correlation between pre- and postsurgery NLR at a cut-off of 2.6 (median pre-chemotherapy NLR) (P < 0.001). NLR pre-chemotherapy was associated positively with necrosis on biopsy (P = 0.027) and excision (P = 0.021) and TAMs on excision (P = 0.049). NLR 1 year postsurgery was associated with high tumour stage (P = 0.050) and low histological grade (P = 0.008). TIL count was lower in NLR-high cases at almost all time-points by histological assessment and CD8 immunostaining (P < 0.050). In multivariate analysis, postsurgery NLR is an independent predictor for overall survival [OS; hazard ratio (HR) = 9.524, P < 0.001], breast cancer-specific survival (BCSS) (HR = 10.059, P = 0.001) and disease-free survival (DFS; HR = 2.824, P = 0.016). CONCLUSIONS: The association between NLR with tumour necrosis, TAMs and TILs illustrates an interaction between the circulating and local immune microenvironment. Late NLR is a strong indicator of outcome and may be useful for prognostication and disease monitoring.

Immunocytochemical markers, molecular testing and digital cytopathology for aspiration cytology of metastatic breast carcinoma.

Fine-needle aspiration cytology (FNAC) is a versatile diagnostic procedure uniquely suited for tissue biopsy of breast carcinomas and axillary metastases and/or recurrences. With the expanding treatment options and accompanying theragnostic tests, it is crucial to recognize the developments on ancillary testing and digital cytopathology techniques related to aspiration cytology of metastatic breast carcinoma. In this review, we aim to summarize and update the evidence of immunocytochemistry, for the detection of carcinoma cells (epithelial markers), confirmation of breast primary (breast-specific markers), assessment of surrogate immunostains (hormone receptors, ki-67 proliferative index and HER2) and theragnostic biomarkers, with discussion on potential diagnostic pitfalls, followed by the application of molecular tests, and digital cytopathologic techniques for assessing metastatic breast carcinoma in cytology.

Comparison and review of abrasive bronchial brushing versus non-abrasive aspiration, lavage and washing - Higher sensitivity but with risk of over-diagnosis for bronchial brushing.

Bronchial exfoliative cytology is classified as non-abrasive (washing, aspiration and bronchoalveolar lavage) and abrasive (brushing). Brush abrasion dislodges epithelial cells but can induce bleeding and cytomorphologic artifacts. In this study, the largest cohort to date of bronchial cytology specimens were referenced against bronchial biopsy as the reference standard. Findings in the study will be useful for selecting biopsy modality and reducing necessary procedural risks. All consecutive bronchial cytology and bronchial biopsy from 1995 to 2022 were retrieved. The diagnoses were reviewed and categorized into five-tiered diagnostic categories to compare diagnostic agreement and concordance. Review of 14,148 specimens yielded 3963 non-abrasive, 2378 abrasive cytology specimens matched to biopsy, with 4355 matches between non-abrasive and abrasive cytology specimens. Agreement between non-abrasive and abrasive cytology was moderate (κ = 0.580), and similar when referenced against biopsy (κ = 0.456 (non-abrasive), κ = 0.498 (abrasive)). Abrasive bronchial cytology showed a higher percentage of malignant diagnosis (20.95 % vs. 12.63 %, p < 0.001) and over-diagnosis rate (36.40 % vs. 29.79 %, p < 0.001), but higher sensitivity (0.747 vs. 0.572, p = 0.002). For subgroup analysis of transbronchial biopsies, matched abrasive cytology showed higher discordant rates (p < 0.05) and lower accuracy (0.907 vs. 0.873, p = 0.020). With the added bleeding risk associated with brushing, abrasive techniques may only be preferable in cases with clinical or bronchoscopic suspicion of malignancy, in particular endobronchial mucosal lesions. For routine bronchoscopy, non-abrasive bronchial cytology appears to be adequate.

Update on triple-negative breast cancers - highlighting subtyping update and treatment implication.

Triple-negative breast cancer (TNBC) remains a major challenge in breast cancer management. Continuing research in the past years aimed at understanding the biology of this tumour and developing more effective therapeutic options. It is now clear that TNBC is vastly heterogeneous with diverse histological, molecular, immunological profiles and clinical differences. Current evidence suggested the existence of at least four predominant subtypes based on expression profiling across studies. These subtypes exhibited specific genomic alterations and tumour microenvironment. Subtype-specific therapeutic strategies were identified. Recognising these subtypes allows not only an improved prognostication but also a better treatment decision. Herein, we provide an overview of the recent findings on TNBC heterogeneity at different levels and corresponding subtyping. The characteristic of subtypes and the implication of these subtypings in therapeutic approaches are also discussed.

Marker assessments in ER-positive breast cancers: old markers, new applications?

Evaluation of oestrogen receptor (ER) expression by immunostaining is essential in the pathological assessment of breast cancer. Its expression is intercorrelated with clinicopathological features, molecular typing, and treatment selection. The development of novel therapeutic agents related to ER status, the recent ASCO introduction of an ER-low positive category of breast cancers, and the ever-increasing plethora of diagnostic and theragnostic markers call for a timely update. In this article we aim to review the clinicopathological features of ER-positive breast cancers, with an emphasis on ER-low positive breast cancers, and a focus on updating the (i) assessment, reporting and interpretation of ER immunohistochemical (IHC) staining, (ii) correlations of ER status with other diagnostic and theragnostic markers, and (iii) implications for treatment selection and response. In the face of the developments in IHC and molecular techniques and targeted therapy, ER immunostaining is still expected to remain as the core component of prognostic and theragnostic assessment of breast cancers.

An update on the pathological classification of breast cancer.

Breast cancer (BC) is a heterogeneous disease, encompassing a diverse spectrum of tumours with varying morphological, biological, and clinical phenotypes. Although tumours may show phenotypic overlap, they often display different biological behaviour and response to therapy. Advances in high-throughput molecular techniques and bioinformatics have contributed to improved understanding of BC biology and refinement of molecular taxonomy with the identification of specific molecular subclasses. Although the traditional pathological morphological classification of BC is of paramount importance and provides diagnostic and prognostic information, current interest focusses on the use of a single gene and multigene assays to stratify BC into distinct groups to guide decisions on systemic therapy. This review considers approaches to the classification of BC, including their limitations, and with particular emphasis on the fundamental role of morphology in establishing an accurate diagnosis of primary invasive carcinoma of breast origin. This forms the basis for further morphological characterization and for all other approaches to BC classification that are used to provide prognostic and therapeutic predictive information.

An international unified approach to reporting and grading invasive breast cancer. An overview of the International Collaboration on Cancer Reporting (ICCR) initiative.

Standardised reporting of breast cancer key pathology data has become the norm in some parts of the world, but are based on national or regional guidelines that differ in certain aspects, resulting in divergent reporting practices and a lack of comparability of data internationally. The International Collaboration on Cancer Reporting (ICCR), a global alliance of major (inter-)national pathology and cancer organizations, have recently produced a new international dataset for the pathology reporting of breast cancer, including resection specimens with invasive cancer and ductal carcinoma in situ (DCIS) of the breast. This initiative aims at providing an international unified approach to reporting cancer. The guidance was prepared by an international expert panel consisting of experienced breast pathologists, a surgeon, and an oncologist. The dataset includes core (essential) and noncore (optional) data items based on a critical review and discussion of current evidence. Commentary is provided for each data item to explain the rationale for selection, its clinical relevance, and to highlight potential areas of disagreement or lack of evidence, in which case a consensus position was formulated. The process concludes with international public consultation, before ratification and publication on the free open access ICCR website, with a synoptic reporting guide. The key aim is to promote high-quality, standardised pathology reporting that can be used worldwide. Histological grade, tumour size, and oestrogen receptor status are used in this article to illustrate this process and the detail provided to support its inclusion.

Anatomical site and size of sentinel lymph node metastasis predicted additional axillary tumour burden and breast cancer survival.

AIMS: Sentinel lymph node (SLN) biopsy is the current standard assessment for tumour burden in axillary lymph node (ALN). However, not all SLN+ patients have ALN metastasis. The prognostic implication of SLN features is not clear. We aimed to evaluate predictive factors for ALN metastasis and the clinical value of SLN features. METHODS AND RESULTS: A total of 228 SLN+ and 228 SLN- (with matched year and grade) cases were included. Clinicopathological features in SLN, ALN and primary tumours, treatment data and survival data were analysed according to ALN status and outcome. Except for larger tumour size and the presence of LVI (both P < 0.001), no significant differences were found in SLN- and SLN+ cases. Only 31.8% of SLN+ cases with ALN dissection had ALN metastasis. The presence of macrometastases (MaM), extranodal extension (ENE), deeper level of tumour invasion in SLN and more SLN+ nodes were associated with ALN metastasis (P ≤ 0.025). Moreover, isolated tumour cells (ITC) and level of tumour invasion in SLN were independent adverse prognostic features for disease-free survival and breast cancer-specific survival, respectively. Interestingly, cases with ITC located in the subcapsular region have better survival than those in cortex (OS: χ2  = 4.046, P = 0.044). CONCLUSIONS: Our study identified features in SLN, i.e. the level of tumour invasion at SLN and tumour size in SLN as useful predictors for both ALN metastasis and breast cancer outcome. The presence of ITC, particularly those with a deeper invasion in SLN, portended a worse prognosis. Proper attention should be taken for their management.

Artificial intelligence in breast cancer histopathology.

This is a review on the use of artificial intelligence for digital breast pathology. A systematic search on PubMed was conducted, identifying 17,324 research papers related to breast cancer pathology. Following a semimanual screening, 664 papers were retrieved and pursued. The papers are grouped into six major tasks performed by pathologists-namely, molecular and hormonal analysis, grading, mitotic figure counting, ki-67 indexing, tumour-infiltrating lymphocyte assessment, and lymph node metastases identification. Under each task, open-source datasets for research to build artificial intelligence (AI) tools are also listed. Many AI tools showed promise and demonstrated feasibility in the automation of routine pathology investigations. We expect continued growth of AI in this field as new algorithms mature.

Bronchial cytology of pulmonary adenoid cystic carcinoma - A multi-institute series with emphasis on immunocytochemistry.

BACKGROUND: Pulmonary adenoid cystic carcinoma (AdCC) is a central and superficial primary lung neoplasm, well-suited for sampling by bronchial cytology. This study aims to review the cytologic features of pulmonary AdCC on bronchial cytology, and to report an experience of applying immunocytochemistry on this rare entity. METHODS: A multi-institute review of bronchial cytology specimens from histologically proven pulmonary AdCCs was performed. Published cases of bronchial cytology of pulmonary AdCC were reviewed. The cytologic features and immunocytochemical profile for pulmonary AdCC was summarized and compared with pertinent differentials. RESULTS: A total of 16 specimens from eight patients were retrieved. The initial cytologic diagnoses were negative (n = 7), atypia (n = 6), suspicious (n = 2) and AdCC (n = 1). Retrospective review showed eight bronchial cytology specimens (including five cases of atypia) with tumor cells present. The tumor cells displayed small basaloid nuclei with occasional small nucleoli, mild nuclear atypia, and scanty cytoplasm. Architectural patterns observed included clusters, tubules, solid sheets, three-dimensional balls, papillary-like fronds, and complex cribriform structures. Basement-membrane-like material, free or associated with tumor cells, were seen in all cases. Immunocytochemistry was performed in one specimen. MYB was positive. TTF-1, synaptophysin and chromogranin were negative. Epithelial and basal markers demonstrated a dual cell population. Literature review yielded 28 cases. Cytologic features described were similar except for cytoplasmic vacuolation in one case. CONCLUSION: Basement membrane-like material is specific for AdCC. MYB positivity, TTF-1 and neuroendocrine marker negativity, support a diagnosis of AdCC. Other immunocytochemistry and cytologic features overlap significantly with adenocarcinoma and small cell carcinoma of lung.

Detection of early (T1) lung cancers and lepidic adenocarcinomas in sputum and bronchial cytology.

BACKGROUND: The lung is an extensively epithelialized organ, producing ample exfoliated material for sputum and bronchial cytology. In view of the updates in the World Health Organization classification of early (T1/≤ 3 cm) lung cancer with respect to adenocarcinomas with lepidic pattern, this study retrospectively reviews sputum and bronchial cytology paired with resection-confirmed lung cancers. METHODS: A computerized search for all lung resection specimens of carcinomas over a 20-year period was performed. Cytologic diagnoses of corresponding sputum and bronchial cytology were classified into five-tiered categories (C1-insufficient/inadequate, C2-benign, C3-atypia, C4-suspicious and C5-malignant). Reports and slides of the resection specimen were reviewed for reclassification of T1 cancers. RESULTS: Totally 472 and 383 sputum and bronchial cytology specimens respectively were included. Sensitivity for T1 lesions on sputum cytology were 10.6 %, 2.1 % and 0.5 % at cutoffs of atypia/C3, suspicious/C4 and malignant/C5 categories, lower than bronchial cytology (35.1 %, 15.5 %, 8.1 %; p < 0.001). T1 lesions correlated with lower detection rates, whereas squamous cell carcinoma histology, larger size and bronchial invasion were associated with increased detection rates in sputum and bronchial cytology (p < 0.050). Detection rates for abrasive bronchial cytology (brushing) were overall higher (p = 0.018- < 0.001), but on subgroup comparison, non-abrasive (aspiration, lavage and washing) cytology demonstrated favorable trends (p = 0.063-0.088) in detecting T1 lesions. Adenocarcinomas with lepidic pattern had lower suspicious/C4 (p = 0.040) or above and malignant/C5 (p = 0.019), but not atypia/C3 or above (p = 0.517) rates. CONCLUSIONS: Most adenocarcinomas with lepidic pattern are only diagnosed as atypia/C3 on cytology. With its modest sensitivity, interpretation of negative and indeterminate cytology results mandates caution.

Combining Analysis of Tumor-infiltrating Lymphocytes (TIL) and PD-L1 Refined the Prognostication of Breast Cancer Subtypes.

BACKGROUND: PD-L1 has been used as a biomarker to select patients for treatment of PD-1/PD-L1 inhibitors. MATERIALS AND METHODS: In this study, we assessed the clinicopathological features of breast cancers that are associated with PD-L1 expression, as well as its relationship with other immune components and its prognostic significance. RESULTS: Totally 1752 cases were included in this cohort. PD-L1 expression in tumor-infiltrating immune cells (PD-L1-IC) expression and in tumor cells (PD-L1-TC) expression were identified in 34.2% and 10.1% of cases, respectively, and they showed a positive correlation with higher tumor grade, morphological apocrine features, presence of necrosis, and higher stromal tumor-infiltrating lymphocytes (sTIL). PD-L1-IC and PD-L1-TC expression correlated positively with each other, and both of them were negatively associated with estrogen receptor and progesterone receptor and positively associated with Ki67, HER2, EGFR, p63, and p-cadherin. In survival analysis, PD-L1-IC expression was associated with better disease-free survival (DFS) and breast cancer-specific survival (BCSS) in HER2-overexpressed (HER2-OE) cancers and high-grade luminal B cancers. In triple-negative breast cancers (TNBC) and HER2-OE cancers, compared with sTIL low PD-L1-IC negative cases, sTIL high cases showed significantly better DFS independent of PD-L1-IC status. sTIL low PD-L1-IC positive cases also demonstrated a better DFS in HER2-OE cancers. In high-grade luminal B cancers, sTIL high PD-L1-IC positive cases showed the best BCSS. CONCLUSION: The data suggested that the combining analysis of sTIL and PD-L1-IC expression refined the prognostication of breast cancer subtypes. Cases with high TIL and PD-LI-IC expression appear to be more immune active.

Papillary lesions of the breast - review and practical issues.

Papillary lesions of the breast represent a heterogeneous group of neoplasm featuring fibrovascular cores covered by epithelial cells with or without intervening myoepithelial cells. According to the World Health Organization classification of breast tumors, papillary lesions of the breast are further classified into intraductal papilloma (including intraductal papilloma with atypical ductal hyperplasia /ductal carcinoma in situ), papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid papillary carcinoma (in situ and invasive) and invasive papillary carcinoma. The overlapping morphological features and immunohistochemical profiles make accurate diagnosis of breast papillary lesion a challenge for pathologists. In this review, the morphological and relevant immunohistochemical features of papillary lesions are discussed, with further emphasis on some commonly encountered practical diagnostic issues. A simple diagnostic algorithm will be established. The relevant molecular characteristics will be discussed as well.

Fine needle aspiration cytology of metastatic carcinomas with papillary architecture: A systemic assessment of clinical, cytological and immunohistochemical parameters.

BACKGROUND: Papillary structures are frequently encountered in metastatic carcinomas from various organs and tumours of different histotypes. This study aims to investigate the predictive value of fine needle aspiration cytology (FNAC), immunohistochemistry (IHC) and the clinical parameters which can be examined in the assessment of the primary sites of metastatic carcinomas with papillary architecture. METHODS: FNAC samples of metastatic carcinomas with papillary architecture were evaluated for overall cellularity, epithelial cohesion, background features, papillary architecture, cytology and IHC. The corresponding clinical information was also reviewed. RESULTS: A total of 130 cases were included. The most common primary sites were thyroid (38.5%), lung (30.8%) and gynecological organs (22.3%); the others were pancreaticobiliary, urothelial, colorectal, and esophageal. Age (P = 0.039), biopsy site (P < 0.001) and laterality (P = 0.006) correlated with primary site. Papillary structures were confirmed on biopsy/excision of most cases (n = 85/87, 97.7%). Thyroid primaries exhibited broad papillary stalks, thin lining epithelium, fewer epithelial polymorphs, and the presence of background giant cells and histiocytes (P = 0.021- < 0.001). Low-grade cytological features, nuclear grooves and inclusions (P < 0.001) were seen in thyroid primaries. High-grade features (P < 0.001-0.49), multinucleated tumour cells, apoptotic bodies and mitoses (P < 0.001-0.49) were more common in lung/gynecological primaries. Multivariate analysis identified nuclear/cytoplasmic ratio, chromatin character, the presence of nuclear grooves and mitosis as independent features (P = 0.001-0.024). TTF1/TGB/PAX8 panel results showed good agreement with the cytological assessment and site of primary. CONCLUSION: Papillary structures and cytological features are reproducible in FNAC assessment of metastases and their corresponding primary sites. Cytological features, IHC and clinical information are invaluable in determining the primary site.

SETD2 alterations and histone H3K36 trimethylation in phyllodes tumor of breast.

PURPOSE: SETD2 is one of the key epigenetic regulatory genes involved in histone modifications. Its alterations were potentially oncogenic and commonly found in cancers. Interestingly, SETD2 is one of the most frequent mutated genes found exclusively in phyllodes tumor of the breast (PT). However, little has been done to further characterize SETD2 alterations in PT. METHODS: In this study, we examined the alterations of SETD2 gene and protein expression in a large cohort of PTs. Their correlations with SETD2 downstream target, H3K36me3 expression, and clinicopathologic features in PT were also assessed. RESULTS: SETD2 mutation was found in 15.9% of our cases and was mostly predicted to be damaging mutations. Interestingly, SETD2 mutations were associated with lower H3K36me3 expression, particularly those with damaging mutations (p = .041). Neither SETD2 mutations nor H3K36me3 expression was associated with PT grading and other clinicopathological features. By contrast, the SETD2 protein expression cannot reflect its mutation status and showed a different trend of clinicopathological correlations from H3K36me3. CONCLUSIONS: Our findings may suggest a potential involvement of epigenetic regulation via SETD2 alterations and downstream H3K36me3 on PT development. SETD2 mutations may occur early in the pathogenic process of PTs and its loss per se may not be sufficient for progression to malignancy. Exclusive alterations of SETD2 in PT can be used as markers for the diagnosis of fibroepithelial lesions. The association of H3K36me3 with SETD2 mutations may also indicate the value of evaluation of H3K36me3 expression in the diagnosis of fibroepithelial lesions.