TRPS1: a highly sensitive and specific marker for breast carcinoma, especially for triple-negative breast cancer

Analysis of the function, mechanism and clinical application prospect of TRPS1, a new marker for breast cancer

It has been discovered that Trichorhinophalangeal Syndrome-1 (TRPS1), a novel member of the GATA transcription factor family, participates in both normal physiological processes and the development of numerous diseases. Recently, TRPS1 has been identified as a new biomarker to aid in cancer diagnosis and is very common in breast cancer (BC), especially in triple-negative breast cancer (TNBC). In this review, we discussed the structure and function of TRPS1 in various normal cells, focused on its role in tumorigenesis and tumor development, and summarize the research status of TRPS1 in the occurrence and development of BC. We also analyzed the potential use of TRPS1 in guiding clinically personalized precision treatment and the development of targeted drugs.

Double hook-type aptamer-based colorimetric and electrochemical biosensor enables rapid and robust analysis of EpCAM expression

Epithelial cell adhesion molecule (EpCAM), which is overexpressed in breast cancer cells and participates in cell signaling, migration, proliferation, and differentiation, has been utilized as a biomarker for cancer diagnosis and therapeutic prognosis. Here, a dual-signal readout nonenzymatic aptasensor is fabricated for the evaluation of EpCAM at the level of three breast cancer cell lines. The central principle of this enzyme-free aptasensor is the use of double hook-type aptamers (SYL3C and SJ3C2)-functionalized magnetic iron oxide (Fe3O4) as capture probes and quasi-CoFe prussian blue analogs (QCoFe PBAs) as nonenzymatic signal probes for colorimetric and electrochemical analysis. Following ligand detachment, the CoFe PBA was transformed to QCoFe PBA (calcined at 350 °C for 1 h), with its metal active sites exposed by controllable pyrolysis. We found that the enhanced sensitivity was attributed to the resonance effect of QCoFe PBA with the remarkable enzymatic properties. The dual-signal readout nonenzymatic aptasensor exhibited limits of detection for EpCAM as low as 0.89 pg mL-1 and 0.24 pg mL-1, within a wide linear range from 0.001 to 100 ng mL-1, respectively. We successfully employed this nonenzymatic aptasensor for monitoring EpCAM expression in three breast cancer cell lines, which provides an economical and robust alternative to costly and empirical flow cytometry. The dual-signal readout nonenzymatic aptasensor provides rapid, robust, and promising technological support for the accurate management of tumors.

Exploring the molecular landscape of cutaneous mixed tumors characterized by TRPS1::PLAG1 gene fusion

The histological similarities between pleomorphic adenomas (PAs) and cutaneous mixed tumors (CMTs) found in certain facial regions can create a diagnostic challenge. Molecular findings reveal common genetic profiles, particularly PLAG1 rearrangements in both PA and CMT. Although molecular distinctions have received limited attention, our observations indicate multiple cases of CMTs carrying the TRPS1::PLAG1 fusion. This clinical experience has driven our investigation into the potential diagnostic utility of TRPS1::PLAG1 fusions for determining tumor origin. Two cohorts consisting of 46 cases of CMT and 45 cases of PA of the salivary glands were obtained from French institutions and reviewed by specialists in each subspecialty. RNA sequencing analysis was conducted to identify the molecular features of cases harboring PLAG1. Clinical, pathological, and molecular data were collected. In this study, cases of CMT exhibited recurrent gene fusions, primarily TRPS1::PLAG1 (74%). These tumors shared characteristic histological features, including tubuloductal differentiation in 55% of cases and squamous metaplasia in varying proportions. In contrast, cases of PA had gene fusions involving PLAG1 with various gene partners, with only one case in which TRPS1::PLAG1 was identified. This disparity was also observed at the transcriptomic level between TRPS1::PLAG1 CMTs and other tumors. However, TRPS1 immunostaining did not correlate with TRPS1::PLAG1 fusion. In conclusion, we report that recurrent TRPS1::PLAG1 fusion CMTs exhibit similar characteristic histological features, including tubuloductal differentiation that is associated with squamous metaplasia in around half of cases. Detection of this fusion could be valuable in correctly identifying the origin of these tumors. © 2024 The Pathological Society of Great Britain and Ireland.

Expression of TRPS1 in Metastatic Tumors of the Skin: An Immunohistochemical Study of 72 Cases

TRPS1 (Tricho-rhino-phalangeal syndrome 1) is a GATA transcriptional activator gene encoding for a protein used as a sensitive immunohistochemical marker of breast carcinomas. In dermatopathology, TRPS1 is used as a marker of mammary and extramammary Paget's disease and is also expressed by a variety of primary cutaneous tumors, mostly of adnexal origin. So far, very limited data exist on the expression of TRPS1 in metastatic skin tumors. We studied the immunohistochemical expression of TRPS1 in 72 cutaneous metastatic tumors from the breast (n: 19) and other origins (n: 53) in order to assess its diagnostic usefulness. The intensity of TRPS1 immunostaining was expressed as a histoscore: the product of the percentage of positive cells (scored semi-quantitatively 0-4) and the staining intensity (scored 0-3). In normal skin, nuclear TRPS1 expression was predominantly observed in cells of adnexal structures (pilosebaceous follicles and sweat glands). Eighteen (18/19, 94.7%) metastatic breast carcinomas showed diffuse and strong TRPS1 positivity (histoscore 12). Lower reactivity was found in some other metastases, including from the lung (11/22), the female genital tract (3/4), and the kidney (2/4), whereas most (20/22) metastases from the digestive system and peritoneum, along with a case of metastatic prostate carcinoma, were negative. These results suggest that a high histoscore for TRPS1 is in favor of the mammary origin of metastatic cutaneous carcinoma. Although TRPS1 is not absolutely specific or sensitive to a particular primary, we consider that it can be added to a panel of other markers when investigating the origin of a cutaneous metastasis, namely when this is the first manifestation of the neoplastic disease.

An engineered model of metastatic colonization of human bone marrow reveals breast cancer cell remodeling of the hematopoietic niche

Incomplete understanding of metastatic disease mechanisms continues to hinder effective treatment of cancer. Despite remarkable advancements toward the identification of druggable targets, treatment options for patients in remission following primary tumor resection remain limited. Bioengineered human tissue models of metastatic sites capable of recreating the physiologically relevant milieu of metastatic colonization may strengthen our grasp of cancer progression and contribute to the development of effective therapeutic strategies. We report the use of an engineered tissue model of human bone marrow (eBM) to identify microenvironmental cues regulating cancer cell proliferation and to investigate how triple-negative breast cancer (TNBC) cell lines influence hematopoiesis. Notably, individual stromal components of the bone marrow niche (osteoblasts, endothelial cells, and mesenchymal stem/stromal cells) were each critical for regulating tumor cell quiescence and proliferation in the three-dimensional eBM niche. We found that hematopoietic stem and progenitor cells (HSPCs) impacted TNBC cell growth and responded to cancer cell presence with a shift of HSPCs (CD34+CD38-) to downstream myeloid lineages (CD11b+CD14+). To account for tumor heterogeneity and show proof-of-concept ability for patient-specific studies, we demonstrate that patient-derived tumor organoids survive and proliferate in the eBM, resulting in distinct shifts in myelopoiesis that are similar to those observed for aggressively metastatic cell lines. We envision that this human tissue model will facilitate studies of niche-specific metastatic progression and individualized responses to treatment.

Metastatic Pleomorphic Lobular Carcinoma of the Breast to the Urinary Bladder: A Report of 10 Cases and Assessment of TRPS1 in the Differential Diagnosis With Plasmacytoid Urothelial Carcinoma

CONTEXT.—

Metastatic pleomorphic lobular carcinoma (MPLC) to the bladder is rare and has considerable histologic and immunohistochemical overlap with plasmacytoid urothelial carcinoma (PUC).

OBJECTIVE.—

To distinguish MPLC from PUC morphologically and immunohistochemically, including a newer marker, TRPS1.

DESIGN.—

Ten MPLCs to the bladder were reassessed and stained with estrogen, progesterone, and androgen receptors; GATA3; keratin 5/6; HMWK; GCDFP-15; and TRPS1. Sixteen PUCs constituted controls.

RESULTS.—

We studied 4 transurethral resections of bladder tumors and 6 biopsies from 10 women (median age, 69 years) who had breast cancer on average 15 years prior. Microscopic patterns included single cells and cords of cells (n = 4), nests/sheets of dyscohesive cells (n = 2), or both (n = 4). All tumors had cells with voluminous eosinophilic cytoplasm and eccentric nuclei mimicking PUC, and 7 of 10 tumors had signet ring cells. MPLCs were positive for estrogen (8 of 10), progesterone (3 of 7), and androgen (4 of 10) receptors; GCDFP-15 (7 of 10); GATA3 (9 of 10); HMWK (7 of 8); and TRPS1 (7 of 10). No MPLCs stained for keratin 5/6 (n = 9). Of 16 PUCs, 2 showed faint and 2 demonstrated strong TRSP1 staining; 7 of 16 were negative for p63.

CONCLUSIONS.—

MPLC to bladder often presents in patients with a remote history of breast cancer, exhibiting significant histologic and immunohistochemical overlap with PUC. Based on prior works and the current study, estrogen receptor (particularly SP-1), mammaglobin, and p63 help differentiate MPLC from PUC. Keratin 5/6 may aid in distinguishing a less frequent basal-type PUC because it is typically negative in MPLC. Some PUCs express TRPS1. Caution should be exercised because immunophenotypes of these tumors greatly overlap, and ramifications of misclassification are major.

UVB-induced TRPS1 regulates MITF transcription activity to promote skin pigmentation

Hyperpigmented dermatoses are characterized by increased skin pigmentation caused by genetic, environmental factors and inflammation, which lasts a long time and is difficult to treat. Ultraviolet (UV), especially ultraviolet B (UVB), is the primary external factor inducing skin pigmentation. However, the specific regulatory mechanisms are not fully understood. Through analysis of GEO datasets from four UV-exposed skin cell/tissue samples, we found that TRPS1 is the only gene differentially expressed in multiple datasets (GSE22083, GSE67098 and GSE70280) and highly positively correlated with the expression of key melanogenesis genes. Consistently, we observed that TRPS1 is highly expressed in sun-exposed skin tissues compared to non-exposed skin. Additionally, the expression of TRPS1 was also significantly upregulated after UVB irradiation in isolated skin tissues and melanocytes, while knockdown of TRPS1 expression inhibited the UVB-induced melanogenesis. Further research revealed that overexpression of TRPS1 increased melanin content and tyrosinase activity in MNT1 cells, as well as upregulated the expression levels of key melanogenesis genes (MITF, TYR, TYRP1, DCT). In contrast, inhibition of TRPS1 expression showed the opposite effect. Moreover, we found that TRPS1 can bind to the promoter region of MITF, inhibiting the expression of MITF can antagonize the melanogenesis induced by TRPS1. In conclusion, UVB-induced TRPS1 promotes melanogenesis by activating the transcriptional activity of MITF.

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.

Single-cell exome sequencing reveals polyclonal seeding and TRPS1 mutations in colon cancer metastasis

Liver metastasis remains the primary cause of mortality in patients with colon cancer. Identifying specific driver gene mutations that contribute to metastasis may offer viable therapeutic targets. To explore clonal evolution and genetic heterogeneity within the metastasis, we conducted single-cell exome sequencing on 150 single cells isolated from the primary tumor, liver metastasis, and lymphatic metastasis from a stage IV colon cancer patient. The genetic landscape of the tumor samples revealed that both lymphatic and liver metastases originated from the same region of the primary tumor. Notably, the liver metastasis was derived directly from the primary tumor, bypassing the lymph nodes. Comparative analysis of the sequencing data for individual cell pairs within different tumors demonstrated that the genetic heterogeneity of both liver and lymphatic metastases was also greater than that of the primary tumor. This finding indicates that liver and lymphatic metastases arose from clusters of circulating tumor cell (CTC) of a polyclonal origin, rather than from a single cell from the primary tumor. Single-cell transcriptome analysis suggested that higher EMT score and CNV scores were associated with more polyclonal metastasis. Additionally, a mutation in the TRPS1 (Transcriptional repressor GATA binding 1) gene, TRPS1 R544Q, was enriched in the single cells from the liver metastasis. The mutation significantly increased CRC invasion and migration both in vitro and in vivo through the TRPS1R544Q/ZEB1 axis. Further TRPS1 mutations were detected in additional colon cancer cases, correlating with advanced-stage disease and inferior prognosis. These results reveal polyclonal seeding and TRPS1 mutation as potential mechanisms driving the development of liver metastases in colon cancer.

Enhancer-promoter hubs organize transcriptional networks promoting oncogenesis and drug resistance

Recent advances in high-resolution mapping of spatial interactions among regulatory elements support the existence of complex topological assemblies of enhancers and promoters known as enhancer-promoter hubs or cliques. Yet, organization principles of these multi-interacting enhancer-promoter hubs and their potential role in regulating gene expression in cancer remain unclear. Here, we systematically identify enhancer-promoter hubs in breast cancer, lymphoma, and leukemia. We find that highly interacting enhancer-promoter hubs form at key oncogenes and lineage-associated transcription factors potentially promoting oncogenesis of these diverse cancer types. Genomic and optical mapping of interactions among enhancer and promoter elements further show that topological alterations in hubs coincide with transcriptional changes underlying acquired resistance to targeted therapy in T cell leukemia and B cell lymphoma. Together, our findings suggest that enhancer-promoter hubs are dynamic and heterogeneous topological assemblies with the potential to control gene expression circuits promoting oncogenesis and drug resistance.

TRPS1, a sensitive marker for different histological and molecular types of breast cancer

OBJECTIVES

We explored Trichorhinophalangeal syndrome type 1 (TRPS1) expression in special types of breast carcinoma, and analyzed the correlation between TRPS1 and androgen receptor (AR) expression in triple-negative breast cancer (TNBC).

METHODS

TRPS1 expression was analyzed in 801 patients with special types of breast carcinoma. A total of 969 TNBC were used to analyze the correlation between the expression of TRPS1 and AR. TRPS1 expression was evaluated in 1975 cases of breast cancer with different molecular types.

RESULTS

A total of 801 special types of breast cancers were stained with TRPS1.TRPS1 was positive in 100% (63/63) of mucinous carcinoma, 100% (7/7) adenoid cystic carcinomas (4 classic adenoid cystic carcinomas and 3 solid-basaloid adenoid cystic carcinomas), 100% (4/4) tubular carcinomas, 100% (2/2) secretory carcinomas, and 99.59% (243/244) invasive lobular carcinomas, 99.26% (267/269) invasive micropapillary carcinomas, 97.44% (38/39) ER-positive neuroendocrine tumors, 94.44% (34/36) metaplastic breast carcinomas (MBCs), 63.73% (65/102) apocrine carcinomas. TRPS1 was negative in all triple-negative neuroendocrine carcinomas (0/7).TRPS1 was positive in 92.86% (26/28) of metastatic special types of breast cancer. TRPS1 and AR expression were analyzed in 969 cases of TNBC. 90.40% were positive for TRPS1, and 42.41% were positive for AR. A significant inverse correlation between TRPS1 and AR expression was shown in TNBC (p < .001). TRPS1 showed a higher positive rate (93.13%) in TNBC compared to GATA binding protein 3 (GATA3), gross cystic disease fluid protein 15 (GCDFP-15) and forkhead box transcription Factor C 1 (FOXC1).

CONCLUSIONS

In conclusion, our study demonstrated that TRPS1 is a highly sensitive marker for most special types of breast carcinoma. TRPS1 was positive in 63.73% of apocrine carcinomas. TRPS1 and AR expression was inversely correlated in TNBC.

TRPS1 expression in MPNST is correlated with PRC2 inactivation and loss of H3K27me3

Initially described as a highly specific immunohistochemical marker for carcinomas of mammary origin, trichorhinophalangeal syndrome type 1 (TRPS1) has subsequently been detected in a variety of other non-mammary tumors. In this study, we examined the immunohistochemical expression of TRPS1 in 114 peripheral nerve sheath tumors, including 43 malignant peripheral nerve sheath tumors (MPNSTs), 58 schwannomas, including 9 cellular neurofibromas, and 13 neurofibromas, including 1 atypical neurofibroma. Notably, TRPS1 was expressed in 49% of MPNSTs and was absent in all schwannomas and neurofibromas. All MPNSTs showed TRPS1 labeling in >50% of nuclei, with 95% of cases demonstrating diffuse labeling. Most cases (67%) showed weak TRPS1 immunoreactivity, while a smaller subset showed moderate (24%) or strong (9%) intensity staining. Analysis of publicly available gene expression datasets revealed higher levels of TRPS1 mRNA in MPNSTs with PRC2 inactivation. In keeping with this finding, TRPS1 expression was more commonly observed in MPNSTs with loss of H3K27me3, suggesting a potential relationship between TRPS1 and the PRC2 complex. This study further broadens the spectrum of TRPS1-expressing tumors to include MPNST.

Deciphering Breast Origin in Malignant Effusions: The Diagnostic Utility of an MGP, GATA-3, and TRPS-1 Immunocytochemical Panel

INTRODUCTION

Defining the origin of metastatic cancer is crucial for establishing an optimal treatment strategy, especially when obtaining sufficient tissue from secondary malignancies is limited. While cytological examination is often used in this diagnostic setting, morphologic analysis alone often fails to differentiate metastases derived from the breast from other primaries. The hormone receptor, human epidermal growth factor receptor-2, gross cystic disease fluid protein 15, and mammaglobin immunohistochemistry are often used to diagnose metastatic breast cancer. However, their effectiveness decreases in estrogen receptor (ER)-negative breast cancers, including the triple-negative breast cancer (TNBC) subtype.

METHODS

We conducted a comprehensive evaluation of GATA-binding protein 3 (GATA-3), trichorhinophalangeal syndrome type 1 (TRPS-1), and Matrix Gla Protein (MGP) immunochemistry across 140 effusion cytology specimens with metastatic adenocarcinoma derived from various primaries, including the breast, colon, pancreaticobiliary, lung, tubo-ovarian, and stomach.

RESULTS

The expression rates of these immunomarkers were significantly higher in metastatic cancers originating from the breast than other primaries. In TNBC, TRPS-1 (80.00%) and MGP (65.00%) exhibited higher positivity rates compared to GATA-3 (40.00%). Additionally, our data suggest that an immunohistochemical panel comprising MGP, GATA-3, and TRPS-1 significantly enhances the detection of metastatic breast cancer in effusion cytology specimens, including TNBC in particular. When considering dual-marker positivity, the diagnostic accuracy was found to be 89.29% across all breast cancer subtypes and 92.93% for TNBC.

CONCLUSIONS

MGP appears to be a robust marker for identifying metastatic breast cancer in malignant effusions, especially TNBC. MGP notably enhances diagnostic accuracy when incorporated together with GATA-3 and TRPS-1 in an immunohistochemical panel.

Disruption of Circadian Clock Induces Abnormal Mammary Morphology and Aggressive Basal Tumorigenesis by Enhancing LILRB4 Signaling

Epidemiological studies have shown that circadian rhythm disruption (CRD) is associated with the risk of breast cancer. However, the role of CRD in mammary gland morphology and aggressive basal mammary tumorigenesis and the molecular mechanisms underlying CRD and cancer risk remain unknown. To investigate the effect of CRD on aggressive tumorigenesis, a genetically engineered mouse model that recapitulates the human basal type of breast cancer was used for this study. The effect of CRD on mammary gland morphology was investigated using wild-type mice model. The impact of CRD on the tumor microenvironment was investigated using the tumors from LD12:12 and CRD mice via scRNA seq. ScRNA seq was substantiated by multiplexing immunostaining, flow cytometry, and realtime PCR. The effect of LILRB4 immunotherapy on CRD-induced tumorigenesis was also investigated. Here we identified the impact of CRD on basal tumorigenesis and mammary gland morphology and identified the role of LILRB4 on CRD-induced lung metastasis. We found that chronic CRD disrupted mouse mammary gland morphology and increased tumor burden, and lung metastasis and induced an immunosuppressive tumor microenvironment by enhancing LILRB4a expression. Moreover, CRD increased the M2-macrophage and regulatory T-cell populations but decreased the M1-macrophage, and dendritic cell populations. Furthermore, targeted immunotherapy against LILRB4 reduced CRD-induced immunosuppressive microenvironment and lung metastasis. These findings identify and implicate LILRB4a as a link between CRD and aggressive mammary tumorigenesis. This study also establishes the potential role of the targeted LILRB4a immunotherapy as an inhibitor of CRD-induced lung metastasis.

TRPS1 Expression Is Frequently Seen in a Subset of Cutaneous Mesenchymal Neoplasms and Tumors of Uncertain Differentiation: A Potential Diagnostic Pitfall

Although extensively studied in cutaneous epithelial neoplasms, the TRPS1 immunoreactivity in cutaneous mesenchymal neoplasms and tumors of uncertain differentiation (CMNTUDs), such as atypical fibroxanthoma (AFX), remains largely unexplored. We assessed TRPS1 immunoreactivity in 135 CMNTUDs, comprising 46 fibrohistiocytic/fibroblastic tumors, 28 vascular tumors, 24 peripheral nerve sheath tumors (PNSTs), 21 tumors of uncertain differentiation, and 16 smooth muscle tumors. Additionally, we included selected cases of melanoma with spindled cell morphology or desmoplastic features (n = 9) and sarcomatoid squamous cell carcinoma (SSCC) (n = 5) to compare TRPS1 expression patterns with those of AFX. TRPS1 expression was prevalent in dermatofibromas (24/24), leiomyomas (8/8), AFXs/pleomorphic dermal sarcoma (PDS) (20/21), dermatofibrosarcomas protuberans (14/22), and leiomyosarcomas (6/8). It was uncommon in angiosarcomas (3/20), Kaposi sarcomas (2/8), and neurofibromas (5/17) and absent in perineuriomas (0/2). AFXs/PDS exhibited the highest median H-score of 240, contrasting with minimal TRPS1 immunoreactivity in vascular neoplasms and PNSTs, with median H-scores consistently below 10. Significant differences in H-score were observed between AFXs/PDS and angiosarcomas (p < 0.001), melanomas (p < 0.001), and leiomyosarcomas (p = 0.029). However, no significant difference was found compared to SSCCs, suggesting limited discriminatory power of TRPS1 in this context. This study sheds light on TRPS1 expression patterns in a subset of CMNTUDs, extending beyond prior studies primarily focused on epithelial tumors, while underscoring potential pitfalls associated with TRPS1 immunohistochemistry.

The Combined Immunohistochemical Expression of GLI1 and BCOR in Synovial Sarcomas for the Identification of Three Risk Groups and Their Prognostic Outcomes: A Study of 52 Patients

Synovial sarcoma (SS) is a rare soft-tissue tumor characterized by a monomorphic blue spindle cell histology and variable epithelial differentiation. Morphologically, SSs may be confused with other sarcomas. Systemic treatment is more effective for patients with high-risk SSs, patients with advanced disease, and younger patients. However, further studies are required to find new prognostic biomarkers. Herein, we describe the morphological, molecular, and clinical findings, using a wide immunohistochemical panel, of a series of SS cases. We studied 52 cases confirmed as SSs by morphological diagnosis and/or molecular studies. Clinical data (gender, age, tumor size, tumor location, resection margins, adjuvant treatment, recurrences, metastasis, and survival) were also retrieved for each patient. All the available H&E slides were examined by four pathologists. Three tissue microarrays (TMAs) were constructed for each of the tumors, and a wide immunohistochemical panel was performed. For time-to-event variables, survival analysis was performed using Kaplan-Meier curves and log-rank testing, or Cox regression. Statistical significance was considered at p < 0.05. The mean age of our patients was 40.33, and the median was 40.5 years. We found a predominance of males versus females (1.7:1). The most frequent morphological subtype was monophasic. TRPS1, SS18-SSX, and SSX-C-terminus were positive in 96% of cases. GLI1 expression was strong in six and focal (cytoplasmic) in twenty patients. Moreover, BCOR was expressed in more than half of SSs. Positive expression of both proteins, BCOR and GLI1, was correlated with a worse prognosis. Multivariate analysis was also performed, but only BCOR expression appeared to be significant. The combination of GLI1 and BCOR antibodies can be used to group SSs into three risk groups (low, intermediate, and high risk). We hypothesize that these findings could identify which patients would benefit from receiving adjuvant treatment and which would not. Moreover, these markers could represent therapeutic targets in advanced stages. However, further, larger series of SSs and molecular studies are necessary to corroborate our present findings.

Enhancer-promoter hubs organize transcriptional networks promoting oncogenesis and drug resistance

Recent advances in high-resolution mapping of spatial interactions among regulatory elements support the existence of complex topological assemblies of enhancers and promoters known as enhancer-promoter hubs or cliques. Yet, organization principles of these multi-interacting enhancer-promoter hubs and their potential role in regulating gene expression in cancer remains unclear. Here, we systematically identified enhancer-promoter hubs in breast cancer, lymphoma, and leukemia. We found that highly interacting enhancer-promoter hubs form at key oncogenes and lineage-associated transcription factors potentially promoting oncogenesis of these diverse cancer types. Genomic and optical mapping of interactions among enhancer and promoter elements further showed that topological alterations in hubs coincide with transcriptional changes underlying acquired resistance to targeted therapy in T cell leukemia and B cell lymphoma. Together, our findings suggest that enhancer-promoter hubs are dynamic and heterogeneous topological assemblies with the potential to control gene expression circuits promoting oncogenesis and drug resistance.

Immunohistochemical Profile of Triple-Negative Breast Cancers: SOX10 and AR Dual Negative Tumors Have Worse Outcomes

Triple-negative breast cancer (TNBC) refers to an estrogen receptor-negative, progesterone receptor-negative, and HER2-negative breast cancer. Although accepted as a clinically valid category, TNBCs are heterogeneous at the histologic, immunohistochemical, and molecular levels. Gene expression profiling studies have molecularly classified TNBCs into multiple groups, but the prognostic significance is unclear except for a relatively good prognosis for the luminal androgen receptor subtype. Immunohistochemistry (IHC) has been used as a surrogate for basal and luminal subtypes within TNBC, but prognostication of TNBC using IHC is not routinely performed. We aimed to study immunophenotypic correlations in a well-annotated cohort of consecutive TNBCs, excluding postneoadjuvant chemotherapy cases. Tissue microarrays were constructed from a total of 245 TNBC cases. IHC stains were performed and consisted of luminal (AR and INPP4B), basal (SOX10, nestin, CK5, and EGFR), and diagnostic (GCDFP15, mammaglobin, GATA3, and TRPS1) markers. Survival analysis was performed to assess the significance of clinical-pathologic variables including age, histology, grade, lymphovascular invasion, Nottingham prognostic index category, American Joint Committee on Cancer (AJCC) stage, stromal tumor-infiltrating lymphocytes at 10% increment, CD8+ T-cell count, Ki-67 index, PD-L1 status, and chemotherapy along with the results of IHC markers. Apocrine tumors show prominent reactivity for luminal markers and GCDFP15, whereas no special-type carcinomas are often positive for basal markers. TRPS1 is a sensitive marker of breast carcinoma but shows low or no expression in apocrine tumors. High AJCC stage, lack of chemotherapy, and dual SOX10/AR negativity are associated with worse outcomes on both univariable and multivariable analyses. Lymphovascular invasion and higher Nottingham prognostic index category were associated with worse outcomes on univariable but not multivariable analysis. The staining for IHC markers varies based on tumor histology, which may be considered in determining breast origin. Notably, we report that SOX10/AR dual negative status in TNBC is associated with a worse prognosis along with AJCC stage and chemotherapy status.

TRPS1 expression in breast angiosarcoma

Angiosarcoma (AS) of the breast, a rare mesenchymal neoplasm, exhibits distinct forms based on etiological and genetic features. While cases with typical clinical presentation and morphology allow for a straightforward diagnosis, challenges arise when clinical data are scarce, diagnostic material is limited, or morphological characteristics overlap with other tumors, including undifferentiated carcinomas. The trichorhinophalangeal syndrome protein 1 (TRPS1), once regarded as highly specific for breast carcinomas, now faces doubts regarding its reliability. This study explores TRPS1 expression in breast AS. Our investigation revealed that 60% of AS cases displayed TRPS1 labeling, contrasting with the 40% lacking expression. Scoring by four independent readers established a consensus, designating 12/35 ASs as unequivocally TRPS1-positive. However, uncertainty surrounded nine further cases due to a lack of reader agreement (being substantial as reflected by a kappa value of 0.76). These findings challenge the perceived specificity of TRPS1, shedding light on its presence in a noteworthy proportion of breast ASs. Consequently, the study underscores the importance of a comprehensive approach in evaluating breast ASs and expands the range of entities within the differential diagnosis associated with TRPS1 labeling.

Overcoming Pitfalls in Breast Fine-Needle Aspiration Cytology: A Practical Review

BACKGROUND

Fine-needle aspiration cytology (FNAC) is a cornerstone technique for the initial assessment of breast lesions, offering a rapid and minimally invasive option for cytological evaluation. While FNACs can forego the need for core needle biopsies (CNBs), variations in technique, subjective interpretation, and intrinsic limitations present diagnostic challenges. The International Academy of Cytology (IAC) established the Yokohama system and is developing the WHO Reporting System for Breast Cytopathology jointly with IARC, to standardize diagnostic criteria, aiming to enhance diagnostic precision and consistency. Due to the preference for CNBs, expertise in breast FNAC is low in the developed world.

SUMMARY

This review assesses common pitfalls in breast cytopathology. These common and uncommon entities may easily lead to false-negative or false-positive diagnoses, due to morphological overlap or misleading clinical and radiological contexts. For instance, pauci-cellular lesions, such as lobular carcinomas, often lead to false-negative diagnoses, whereas complex sclerosing lesions, fibroadenomas, and papillary lesions may show concerning features, resulting in a false positive. The same is true for some benign inflammatory pathologies, such as steatonecrosis, and uncommon lesions, such as collagenous spherulosis. Ductal carcinoma in situ can lead to both false-negative and false-positive diagnoses, and high-grade lesions are impossible to tell apart from invasive carcinomas. These are discussed in detail. Procedural and preanalytical conditions, and the role of ancillary testing, are also briefly addressed.

KEY MESSAGES

Breast FNAB is a powerful diagnostic technique, fast and minimally invasive. Even in contexts which lack expertise, this technique can be successfully adopted with a cautious approach and as long as pitfalls are kept in mind, benefiting patients and healthcare systems.

TRPS1 Is Consistently Expressed in Hidradenoma Papilliferum

TRPS1 is a novel immunohistochemical marker, so far quite specific and sensitive for breast cancer and especially useful for the diagnosis of triple-negative breast cancer. TRPS1 expression has recently been reported in normal skin appendages, as well as in a variety of benign and malignant cutaneous tumors, including adnexal tumors. However, it has not yet been reported in hidradenoma papilliferum (papillary hidradenoma), a benign adnexal neoplasm, accepted to originate from mammary-like glands in the vulvar or anogenital region of middle-aged women. We report consistent nuclear expression of TRPS1 in the epithelium of 9/9 cases of hidradenoma papilliferum, while in 2/2 cases with foci of oxyphilic metaplasia, these foci were consistently negative for TRPS1 immunohistochemistry. Our findings are in line with the theory that hidradenoma papilliferum is derived from mammary-like glands and showed that TRPS1 can be an additional sensitive immunohistochemical marker for hidradenoma papilliferum.

Diagnostic utility and sensitivities of matrix Gla protein (MGP), TRPS1 and GATA3 in breast cancer: focusing on metastatic breast cancer, invasive breast carcinoma with special features, and salivary gland-type tumours

Matrix Gla protein (MGP) and trichorhinophalangeal syndrome type 1 (TRPS1) have recently emerged as novel breast-specific immunohistochemical (IHC) markers, particularly for triple-negative breast cancer (TNBC) and metaplastic carcinoma. The present study aimed to validate and compare the expression of MGP, TRPS1 and GATA binding protein 3 (GATA3) in metastatic breast carcinoma (MBC), invasive breast carcinoma (IBC) with special features, including special types of invasive breast carcinoma (IBC-STs) and invasive breast carcinoma of no special type with unique features, and mammary and non-mammary salivary gland-type tumours (SGTs). Among all enrolled cases, MGP, TRPS1 and GATA3 had comparable high positivity for ER/PR-positive (p=0.148) and HER2-positive (p=0.310) breast carcinoma (BC), while GATA3 positivity was significantly lower in TNBC (p<0.001). Similarly, the positive rates of MGP and TRPS1 in MBCs (99.4%), were higher than in GATA3 (90.9%, p<0.001). Among the IBC-STs, 98.4% of invasive lobular carcinomas (ILCs) were positive for all three markers. Among neuroendocrine tumours (NTs), all cases were positive for TRPS1 and GATA3, while MGP positivity was relatively low (81.8%, p=0.313). In the neuroendocrine carcinoma (NC) subgroup, all cases were positive for GATA3 and MGP, while one case was negative for TRPS1. All carcinomas with apocrine differentiation (APOs) were positive for GATA3 and MGP, while only 60% of the cases demonstrated moderate staining for TRPS1. Among mammary SGTs, MGP demonstrated the highest positivity (100%), followed by TRPS1 (96.0%) and GATA3 (72.0%). Positive staining for these markers was also frequently observed in non-mammary SGTs. Our findings further validate the high sensitivity of MGP and TRPS1 in MBCs, IBC-STs, and breast SGTs. However, none of these markers are capable of distinguishing between mammary and non-mammary SGTs.

TRPS1 is a Highly Sensitive Marker for Breast Cancer: A Tissue Microarray Study Evaluating More Than 19,000 Tumors From 152 Different Tumor Entities

Trichorhinophalangeal syndrome 1 (TRPS1) is a nuclear protein highly expressed in breast epithelial cells. TRPS1 immunohistochemistry (IHC) has been suggested as a breast cancer marker. To determine the diagnostic and prognostic utility of TRPS1 IHC, tissue microarrays containing 19,201 samples from 152 different tumor types and subtypes were analyzed. GATA3 IHC was performed in a previous study. TRPS1 staining was seen in 86 of 152 tumor categories with 36 containing at least one strongly positive case. TRPS1 staining predominated in various types of breast carcinomas (51%-100%), soft tissue tumors (up to 100%), salivary gland tumors (up to 46%), squamous cell carcinomas (up to 35%), and gynecological cancers (up to 40%). TRPS1 positivity occurred in 1.8% of 1083 urothelial neoplasms. In invasive breast carcinoma of no special type, low TRPS1 expression was linked to high grade ( P = 0.0547), high pT ( P < 0.0001), nodal metastasis ( P = 0.0571), loss of estrogen receptor and progesterone receptor expression ( P < 0.0001 each), and triple-negative status ( P < 0.0001) but was unrelated to patient survival ( P = 0.8016). In squamous cell carcinomas from 11 different sites, low TRPS1 expression was unrelated to tumor phenotype. Positivity for both TRPS1 and GATA3 occurred in 47.4% to 100% of breast cancers, up to 30% of salivary gland tumors, and 29 (0.3%) of 9835 tumors from 134 other cancer entities. TRPS1 IHC has high utility for the identification of cancers of breast (or salivary gland) origin, especially in combination with GATA3. The virtual absence of TRPS1 positivity in urothelial neoplasms is useful for the distinction of GATA3-positive urothelial carcinoma from breast cancer.

Trichorhinophalangeal Syndrome Type 1 Immunohistochemical Expression in Carcinomas of Gynecologic Origin

Trichorhinophalangeal syndrome type 1 (TRPS1) is a new reportedly sensitive and specific immunohistochemical marker for carcinomas of breast origin, including triple-negative (estrogen receptor, progesterone receptor, and HER2) tumors. In our practice, we have observed a subset of cases of nonmammary carcinomas that are positive for TRPS1, with higher frequency in cytology effusion samples with metastatic gynecologic malignancies. This study aimed to evaluate the expression of TRPS1 in a large tissue cohort of Müllerian carcinomas. We retrospectively retrieved 105 cases of formalin-fixed paraffin-embedded gynecologic tumors from our surgical pathology archives. Cases corresponded to tumors of tubo-ovarian (17 high-grade serous carcinomas, 3 low-grade serous carcinomas, 2 clear cell carcinomas, and 8 endometrioid adenocarcinomas), endometrial (25 endometrioid adenocarcinomas, 8 serous carcinomas, 6 clear cell carcinomas, 12 carcinosarcomas, 1 dedifferentiated carcinoma, and 1 mesonephric-like adenocarcinoma), cervical (6 human papillomavirus [HPV]-associated squamous cell carcinomas [SCCs], 11 HPV-associated endocervical adenocarcinomas, and 2 HPV-independent gastric-type endocervical adenocarcinomas), and vulvar (2 HPV-independent SCCs and 1 HPV-associated SCC) origins. Immunohistochemistry for TRPS1 was performed in whole tissue sections and assessed for positivity (≥5% of nuclear labeling), distribution (focal: 5% to 49%, diffuse: 50% to 100%), and intensity (1+, 2+, 3+) in tumor cells. Positive TRPS1 staining was observed in 51.4% (54/105) of cases. Most tumors (64.8%) demonstrated diffuse labeling, while focal in 35.2%. Among positive cases, the intensity was predominantly 1+ (57.4%), followed by 2+ (33.3%) and 3+ (9.2%). Tumors with a high percentage of positivity overall consisted of tubo-ovarian (70%) and endometrial carcinomas (58.4%). TRPS1 immunostain is often expressed in gynecologic carcinomas. Awareness of this phenomenon is crucial when evaluating challenging cases in which the differential diagnosis includes a malignancy of breast origin, to avoid misclassification of the primary site.

Recent Advances in Pathology of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICCA) is a malignant epithelial neoplasm characterized by biliary differentiation within the liver. ICCA is molecularly heterogeneous and exhibits a broad spectrum of histopathological features. It is a highly aggressive carcinoma with high mortality and poor survival rates. ICCAs are classified into two main subtypes: the small-duct type and large-duct types. These two tumor types have different cell origins and clinicopathological features. ICCAs are characterized by numerous molecular alterations, including mutations in KRAS, TP53, IDH1/2, ARID1A, BAP1, BRAF, SAMD4, and EGFR, and FGFR2 fusion. Two main molecular subtypes-inflammation and proliferation-have been proposed. Recent advances in high-throughput assays using next-generation sequencing have improved our understanding of ICCA pathogenesis and molecular genetics. The diagnosis of ICCA poses a significant challenge for pathologists because of its varied morphologies and phenotypes. Accurate diagnosis of ICCA is essential for effective patient management and prognostic determination. This article provides an updated overview of ICCA pathology, focusing particularly on molecular features, histological subtypes, and diagnostic approaches.

Identification of hub genes and diagnostic efficacy for triple-negative breast cancer through WGCNA and Mendelian randomization

OBJECTIVE

Triple-negative breast cancer (TNBC) represents a particularly aggressive form of breast cancer with a poor prognosis due to a lack of targeted treatments resulting from limited a understanding of the underlying mechanisms. The aim of this study was the identification of hub genes for TNBC and assess their clinical applicability in predicting the disease.

METHODS

This study employed a combination of weighted gene co-expression network analysis (WGCNA) and differentially expressed genes (DEGs) to identify new susceptible modules and central genes in TNBC. The potential functional roles of the central genes were investigated using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses. Furthermore, a predictive model and ROC curve were developed to assess the diagnostic performance of the identified central genes. The correlation between CCNB1 and immune cells proportion was also investigated. At last, a Mendelian randomization (MR) analysis utilizing Genome-Wide Association Study (GWAS) data was analyzed to establish the causal effect of CCNB1 level on TNBC.

RESULTS

WGCNA was applied to determine gene co-expression maps and identify the most relevant module. Through a screening process, 1585 candidate hub genes were subsequently identified with WGCNA and DEGs. GO and KEGG function enrichment analysis indicated that these core genes were related to various biological processes, such as organelle fission, chromosome segregation, nuclear division, mitotic cell cycle phase transition, the cell cycle, amyotrophic lateral sclerosis, and motor proteins. Using STRING and Cytoscape, the top five genes with high degrees were identified as CDC2, CCNB1, CCNA2, TOP2A, and CCNB2. The nomogram model demonstrated good performance in predicting TNBC risk and was proven effective in diagnosis, as evidenced by the receiver operating characteristic (ROC) curve. Further investigation revealed a causal association between CCNB1 and immune cell infiltrates in TNBC. Survival analysis revealed high expression of the CCNB1 gene leads to poorer prognosis in TNBC patients. Additionally, analysis using inverse variance weighting revealed that CCNB1 was linked to a 2.8% higher risk of TNBC (OR: 1.028, 95% CI 1.002-1.055, p = 0.032).

CONCLUSION

We established a co-expression network using the WGCNA methodology to detect pivotal genes associated with TNBC. This finding holds promise for advancing the creation of pre-symptomatic diagnostic tools and deepening our comprehension of the pathogenic mechanisms involved in TNBC risk genes.

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.

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.

Osteopontin promotes tumor growth and metastasis and GPX4-mediated anti-lipid peroxidation in triple-negative breast cancer by activating the PI3k/Akt/mTOR pathway

PURPOSE

Triple-negative breast cancer (TNBC) features high aggressiveness, metastasis rate, drug resistance as well as poor prognosis. Osteopontin (OPN) is a key protein in the process of osteogenesis and has emerged as a new tumor marker in recent years.

METHODS

Cell viability was tested with the CCK-8 kit. Transwell and wound healing were adopted to test cell invasive and migratory abilities. Tumor sphere formation was detected by tumor sphere formation assay. Human umbilical vein endothelial cell (HUVEC) tube formation assay was used to measure the angiogenesis of tumor cells. Western blot was applied for the estimation of the expression of cancer stem cell markers, angiogenesis-, signaling pathway-related proteins as well as OPN. Bioinformatics tools predicted OPN expression in breast cancer tissues. The levels of oxidative stress-related markers were assessed with ELISA. Following the overexpression of OPN in MD-MB-436 cells and the addition of the PI3K/AKT/mTOR pathway inhibitor LY294002, the aforementioned functional experiments were implemented again to investigate the mechanism. Finally, in vivo experiments of tumor-bearing mice were performed for further verification.

RESULTS

The proliferative, invasive, migratory and tumor sphere formation capabilities as well as angiogenesis of TNBC cells were conspicuously increased in contrast to non-TNBC cell lines. OPN expression in TNBC tissues and cells was dramatically enhanced. OPN upregulation significantly elevated cell proliferative, invasive and migratory capabilities as well as tumor sphere formation and angiogenesis. The mechanism might be achieved by activating PI3K/AKT/mTOR signaling to regulate glutathione peroxidase 4 (GPX4)-mediated anti-lipid peroxidation.

CONCLUSION

OPN promoted tumor sphere formation and angiogenesis in TNBC by activating the PI3K/AKT/mTOR pathway to regulate GPX4-mediated anti-lipid peroxidation levels.

Case report: Metastatic ovarian mucinous carcinoma to the breast: diagnostic challenges and pitfalls

Metastases to the breast from extramammary sources are extremely rare, with the ovary, primarily high-grade serous carcinoma, being the most common origin. We report a case of breast metastases from advanced stage ovarian mucinous carcinoma in a 48-year-old female- a case hitherto unreported in the literature. The case is noteworthy for its atypical presentation marked by an areolar rash, clinically suggestive of Paget disease of the nipple. This unique clinical scenario, coupled with histopathological examination revealing in-situ-like carcinoma component, posed a diagnostic challenge in discerning the tumour origin. We emphasize the need for heightened awareness among pathologists to avoid misdiagnosing metastatic carcinomas as primary breast tumours, a potential pitfall with significant clinical implications.

Potential biomarkers in breast cancer drug development: application of the biomarker qualification evidentiary framework

Breast cancer treatments have evolved rapidly, and clinically meaningful biomarkers have been used to guide therapy. These biomarkers hold utility within the drug development process to increase the efficiency and effectiveness. To this purpose, the US FDA developed an evidentiary framework. Literature searches conducted of literature published between 2016 and 2022 identified biomarkers in breast cancer. These biomarkers were reviewed for drug development utility through the biomarker qualification evidentiary framework. In the breast cancer setting, several promising biomarkers (ctDNA, Ki-67 and PIK3CA) were identified. There is a need for increased transparency regarding the requirements for qualification of specific biomarkers and increased awareness of the processes involved in biomarker qualification.

Cholangiocarcinoma: Pathologic and Molecular Classification in the Era of Precision Medicine

CONTEXT.—

Cholangiocarcinoma (CCA) is a heterogeneous cancer of the bile duct, and its diagnosis is often challenging.

OBJECTIVE.—

To provide insights into state-of-the-art approaches for the diagnosis of CCA.

DATA SOURCES.—

Literature review via PubMed search and authors' experiences.

CONCLUSIONS.—

CCA can be categorized as intrahepatic or extrahepatic. Intrahepatic CCA is further classified into small-duct-type and large-duct-type, whereas extrahepatic CCA is classified into distal and perihilar according to site of origin within the extrahepatic biliary tree. Tumor growth patterns include mass forming, periductal infiltrating, and intraductal tumors. The clinical diagnosis of CCA is challenging and usually occurs at an advanced tumor stage. Pathologic diagnosis is made difficult by tumor inaccessibility and challenges in distinguishing CCA from metastatic adenocarcinoma to the liver. Immunohistochemical stains can assist in differentiating CCA from other malignancies, such as hepatocellular carcinoma, but no distinctive CCA-specific immunohistochemical profile has been identified. Recent advances in next-generation sequencing-based high-throughput assays have identified distinct genomic profiles of CCA subtypes, including genomic alterations that are susceptible to targeted therapies or immune checkpoint inhibitors. Detailed histopathologic and molecular evaluations of CCA by pathologists are critical for correct diagnosis, subclassification, therapeutic decision-making, and prognostication. The first step toward achieving these goals is to acquire a detailed understanding of the histologic and genetic subtypes of this heterogeneous tumor group. Here, we review state-of-the-art approaches that should be applied to establish a diagnosis of CCA, including clinical presentation, histopathology, staging, and the practical use of genetic testing methodologies.

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.

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

CONTEXT.—

Immunohistochemistry has become a valuable ancillary tool for the accurate classification of pleuropulmonary and mediastinal neoplasms necessary for therapeutic decisions and predicting prognostic outcome. Diagnostic accuracy has significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

OBJECTIVE.—

To increase the accuracy of diagnosis and classify pleuropulmonary neoplasms through immunohistochemistry.

DATA SOURCES.—

Literature review and the author's research data and personal practice experience.

CONCLUSIONS.—

This review article highlights that appropriately selecting immunohistochemical panels enables pathologists to effectively diagnose most primary pleuropulmonary neoplasms and differentiate primary lung tumors from a variety of metastatic tumors to the lung. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoid potential diagnostic errors.

TRPS1 expression in non-melanocytic cutaneous neoplasms: an immunohistochemical analysis of 200 cases

BACKGROUND

Although trichorhinophalangeal syndrome type 1 (TRPS1) was initially thought to be highly sensitive and specific for carcinomas and mesenchymal tumors of mammary origin, more recent data suggest its expression is not limited to breast neoplasms but also can be seen in other cutaneous neoplasms, such as extramammary Paget disease and squamous cell carcinoma (SCC) in situ.

METHODS

Two-hundred cases of non-melanocytic cutaneous neoplasm, including basal cell carcinomas (BCCs) (n = 41), SCCs (n = 35), Merkel cell carcinomas (MCCs) (n = 25), and adnexal neoplasms (n = 99), were tested for TRPS1 expression using a monoclonal anti- TRPS1 rabbit anti-human antibody.

RESULTS

TRPS1 expression was present in almost all cases of SCC (94%), with a median H-score of 200, while it was either absent or only focally present in most BCCs (90%), with a median H-score of 5. The difference between BCCs and SCCs in H-score was significant (p < .001). All MCCs (100%) lacked TRPS1 expression. TRPS1 expression was frequently seen in most adnexal neoplasms, benign and malignant, in variable intensity and proportion but was consistently absent in apocrine carcinomas. All endocrine mucin-producing sweat gland carcinomas (EMPSGCs) (100%, 6/6) showed diffuse and strong TRPS1 immunoreactivity, with a median H-score of 300, which was significantly different (p < .001) than that of BCCs.

CONCLUSIONS

Our study shows that TRPS1 may be an effective discriminatory marker for BCCs and SCCs. It also has a role in distinguishing BCCs from EMPSGCs.

A Comparative Evaluation of TRPS1 and GATA3 in adenoid cystic, secretory, and acinic cell carcinomas of the breast and salivary gland

GATA3 is the most used marker to determine tumors' breast origin, but its diagnostic value in triple-negative breast cancer (TNBC) is limited. The newly identified TRPS1 is highly sensitive and specific for breast carcinoma, especially TNBC. Here, we compared the utility of TRPS1 and GATA3 expression in a subset of salivary gland-type breast tumors (including adenoid cystic, acinic cell, and secretory carcinomas [AdCC, ACC, and SC, respectively]), and we compared TRPS1 and GATA3 expression of such tumors with head and neck (H&N) and AdCC of upper respiratory tumors. TRPS1 was strongly expressed in basaloid TNBC and AdCCs with solid components, including 100 % of mixed and solid breast AdCCs. However, TRPS1 was positive in only 50 % cribriform AdCCs. Expression patterns of TRPS1 in H&N and upper respiratory AdCC were similar. TRPS1 was positive in 30 % of H&N cribriform AdCCs but was strongly expressed in mixed AdCC (67 %) and solid AdCC (100 %). In the upper respiratory AdCCs, TRPS1 was positive in 58.4 % of cribriform AdCCs and positive in 100 % of AdCCs with solid components. On the contrary, GATA3 was negative in predominant AdCCs of the breast, H&N, and upper respiratory tract. These data show that GATA3 and TRPS1 expression varies AdCCs. In addition, TRPS1 and GATA3 expression patterns were similar SC and ACC of breast and H&N. Both markers were positive in SC and negative in ACC. Therefore, TRPS1 and GATA3 cannot be used to differentiate salivary gland-type carcinomas of breast origin from those of upper respiratory or H&N origin.

Mucinous cystadenocarcinoma of the breast harbours TRPS1 expressions and PIK3CA alterations

AIMS

Breast mucinous cystadenocarcinoma (BMCA) is a rare tumour recently recognised as a distinct entity by the World Health Organisation Tumour Classification Series. BMCA is a triple-negative tumour that lacks specific immunohistochemical markers; therefore, distinguishing it from mimickers such as ovarian and pancreatic cystadenocarcinomas requires careful clinicopathological correlation. Due to its rarity, little is known about the molecular alterations that underlie BMCA.

METHODS AND RESULTS

In this study, we used immunohistochemical staining methods to investigate TRPS1 (trichorhinophalangeal syndrome type 1) expression in BMCA and compare it to expression in ovarian and pancreatic mucinous cystadenocarcinomas. We also collected tumour samples from three BMCA patients for molecular analysis by MALDI-TOF mass spectrometry, real-time polymerase chain reaction, whole exome sequencing and fluorescence in-situ hybridisation. TRPS1 immunoreactivity was found only in BMCA tumour cells and not in the ovarian and pancreatic counterparts. One of the three BMCA tumours also showed a PIK3CA hot-spot mutation, which was confirmed by whole genome next-generation sequencing (NGS). No KRAS, NRAS, BRAF or AKT mutations were found.

CONCLUSIONS

To our knowledge, this is the first demonstration of TRPS1 expression in BMCA patients and the first identification of a PIK3CA hotspot mutation in these tumours. These findings provide insights into the molecular mechanisms underlying BMCA tumorigenesis and suggest a potential drug target for this rare and poorly understood cancer.

TRPS1 and GATA3 Expression in Invasive Breast Carcinoma With Apocrine Differentiation

CONTEXT.—

The recently identified immunohistochemical marker TRPS1 is highly sensitive and specific for invasive breast carcinoma, especially triple-negative breast carcinoma. However, TRPS1 expression in special morphologic subtypes of breast cancer is unclear.

OBJECTIVE.—

To investigate the expression of TRPS1 in invasive breast cancer with apocrine differentiation, in comparison to the expression of GATA3.

DESIGN.—

A total of 52 invasive breast carcinomas with apocrine differentiation, comprising 41 triple-negative breast carcinomas and 11 estrogen receptor (ER) and progesterone receptor (PR)-negative, human epidermal growth factor receptor 2 (HER2)-positive cases, along with 11 triple-negative breast carcinomas without apocrine differentiation, were evaluated for TRPS1 and GATA3 expression by immunohistochemistry. All tumors were diffusely positive (>90%) for androgen receptor (AR).

RESULTS.—

Triple-negative breast carcinoma with apocrine differentiation had positive TRPS1 expression in 12% of cases (5 of 41), whereas GATA3 was positive in all cases. Similarly, HER2+/ER- invasive breast carcinoma with apocrine differentiation showed positive TRPS1 in 18% of cases (2 of 11), whereas GATA3 was positive in all cases. In contrast, triple-negative breast carcinoma with strong AR expression but without apocrine differentiation showed both TRPS1 and GATA3 expression in 100% (11 of 11) of cases.

CONCLUSIONS.—

Most ER-/PR-/AR+ invasive breast carcinomas with apocrine differentiation are TRPS1 negative and GATA3 positive, regardless of HER2 status. Therefore, TRPS1 negativity does not exclude breast origin in tumors with apocrine differentiation. A panel of TRPS1 and GATA3 immunostains can be helpful when the tissue origin of such tumors is clinically relevant.

Utility of GATA-3 immunocytochemistry for the assessment of fine-needle aspiration in breast cancer patients with suspicious axillary lymph nodes at ultrasound

BACKGROUND

Ultrasound-guided fine-needle aspiration cytology (FNAC) is a routine preoperative method for evaluating suspicious axillary lymph nodes (ALNs) in patients with breast cancer. However, a range of reasons such as morphological pitfalls, technical artifacts, and sampling errors restrict the sensitivity and accuracy of FNAC. This retrospective study investigated the diagnostic value of GATA-binding protein 3 (GATA-3) immunocytochemistry for FNAC.

METHODS

Breast cancer patients who underwent preoperative FNAC for suspicious ALNs, relevant GATA-3 immunocytochemistry, and postoperative status of ALNs were reviewed from the period of March 2020 to February 2022. Altogether, 102 patients were included in the study. FNAC material smears stained with hematoxylin and eosin was initially assessed by two cytopathologists and categorized into five groups: nondiagnostic, negative, atypical, suspicious, and positive for malignancy. Only group of cells positive for malignancy was considered positive. For each case, two selected slides were digitized (whole slide imaged) at ×40 magnification and decolored for GATA-3 immunocytochemistry. The expression of GATA-3 was scored ranging from 0 to 9 (Score ≥3: Positive, Score ≤2: Negative). If either FNAC or GATA-3 immunocytochemistry was positive or the combined test positive, then the case was considered positive. The sensitivity, specificity, and accuracy of FNAC, GATA-3 immunocytochemistry, and combined FNAC/GATA-3 immunocytochemistry were analyzed by χ2 and Fisher's tests.

RESULTS

The mean age of the study participants was 50.62 (ranging: 30-73 years). Invasive breast carcinoma (not otherwise specified) accounted for most histological subtypes, and grade 2 was the leading Nottingham grade. Sixteen cases directly underwent mastectomy while the other 86 patients had neoadjuvant therapy. A more serious diagnosis was made based on GATA-3 detection in 22.5% (n = 23) of 102 cases. Of the 23 cases, metastasis was confirmed by GATA-3 detection in 21 cases, and an uncertain diagnosis was ascertained based on GATA-3 immunocytochemistry in 2 with nondiagnostic FNAC results. The sensitivity (77/87, 88.5%) of GATA-3 detection for distinguishing malignancies from benign lesions was higher than that of FNAC alone (62/87, 71.3%) (p < .05).

CONCLUSIONS

GATA-3 immunocytochemistry exhibited high diagnostic efficacy in distinguishing malignant breast cancer cells. Moreover, combined FNAC and GATA-3 immunocytochemistry achieved optimal results in terms of reducing the false-negative rate and promoting accuracy.

TRPS1 modulates chromatin accessibility to regulate estrogen receptor alpha (ER) binding and ER target gene expression in luminal breast cancer cells

Common genetic variants in the repressive GATA-family transcription factor (TF) TRPS1 locus are associated with breast cancer risk, and luminal breast cancer cell lines are particularly sensitive to TRPS1 knockout. We introduced an inducible degron tag into the native TRPS1 locus within a luminal breast cancer cell line to identify the direct targets of TRPS1 and determine how TRPS1 mechanistically regulates gene expression. We acutely deplete over 80 percent of TRPS1 from chromatin within 30 minutes of inducing degradation. We find that TRPS1 regulates transcription of hundreds of genes, including those related to estrogen signaling. TRPS1 directly regulates chromatin structure, which causes estrogen receptor alpha (ER) to redistribute in the genome. ER redistribution leads to both repression and activation of dozens of ER target genes. Downstream from these primary effects, TRPS1 depletion represses cell cycle-related gene sets and reduces cell doubling rate. Finally, we show that high TRPS1 activity, calculated using a gene expression signature defined by primary TRPS1-regulated genes, is associated with worse breast cancer patient prognosis. Taken together, these data suggest a model in which TRPS1 modulates the genomic distribution of ER, both activating and repressing transcription of genes related to cancer cell fitness.

Elucidating the relationship between breast cancer and brain cortical structure: a Mendelian randomization study

Cancer-associated cognitive impairment is a significant challenge for individuals who have survived breast cancer, affecting their quality of life. In this study, we conducted an inaugural comprehensive Mendelian randomization analysis discerning the causal relationship between breast cancer, including its two subtypes, and the cerebral cortical structure. Our analysis indicated that estrogen receptor-negative breast cancer significantly decreased surface area (β = -593.01 mm2, 95% CI: -1134.9 to -51.1 mm2, P = 0.032). At the regional level, estrogen receptor-negative breast cancer showed a significant association with surface area and thickness in 17 cortical regions. These regions included the insula, posterior cingulate, superior frontal, precuneus, fusiform, lateral occipital, and rostral middle frontal. Specifically, estrogen receptor-negative breast cancer had a significant impact on decreasing the surface area of the insula without considering global weight (β = -14.09 mm2, 95% CI: -22.91 to -5.27 mm2, P = 0.0017). The results from meta-analysis and LD Score Regression provide support for our findings. This investigation unveils the correlations between breast cancer, its various subcategories, and the cerebral cortical structure. Notably, breast cancer of the estrogen receptor-negative variety may elicit more widespread cerebral atrophy.

Use of Multiple Machine Learning Approaches for Selecting Urothelial Cancer-Specific DNA Methylation Biomarkers in Urine

Diagnosing urothelial cancer (UCa) via invasive cystoscopy is painful, specifically in men, and can cause infection and bleeding. Because the UCa risk is higher for male patients, urinary non-invasive UCa biomarkers are highly desired to stratify men for invasive cystoscopy. We previously identified multiple DNA methylation sites in urine samples that detect UCa with a high sensitivity and specificity in men. Here, we identified the most relevant markers by employing multiple statistical approaches and machine learning (random forest, boosted trees, LASSO) using a dataset of 251 male UCa patients and 111 controls. Three CpG sites located in ALOX5, TRPS1 and an intergenic region on chromosome 16 have been concordantly selected by all approaches, and their combination in a single decision matrix for clinical use was tested based on their respective thresholds of the individual CpGs. The combination of ALOX5 and TRPS1 yielded the best overall sensitivity (61%) at a pre-set specificity of 95%. This combination exceeded both the diagnostic performance of the most sensitive bioinformatic approach and that of the best single CpG. In summary, we showed that overlap analysis of multiple statistical approaches identifies the most reliable biomarkers for UCa in a male collective. The results may assist in stratifying men for cystoscopy.

Trichorhinophalangeal Syndrome Type 1 Is a Highly Sensitive and Specific Marker for Diagnosing Triple-Negative Breast Carcinomas on Cytologic Samples

CONTEXT.—

Definitive diagnosis of metastatic triple-negative breast carcinoma (TNBC) is challenging on cytologic samples. Recent studies demonstrated that trichorhinophalangeal syndrome type 1 (TRPS1) is a highly sensitive and specific marker for diagnosing breast carcinomas, including TNBC, on surgical specimens.

OBJECTIVE.—

To evaluate TRPS1 expression in TNBCs on cytologic samples and a large series of nonbreast tumors on tissue microarray sections.

DESIGN.—

Immunohistochemical (IHC) analysis of TRPS1 and GATA-binding protein 3 (GATA3) was performed on 35 TNBC cases on surgical specimens, and 29 consecutive TNBC cases on cytologic specimens. IHC analysis of TRPS1 expression was also performed on 1079 nonbreast tumors on tissue microarray sections.

RESULTS.—

Of the surgical specimens, 35 of 35 TNBC cases (100%) were positive for TRPS1, all with diffuse positivity, whereas 27 of 35 (77%) were positive for GATA3, with diffuse positivity in 7 cases (26%). Of the cytologic samples, 27 of 29 TNBC cases (93%) were positive for TRPS1, with diffuse positivity in 20 cases (74%), whereas 12 of 29 (41%) were positive for GATA3, with diffuse positivity in 2 cases (17%). Of the nonbreast malignant tumors, TRPS1 expression was seen in 9.4% (3 of 32) of melanomas, 10.7% (3 of 28) of small cell carcinomas of the bladder, and 9.7% (4 of 41) of ovarian serous carcinomas.

CONCLUSIONS.—

Our data confirm that TRPS1 is a highly sensitive and specific marker for diagnosing TNBC cases on surgical specimens as reported in the literature. In addition, these data demonstrate that TRPS1 is a much more sensitive marker than GATA3 in detecting metastatic TNBC cases on cytologic samples. Therefore, inclusion of TRPS1 in the diagnostic IHC panel is recommended when a metastatic TNBC is suspected.

TRPS1 expression in primary and metastatic prostatic adenocarcinoma, muscle invasive bladder urothelial carcinoma, and breast carcinoma: Is TRPS1 truly specific and sensitive for a breast primary?

Trichorhinophalangeal syndrome type 1 (TRPS1) has been reported to be a sensitive and specific immunohistochemical (IHC) marker for breast carcinomas, especially when determining primary site of origin. However, there is limited data on TRPS1 expression in prostate and bladder cancers. A two-phase study was performed with 1) an exploratory cohort analyzing TRPS1 gene alterations in prostate, bladder, and breast carcinoma and TPRS1 mRNA expression data in prostate and bladder carcinoma; and 2) TRPS1 and GATA3 IHC in a confirmatory cohort in prostate, bladder, and breast carcinoma samples. Gene alterations were identified in a subset of breast, bladder, and prostate carcinomas and mRNA was consistently detected. In the IHC cohort, 183/210 (87.1 %) of breast, 22/69 (31.9 %) of prostate, and 20/73 (27.4 %) of urothelial carcinomas showed staining with TRPS1. Intermediate to high expression of TRPS1 was observed in 173/210 (82.8 %) of breast, 17/69 (24.6 %) of prostate, and 15/73 (20.5 %) of urothelial carcinomas. Furthermore, in prostate cancer, 26.9 % of pelvic lymph node metastases and 50 % in sites of distant metastases showed expression. Increased TRPS1 mRNA expression (p = 0.032) and IHC expression (p = 0.040) correlated with worse overall survival in bladder cancer. By comparison, GATA3 IHC stained 136/210 (64.8 %) of breast, 0/69 (0 %) of prostate, and 63/73 (93 %) of bladder carcinomas. Intermediate to high expression of GATA3 was seen in 131/210 (62.4 %) of breast and 63/73 (93 %) of bladder carcinomas. This study shows there is significant staining of TRPS1 in bladder and prostate cancers. As a result, comprehensive studies are needed to establish the true specificity of TRPS1 IHC stain across various tumor types before its widespread clinical adoption.

Updates in the Use of Immunohistochemical Stains in Breast and Gynecologic Pathology

CONTEXT.—

The use of immunohistochemical stains in breast and gynecologic pathology has become increasingly complex, with various diagnostic, prognostic, and predictive applications.

OBJECTIVE.—

To provide an update and review of immunohistochemical stains used in the practice of breast and gynecologic pathology. Established and new entities are reviewed, with descriptions of histomorphology and immunohistochemical staining patterns and discussion of interpretive pitfalls.

DATA SOURCES.—

Data were obtained from review of the English-language literature and firsthand experience of the authors in breast and gynecologic pathology.

CONCLUSIONS.—

Many entities in breast and gynecologic pathology benefit from evaluation with various immunohistochemical stains. These studies not only aid in the diagnosis and staging of tumors but also can provide prognostic and predictive information. Updated guidelines for recommended ancillary studies such as mismatch repair, p53, and human epidermal growth factor receptor 2 (HER2) studies in endometrium, as well as estrogen and progesterone receptors and HER2 in breast, are discussed. Finally, the use and interpretation of established and novel immunohistochemical stains are discussed in various breast and gynecologic malignancies.

TRPS1 expression in primary and secondary extramammary Paget diseases: An immunohistochemical analysis of 93 cases

Extramammary Paget disease (EMPD) predominantly manifests de novo as primary EMPD, with less than 30 % of cases associated with underlying internal malignancy (secondary EMPD). Differentiating primary from secondary EMPDs based solely on histopathology poses challenges, often necessitating supplementary screening, such as endoscopy or imaging studies, to definitively exclude underlying carcinomas like colonic adenocarcinoma. Recently, TRPS1 immunohistochemistry, initially identified as a sensitive and specific marker for carcinomas and mesenchymal tumors of mammary origin, has been proposed for EMPD. In this study, we conducted a systematic assessment of TRPS1 expression across 93 EMPD cases, comprising 82 primary EMPDs and 11 secondary EMPDs. Our aim was to assess the potential utility of TRPS1 as a marker to differentiate between primary and secondary EMPDs. Our findings revealed that 88 % (72/82) of primary EMPDs displayed TRPS1 expression, while secondary EMPDs consistently lacked TRPS1 expression (100 %; 11/11). Within the primary EMPD group, consistent TRPS1 immunoreactivity was observed in lesions originating outside the perianal region, such as the groin/inguinal area, axilla, and trunk. Interestingly, a majority (91 %; 10/11) of primary EMPDs originating in the perianal region exhibited an absence of TRPS1 expression. Upon excluding cases of perianal primary EMPDs, the sensitivity and specificity of TRPS1 for primary EMPDs reached 100 %. Our findings suggest that TRPS1 expression holds notable sensitivity and specificity for primary EMPDs, particularly when arising from non-perianal cutaneous sites. Hence, in suitable clinical contexts, TRPS1 immunohistochemistry may emerge as a promising and valuable tool for distinguishing primary and secondary EMPDs.

Comprehensive analysis of cancer of unknown primary and recommendation of a histological and immunohistochemical diagnostic strategy from China

BACKGROUND

Previous studies on cancer of unknown primary (CUP) mainly focus on treatment and prognosis in western populations and lacked clinical evaluation of different IHC markers, so this study aimed to evaluate characteristics of CUP and recommend a diagnostic strategy from a single center in China.

METHODS AND RESULTS

Data of 625 patients with CUP were retrospectively collected and reviewed. The patients ranged in age from 20 to 91 years, with a female-to-male ratio of 1.3:1. The predominant histological type was poor or undifferentiated adenocarcinomas (308; 49.3%). The results of Canhelp-Origin molecular testing for the identification of the tissue of origin in 262 of 369 patients (71.0%) were considered predictable (similarity score > 45), with the most common predicted primary tumor site being the breast (57, 21.8%). Unpredictable molecular results correlated with more aggressive clinical parameters and poor survival. Thee positivity rates of several targeted antibodies (GATA3, GCDFP15, TTF1, Napsin A, and PAX8), based on the clinically predicted site, were lower than those reported for the corresponding primary tumors. Nonetheless, TRPS1 and INSM1 were reliable markers of predicted breast carcinoma (75.0%) and neuroendocrine tumors (83.3%), respectively. P16 expression, as well as HPV and EBER testing contributed significantly to the diagnosis of squamous cell carcinomas. Survival analysis revealed that older ages (> 57), ≥ 3 metastatic sites, non-squamous cell carcinomas, bone/liver/lung metastases, unpredictable molecular results, and palliative treatment correlated with poor overall survival.

CONCLUSIONS

We recommend a CUP diagnostic strategy involving the use of targeted antibody panels as per histological findings that is potentially applicable in clinical practice. The markers TRPS1, INSM1, and P16 expression, as well as HPV and EBER testing are particularly valuable in this aspect. Molecular testing is also predictive of survival rates.

Current Approach to Undifferentiated Neoplasms, With Focus on New Developments and Novel Immunohistochemical Stains

CONTEXT.—

Workup of the poorly differentiated or undifferentiated tumor remains a significant and challenging entity in the practice of anatomic pathology. Particularly in the setting of small biopsies and limited material, these cases demand a balanced approach that considers the patient's clinical and radiologic presentation, a basic assessment of tumor morphology, a reasonably broad immunohistochemical panel, and diligent preservation of tissue for prognostic and therapeutic studies.

OBJECTIVE.—

To illustrate some of the new and emerging immunohistochemical markers in the evaluation of tumors with undifferentiated or poorly differentiated morphology, with a focus on the workup in limited tissue samples to raise awareness of the issues involved with the pathologic workup in these challenging tumors.

DATA SOURCES.—

A literature review of new ancillary studies that can be applied to cytologic specimens was performed.

CONCLUSIONS.—

Knowledge of the patient's history and communication with the patient's clinical team is essential in formulating a differential diagnosis that can appropriately limit the differential diagnosis based on morphology, especially in small specimens. This information, in conjunction with classifying the tumor morphology (eg, epithelioid, spindled, neuroendocrine, basaloid/biphasic, mixed) gives a logical approach to choosing an initial immunohistochemical panel. Fortunately, immunohistochemistry is evolving quickly in the wake of groundbreaking molecular studies to develop new and better markers to further classify these difficult tumors beyond where we traditionally have been able to go.

High-throughput analysis of CircRNA in cows with naturally infected Staphylococcus aureus mammary gland

Circular RNAs (CircRNA) are a special type of non-coding RNA molecule with a closed ring structure and are not affected by RNA exonucases. It has stable expression, is not easy to degrade, and exists in most eukaryotes. However, circRNA regulation of cow mastitis has not been widely recognized. Mammary epithelial tissues were collected from healthy Holstein cows (HCN) and mastitis Holstein cows (HCU). RNA sequencing (RNA SEQ) was performed for the differentially expressed circRNAs, and analysis results showed that 19 differentially expressed circRNAs were identified in HCN and HCU, among which 6 circRNAs were up-regulated and 13 circRNAs were down-regulated. We randomly selected nine circRNAs for Q-PCR verification, and the results showed consistent expression. Three circRNAs: circRNA2860, circRNA5323 and circRNA4027 were confirmed to be significantly differentially expressed circRNAs in cow mastitis. Also, their host genes TRPS1, SLC12A2 and MYH11 might be directly or indirectly play a role in cow mastitis. Furthermore, RNA polymerase transcription factor binding and tight junction are most enriched in GO and KEGG pathways, respectively. In addition, the regulatory network of circRNA-miRNA has been inferred from a bioinformatics perspective, which may help to understand the underlying molecular mechanism of circRNAs involved in regulating mastitis in cows.