T regulatory lymphocytes specific for SARS-CoV-2 display increased functional plasticity.

The study of phenotypic and functional characteristics of immune cells involved in host response to SARS-CoV-2 is relevant for understanding COVID-19 pathogenesis and individual differences in disease progression. We have analyzed chemokine receptor expression in SARS-CoV-2-specific CD4+ T lymphocytes from vaccinated donors, and have found an increase of CCR9+ and CCR6+ cells. CCR9+ specific CD4+ cells are enriched in T regulatory (Treg) lymphocytes. These cells specifically show heterogeneous regulatory activity, associated with different profiles of CCR9/CCR6 expression, individual differences in IL-10 and IL-17 production, and variable FoxP3 and Notch4 expression. A higher heterogeneity in FoxP3 is selectively observed in convalescent individuals within vaccinated population. Accordingly, SARS-CoV-2-specific CD4+ lymphocytes from COVID-19 patients are also enriched in CCR9+ and CCR6+ cells. CCR6+ specific Treg lymphocytes are mainly increased in critically ill individuals, indicating a preferential role for these cells in lung injury pathogenesis. We provide experimental evidence for a SARS-CoV-2-specific Treg population with increased plasticity, which may contribute to the differential pathogenic response against SARS-CoV-2 among individuals, and underlie the development of autoimmune conditions following SARS-CoV-2 infection.

Immune-related gene expression signatures: a step forward in the stratification of patients with ovarian clear cell carcinoma†.

Clear cell carcinoma of the ovary (CCC) is one of the five major histological types of ovarian cancer and presents specific clinicopathological features, such as a higher prevalence in the Asian population and a poor response to conventional chemotherapy. In a recent publication in The Journal of Pathology, Heong, Tan, Miwa et al demonstrated the heterogeneity of the immune landscape of CCC. They reported the immune signatures observed in a large cohort of CCC, including tumours from both Asian and Caucasian women. The authors analysed three cohorts from Europe, Japan, and Singapore, with a total of 246 tumours, and evaluated 730 immune-related genes using NanoString technology. The study revealed four main transcriptional subtypes characterised by the expression of specific sets of genes: PD1-high (11%), CTLA4-high (29%), antigen-presentation (42%), and a pro-angiogenic subtype (18%). The two main conclusions of the study were: (1) that CCCs in women of Asian and Caucasian descent share significant molecular similarities, since all four molecular signatures are present in all the cohorts analysed, without any evident differences in frequency; and (2) that the PD1-high and CTLA4-high subtypes were associated with worse clinical outcomes and may be useful when stratifying treatment in early-stage tumours. The immune signature could represent a promising biomarker of immunotherapy response if future prospective studies confirm it. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Extramammary Paget Disease: a Therapeutic Challenge, for a Rare Entity.

PURPOSE OF REVIEW: Extramammary Paget disease (EMPD) is a rare entity which is more frequently localized at the vulva, though it only accounts for 1-2% of vulvar neoplasms. It is a primary cutaneous adenocarcinoma whose cell of origin is still a matter of controversy: it can either arise from apocrine/eccrine glands or from stem cells. The diagnosis demands a biopsy and entails a histopathological analysis by which cells show similar characteristics as breast Paget disease. RECENT FINDINGS: Treatment approach can entail surgery, radiotherapy, photodynamic therapy, systemic chemotherapy, and topical chemotherapy. For metastatic disease, many different chemotherapy regimens have been explored and even targeted therapy can play an important role in this disease. Since almost 30-40% of patients overexpress HER-2, trastuzumab and anti-HER-2 therapies can be employed in this setting. Due to its low incidence, there is almost no specific evidence on therapeutic interventions for this disease. Thus, there is a neat unmet need for molecular characterization of EMPD and diagnostic tools that allow clinicians to guide treatment both in the early and in the advanced disease settings. In this review, we aim to summarize available evidence about diagnosis and treatment of EMPD, both localized and metastatic, and to provide a comprehensive analysis that may help clinicians for therapeutic decisions.

The Prognostic Significance of Tumor-Infiltrating Lymphocytes, PD-L1, BRCA Mutation Status and Tumor Mutational Burden in Early-Stage High-Grade Serous Ovarian Carcinoma-A Study by the Spanish Group for Ovarian Cancer Research (GEICO).

Early stages are under-represented in studies on the molecular and immune features of high-grade serous ovarian carcinoma (HGSOC), and specific studies focused on early-stage HGSOC are required for a better prognostic stratification and to personalize chemotherapy. The aim of this study was to determine the prognostic significance of CD8+ and CD4+ tumor-infiltrating lymphocytes (TILs), tumoral cell PD-L1 expression, BRCA mutational status and tumor mutation burden (TMB) in early-stage HGSOC. A retrospective study was performed on stage I and II HGSOC from the Molecular Reclassification of Early Stages of Ovarian Cancer (RECLAMO) cohort from the Spanish Group of Ovarian Cancer Research (GEICO). Centralized histological typing was performed based on morphological and immunohistochemical features. Intraepithelial (i) and stromal (s) CD8+ and CD4+ T cells and PD-L1 were evaluated on tissue microarrays by immunohistochemistry. BRCA1 and BRCA2 mutation status and TMB were analyzed in tumor DNA using next-generation sequencing. The study included 124 tumors. High iCD8+ (>20 TILs/core), low/intermediate CD4+ (<20 TILs/core) and high CD8+/CD4+ ratio (>35/core) were associated with favorable outcomes. Tumor cell PD-L1 expression (TPS ≥ 1) was present in only 8% of tumors. In total, 11 (16%) and 6 (9%) out of 69 HGSOC tested carried pathogenic or likely pathogenic BRCA1 or BRCA2 mutations, respectively. Median TMB of 40 tumors analyzed was 5.04 mutations/Mb and only 6 tumors had 10 or more mutations/Mb. BRCA status and TMB were not associated with TILs or prognosis. When compared with studies on advanced HGSOC, our results suggested that prognostic variables differed according to stage and that more studies focused on early stages of HGSOC are needed to better stratify these tumors.

Pulmonary vascular proliferation in patients with severe COVID-19: an autopsy study.

Diffuse alveolar damage and thrombi are the most common lung histopathological lesions reported in patients with severe COVID-19. Although some studies have suggested increased pulmonary angiogenesis, the presence of vascular proliferation in COVID-19 lungs has not been well characterised. Glomeruloid-like microscopic foci and/or coalescent vascular proliferations measuring up to 2 cm were present in the lung of 14 out of 16 autopsied patients. These lesions expressed CD31, CD34 and vascular endothelial cadherin. Platelet-derived growth factor receptor-ß immunohistochemistry and dual immunostaining for CD34/smooth muscle actin demonstrated the presence of pericytes. These vascular alterations may contribute to the severe and refractory hypoxaemia that is common in patients with severe COVID-19.

Vulvar Pilomatrix Carcinoma: Morphologic and Molecular Features.

Pilomatrix carcinoma (PC) is a rare malignant variant of pilomatrixoma, a skin adnexal tumor originating from hair matrix cells. It is most often located in the head, neck region, upper back and upper extremities. PC has a locally aggressive behavior but metastasis only occur in 10% of cases. Mutations in CTNNB1, the encoding gene of beta-catenin, have been found in both pilomatrixoma and PC, but other molecular alterations are unknown. The authors present a case of PC in the clitoris, the third known reported case located on the external genitalia. The tumor followed an unusual clinical course with the development of multiple metastases. Next-generation sequencing analysis of the tumor identified, in addition to a characteristic CTNNB1 mutation, pathogenic mutations in PTEN, PIK3CA, and ARID1A, which could explain the aggressive course of the disease. The diagnostic criteria of PC and the differential diagnoses of this unusual tumor in the genital area are discussed.

Epithelial Mesenchymal Transition and Immune Response in Metaplastic Breast Carcinoma.

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent triple negative (TN) invasive carcinomas with poor prognosis. MBCs have a different clinical behavior from other types of triple negative breast cancer (TNBC), being more resistant to standard chemotherapy. MBCs are an example of tumors with activation of epithelial-mesenchymal transition (EMT). The mechanisms involved in EMT could be responsible for the increase in the infiltrative and metastatic capacity of MBCs and resistance to treatments. In addition, a relationship between EMT and the immune response has been seen in these tumors. In this sense, MBC differ from other TN tumors showing a lower number of tumor-infiltrating lymphocytes (TILS) and a higher percentage of tumor cells expressing programmed death-ligand 1 (PD-L1). A better understanding of the relationship between the immune system and EMT could provide new therapeutic approaches in MBC.

Molecular genetic heterogeneity in undifferentiated endometrial carcinomas.

Undifferentiated and dedifferentiated endometrial carcinomas are rare and highly aggressive subtypes of uterine cancer, not well characterized at a molecular level. To investigate whether dedifferentiated carcinomas carry molecular genetic alterations similar to those of pure undifferentiated carcinomas, and to gain insight into the pathogenesis of these tumors, we selected a cohort of 18 undifferentiated endometrial carcinomas, 8 of them with a well-differentiated endometrioid carcinoma component (dedifferentiated endometrioid carcinomas), and studied them by immunohistochemistry and massive parallel and Sanger sequencing. Whole-exome sequencing of the endometrioid and undifferentiated components, as well as normal myometrium, was also carried out in one case. According to The Cancer Genome Atlas classification, we distributed 95% of the undifferentiated carcinomas in this series as follows: (a) hypermutated tumors with loss of any mismatch repair protein expression and microsatellite instability (eight cases, 45%); (b) ultramutated carcinomas carrying mutations in the exonuclease domain of POLE (two cases, 11%); (c) high copy number alterations (copy-number high) tumors group exhibiting only TP53 mutations and high number of alterations detected by FISH (two cases, 11%); and (d) low copy number alterations (copy-number low) tumors with molecular alterations typical of endometrioid endometrial carcinomas (five cases, 28%). Two of the latter cases, however, also had TP53 mutations and higher number of alterations detected by FISH and could have progressed to a copy-number high phenotype. Most dedifferentiated carcinomas belonged to the hypermutated group, whereas pure undifferentiated carcinomas shared molecular genetic alterations with copy-number low or copy-number high tumors. These results indicate that undifferentiated and dedifferentiated endometrial carcinomas are molecularly heterogeneous tumors, which may have prognostic value.

Single-cell RNA sequencing in endometrial cancer: exploring the epithelial cells and the microenvironment landscape.

Single-cell RNA sequencing (scRNA-seq) technology has emerged as a powerful tool for dissecting cellular heterogeneity and understanding the intricate biology of diseases, including cancer. Endometrial cancer (EC) stands out as the most prevalent gynecological malignancy in Europe and the second most diagnosed worldwide, yet its cellular complexity remains poorly understood. In this review, we explore the contributions of scRNA-seq studies to shed light on the tumor cells and cellular landscape of EC. We discuss the diverse tumoral and microenvironmental populations identified through scRNA-seq, highlighting the implications for understanding disease progression. Furthermore, we address potential limitations inherent in scRNA-seq studies, such as technical biases and sample size constraints, emphasizing the need for larger-scale research encompassing a broader spectrum of EC histological subtypes. Notably, a significant proportion of scRNA-seq analyses have focused on primary endometrioid carcinoma tumors, underscoring the need to incorporate additional histological and aggressive types to comprehensively capture the heterogeneity of EC. By critically evaluating the current state of scRNA-seq research in EC, this review underscores the importance of advancing towards more comprehensive studies to accelerate our understanding of this complex disease.