AIRE illuminates the feature of medullary thymic epithelial cells in thymic carcinoma.

Despite the clear distinction between cortical (cTECs) and medullary thymic epithelial cells (mTECs) in physiology, the cell of origin of thymic carcinomas (TCs) and other thymic epithelial tumors remained enigmatic. We addressed this issue by focusing on AIRE, an mTEC-specific transcriptional regulator that is required for immunological self-tolerance. We found that a large proportion of TCs expressed AIRE with typical nuclear dot morphology by immunohistochemistry. AIRE expression in TCs was supported by the RNA-seq data in the TCGA-THYM database. Furthermore, our bioinformatics approach to the recent single-cell RNA-seq data on human thymi has revealed that TCs hold molecular characteristics of multiple mTEC subpopulations. In contrast, TCs lacked the gene signatures for cTECs. We propose that TCs are tumors derived from mTECs.

Pleomorphic type undifferentiated gastric sarcoma, report of a case.

Reports on pleomorphic type of undifferentiated sarcoma (PUS) originating from the gastrointestinal tract, especially the stomach, are extremely rare. We herein report a case of pleomorphic type undifferentiated gastric sarcoma. The patient was a 67-year-old woman. The chief complaint was upper abdominal pain. Upper gastrointestinal endoscopy, ultrasonography, and contrast-enhanced computed tomography showed two submucosal tumors at the greater curvature of the fundus and the lesser curvature of the gastric angle. Endoscopic ultrasound-guided fine-needle aspiration revealed a c-kit-negative spindle cell tumor at the greater curvature of the fundus. Total gastrectomy, splenectomy, and partial resection of the diaphragm and liver were performed. One lesion had invaded the lateral segment of the liver, left diaphragm and spleen. The postoperative course was uneventful. Histopathological and immunohistochemical examinations of the resected specimen revealed PUS. Peritoneal dissemination was detected at 8 months after surgery. However, no effective therapeutic agents were adopted for chemotherapy. The patient had poor performance status due to disease progression and underwent best supportive care. The patient died 10 months after surgery. This case highlights the imaging, histological diagnosis, and treatment strategy for PUS originating from the stomach. Surgeons should be aware of PUS as a differential diagnosis in cases with submucosal tumor of the stomach.

Histological and immunohistochemical analysis of epithelial cells in epidermoid cysts in intrapancreatic accessory spleen.

BACKGROUND: Epidermoid cysts in intrapancreatic accessory spleen (ECIPAS) are a rare lesion. Its pathogenesis, including the origin of cystic epithelium, is not well established. We aimed to elucidate new aspects of the pathological features of ECIPAS to clarify its pathogenesis. METHODS: Six cases of ECIPAS were included in this study. As well as histopathological analysis, to elucidate the features and nature of cystic epithelial cells, immunohistochemical analysis including Pbx1 and Tlx1 and imaging mass spectrometry was performed. RESULTS: Histologically, the cysts were covered by either monolayered or multilayered epithelium. Immunohistochemistry revealed that the epithelial cells in multilayered epithelium exhibited different attributes between the basal and superficial layers. Few epithelial cells had abundant clear cytoplasm and were immunohistochemically positive for adipophilin, suggesting lipid-excreting function. The intracystic fluid contained cholesterol clefts and foamy macrophages, and imaging mass spectrometry revealed the accumulation of lipids. Immunohistochemical analysis indicated that the epithelial cells were positive for Pbx1 in some cases. CONCLUSION: Novel histological features of epithelial cells of ECIPAS were indicated. Although more cases need to be evaluated, we propose that the cause of ECIPAS may be different from that of pancreatic ductal origin. J. Med. Invest. 70 : 251-259, February, 2023.

Axillary lymphangioma that developed following COVID-19 vaccination: a case report.

BACKGROUND: Extensive vaccination programs are being implemented worldwide for coronavirus disease 2019 (COVID-19). With the spread of vaccination, swelling of the lymph nodes after vaccination is frequently seen. We encountered a patient who developed left axillary lymphadenoma following vaccine administration. CASE PRESENTATION: The patient was a Japanese woman in her 80 s who had previously undergone surgery for right breast cancer. She received two injections of the Pfizer-BioNTech COVID-19 vaccine in her left arm. Approximately 3 months later, she complained of left axillary swelling, and imaging resulted in a diagnosis of left axillary lymphangioma. In accordance with the patient's wishes, we performed axillary mass resection. The pathological diagnosis was lymphangioma. CONCLUSION: Our examination findings indicated that congestion of the axillary lymph vessels might have been caused by upper-arm injections of the COVID-19 vaccine.

Triple-negative breast cancer and basal-like subtype†: Pathology and targeted therapy.

Triple-negative breast cancer (TNBC) is a heterogenous disease. For personalized medicine, it is essential to identify and classify tumor subtypes to develop effective therapeutic strategies. Although gene expression profiling has identified several TNBC subtypes, classification of these tumors remains complex. Most TNBCs exhibit an aggressive phenotype, but some rare types have a favorable clinical course. In this review, we summarize the classification and characteristics related to the various TNBC subtypes, including the rare types. Therapeutic methods that are suitable for each subtype are also discussed. Of the intrinsic breast cancer subtypes identified by gene expression analysis, the basal-like subtype specifically displayed decreased expression of an estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) cluster. We also present results that characterize the TNBC and basal-like phenotypes. TNBC may be categorized into four major classes : basal-like, immune-enriched, mesenchymal, and luminal androgen receptor. Therapeutic strategies for each subtype have been proposed along with newly approved targeted therapies for TNBC, such as immune checkpoint inhibitors. Understanding the classification of TNBC based on gene expression profiling in association with clinicopathological factors will facilitate accurate pathological diagnosis and effective treatment selection. J. Med. Invest. 68 : 213-219, August, 2021.

Clinical Significance of Vascular Endothelial Growth Factor Expression and Microvessel Density in Invasive Cervical Cancer.

To determine whether vascular endothelial growth factor (VEGF) expression and microvessel density are predictive of prognosis in cases of invasive cervical cancer, correlations among VEGF expression, microvessel density, and clinicopathological parameters were identified. VEGF expression was evaluated in 50 cervical cancer samples by immunohistochemical staining. Microvessel density was assessed by immunostaining for CD31-positive endothelial cells in the most vascularized areas of tumors. VEGF expression and microvessel density were significantly higher in adenocarcinomas than in squamous cell carcinomas. However, in cases of adenocarcinoma, no significant correlations were found among VEGF expression, microvessel density, and clinicopathological parameters. In contrast, for squamous cell carcinomas, microvessel density was significantly higher in cases at an advanced stage and in those with several other poor prognostic factors. The finding that cervical adenocarcinomas exhibited greater VEGF expression and microvessel density than squamous cell carcinomas may explain the poorer prognosis of adenocarcinoma compared with squamous cell carcinoma. Moreover, microvessel density in squamous cell carcinomas was significantly correlated with poor prognostic factors. Therefore, there is possibility that bevacizumab, a humanized monoclonal antibody against VEGF-A, may be useful in the initial treatment targeting angiogenesis for early-stage cervical cancer.

Gene gun-mediated skin transfection with FL gene suppresses the growth of murine fibrosarcoma.

AIM: Particle-mediated transfection is known as an efficient method of non-viral gene transfer. Flt3 ligand (FL) is a growth factor for hematopoietic progenitors; it promotes the growth of dendritic cells (DC). DCs are powerful antigen-presenting cells (APCs) and show a remarkable capacity to stimulate antigen-specific T-cell responses. In this study, we intended to investigate the suppressive effect on tumor growth by gene gun-mediated transfer of FL in a murine model. METHODS: C57BL/6J mice were injected intradermally with MCA205 cells. DNA (pNGVL-hFLex)-coated gold particles were delivered to the mouse skin surrounding the target tumor. The expression of FL was determined by RT-PCR. Analyses by immunohistochemistry and fluorescence-activated cell sorter (FACS) revealed an increase in the number of DC after treatment with FL. RESULTS: Gene gun-mediated pNGVL-hFLex transfer significantly inhibited the growth of the MCA205 tumor. FL transfer markedly increased the number of CD11c(+) DCs in the tumor tissue. Further, the FL-transfected mice exhibited a significantly higher number of CD80(+) MHC-II cells. CONCLUSION: We successfully performed FL therapy using an in vivo gene gun in order to effectively mobilize DCs in situ and induce suppressive immunity.