Flagellin suppresses experimental asthma by generating regulatory dendritic cells and T cells.

BACKGROUND: Although the hygiene hypothesis suggests that microbial infections could subvert asthma and thus a microbial product might serve as a therapeutic adjuvant for asthma, the relationship between bacterial components and asthma is complex. Recently, low levels of flagellin, the Toll-like receptor (TLR) 5 ligand, have been reported to promote asthma. OBJECTIVE: We show that a therapeutic dose of flagellin suppresses asthma and that the effect occurs through generating regulatory dendritic cells (rDCs) and regulatory T (Treg) cells. METHODS: Ovalbumin (OVA)-induced wild-type and TLR5 knockout asthmatic mice were treated intranasally with a mixture of OVA and 10 µg of a flagellin B (FlaB; of Vibrio vulnificus). OVA/FlaB-treated rDCs were adoptively transferred to mice with OVA-induced asthma. Anti-CD25 mAb was used to deplete Treg cells. A mixture of house dust mite (HDM) and FlaB was used to treat mice with HDM-induced asthma. Blood CD14(+) monocyte-derived dendritic cells from HDM-sensitive asthmatic patients were treated with FlaB and incubated with autologous CD4(+) T cells. RESULTS: An OVA/FlaB mixture ameliorated OVA-induced asthma by inhibiting TH1/TH2/TH17 responses in a TLR5-dependent manner through generating rDCs and Treg cells. The adoptive transfer of OVA/FlaB-treated dendritic cells inhibited OVA-induced asthma, whereas the depletion of CD25(+) cells eliminated the inhibitory effect. A similar effect of FlaB was observed in mice with HDM-induced asthma. In patients with HDM-sensitive asthma, FlaB-treated rDCs inhibited HDM-stimulated TH1/TH2 responses while enhancing Treg cells in an IL-10-dependent manner. CONCLUSION: These findings collectively suggest that flagellin could be used as a tolerogenic adjuvant to treat allergic asthma.

Expression of matrix metalloproteinases and their inhibitors in different immunohistochemical-based molecular subtypes of breast cancer.

BACKGROUND: Metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs) are involved in several key pathways of tumor growth, invasion and metastasis, but little is known about their expression according to different molecular subtypes of breast cancer. The aims of this study were to assess the prevalence and clinical significance of MMP and TIMP expression in invasive breast cancer and to determine its association with immunohistochemical-based molecular classification. METHODS: Tissue microarray sections were immunostained for estrogen receptor-α (ER-α), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), cytokeratin (CK) 5/6, epidermal growth factor receptor (EGFR) and with specific antibodies against MMP-1, 2, 7, 9, 11, 13, and 14 and TIMP-1, 2, and 3. Based on the immunostaining data from five of the markers used (ER-α, PR, HER2, EGFR and CK5/6), three major subtypes (123 luminal A, 31 basal-like, and 17 HER2-overexpressing) were selected. RESULTS: Statistically significant differences in the expression of MMPs and TIMPs among the three subtypes were found in tumoral MMP7 (P = 0.005), tumoral MMP-9 (P = 0.000), tumoral MMP-13 (P = 0.016) and stromal MMP-13 (P = 0.016). The incidence of tumoral MMP-9 expression in the HER2-overexpressing subtype was significantly higher than in the luminal A subtype (P = 0.021). Tumoral MMP-9 and stromal MMP-13 expression were significantly higher in the HER2-overexpressing subtype than in the basal-like subtype (P = 0.000 and P = 0.016, respectively). Tumoral MMP-7 expression was significantly higher in the basal-like subtype compared to luminal A (P = 0.007) and HER2-overexpressing subtype (P = 0.004). Tumoral MMP-13 showed a higher expression in the basal-like subtype than in the HER2-overexpressing subtype (P = 0.010). In multivariate analysis, stage and stromal MMP-1 expression were significantly related to overall survival. Stage was of independent prognostic significance for disease-free survival. CONCLUSION: We found some variations in MMP and TIMP expression among the immunohistochemical-based molecular subtypes of breast carcinomas, suggesting differences in their tumor pathophysiology. Additional studies are needed to determine the mechanisms underlying the differences of MMP and TIMP expression in the molecular subtypes for the development of specific therapeutic targets for breast cancer subtypes.

Insulin-like growth factor-II mRNA-binding protein 3 expression in effusion cytology: a marker for metastatic adenocarcinoma cells and a potential prognostic indicator in gastric adenocarcinoma.

OBJECTIVE: The aim of our study was to identify the diagnostic value of insulin-like growth factor-II mRNA-binding protein 3 (IMP3) in distinguishing metastatic adenocarcinoma cells (MAC) from reactive mesothelial cells (RMC) in effusions. We also investigated the role of IMP3 as a prognostic indicator for patients with malignant effusion. STUDY DESIGN: A total of 156 cell block specimens, including 116 malignant effusions with MAC and 40 benign effusions with RMC, were subjected to immunocytochemical staining for IMP3. RESULTS: Immunocytochemical studies showed positive staining for IMP3 in 91 of 116 (78.4%) cases of MAC and in 3 of 40 (7.5%) cases of RMC. With regard to distinguishing MAC from RMC, the IMP3 reactivity was found to be 78.4% sensitive and 92.5% specific with a positive predictive value of 96.8% and a negative predictive value of 59.7%. Diffuse IMP3 expression (>25%) in MAC from patients with gastric adenocarcinoma was associated with shorter survival (p = 0.001). CONCLUSION: Our data suggest that IMP3 is a helpful marker for differentiating MAC from RMC, and that diffuse IMP3 expression is a poor prognostic indicator in patients with gastric adenocarcinoma and malignant effusion.

Gastric-type adenocarcinoma of the uterine cervix presenting in urine cytology specimens: A case report and literature review.

Gastric-type endocervical adenocarcinoma (GEA) is a rare type adenocarcinoma of the uterine cervix that is unrelated to human papillomavirus (HPV). GEA is difficult to diagnose due to its bland-looking morphological characteristics and is therefore often underdiagnosed. Although abnormal cells may be seen on cervical cytology specimens, they are rarely diagnosed as malignant and are often classified as atypical glandular cells. As a result, GEA may be diagnosed at advanced stages, with cytology samples from other organs after it has already invaded adjacent organs. Here, we report a case of GEA diagnosed by both cytological and histological examinations of urinary bladder and uterine cervix, after being identified as a non-urothelial malignancy on a urine cytology. We also review and summarize the differential diagnoses for non-urothelial lesions, particularly for glandular lesions observed on urinary cytology specimens, as well as the cytological and histological characteristics of GEA.

Amelioration of experimental autoimmune encephalomyelitis by probiotic mixture is mediated by a shift in T helper cell immune response.

The immunomodulatory effect of probiotics has been shown mainly in gastro-intestinal immune disorders and little information is available on the inflammation of central nervous system. Recently we reported that IRT5 probiotics, a mixture of 5 probiotics, could suppress diverse experimental inflammatory disorders. In this study, we evaluated the prophylactic and therapeutic effects of IRT5 probiotics in experimental autoimmune encephalomyelitis (EAE), a T cell mediated inflammatory autoimmune disease of the central nervous system. Pretreatment of IRT5 probiotics before disease induction significantly suppressed EAE development. In addition, treatment with IRT5 probiotics to the ongoing EAE delayed the disease onset. Administration of IRT5 probiotics inhibited the pro-inflammatory Th1/Th17 polarization, while inducing IL10(+) producing or/and Foxp3(+) regulatory T cells, both in the peripheral immune system and at the site of inflammation. Collectively, our data suggest that IRT5 probiotics could be applicable to modulate T cell mediated neuronal autoimmune diseases, including multiple sclerosis.

Generation of regulatory dendritic cells and CD4+Foxp3+ T cells by probiotics administration suppresses immune disorders.

The beneficial effects of probiotics have been described in many diseases, but the mechanism by which they modulate the immune system is poorly understood. In this study, we identified a mixture of probiotics that up-regulates CD4(+)Foxp3(+) regulatory T cells (Tregs). Administration of the probiotics mixture induced both T-cell and B-cell hyporesponsiveness and down-regulated T helper (Th) 1, Th2, and Th17 cytokines without apoptosis induction. It also induced generation of CD4(+)Foxp3(+) Tregs from the CD4(+)CD25(-) population and increased the suppressor activity of naturally occurring CD4(+)CD25(+) Tregs. Conversion of T cells into Foxp3(+) Tregs is directly mediated by regulatory dendritic cells (rDCs) that express high levels of IL-10, TGF-beta, COX-2, and indoleamine 2,3-dioxygenase. Administration of probiotics had therapeutical effects in experimental inflammatory bowel disease, atopic dermatitis, and rheumatoid arthritis. The therapeutical effect of the probiotics is associated with enrichment of CD4(+)Foxp3(+) Tregs in the inflamed regions. Collectively, the administration of probiotics that enhance the generation of rDCs and Tregs represents an applicable treatment of inflammatory immune disorders.

Diagnostic usefulness of MUC1 and MUC4 for distinguishing between metastatic adenocarcinoma cells and reactive mesothelial cells in effusion cell blocks.

OBJECTIVE: The aim of our study was to determine the diagnostic value of MUC1 and MUC4 for distinguishing between metastatic adenocarcinoma cells (MAC) and reactive mesothelial cells (RMC) in effusion fluids. STUDY DESIGN: A total of 237 cell block specimens from pleural and peritoneal effusions, including 196 malignant effusions with MAC and 41 benign effusions with RMC, were stained with antibodies against MUC1 and MUC4. Membranous staining with or without cytoplasmic staining was considered to be positive. RESULTS: MUC1 immunoreactivity was observed in 194 (99.0%) of 196 cases of MAC and in 20 (48.8%) of 41 cases of RMC. MUC4 immunoreactivity was observed in 174 (88.8%) of 196 cases of MAC and in 4 (9.8%) of 41 cases of RMC. For distinguishing MAC from RMC, the MUC1 reactivity was found to be 99.0% sensitive and 51.2% specific with a positive predictive value of 90.7% and a negative predictive value of 91.3%. The sensitivity of MUC4 for MAC was 88.8%, the specificity was 90.2%, the negative predictive value was 62.7%, and the positive predictive value was 97.8%. CONCLUSION: Our data suggest that MUC4 appears to be a sensitive and specific marker for differentiating between MAC and RMC.

Uterine rupture due to adenomyosis in an adolescent: A case report and review of literature.

BACKGROUND: Uterine rupture is a fatal medical complication with a high mortality rate. Most cases of uterine rupture occur in late pregnancy or during labor and are mainly related to uterine scarring due to previous surgical procedures. Adenomyosis is a possible risk factor for uterine rupture. However, spontaneous uterine rupture due to severe adenomyosis in a non-gravida-teenaged female has not been reported in the literature to date. CASE SUMMARY: A 16-year-old girl was referred to our hospital for acute abdominal pain and hypovolemic shock with a blood pressure of 90/50 mmHg. Radiologic studies revealed a huge endometrial mass with multiple nodules in the lung, suggesting lung metastasis. The patient underwent an emergency total hysterectomy and wedge resection of the lung nodules. Histologically, the uterus showed diffuse adenomyosis with glandular and stromal dissociation. Lung nodules were endometrioma with massive hemorrhage. Immunohistochemistry demonstrated that the tumor cells were positive for PAX8, ER, and PR expression, leading to a final diagnosis of pulmonary endometriosis and uterine adenomyosis. Following surgery, the patient remains in good condition without recurrence. CONCLUSION: This is the first case of spontaneous uterine rupture due to adenomyosis in a non-gravida adolescent.

Usefulness of the human papillomavirus DNA chip test as a complementary method for cervical cytology.

Objectives: As a convenient and economical method of screening cervical cancer and precancerous pathologies, the Papanicolaou smear (Pap smear) has been most widely used. Nevertheless, it requires cytological changes for making diagnoses and reportedly has a high false-negative rate. In this study, the usefulness of the human papillomavirus (HPV) DNA chip test as a complementary method that can compensate for the defect of the Pap smear was investigated. Material and Methods: Of the 6516 patients who simultaneously underwent a Pap smear and an HPV DNA chip test at Chonnam National University Hospital between January 2015 and December 2016, 1897, an initial PAP smear-negative patients who had undergone an additional Pap smear during their 2-year follow-up period were selected for this study. Of the subject patients, 281 underwent a cervical biopsy. Results: The Pap smear follow-up of an initial Pap smear-negative subjects showed 53 (75.7%) HPV high-risk positive cases in the cytology low-grade lesion group (70 cases) and 46 (97.8%) HPV high-risk positive cases in the cytology high-grade lesion group (47 cases). The 281 biopsy cases included 67 biopsy low-grade lesion cases and 74 biopsy high-grade lesion cases, of which there were 45 (67.2%) and 67 (90.5%) HPV high-risk positive cases, respectively. The follow-up cytology on the high-risk HPV-positive subjects showed that the ratio of their high-grade lesions was 260.8 times greater than that of the high-risk HPV-negative subjects (OR = 260.8 and 95% CI: 36.1 and 1886.1); and their biopsy showed that the ratio of their high-grade lesions was 102.7 times greater than that of the HPV-negative subjects (OR = 102.7 and 95% CI: 14.0 and 753.3). Conclusion: The complementary use of the HPV DNA chip test may be useful in increasing the accuracy of screening examinations for the early diagnosis of uterine cervix cancer when combined with the Pap smear.

Primary duodenal dedifferentiated liposarcoma: A case report and literature review.

BACKGROUND: Dedifferentiated liposarcoma (DDLPS) is an extremely rare neoplasm that exhibits various morphologies. The tumor is characterized by immunoreactivity to MDM2 and CDK4 and can be confirmed by detecting MDM2 amplification via fluorescence in situ hybridization (FISH). Herein, we report an unusual case of DDLPS arising from the duodenum. CASE SUMMARY: A 64-year-old man presented with repeated abdominal pain and weight loss. Radiologic studies revealed a mass of the duodenum involving the pancreas. The patient was treated with pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor showed a high-grade sarcoma. Immunohistochemistry demonstrated that the tumor cells were positive for MDM2 and CDK4 expression. MDM2 amplification was detected via FISH, leading to the final diagnosis of DDLPS. Following surgery, the patient was treated in the intensive care unit due to peritonitis, and died 60 d after surgery. CONCLUSION: To the best of the authors' knowledge, this is the first case of primary duodenal DDLPS in Korea and the third case in the English-language literature. Care must be taken not to misdiagnose DDLPS as another high-grade tumor. Liposarcoma should be in the differential diagnosis list.

Mucin-positive epithelial mesothelioma of the peritoneum: small bowel involvement.

Mucin-positive epithelial mesothelioma has been reported in the peritoneum only once, and that mainly involved the stomach wall. We report the second peritoneal case and this is the first case mainly involving the small bowel wall. A 65-year-old man showed diffuse involvement from the duodenum to the ileum and metastatic masses in the left adrenal gland. Segmental resection of the small bowel was performed; 2 months later the patient died. Light microscopy showed diffusely anaplastic epithelioid cell proliferation and foci of glandular formation with granular mucinous materials in the cytoplasmic vacuoles or within glandular lumina. Histochemically, these mucin materials were PAS-positive and diastase-resistant. Immunohistochemically, the various mesothelial markers were positive, and a few adenocarcinoma markers were focally positive. Ultrastructurally, the tumor cells showed long slender microvilli on the apical surface, consistent with mesothelioma. Electron microscopy can play a decisive role in the case of ambiguous histochemical and immunohistochemical results.

Promoter methylation status of hMLH1, hMSH2, and MGMT genes in colorectal cancer associated with adenoma-carcinoma sequence.

PURPOSE: Epigenetic silencing of the DNA mismatch repair genes has been poorly described in colorectal carcinomas showing the classic adenoma-carcinoma pathway of carcinogenesis. The aim of this study was to investigate the methylation status of MutL homolog 1 (hMLH1), MutS homolog 2 (hMSH2), and O-6-methylguanine-DNA methyltransferase (MGMT) in a series of colorectal carcinomas that contain both adenomas and carcinomas. METHODS: Promoter methylation of hMLH1, hMSH2, and MGMT was evaluated in normal mucosa, adenoma, and carcinoma samples from 112 colorectal cancer patients. Methylation was assessed by bisulfite modification and methylation-specific PCR. Expression of the gene products was also examined by immunohistochemistry. RESULTS: Of the 112 adenomas, methylation was detected for hMLH1 (2, 1.8%), hMSH2 (9, 8.0%), and MGMT (38, 33.9%). In the carcinoma samples, methylation was seen in hMLH1 (2, 1.8%), hMSH2 (15, 13.4%), and MGMT (53, 47.3%). In normal mucosa, hMSH2 (6, 5.4%) and MGMT (12, 10.7%) were methylated, whereas hMLH1 was not. Immunohistochemical analysis revealed abnormal hMLH1 (14, 12.5%), hMSH2 (11, 9.8%), and MGMT (53, 47.3%) expression with a significant correlation between aberrant MGMT methylation and a loss of MGMT expression. CONCLUSIONS: These data suggest that CpG island methylation in hMSH2 and MGMT, but not hMLH1, is closely related to carcinogenesis in colorectal carcinomas presenting with a conventional adenoma-carcinoma sequence. Therefore, the detection of hMSH2 and MGMT methylation may have clinical significance in the evaluation of colon cancer patients and in tumor-specific management of the disease.

Assessment of DNA methylation for the detection of cervical neoplasia in liquid-based cytology specimens.

OBJECTIVE: DNA methylation is an early event in carcinogenesis. Testing for DNA methylation has potential in cancer screening. The aim of this study was to investigate the feasibility of methylated DNA detection as a screening tool for squamous cell carcinomas (SCC) and squamous intraepithelial lesions (SIL) in cervical scrapings. METHODS: A multiplex, nested, methylation-specific polymerase chain reaction approach was used to examine promoter methylation of 12 genes (CDH1, DAPK, GSTP1, HIC-1, HIN-1, hMLH1, MGMT, p16, RAR-beta, RASSF1A, SHP-1, and Twist) in biopsy-proven SCC (n=69), high-grade SIL (HSIL, n=67), low-grade SIL (LSIL, n=32), and negative (n=41) liquid-based cytology samples. RESULTS: The methylation frequency in normal, LSIL, HSIL, and SCC was significantly different (p<0.01) for eight genes (DAPK, HIC-1, HIN-1, MGMT, RAR-beta, RASSF1A, SHP-1, and Twist). There was a trend toward increasing methylation of HIN-1, MGMT, RAR-beta, RASSF1A, and SHP-1 with increasing severity of cervical squamous lesions. The number of methylated genes increased with the severity of cervical squamous lesions (p<0.001). In receiver-operating characteristic analysis, the three-gene combination (RAR-beta/Twist/MGMT) showed the best performance to distinguish HSIL/SCC from LCIS/negative samples. The estimated specificity of this three-gene panel for detecting HSIL/SCC was 82.2%, and its sensitivity was 78.7%. CONCLUSION: Although aberrant DNA methylation has the potential to function as a molecular biomarker of HSIL and SCC in liquid-based cytology tests, additional genes that are selectively methylated in HSIL and SCC are needed to improve clinical performance.

Significance of human papillomavirus genotyping with high-grade cervical intraepithelial neoplasia treated by a loop electrosurgical excision procedure.

OBJECTIVE: This study was conducted to determine whether the human papillomavirus (HPV) genotype by the HPV DNA chip test (HDC) is predictive of residual or recurrent high-grade cervical intraepithelial neoplasia (CIN) 2-3 following a loop electrosurgical excision procedure (LEEP). STUDY DESIGN: Between January 2001-February 2007, 672 patients with CIN2-3 were treated by a LEEP and followed up with cytology, the hybrid capture II assay, and the HDC. RESULTS: A total of 37 (5.5%) patients developed a recurrence, and those who developed a recurrence tested positive for the same high-risk (HR) HPV genotype before and after the LEEP. The same HR-HPV genotype by the HDC during the follow-up had a sensitivity and negative predictive value of 100% for detecting residual/recurrent disease. Persistent HPV-16 and HPV-18 were significantly associated with recurrent CIN2-3 (P < .05). CONCLUSION: Persistent infection with the same HR-HPV genotype, especially HPV-16 and HPV-18, should be considered a risk factor for developing residual/recurrent CIN2-3.

Peritoneal melanosis associated with mucinous cystadenoma of the ovary and adenocarcinoma of the colon.

Peritoneal melanosis, a diffuse, black pigmentation of the peritoneum, is a very rare condition characterized by melanin pigment deposition in the peritoneum. In this paper, we describe a case of peritoneal melanosis associated with a mucinous cystadenoma on an ovary and adenocarcinoma in the colon of 68-year-old women. The patient was referred for an evaluation of lower abdominal pain and distension. Laboratory results showed anemia and elevated CA 125 levels. A pelvic computed tomographic scan revealed a huge multicystic mass on the right ovary and a well-enhancing intraluminal mass located at the rectosigmoid junction. During a surgical procedure, India-ink-colored (black) pigmentation was seen in the peritoneum, in the omentum, and on the surface of the ovary. Biopsies of the omentum and peritoneum showed pigment in the stroma and pigment-laden histiocytic aggregation. Pigment was also present in the wall of the mucinous cystadenoma of the ovary and colonic serosa. An ultrastructural study found melanosome in the cytoplasm of the histiocytes.

Human papillomavirus L1 capsid protein and human papillomavirus type 16 as prognostic markers in cervical intraepithelial neoplasia 1.

INTRODUCTION: The aim of the study was to determine whether human papillomavirus (HPV) L1 capsid protein and the HPV genotype can predict the disease course as prognostic markers for cervical intraepithelial neoplasia 1 (CIN1). METHODS: Immunohistochemical staining was performed for HPV L1 capsid protein in 101 women who had been confirmed to have CIN1 by histologic examination and HPV high-risk infection by HPV genotyping. The disease course was analyzed by follow-up histologic examination according to the HPV L1 capsid protein and HPV genotype over a minimum of 12 months. RESULTS: The CIN1 regressed spontaneously in 60.4% of the women; most cases of regression occurred within 1 year (90.9% of regression cases). The HPV L1 capsid protein-positive patients had a spontaneous regression rate of 72.7% (48/66) and a rate of persistent disease or progression to higher grade disease of 27.3% (18/66). The HPV L1 capsid protein-negative women had a regression rate of 37.1% (13/35) and a rate of persistent disease or progression of 62.9% (22/35; P < 0.001). The HPV-16-infected patients had a regression rate of 38.6% (17/44) and a rate of persistent disease or progression of 61.4% (27/44), whereas the non-HPV-16-infected patients had a regression rate of 77.2% (44/57) and a rate of persistent disease or progression of 22.8% (13/57; P < 0.001). CONCLUSIONS: The HPV L1 protein expression is closely related to spontaneous disease regression, but HPV-16 infection is related to persistent disease or progression to high-grade lesions in patients with CIN1.

Utility of thyroid transcription factor-1 and CDX-2 in determining the primary site of metastatic adenocarcinomas in serous effusions.

OBJECTIVE: To evaluate the usefulness of thyroid transcription factor-1 (TTF-1) and CDX-2 in determining the primary tumor site of metastatic adenocarcinomas (ACs) in serous effusions. STUDY DESIGN: Cell blocks were constructed from cells in metastatic AC effusion fluids (n = 97) that had been previously stained with a panel of antibodies against MOC-31, D2-40 and calretinin. Primary tumor sites included the lungs (n = 52), ovaries (n = 6), pancreas (n = 4), breasts (n = 3), bile duct (n = 2) and gastrointestinal (GI) tract (30), including stomach (n = 28) and colon (n = 2). Primary sites were determined by tissue confirmation of the original tumor or review of the clinical charts. Immunocytochemical staining was performed with antibodies against TTF-1 and CDX-2. RESULTS: The lung ACs showed TTF-1 positivity in 58% (30/52) of cases. All nonpulmonary ACs lacked TTF-1 staining. Among the 30 GI ACs, 9 (30%) (7 from the stomach and 2 from the colon) showed CDX-2 positivity. All non-GI ACs lacked CDX-2 staining. Specificities and positive predictive values for TTF-1 and CDX-2 equaled 100% for metastatic pulmonary and GI ACs, respectively. CONCLUSION: Our results suggested that TTF-1 and CDX-2 are specific markers to separate metastatic pulmonary and GI ACs, respectively, from other metastatic ACs in serous effusions. However, sensitivity values of these markers were low.

TFE3-expressing malignant perivascular epithelioid cell tumor of the mesentery: A case report and review of literature.

BACKGROUND: Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal tumor that exhibits an epithelioid and spindle cell morphology. The tumor is characterized by immunoreactivity for melanocytic and myogenic markers but can be misdiagnosed as more common tumors with similar characteristics, including gastrointestinal stroma tumors or leiomyosarcomas. Recently, a subset of PEComas has been reported to harbor a transcription factor binding to TFE3 fusion. Herein, we report a rare case of TFE3-expressing malignant PEComa arising from the mesentery. CASE SUMMARY: A 50-year-old woman presented with abdominal discomfort for 3 months. Results of laboratory tests were all within the normal ranges, and the patient had no notable medical history. Magnetic resonance imaging revealed a large tumor on the right side of the pelvic floor, which was originally suspected to be a primary ovarian tumor. However, during surgery, the tumor was revealed to have originated from the mesentery. Histologically, the tumor was composed of bundles of spindle cells and sheets of epithelioid cells. Extensive coagulative necrosis and numerous mitotic figures were observed. Immunohistochemistry revealed that the tumor cells were positive for smooth muscle actin, HMB-45, and TFE3 expression. Tumor involvement of the rectal serosa was identified, leading to a final diagnosis of malignant PEComa of the mesentery. Surgical resection was followed by adjuvant chemotherapy. No recurrence or metastasis was observed over a 6-month follow-up period. CONCLUSION: Malignant PEComa of the mesentery is extremely rare and should be distinguished from morphological mimics through differential diagnosis and immunohistochemistry.

ETS1 Suppresses Tumorigenesis of Human Breast Cancer via Trans-Activation of Canonical Tumor Suppressor Genes.

ETS1 has shown dichotomous roles as an oncogene and a tumor suppressor gene in diverse cancers, but its functionality in breast cancer tumorigenesis still remains unclear. We utilized the Cancer Genome Atlas (TCGA) database to analyze comprehensive functions of ETS1 in human breast cancer (BRCA) patients by investigating its expression patterns and methylation status in relation to clinical prognosis. ETS1 expression was significantly diminished by hyper-methylation of the ETS1 promoter region in specimens from BRCA patients compared to a healthy control group. Moreover, ETS1 high BRCA patients showed better prognosis and longer survival compared to ETS1 low BRCA patients. Consistent with clinical evidence, comparative transcriptome analysis combined with CRISPR/Cas9 or shRNA based perturbation of ETS1 expression revealed direct as well as indirect mechanisms of ETS1 that hinder tumorigenesis of BRCA cells. Taken together, our study enlightens a novel function of ETS1 as a tumor suppressor in breast cancer cells.