Epithelial cell adhesion molecule (EpCAM) is a marker for circulating tumor cells (CTCs) in various types of cancer, while cluster of differentiation 44 (CD44) is a marker for gastric cancer (GC) stem cells. To evaluate the clinical significance of CD44+ CTCs in patients with GC in the present study, the number of EpCAM+CD44+ and EpCAM+CD44‑ cells were detected in the peripheral blood of 26 GC patients and 12 healthy volunteers using flow cytometry. The number (mean ± standard deviation) of EpCAM+CD44+ cells in the GC patients and healthy volunteers was 69.9±52.0 and 0.91±2.10, respectively (P=0.0001), while that of EpCAM+CD44‑ cells was 59.1±88.0 and 9.83±9.91, respectively (P=0.0313). The sensitivity and specificity of EpCAM+CD44+ cell detection for the identification of GC patients were 92.3 and 100%, respectively. By contrast, the values of EpCAM+CD44‑ cell detection were 76.9 and 83.3%, respectively. The number of EpCAM+CD44+ cells in the GC patients was correlated with the disease stage (P=0.0423), the depth of the tumor (P=0.0314) and venous invasion (P=0.0184) in the resected tumor specimens, while the number of EpCAM+CD44‑ cells did not correlate with any clinicopathological factors. The number of EpCAM+CD44+ cells significantly decreased following surgical resection of the tumor or induction of systemic chemotherapy. Additionally, atypical cells with a high nuclear to cytoplasmic ratio were morphologically detected in the sorted EpCAM+CD44+ cells. These results suggested that CD44+ CTCs, but not CD44‑ CTCs, reflect the malignant status of the primary tumor in patients with GC, providing a candidate biomarker for diagnosis and treatment response.

Despite advances in radical esophagectomies and adjuvant therapy, the postoperative prognosis in esophageal squamous cell carcinoma (ESCC) patients remains poor. The aim of this study was to identify a molecular signature to predict postoperative favorable outcomes in patients with ESCC. As a training data set, total RNA was extracted from formalin-fixed paraffin-embedded samples of surgically removed specimens from 19 ESCC patients who underwent curative esophagectomy. The expression of microRNA (miRNA) was detected using a miRNA oligo chip on which 885 genes were mounted. As a validation data set, we obtained frozen samples of surgically resected tumors from 12 independent ESCC patients and the expression of miR-574-3p was detected by quantitative real-time PCR. Our microarray analysis in the training set patients identified three miRNAs (miR-574-3p, miR-106b, and miR-1303) and five miRNAs (miR-1203, miR-1909, miR-204, miR-371-3p, miR-886-3p) which were differentially expressed between the patients with (n = 14) and without (n = 5) postoperative tumor relapse (p < 0.01 and p < 0.05, respectively). Higher expression of miR-574-3p, which showed the most significant association with non-relapse (p = 0.001), was associated with favorable overall survival (p = 0.016). Real-time PCR experiments on the validation set patients confirmed that higher expression of miR-574-3p was associated with non-tumor relapse (p = 0.029) and better overall survival (p = 0.004). Our results suggest that the aberrant expression of the miRNAs identified in this study plays key roles in the progression of ESCC. miR-574-3p was suggested to have a tumor suppressor effect, and thus, to be a predictor of postoperative outcome in patients with ESCC.

Mitotically quiescent cancer stem cells (CSCs) possess higher malignant potential than other CSCs, indicating their higher contribution to therapeutic resistance than that of other CSCs. In esophageal squamous cell carcinoma (ESCC), p75 neurotrophin receptor (p75NTR) is expressed in a candidate CSC population showing high tumorigenicity and chemoresistance. In the present study, we isolated and characterized quiescent CSCs population in ESCC based on p75NTR expression and cell cycle status. Expression of p75NTR and Ki-67 in ESCC cell lines (KYSE cells) and surgically resected ESCC specimens was detected by performing immunocytochemical analysis. p75NTR-positive KYSE cells were fractionated into quiescent and proliferating cells by performing flow cytometry with a fluorescent DNA-staining dye to determine their CSC phenotype. Immunocytochemical analysis showed that 21.8 and 36.5% of the p75NTR-positive cells were Ki-67-negative (G0), which accounted for 11.4 and 15.7% of cells in KYSE-30 and KYSE-140 cell lines, respectively. Flow cytometric cell sorting showed that p75NTR-positive cells in the G0-G1 phase (p75NTR-positive/G0-1 cells) but not in the S-G2-M phase (p75NTR-positive/S-G2-M cells) showed strong expression of stem cell-related genes Nanog, BMI-1, and p63; high colony formation ability; high tumorigenicity in a mouse xenograft model; and strong chemoresistance against cisplatin because of the expression of drug resistance genes ABCG2 and ERCC1. Label-retention assay showed that 3.4% p75NTR-positive cells retained fluorescent cell-tracing dye, but p75NTR-negative cells did not. Immunohistochemical analysis of ESCC specimens showed p75NTR expression in 39 of 95 (41.1%) patients, with a median of 13.2% (range, 3.0-80.1%) p75NTR-positive/Ki-67-negative cells, which were found to be associated with poorly differentiated histology. Our results suggest that p75NTR-positive/G0-1 cells represent quiescent CSCs in ESCC and indicate that these cells can be used as targets to investigate molecular processes regulating CSC phenotype and to develop novel therapeutic strategies.

Introduction: Mesenteric hematoma is a rare condition caused by bleeding localized in the mesenteric vascular tree. This is a first report of spontaneous mesenteric hematoma caused by rivaroxaban. Presentation of case: The patient was a 71-year-old man who had taken rivaroxaban for paroxysmal atrial fibrillation. He had experienced abdominal pain and diarrhea for the prior 3 days. He had little melena and was referred to our institute. He presented with hypotension on arrival. Computed tomography (CT) revealed a 10 cm mass in the mesentery of the sigmoid colon with extravasation. Active bleeding from the sigmoid colic arteries was embolized with angiography on the day of admission. On the second day, we operated on the patient. We detected 200 mL of bloody ascites accumulated in the abdomen. The serosa of the sigmoid colon was ruptured along the tenia due to the compression of the hematoma in the mesentery. The sigmoid colon was resected and a descending colostomy was reconstructed. Operative and pathological findings did not reveal the cause of bleeding. We finally diagnosed the patient with spontaneous mesenteric hematoma associated with rivaroxaban. Discussion: Previous reports of mesenteric hematoma with anticoagulant were associated with warfarin. Since rivaroxaban is not affect to the value of prothrombin time (PT) and activated partial thromboplastin time (APTT) and mesenteric hematoma presents non-specific symptoms, it is difficult to diagnose mesenteric hematoma in the patients taking rivaroxaban. Conclusion: It is important to keep in mind that mesenteric hematoma is one of the critical complications in patients taking rivaroxaban. Highlights:

Mitotically quiescent cancer stem cells (CSC) are hypothesized to exhibit a more aggressive phenotype involving greater therapeutic resistance and metastasis. The aim of our study was to develop a method for identifying quiescent CSC in esophageal squamous cell carcinoma (ESCC) based on their expression of the p75 neurotrophin receptor (p75NTR) and other proposed CSC markers, such as CD44 and CD90. Double immunostaining of surgical ESCC specimens revealed that the mean Ki-67-labeling index of the p75NTR-positive cells was significantly lower than that of the p75NTR-negative cells. Real-time PCR analysis of sorted fractions of ESCC cell lines (KYSE cells) revealed that stem cell-related genes (Nanog, p63 and Bmi-1) and epithelial-mesenchymal transition (EMT)-related genes (N-cadherin and fibronectin) were expressed at significantly higher levels in the p75NTR-positive fractions than in the CD44-positive or CD90-positive fractions. In addition, the p75NTR-positive fractions exhibited significantly higher colony formation in vitro, significantly enhanced tumor formation in mice, and significantly greater chemoresistance against cisplatin (CDDP) than the CD44‑positive or CD90‑positive fractions. Furthermore, in both the cultured cells and those from the mouse xenograft tumors, the p75NTR‑positive/CD44-negative and p75NTR‑positive/CD90-negative KYSE cell fractions contained significantly higher proportions of mitotically quiescent cells. These results suggest that the mitotically quiescent CSC population in ESCC can be identified and isolated based on their p75NTR expression, providing researchers with a novel diagnostic and therapeutic target.