Breast cancer is the leading cause of cancer death among women worldwide. Accumulating evidence indicates that the local recurrent and/or distant metastatic tumors, the major causes of lethality in the clinic, are related to the aggressive phenotype of a small fraction of cancer cells loosely termed as cancer stem cells (CSCs), tumor initiating cells (TICs), or cancer metastasis-initiating cells (CMICs). Breast cancer stem cells (BCSCs) are shown to exhibit unique growth abilities including self-renewal, differentiation potential, and resistance to most anti-cancer agents including chemo- and/or radiotherapy, all of which are believed to contribute to the development and overall aggressiveness of the recurrent or metastatic lesions. It is in urgent need not only to further define the nature of heterogeneity in each tumor but also to characterize the precise mechanisms governing tumor-host cross-talk which is assumed to be initiated by BCSCs. In this review, we will focus on recently identified key factors, including the BCSCs among circulating tumor cells, interaction of BCSCs with the host, epithelial mesenchymal transition (EMT), tumor microenvironment, the intrinsic resistance due to HER2 expression, potential biomarkers of BCSCs and cancer cell immune signaling. We believe that new evidence coming from both bench and clinical research will help to develop more effective approaches to control or significantly reduce the aggressiveness of metastatic tumors.

Coronavirus disease 2019 (COVID‐19) broke out in Wuhan, Hubei, China in December 2019. Tens thousands of people have been infected with the disease. Our aim was to distinguish severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)‐positive patients from SARS‐CoV‐2‐negative patients. We retrospectively compared the data of COVID‐19 patients with those of suspected and confirmed SARS‐CoV‐2‐negative patients (control patients). There were 78 COVID‐19 patients and 26 control patients, whose median ages were significantly different (P = .001). The percentage of COVID‐19 patients admitting exposure to Wuhan was obviously higher than that of control patients (X2 = 29.130; P < .001). Fever and cough appeared more frequently in COVID‐19 patients than in the control patients. The routine blood workup parameters of COVID‐19 patients did not change much and their mean counts were in the normal range. There were 38.5% of control patients had higher procalcitonin (PCT) levels than 0.5 ng/mL, which was significantly higher than that percentage of COVID‐19 patients (X2 = 22.636; P < .05), and COVID‐19 patients were also more likely to have decreased or normal urea and creatinine levels than control patients (X2 = 24.930, 8.480; P < .05).Younger age, exposure to Wuhan, fever, cough, and slight changes in routine blood workup parameters, urea and creatinine were important features discriminating COVID‐19 from control patients. Slightly increased, but far less than 0.5 ng/mL, PCT levels also differentiated COVID‐19 patients from control patients.

Abstract. Primary mediastinal seminoma often occurs in the anterior mediastinum of young males. It is unusual for the tumor to originate in the middle or posterior mediastinum, and such cases have rarely been reported in the English literature. The present study reports the case of a 52-year-old man with a 3.0-cm primary seminoma arising in the middle mediastinum. The patient presented with the symptoms of cough and chest tightness. Fluorine-18 fluorodeoxyglucose-positron emission tomography ( 18 F-FDG-PET) scans revealed unique abnormal FDG uptake in the middle mediastinum. A mediastinoscopy was performed and integral excision was found to be difficult. A biopsy was performed and the histological examination revealed a primary seminoma. Following 4 cycles of a standard bleomycin, etoposide and cisplatin chemotherapy regimen, and chest irradiation at a total dose of 40 Gy in 20 fractions, the tumor exhibited a partial response, decreasing in size, and FDG uptake was no longer observed on 18 F-FDG-PET scan. The last follow-up date was April 2016 and the patient has remained disease-free for 20 months.

Abstract. The present study was performed to explore the prognostic significance of periostin expression in a cohort of patients with early-stage breast cancer treated with breast conserving surgery following radiotherapy. A tissue microarray of tumor samples from 259 patients with early-stage breast cancer was assayed for periostin, estrogen receptor (ER), progesterone receptor (PR), ErbB2 receptor tyrosine kinase 2 and Ki-67 expression by immunohistochemistry. The association of periostin with other clinicopathological parameters and clinical outcomes, including local recurrence free survival (RFS), distant metastasis free survival (DFS) and overall survival (OS), were assessed through log-rank tests and univariate and multivariate analysis. Periostin expression was identified in 91 of the 259 tissue samples (35%). The periostin status was significantly associated with histological grade (P=0.001), nodal status (P=0.023), molecular subtype (P<0.01), ER status (P<0.01), PR status (P<0.01) and Ki-67 expression (P=0.011). Furthermore, periostin expression was associated with an increased risk of five-year local recurrence (95.8% vs. 89.0%; P=0.017) and distant metastasis (92.3% vs. 79.1%; P=0.001) in patients with early stage breast cancer. Multivariate analysis using Cox's proportional hazards model demonstrated that periostin expression was an independent predictor of all clinical outcomes in breast cancer (RFS, P=0.018; DFS, P=0.025; OS, P=0.047). Therefore, it was concluded that periostin is associated with an increased risk of local relapse and distant metastasis in early-stage breast cancer treated with conserving surgery and radiotherapy. This association should be further investigated in larger cohorts to validate the clinical significance of periostin expression.

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