Quiescent state has been observed in stem cells (SCs), including in adult SCs and in cancer SCs (CSCs). Quiescent status of SCs contributes to SC self-renewal and conduces to averting SC death from harsh external stimuli. In this review, we provide an overview of intrinsic mechanisms and extrinsic factors that regulate adult SC quiescence. The intrinsic mechanisms discussed here include the cell cycle, mitogenic signaling, Notch signaling, epigenetic modification, and metabolism and transcriptional regulation, while the extrinsic factors summarized here include microenvironment cells, extracellular factors, and immune response and inflammation in microenvironment. Quiescent state of CSCs has been known to contribute immensely to therapeutic resistance in multiple cancers. The characteristics and the regulation mechanisms of quiescent CSCs are discussed in detail. Importantly, we also outline the recent advances and controversies in therapeutic strategies targeting CSC quiescence.

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Acute lymphoblastic leukemia (ALL) as a common cancer is a heterogeneous disease which is mainly divided into BCP-ALL and T-ALL, accounting for 80–85% and 15–20%, respectively. There are many differences between BCP-ALL and T-ALL, including prognosis, treatment, drug screening, gene research and so on. In this study, starting with methylation and gene expression data, we analyzed the molecular differences between BCP-ALL and T-ALL and identified the multi-omics signatures using Boruta and Monte Carlo feature selection methods. There were 7 expression signature genes (CD3D, VPREB3, HLA-DRA, PAX5, BLNK, GALNT6, SLC4A8) and 168 methylation sites corresponding to 175 methylation signature genes. The overall accuracy, accuracy of BCP-ALL, accuracy of T-ALL of the RIPPER (Repeated Incremental Pruning to Produce Error Reduction) classifier using these signatures evaluated with 10-fold cross validation repeated 3 times were 0.973, 0.990, and 0.933, respectively. Two overlapped genes between 175 methylation signature genes and 7 expression signature genes were CD3D and VPREB3. The network analysis of the methylation and expression signature genes suggested that their common gene, CD3D, was not only different on both methylation and expression levels, but also played a key regulatory role as hub on the network. Our results provided insights of understanding the underlying molecular mechanisms of ALL and facilitated more precision diagnosis and treatment of ALL.

Rationale:Angiosarcomas are malignant vascular tumors, and angiosarcoma occurring in the anterior mediastinum is rare. Here we report a case of angiosarcoma that originated in the anterior mediastinum treated with surgery, followed by radiotherapy and synchronous chemotherapy.Patient concerns:A 56-year-old female was admitted to our hospital with chest pain for 3 days. Chest computerized tomogram (CT) examination showed a heterogeneous mass in the anterior superior mediastinum, and after injection of contrast agent, the mass showed obvious heterogeneous enhancement. Magnetic resonance imaging (MRI) with T1 weighted image (T1WI) showed isointensity and T2 weighted image (T2WI) showed heterogeneous signal intensity, the mass showed an obvious heterogeneously enhancement after intravenous administration of contrast material.Diagnosis and interventions:Surgical resection operation was carried out. According to its morphologic and immunohistochemic feature of tumor cells which expressing CD31, CD34, and ERG, the tumor was categorized as an angiosarcoma. After operation, the patient received radiotherapy and synchronous chemotherapy.Outcomes:At present, 8 months postoperatively, no signs of recurrence have been observed.Lessons:Although angiosarcoma in anterior mediastinum is rare, when a mass located in this area, a more careful immunohistological analysis should be performed to avoid overlooking the presence of angiosarcoma.

Thyroid paraganglioma (TP) is an uncommon neuroendocrine tumor with potential for misdiagnosis. Case 1 (male; 44 years old) presented with hoarseness for 3 months. A 2.5-cm gray nodule in the left thyroid was diagnosed as TP by immunohistochemistry. Lymph node metastasis was confirmed by H&E staining and immunohistochemistry. The patient was followed-up for 3 years without any signs of recurrence or metastasis. Case 2 (female; 39 years old) presented with an asymptomatic but rapidly growing thyroid nodule. The patient underwent thyroidectomy 8 years ago (2008) and was diagnosed with TP postoperatively. The patient was diagnosed with recurrence and exhibited trachea invasion. Thyroidectomy and partial trachea resection were performed. A literature review revealed that 62 other cases of TP have been reported, and most of them exhibited low malignant potential. However, the two cases presented in the current case report exhibited a high malignant potential, accompanied by lymph node metastasis or trachea invasion, and these features imply that the choice of treatment for patients should be based on their different degrees of malignancy.