Cancer stem cells (CSCs) are a small subpopulation of cells within tumors with capabilities of self-renewal, differentiation, and tumorigenicity. Successful cancer treatment would need to eliminate CSCs. The CSCs can be identified and isolated by both CSC-specific cell surface marker expression and functional assay, such as floating spheres, and aldehyde dehydrogenase (ALDH) activity assay. However, lack of universal expression of surface markers limits their usage to identify CSCs. Here, we give a brief overview of the current known surface markers of CSCs and associated tumor types. Finally, the possible reasons for contradiction are discussed in these surface markers. In this review, I not only provide an overview of the current known surface markers but also highlight the importance of achieving maximal accuracy of a new marker.

Malignant tumors seriously endanger human health and life, and restrict economic development. Human leukocyte antigen (HLA) is the expression product of the human major histocompatibility complex, which, at present, is the most complex known polymorphic system. The polymorphism and expression of HLA molecules have been demonstrated to be associated with the occurrence and development of tumors. HLA molecules can regulate the proliferation of tumor cells and inhibit antitumor immunity. In the present review, the structure and function of HLA molecules, the polymorphism and expression of HLA in tumor tissue, the roles of HLA in tumor cells and tumor immunity, and the potential clinical application of HLA in tumor immunotherapy are summarized. The overall aim of the present review is to provide relevant information for the development of antitumor immunotherapies involving HLA in the clinic.

Prognostic significance of CD44 in human colon cancer and gastric cancer: Evidence from bioinformatic analyses

Cancer stem cells (CSC) theory has ushered in a new era of cancer research. Tumor recurrence, metastasis and chemotherapy resistance are all related to the existence of cancer stem cells. Further understanding of tumor heterogeneity will contribute to targeted treatment. Liver cancer and pancreatic cancer are common digestive gland tumors with high lethality. This article reviews the identification and isolation of CSC markers in hepatocellular carcinoma and pancreatic cancer. The markers related signal pathways are involved in the occurrence and development of tumors, and have a significant impact on the proliferation, metastasis and invasion of cancer cells, which can be used as potential molecular therapeutic targets. This study will be helpful to understand cancer stem cell like cells.

Breast cancer is the most commonly malignant cancers in women. CD133 protein is a widely used marker for isolating cancer stem cell (CSC). Its expression is associated with the prognosis of many cancers. However, whether CD133 mRNA could be used as an independent prognostic factor for breast cancer remains inconsistent in previous studies. In this study, I used the Gene Expression-Based Outcome for Breast Cancer Online algorithm (GOBO) software to analysis the prognostic roles of CD133 mRNA in the subtypes of breast cancer. I found that CD133 mRNA is associated with distant metastasis free survival (DMFS) in the patient with all tumors, ER-positive tumors, tamoxifen (TAM) tumors, LN-negative tumors, ER-positive/LN-negative tumors, ER-negative tumors, grade 2 tumors, HER2 enriched tumors, and untreated tumors. These results could provide a molecular target for the subtypes of breast cancer. In this study, I conclude that CD133 mRNA may be a suitable prognostic marker for human breast cancer.