Breast cancer and tumor stem cells. Review

In recent years the existence of cancer stem cells (CSCs) was demonstrated in malignant tumors of various localizations, animal and human stable tumor cell lines. Breast cancer was the first solid tumor, in which the presence of CSCs was revealed. The first evidence of the existence of CSCs was reveled in breast. Identification of breast CSCs is a complex problem because of their heterogeneity and plasticity. By this moment, a significant body of experimental data on the biological nature of breast CSCs has been accumulated. This cell fraction is characterized by a higher resistance to the action of low-LET radiation and chemotherapy compared to other tumor cells. In this review we analyze the possibility of applying the acquired knowledge about the CSC resistance to antitumor agents, molecular-cellular features of CSCs and its prognostic value in clinical practice to improve the results of treatment of patients with breast malignant tumors. Clinical data on the relationship of breast CSCs with the formation of resistance to anticancer treatment, including radiation therapy, are not yet numerous, but indicate the prospects of further work in this direction.