Participation of BMI-1 protein in cancer.

BMI-1 (B-lymphoma Mo-MLV insertion region 1) protein is a constituent of Polycomb Repressive Complex 1 (PRC1) that via ubiquitination of histone H2A affects expression of many genes. BMI-1 is involved in cellular processes such as DNA repair, proliferation, growth, senescence and apoptosis. BMI-1 plays a key role in biology of stem cells including cancer stem cells by regulation of their self-renewal and differentiation. Accumulating evidence has revealed that overexpression of BMI-1 in many human cancers correlates with disease progression and therapy failure. The results of in vitro and in vivo studies confirm the involvement of BMI-1 in tumor initiation as well as invasion, metastasis and chemoresistance. Taking into account significant role of BMI1 in tumorigenesis, especially associated with cancer stem cells, it seems that this gene may be a promising target of anticancer therapies.