Molecular genetic mechanisms of drug resistance in prostate cancer

Drug resistance and especially cross-resistance are the most important problems of therapy of prostate cancer. Drug resistance mechanisms, including ligand-dependent (requiring the presence of androgens in the cell) and independent (not requiring androgens) ones, are reviewed. The mechanisms are mainly based on mutations of the androgen receptor (AR) gene, expression of aberrant constitutively active AR splice variants, and upregulation of androgen synthesis genes.