CDKN1A and Familial prostate cancer: Similar results were reported by Shi et al. (2003)[25] that the treatment of prostate cancer cell with BBSKE, a novel organoselenium compound, results in S-phase arrest and increase in the protein levels of cyclin A, cyclin E, and p21, but decrease in the levels of cyclin B1, cyclin D1, and CDK4[25].