CDK5R1 and Familial prostate cancer: CDK5 has known antiapoptotic roles in thyroid and prostate cancer cells and is known to facilitate the DNA damage repair response, and although CDK5 kinase activity in non-neuronal cells is generally described as p35-dependent, it is possible that other, less studied or unknown coactivators enable CDK5 to continue serving these roles even when p35 expression is ablated (39).