PC and Familial prostate cancer: The surviving fraction (SF) at 2Gy (SF2) for C4-2 cells was reduced from 59.3%±1.9% to 40.4%±10% when we knockdown endogenous PC-1 expression, and the SF2 of LNCaP was increased from 43.9%±3% to 55.3%±3.2% when we overexpressed PC-1 gene in it, suggesting PC-1 increased radioresistance in prostate cancer cells.