USF1 and Familial prostate cancer: Based on the role of USF‐1 in radioresistance that was confirmed by USF‐1 gain of function studies in PC‐3 cells using real time RT PCR, reporter assays and colony forming assays, and since USF‐1 has been shown to upregulate the expression of several genes linked to cellular proliferation, it was of great interest to investigate whether inhibition of USF‐1 can result in radiosensitivity of prostate cancer cells, in turn reversing radioresistance.