A direct association of Ku70/Ku80 with AR has already been reported for prostate cancer cells, in which, however, Ku70 and Ku80 were implicated in control of AR-dependent transcription (Mayeur et al., 2005), rather than AR being required for Ku70/Ku80 association with RNA Pol II. This evidence concerns the gene XRCC5 and prostate carcinoma.