Using domain constructs it was shown that GRIP-1/TIF-2 enhances AF-2 but not AF-1 mediated AR transactivation.[47] Bicalutamide has been shown to block recruitment of GRIP-1/TIF-2, presumably by preventing the formation of a co-activator binding surface.[48] Using reverse transcriptase PCR GRIP-1/TIF and RAC-3 were found at low levels in prostate cancer specimens[49] suggesting it may not be as significant as SRC-1 in prostate cancer progression. This evidence concerns the gene RAC3 and Familial prostate cancer.