TDRD1 and prostate carcinoma: In addition, we did not observe TDRD1 to be essential for viability and proliferation of prostate cancer cells in vitro. While it is conceivable that TDRD1 expression confers a selective advantage to prostate cancer cells only in vivo, we cannot exclude that the impact of TDRD1 silencing on cell viability in vitro may be masked by the expression of another protein with a redundant function.