RAD51 and breast cancer: In breast cancer, pancreatic cancer, soft tissue sarcoma, and non–small cell lung cancer, Rad51 overexpression was associated with poor prognoses, suggesting that Rad51 overexpression may enhance genetic instability and maintain DNA damage at a tolerable level to permit cell survival.15,18,21,22 The relationship between overexpression of double-stranded break (DSB) repair genes and the ability of tumor cells to undergo migration has not yet been elucidated.