SYCP2 and breast cancer: Knockdown (KD) of SYCP2 in cervical cancer cell line HeLa and a panel of breast cancer cells by siRNA (siSYCP2) significantly reduced colony forming rate of these cancer cell lines, however, effects of SYCP2 in normal BJ and normal breast MCF10A cells were subtle (Supplementary Fig. 2A), suggesting that SYCP2 contributes to the fitness of cancer cells.