Our data showed that silencing GTSE1 significantly increased S phase (Fig. 7c and d), suggesting that it may have an S phase arrest; while overexpression of GTSE1 increased the percentage of cells in the G2 peak (Fig. 7e and f), indicating that overexpression of GTSE1 could delay the M-to-G2 phase transition of breast cancer cells, which is consistent to a previous study. This evidence concerns the gene GTSE1 and breast cancer.