Therefore, we next analyzed the effects of SHMT2 in BLCA cell cycle, and the results demonstrated that overexpression of SHMT2 promote G1/S phase transition, silencing of SHMT2 significantly inhibited cell cycle G0/G1 phase to S phase transition by downregulating cyclin E1 and cyclin D1 protein expression. The gene discussed is CCND1; the disease is bladder transitional cell carcinoma.