STAT3 and cancer: It has been reported that phospho-STAT3 (p-STAT3) induces methylation of estrogen receptor 1 (ESR1) promoter in bladder cancer [15], and RacGAP1 induces phosphorylation of STAT3 [16], which increases the expression of p-STAT3 and promotes its translocation into the nucleus to play a cancer-promoting role.