DNMT1 and renal cell carcinoma: Furthermore, the ESRP1 promoter was hypermethylated in RCC cells, and treatment with 5-aza-2’-deoxycytidine (5-Aza-CdR), a DNMT inhibitor, effectively demethylated the CpG sites within the promoter region of ESRP1, thereby upregulating the transcriptional activity of the ESRP1 promoter and gene expression both in vitro and in vivo.