TGFBR3 Co-Downregulated With GATA3 Is Associated With Methylation of the GATA3 Gene in Bladder Urothelial Carcinoma

Bladder urothelial carcinoma (BUC) accounts for approximate to 90% of all cases of bladder cancer. Reduced expression of TGFBR3 has been frequently observed in several types of human cancers. However, little is known about whether expression of TGFBR3 reduced in BUC and the underlying mechanisms. In the present study, we performed quantitative real-time PCR to examine the mRNA expression of TGFBR3 and GATA3, and bisulfite genomic sequencing to evaluate the methylation status in TGFBR3 and GATA3 promoter regions in fresh tumor and the corresponding paracarcinoma tissues from 29 patients with BUC. As a result, the expression of TGFBR3 and GATA3, a transcriptional factor of the TGFBR3 gene, were found to be co-downregulated in BUC. Moreover, our findings indicated that GATA3 promoter methylation was one of the reasons for silencing of GATA3 and TGFBR3 in BUC, albeit TGFBR3 methylation and mutation were not associated with reduced expression of TGFBR3 mRNA in BUC. In summary, our findings suggest that methylation in the GATA3 promoter region may inhibit the expression of GATA3 mRNA, which leads to the reduced expression of TGFBR3 mRNA in BUC. Anat Rec, 296:1717-1723, 2013. (c) 2013 Wiley Periodicals, Inc.