Regulatory region mutations of TERT, PLEKHS1 and GPR126 genes as urinary biomarkers in upper tract urothelial carcinomas.

Abstract

Background: The hotspot regulatory region mutations of the TERT, PLEKHS1 and GPR126 genes have been shown to occur frequently in urothelial bladder carcinoma (UBC). However, it is currently unclear whether these mutations are all present in upper tract urothelial carcinomas (UTUC) including renal pelvic carcinoma (RPC) and ureter carcinoma (UC), although TERT promoter mutations were previously observed in these malignancies.Methods: The hotspot mutations of TERT and PLEKHS1 promoters and GPR126 intron 6 (enhancer) in tumors derived from 164 patients with UTUC were determined using Sanger sequencing, and the obtained results were further compared with the mutation frequency in 106 UBCs. The mutations were also assessed in urine from patients with UTUC and UBC.Results: The mutation frequencies in UTUC tumors were 28%, 5.8% and 11% for TERT and PLEKHS1 promoters and GPR126 intron 6, respectively, which were lower than those (44.3%, 26.4%, and 31.4%, respectively) in UBCs. The total frequencies for the presence of any of these mutations were 50.8% and 34.4% for RPCs and UCs, respectively. All these mutated DNA sequences were detectable in urine from both UTUC and UBC patients and disappeared rapidly in most patients after surgery.Conclusions: This proof-of-concept study demonstrates that the hotspot mutations in the TERT, PLEKHS1 and GPR126 non-coding regions are present in UTUCs, and that urinary assays of these mutated sequences serve as potential biomarkers for UTUC diagnostics and disease monitoring.