Impact of BCL-2 rs2279115 and rs3943258 variants on protein expression and clinical outcome of urothelial bladder carcinoma

Abstract

Urothelial bladder carcinoma (UBC) is the ninth most common malignancy worldwide and ranks thirteenth in cancer-related mortality. A significant challenge in managing non-muscle-invasive UBC (NMIBC) is the high recurrence rate, compounded by a paucity of robust prognostic biomarkers. Given that evasion of apoptosis is a hallmark of carcinogenesis, the apoptosis regulator BCL-2 oncogene plays a critical role by negatively regulating the intrinsic apoptotic pathway, often leading to protein overexpression and malignant cell immortalization. Methods and Results: This study evaluated the BCL-2 allelic variants rs2279115 (G > T) and rs3943258 (T > C), including their haplotype structures, in association with BCL-2 immunohistochemical expression in UBC patients. Genetic and immunostaining data were analyzed alongside prognostic factors, environmental exposure, and clinical history. Furthermore, we sought to exhibit BCL-2 immunohistochemical staining patterns via immunofluorescence in selected samples. Our findings revealed that the rs2279115 variant is significantly associated with BCL-2 positive expression. Specifically, the TT genotype in the genotypic model (p = 0.035) and the GT genotype in the overdominant model (p = 0.045) were linked to protein status. Additionally, the CT haplotype was independently associated with high-grade tumors. Conclusions: The presence of the CT haplotype — in either homozygosity or heterozygosity — exerted a risk effect of high-grade (p = 0.020). In conclusion, these findings suggest that BCL-2 variants, haplotype structures, and immunohistochemical expression may offer relevant insights into the molecular characteristics of urothelial bladder cancer. Further prospective validation is needed to determine whether BCL-2 profiling can serve as a useful complementary tool for risk assessment in clinical practice.