Abstract 883: Genetic characteristics between males and females with urothelial bladder cancer
Authors: Nair Rishi , Khalife Roy , Magliocco Anthony 
Published: March 2024

Abstract
Urothelial bladder cancer (UBC) affects the epithelial cells of the urinary tract and is the most common type of bladder cancer worldwide. Statistically, males are four times more likely to develop UBC than females. It is known that decreased expression of the KDM6A gene, coded on the X chromosome, corresponds with a higher incidence of UBC. KDM6A mutations are known to be more prevalent in females with non-muscle-invasive UBC. These mutations are targetable by inhibiting EZH2, an enzyme coded by its namesake gene. On the environmental side, males are at a higher risk of developing carcinogenic complications due to smoking and environmental toxins. However, this discrepancy fails to exist when comparing males and females who smoke similar levels. Though environmental factors may play a role in influencing behavior and altering levels of risk to develop UBC, research suggests that they do not single-handedly explain sex-based disparities in UBC. In this study, we characterize the molecular mechanisms associated with altered overall survival by uncovering previously unreported data on the expression of KDM6A and FGFR3, a commonly altered oncogene, in UBC patients. Our in silico approach consisted of broad survival data analysis through cBioPortal (n=1486), sequencing-based gene expression data through ICGC Portal (n=295), and single nucleotide polymorphism identification with the PLCO Atlas (n=69,429). The 5-year overall survival (OS) curves of 13 therapeutic and/or significantly altered genes between males and females were analyzed. BRCA2 was the only gene associated with worse survival for females with alterations. Interestingly, males with alterations to the following genes had significantly better OS outcomes: ERCC2, KDM6A, BRCA2, FGFR3. However, there was no gene whose alterations were associated with significantly better OS outcomes for females. KDM6A and FGFR3, two genes whose alterations are typically associated with worse OS outcomes in males, exhibit the opposite effect. Additionally, males exhibited significantly worse OS outcomes when presenting with CDKN2A and CDKN2B alterations, while females exhibited significantly worse OS outcomes when presenting with CDKN2A and NTRK1. A majority of European males had SNPs on the following genes: CDKN2B, ERBB2, CREBBP, while a majority of European females had SNPs on BRCA2. Differential expression also revealed 714 genes that were significantly expressed in one sex when compared to the other. Therefore, we suggest that there are unique molecular differences between sex that conflict with previous analyses; further research should be conducted to explore the effect of sex via the tumor-suppressive characteristics of KDM6A as well as oncogenic properties of FGFR3.
Citation Format: Rishi Nair, Roy Khalife, Anthony Magliocco. Genetic characteristics between males and females with urothelial bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 883.