APC and bladder transitional cell carcinoma: The investigation carried out by Bilgrami et al. [23] on various tumor suppressor genes evaluated the correlation between their promoter methylation with tumor grade and BLCA invasiveness; this study found significant hypermethylation of the APC gene promoter in the 33 high-grade BLCA patients studied compared to the 43 that were low grade (p-value <0.001) and normal controls (p-value<0.05).