Alterations in DNA Methylation May Be the Key to Early Detection and Treatment of Schistosomal Bladder Cancer

Bladder cancers arise from transformed urothelial cells that line the bladder. These cancers are urothelial or squamous cell carcinomas or, more rarely, additional histologic variants such as adenocarcinoma. The most important bladder cancer risk factors worldwide are arguably smoking and urogenital schistosomiasis. The parasitic Schistosoma haematobium worm causes urogenital schistosomiasis in approximately 112 million people, primarily in sub-Saharan Africa and the Middle East [1]. During infection, S. haematobium worms lay highly inflammatory eggs in the bladder wall. This inflammation is thought to promote carcinogenesis through unclear mechanisms. People with chronic urogenital schistosomiasis exhibit increased risk and earlier onset of bladder cancer (up to two decades earlier), with a predominance of squamous cell carcinoma [2]. Consequently, S. haematobium has been categorized as a Group I carcinogen (“carcinogenic to humans”) by the International Agency on Research on Cancer of the World Health Organization [3].