Probiotics-based Anticancer Immunity In Bladder Cancer

Bladder cancer accounts for an estimated 500,000 new cases and 200,000 deaths annually. The prevalence of bladder cancer is high, with more than 1.6 million people affected worldwide. Modern techniques not based on microbiological cultures, such as Next Generation Sequencing (NGS) of the 16S rRNA gene, have provided robust evidence that a urinary commensal microbiota exists. Few studies have shown a detailed analysis of the urinary microbiota in patients with bladder cancer. Therefore, the nature and role of many relevant bladder bacteria in the initiation and progress of bladder cancer remain under investigation. This chapter describes the main studies in this regard, as well as the underlying mechanisms, mainly immune-based. Moreover, if we talk about bladder cancer and the feasibility of probiotics as an alternative treatment acting on the microbiota, we must start by mentioning the functionality of the Bacille Calmette-Guérin (BCG) vaccine. Based on the immunogenic performance of the BCG vaccine, new therapies with probiotic bacteria were proposed, and in vivo and in vitro studies were performed with positive results in terms of tumor size reduction and recurrence reduction. Finally, the potential use of Bifidobacterium as a vector in specific gene therapy against bladder cancer is described.