The role of molecular genetic alterations in sensitivity of the adjuvant intravesical therapy for non-muscle invasive bladder cancer

Abstract

Bladder cancer (BC) is represented by non-muscle-invasive forms at the stage Ta, T1, CIS (NMBC) in 75 % of cases. The gold standard of treatment of NMBC patients is transurethral resection, but its implementation does not always allow the patient to be relieved of the recurrence of the disease. In this regard, patients with a low risk of progression after transurethral resection are administered by intravesical chemotherapy, with high risk (T1G2/3) – using instillation with BCG (Bacillus Calmette–Guerin) vaccine. Searching of NMBC markers for laboratory diagnostics, which would help to determine sensitivity or resistance to the planned type of adjuvant therapy remains an actual problem. The data published mainly in the last 5–7 years about genetic predictors of the response to adjuvant chemotherapy and, to a greater extent, immunotherapy with BCG vaccine, are reviewed in this work. Allele combinations in the genes involved in immune response, xenobiotic biotransformation and other loci that are associated with the response to the adjuvant NMBC therapy in meta-analyzes are systematized. Also, expression profiles of mRNA, microRNA and proteins, as well as panels of methylated loci associated with the effectiveness of chemotherapy and immunotherapy of NMBC are considered. It was demonstrated that the somatic mutations sequencing in the primary tumor and the total mutational load using high-throughput sequencing technologies (NGS) identified a number of potential prognostic markers. Perhaps, the mutational load will be more widely used as a highly informative predictor of immunotherapeutic effect in BC: BCG therapy of NMBC and BC targeted therapy using the inhibitors of immune control points, after the standardization of the analysis. This review is intended to oncologists, geneticists, molecular biologists, urologists, pathologists and other specialists working in the field of molecular genetics in oncological urology.