Biomarkers for assessing therapeutic response in bladder cancer

Reliable markers for assessing therapeutic response are needed to select the most effective treatment strategy for bladder cancer patients. We analyzed the role of biomarkers predicting response of non-muscle invasive bladder cancer (NMIBC) on BCG induction, and of non-organ confined muscle invasive bladder cancer (MIBC) on neoadjuvant chemotherapy. A critical, non-structured review of the literature was conducted. For assessing BCG therapy outcome, measurement of urinary IL-2 levels seems to be the most potent marker of all the clinical parameters reviewed. Measurements of urinary interleukins IL-8, IL-18, and tumour necrosis factor apoptosis-inducing ligand levels seem promising as well. Immunohistochemical markers (ie, TP53, Ki-67, and Rb)display contradictory results and seem unsuitable. Gene polymorphisms need to be studied more thoroughly before their clinical relevance can be determined. Regarding assessing and predicting response of MIBC to neoadjuvant chemotherapy, a set of potent markers has been studied. However, no conclusive evidence is yet available on their additional value over the established clinicopathological variables. Prospective trials are needed to validate the clinical benefit of molecular markers to predict response to BCG (NMIBC) and neoadjuvant chemotherapy (MIBC) before predictive biomarkers can become part of clinical practice.