Predictive markers in bladder cancer: Do we have molecular markers ready for clinical use?

Bladder cancer (BC) is a heterogeneous disease. Approximately 75% of patients present with non-muscle-invasive BC (NMIBC), which has a high recurrence rate and a low but unpredictable progression rate. Conversely, patients with muscle-invasive BC (MIBC) are at high risk for progression and cancer-specific mortality, but, again, disease behavior is unpredictable. To date, risk assessment for tumor recurrence and progression is based on clinico-pathological factors only. A risk assessment calculator that is based on several such parameters is available for NMIBC, but it has been reported to have potential flaws. In the last two decades, great effort has been made to evaluate the prognostic and predictive role of several molecular markers in MIBC and, even more so, in NMIBC, where the need for more precise risk stratification is urgently needed. This review addresses current evidence for the role of several molecular markers easily assessable by immunohistochemical techniques in prognosticating/predicting the outcome of NMIBC and MIBC. To date, because of divergent results among the many studies, no molecular marker has yet entered routine clinical practice; however, some of them (e.g., p53, pRb, p21, and survivin) have proved their predictive value in studies that included a homogeneous patient population on standardized treatment, and, therefore, are probably ready for clinical validation on a larger scale. Even more interesting is the possibility of constructing multimarker panels that could be used in routine clinical practice, as all these markers can easily be evaluated by immunohistochemistry on routine surgical pathology specimens. The molecular markers described herein hold promise for becoming widely available and cost-effective tools for reliable risk assessment, which would represent a great advancement in counseling patients, in selecting them for neoadjuvant and adjuvant treatments, and in determining their eligibility for clinical trials.