Short Communication Genoproteomic Mining of Urothelial Cancer Suggests -Glutamyl Hydrolase and Diazepam-Binding Inhibitor as Putative Urinary Markers of Outcome after Chemotherapy

Urinary biomarkers for the detection of bladder cancer have been developed, but no similar markers exist for prediction of clinical outcomes after receiving chemotherapy. Here we evaluate an approach that combines genomic, proteomic, and therapeutic outcome datasets to identify novel putative urinary biomarkers of clinical outcome after neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC). Using this method, we identified -glutamyl hydrolase (GGH), emmprin, survivin, and diazepam-binding inhibitor (DBI). Interestingly, GGH is a protein associated with methotrexate resistance, whereas emmprin, survivin, and DBI had been previously identified as predictors of outcome after platinum-containing chemotherapeutic regimens when assessed on tumor tissue. Using disease-free survival as a marker for clinical outcome, we evaluated the ability of GGH, emmprin, survivin, and DBI expression in tumor tissue to stratify 27 patients treated with neoadjuvant MVAC. DBI (P 0.046) but not GGH (P 0.190), emmprin (P 0.066), or survivin (P 0.393) successfully stratified patients. When GGH was used with DBI the significance of stratification improved (P 0.024), whereas the addition of survivin or emmprin to this latter two-gene model reduced its significance (P 0.036 and P 0.040, respectively). Although these predictive results were obtained on tumor tissues, the presence of GGH and DBI in urine serves as a rationale for developing them as urinary markers of clinical outcomes for patients treated with neoadjuvant MVAC. (Am J Pathol 2009, 175:1824–1830; DOI: 10.2353/ajpath.2009.090155) In 2008 approximately 69,000 individuals in the United States were diagnosed with bladder cancer, and 14,000 will ultimately die as a result of the disease. Most of the patients who die initially present with muscle-invasive disease that later metastasizes. Randomized studies have shown that neoadjuvant chemotherapy with MVAC (methotrexate, vinblastine, doxorubicin, and cisplatin) in patients with muscle-invasive disease improves median survival from 46 to 77 months. However, despite these promising results, only a subgroup of patients benefit from this approach and determining who they are is not currently possible. Hence, biomarkers that predict such outcomes would be of great practical utility, allowing only patients who are likely to derive the greatest benefit to be treated. Despite the fact that bladder cancer is ideally suited for noninvasive molecular evaluation based on analysis of urine, no urinary biomarkers have been found to robustly predict clinical outcomes after chemotherapy. Recently, tissue expression of two genes, emmprin and survivin, was found to independently predict outcome in patients with bladder cancer treated with cisplatinum-containing regimens. Interestingly, both emmprin and survivin have been identified in urine. In addition, a recent study described a 14-gene signature predictive of therapeutic response in patients with bladder cancer treated with neoadjuvant MVAC. One of the 14 genes in this model, diazepam-binding inhibitor (DBI), is found in urine. Taken together, these findings suggested it may be possible to develop a general method that can identify genes encoding proteins that are both predictors of clin-