Overexpression of ribonucleotide reductase subunit M1 protein predicts shorter survival in metastatic bladder cancer patients treated with gemcitabine-containing combination chemotherapy

ObjectivesTo identify biomarkers predicting prognosis in bladder cancer patients undergoing the gemcitabine and cisplatin regimen. MethodsWe studied 52 patients with metastatic bladder cancer treated with the gemcitabine and cisplatin regimen by evaluating the relationship between the expression of two biomarkers, ribonucleotide reductase subunit M1 and excision repair cross complementing 1, by immunohistochemistry and clinical outcomes. ResultsThe patients with low expression of ribonucleotide reductase subunit M1 showed a higher objective response rate by the gemcitabine and cisplatin regimen than those with high expression of ribonucleotide reductase subunit M1 (80.0% and 45.5%, respectively). No differences were observed according to the expression level of excision repair cross complementing 1. Low expression of ribonucleotide reductase subunit M1 significantly prolonged overall survival and progression-free survival compared with the high expression group. Low expression of excision repair cross complementing 1 tended to prolong overall survival and progression-free survival, but there were no significant differences (P = 0.07 and 0.10, respectively). Multivariate analysis showed that the expression of ribonucleotide reductase subunit M1 was the only independent prognostic factor (P = 0.012). ConclusionsThe expressions of ribonucleotide reductase subunit M1 seem to be associated with clinical response and survival in patients with metastatic bladder cancer treated with gemcitabine and cisplatin-based chemotherapy.