Background: Tumour expression of selected microRNAs (miRs) correlates with cisplatin efficacy in multiple cancers. We investigated the role of selected miRs in patients receiving cisplatin-based therapy for advanced urothelial carcinoma (UC). Methods: RNA was extracted from formalin-fixed paraffin-embedded tumour from 83 advanced UC patients who received cisplatin. A miR panel based on relevance for platinum sensitivity and UC was studied by quantitative reverse transcription quantitative PCR (RT–qPCR). Association of progression-free survival (PFS) with miR expression was analysed using cox regression. Selected TFs were chosen by association with the panel of miRs using the Transcription Regulation algorithm (GeneGo MetaCore+MetaDrug version 6.23 build 67496). Bladder cancer (BC) cell lines were used to investigate the previously described role of miR-21 mediating cisplatin sensitivity. Results: The 83 patients had a median PFS of 8 months. In multivariate analysis, higher levels of E2F1 (P=0.01, HR: 1.95 (1.14, 3.33)), miR-21 (P=0.01, HR: 2.01 (1.17, 3.45)) and miR-372 (P=0.05, HR: 1.70 (1.00, 2.89)) were associated with a shorter PFS. In the 8 BC cell lines, miR-21 was not shown to be necessary nor sufficient for modulating cisplatin sensitivity. Conclusions: In metastatic UC patients treated with cisplatin-based therapy, high primary tumour levels of E2F1, miR-21 and miR-372 are associated with poor PFS independent of clinical prognostic factors. The in vitro study could not confirm miR-21 levels role in modulating platinum sensitivity.
