Urothelial bladder cancer (UBC) is rare in young patients and as a result little information as to tumor type and clinical course are available. We present clinicopathological data of a large series of patients less than 40 years with bladder carcinoma. We included in this retrospective study covering the period from 1992 to 2013 patients less than 40 years with a first diagnosis of bladder cancer. Lesions were classified according to the WHO 2004 classification by uropathologists of ten centers. Stage, grade, multifocality, smoking habits, recurrence, and survival were studied. The cohort comprised of 152 patients, 113 males and 39 females with a mean age of 33.2 years. The large majority of the patients (142) was diagnosed with an urothelial carcinoma, the ten others with various histopathological diagnoses. In the age group less than 30 years old, 40.3 % of the cases concerned a papillary urothelial neoplasia of low malignant potential (PUNLMP). In the age group over 30 years, the proportion of PUNLMP decreased to 27.2 %. Only 5.6 % of the UBC was associated with carcinoma in situ. In 14.1 %, a high grade muscle invasive UC was found; 7.0 % had lymph node and 4.9 % distant metastasis at time of presentation. Four patients presented with a history of schistosomiasis; all had an infiltrating carcinoma. After initial resection, 36 patients relapsed, 17 % as PUNLMP, 53 % as pTa low grade, and 30 % as pTa-pT2 high grade UC. During follow-up, 6 % of the patients died. PUNLMP is the most frequent entity in this patient group. It is important that the PUNLMP entity is maintained in future classification systems.

The aim of this study was to evaluate the expression levels of microRNAs (miRNAs) in bladder tumors in order to identify miRNAs involved in bladder carcinogenesis with potential prognostic implications. Expression levels of miRNAs were assessed by quantitative real-time RT-PCR in 11 human normal bladder and 166 bladder tumor samples (86 non-muscle-invasive bladder cancer (NMIBC) and 80 muscle-invasive bladder cancer (MIBC)). The expression level of 804 miRNAs was initially measured in a well-defined series of seven NMIBC, MIBC and normal bladder samples (screening set). The most strongly deregulated miRNAs in tumor samples compared to normal bladder tissue were then selected for RT-PCR validation in a well-characterized independent series of 152 bladder tumors (validation set), and in six bladder cancer cell lines. Expression levels of these miRNAs were tested for their association with clinical outcome. A robust group of 15 miRNAs was found to be significantly deregulated in bladder cancer. Except for two miRNAs, miR-146b and miR-9, which were specifically upregulated in MIBC, the majority of miRNAs (n 5 13) were deregulated in the same way in the two types of bladder tumors, irrespective of pathological stage : three miRNAs were upregulated (miR-200b, miR-182 and miR-138) and the other 10 miRNAs were downregulated (miR-1, miR-133a, miR-133b, miR-145, miR-143, miR-204, miR-921, miR-1281, miR-199a and miR-199b). A 3-miRNA signature (miR-9, miR-182 and miR-200b) was found to be related to MIBC tumor aggressiveness and was associated with both recurrence-free and overall survival in univariate analysis with a trend to significance in the multivariate analysis (p 5 0.05). Our results suggested a promising individual prognostic value of these new markers.