Reduced expression of microRNA-100 confers unfavorable prognosis in patients with bladder cancer

Expression levels of miR-100 in 126 pairs of bladder cancer and adjacent normal tissues were detected by TaqMan real-time quantitative RT-PCR assay. In order to determine its prognostic value, overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.Expression levels of miR-100 in bladder cancer tissues were significantly lower than those in adjacent normal tissues (mean expression level: 2.6？±？1.2 vs. 3.9？±？1.5, P？<？0.001). When categorized into low vs. high expression, low miR-100 expression was negatively associated with the stage (P？=？0.01), the recurrence (P？=？0.008), the progression (P？=？0.01), and the death (P？<？0.001) of patients with bladder cancer. Moreover, low miR-100 expression clearly predicted poorer PFS (P？=？0.001) and OS (P？<？0.001). In the multivariate analysis, low miR-100 expression was an independent prognostic factor for both PFS (P？=？0.01) and OS (P？=？0.008).Our data offer the convincing evidence that miR-100 may play an important role in the progression of bladder cancer and that the reduced expression of this miRNA may be independently associated with shorter PFS and OS of patients, suggesting that miR-100 might be a potential marker for further risk stratification in the treatment of this cancer.The virtual slides’ for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1105483419841671 webciteBladder cancer is the seventh most common malignant neoplasm and the eighth leading cause of cancer death worldwide, with an estimated 68,810 new cases and 14,100 deaths in the USA in 2008 alone [1,2]. This malignancy affects the lining of the urinary bladder with a complicated, multifactorial etiology, involving both genetic and environmental factors. There are two principal forms of bladder cancers: low-grade superficial tumors and high-grade invasive cancer. The former are often papillary and mu