Using urinary microRNA as a potential biomarker for bladder cancer
Poster session, 25th Anniversary EAU Congress, Barcelona
Monday, 31 May 2010- MicroRNAs are single stranded non-coding RNA molecules 19-25nt in length. They regulate the expression of protein-coding genes at the translational level. Both functional and observation data suggest an important role for microRNA in human cancer.
S. Miah and colleagues (Sheffield, UK) has established the differential expression of microRNA with respect to benign urothelium, low and high grade bladder tumours. They presented their findings at the 25th Anniversary EAU Congress held in Barcelona, Spain.
In the study, the researchers investigated the presence of microRNA in urine and evaluate the stability of these molecules. They then compare the expression profiles of urinary microRNA in patients with or without bladder cancer, to explore its value as a diagnostic test.
The researchers compared microRNA yields from freshly voided and frozen urinary samples, using various extraction protocols. They also evaluated samples processed immediately, those stored at room temperature and those with repeated freeze/thawing. The researchers then profiled the expression of a panel of microRNAs in 134 urine samples from 50 benign controls and 74 from patients with bladder cancer (with the disease spectrum). They used triplicate real time multiplex rtPCR reactions to measure RNA concentration. Standard statistical analyses were used to evaluate the data.
The investigators optimised the best method for microRNA retrieval from urine samples. Correctly handled urine samples yielded around 1.5ug microRNA per 200 mls, without the need for RNase inhibitors.
All 134 samples were successfully analysed for each microRNA and two endogenous controls. Using four microRNA (miRs-133b/135b/211/183/211) the researchers were able to discriminate urinary samples from benign from cancerous patients (T Test of quantified concentrations, p=0.04). Individual loci analysis suggested miR-135b was the most discriminate molecule for cancer (C-index 0.79).
"Reasonable yields of microRNA can be obtained in urinary samples from patients with cancer and matching controls. Profiling of microRNA expression shows differences between patients with bladder cancer and matching controls, suggesting that this could be used as a diagnostic test for the disease. Further evaluation is required in a larger cohort," the researchers concluded.
Source: S. Miah, et al., "The utilisation of urinary microRNA as a potential biomarker for bladder cancer," Abstract 816, Poster Session on Urothelial tumours: Basic research 1; 25th Anniversary EAU Congress, Barcelona, Spain, April 16-20, 2010.
