Background: MicroRNAs (miRNAs), small noncoding RNAs, are involved in tumorigenesis and in the development of various cancers. Quantitative real-time polymerase chain reaction (qPCR) is the most commonly used tool to investigate miRNA expression, and qPCR low-density arrays are increasingly being used as an experimental technique for both the identification of potentially relevant miRNAs and their subsequent validation. Due to the reduced number of microRNAs to be validated, this phase is generally performed on ad hoc customized cards for which a technical robustness is assumed similar to that of the high-throughput cards used during the identification phase.
Methods: With the aim of investigating the degree of reproducibility between the 2 types of cards, we analyzed plasma-circulating miRNAs evaluated in 60 subjects enrolled in a colorectal cancer screening program.
Results: Our results showed a reproducibility between the 2 methods that was not fully satisfactory, with a concordance correlation coefficient equal to 0.69 (95% confidence interval, 0.12-0.92).
Conclusions: This report highlights the need to add a technical validation step to the high-throughput-based miRNA identification workflow, after their discovery and before the validation step in an independent series.