Vychytilova-Faltejskova P, et al. - Recent identification of circulating PIWI-interacting RNAs (piRNA) as promising biomarkers of colon cancer inspired researchers to evaluate the profiles of piRNAs in blood serum of colon cancer patients to find those with high diagnostic potential. In this 3-phase biomarker study, they analyzed blood serum samples from 403 colon cancer patients and 276 healthy donors. They performed large-scale piRNA expression profiling by using Illumina small RNA sequencing. Further validation of the diagnostic potential of selected piRNAs was carried out on independent training and validation sets of samples using RT-qPCR. Findings showed plentiful piRNAs in human blood serum and significantly deregulated levels of these in colon cancer. Overall, they concluded that piRNAs could be effective noninvasive biomarkers for early detection of colon cancer.