Figure 3. Relative expression of 4 microRNAs in HC, CRA and CRC, and ROC curve analysis for predicting the 4 microRNAs as CRC diagnosis biomarkers. (A–D) qRT-PCR analysis was used to detect the expression of miR-20b-5p, miR-329-3p, miR-374b-5p and miR-503-5p in 585 plasma samples from healthy controls, 19 samples of CRA patients and 597 plasma samples from CRC patients. Data was log-transformed and was presented as mean ± SD. Data was analyzed with student t test. “***” indicated p < 0.001. (E) ROC curve for the 4-microRNA signature to separate 60 CRC cases from 60 controls in the training set with the AUC presented in the right. (F) ROC curve analysis was used for the 4-microRNA signature to differentiate 597 CRC cases from 585 controls in the validation set with the AUC presented in the right. Factor1, 2, 3, 4 and merged represented the miR-20b-5p, miR-329-3p, miR-374b-5p, miR-503-5p and the combination of the 4 microRNAs.