NDRG4 and colorectal carcinoma: Stool DNA-based DNA methylation assays using several epigenetic biomarkers such as BMP3, NDRG4, SDC2, SFRP2, TFPI2, and VIM have been reported as potential noninvasive tools for early CRC detection [8, 15–21], with sensitivities ranging from 46 to 90% and specificities ranging from 76.8 to 93%.