PPP1R14A and colorectal carcinoma: PPP1R14A mRNA codes protein CPI-17, which directly deactivates tumor suppressor merlin (encoded by neurofibromatosis type 2 gene NF2) through merlin phosphorylation and tumorigenic Ras signaling activation [82, 83], and PPP1R14A has been reported to be aberrantly methylated in CRC [84] and serves as an epigenetic biomarker for CRC early detection [85].