PTEN and colorectal carcinoma: The KRAS gene is the most frequently mutated gene in CRC and is associated with the modulation of several downstream effectors to include: RAF/MEK/ERK, PTEN-PI3K-AKT-mTOR, RalGDS/p38MAPK, and Rac/Rho during tumorigenesis and the tumor progression of CRC [11].