KRAS and colorectal carcinoma: Indeed, ∼35% of CRC tissues carry a mutation in codons 12 or 13 of KRAS that leads to the constitutive activation of downstream pathways, including the Ras/Raf/MAP/MEK/ERK and/or PTEN/PI3K/Akt pathways (Kinzler and Vogelstein, 1999; Wan et al, 2004; Benvenuti et al, 2007; Di Nicolantonio et al, 2008; Souglakos et al, 2009).