KRAS and colorectal neoplasm: Colorectal tumours with RASSF2 methyaltion showed K-ras/BRAF mutations significantly more frequently than those without RASSF2 methyaltion (Akino et al, 2005), although earlier studies have showed that K-ras mutation and RASSF2 methylation are mutually exclusive (Hesson et al, 2005).