FTIs can also block the farnesylation and membrane association of the RAS isoforms more commonly mutated in cancer (KRAS and NRAS); however, when FTase activity is blocked, these RAS isoforms can undergo modification by a related lipid geranylgeranyl transferase enzyme (GGTase-I), overcoming the actions of FTI treatment. The gene discussed is KRAS; the disease is cancer.