It is interesting that KRAS mutations were found in both cell lines (HuCCT1 and OZ) considered refractory to vandetanib in this study, and KRAS mutation has been reported as a mechanism of resistance to EGFR inhibitors in lung and colorectal cancers (Pao et al, 2005; Lievre et al, 2006). Here, EGFR is linked to colorectal cancer.