Interestingly, results from the CALGB 80203 study, where metastatic colorectal cancer patients were randomly allocated to receive either leucovorin/fluorouracil/irinotecan (FOLFIRI) or leucovorin/fluorouracil/oxaliplatin (FOLFOX) with or without cetuximab, showed that KRAS wild-type patients with high levels of HER3 did not benefit from cetuximab and were associated with therapy resistance [43]. Here, KRAS is linked to metastatic colorectal cancer.