In these studies, objective response rate (ORR) and progression-free survival (PFS) were significantly improved with the addition of an EGFR mAb to FOLFOX4 among patients with tumours assessed as wild type at codons 12 and 13 of KRAS exon 2; in the PRIME study, a significant improvement in overall survival (OS) was also observed. The gene discussed is EGFR; the disease is neoplasm.