Moreover, a recent retrospective study found patients carrying ERBB2 mutations in lung cancer developed more brain metastases on treatment than patients with KRAS mutations [28 vs. 8%; hazard ratio (HR), 5.2; p < 0.001] and trended more than patients with EGFR mutations [28 vs. 16%; HR, 1.7; p = 0.06; (33)]. This evidence concerns the gene KRAS and lung cancer.