From 157 patients with lung or colorectal cancer, 29 patients (18%) showed positive ctDNA liquid biopsies, with genetic mutations in EGFR (n = 9), BRAF (n = 3), neuroblastoma rat sarcoma virus (NRAS) (n = 1), and Kirsten rat sarcoma virus (KRAS) (n = 16). The gene discussed is KRAS; the disease is colorectal cancer.