Sensitivities of 0.005–0.1% for EGFR-T790M (own unreported data, [28]), 0,1% and 0,5% for ALK-C1156Y and ALK-G1269A in lung cancer [35] and 0.025% for KRAS in CRC [36] are reached. The gene discussed is KRAS; the disease is colorectal carcinoma.