All these classifications have clinical utility as exemplified by the fact that KRAS-positive CRC are resistant against the anti-epidermal growth factor receptor (anti-EGFR) antibody cetuximab [7, 8], immunoscore-positive resectable CRC have an intrinsically good prognosis and can be spared adjuvant chemotherapy [9, 10], and MMR-deficient, MSI-high cancers are particularly susceptible to immunotherapy with the PD-1-blocking antibody nivolumab [11–13]. The gene discussed is EGFR; the disease is cancer.