REG4 and colorectal carcinoma: Resistance to AZD8931 and to afatinib was associated to a molecular signature enriched for developmental genes (P=1.03 × 10−6 and 1 × 10−9), including the oncogene ETV5 (Supplementary Data 15) and for AZD8931, REG4, a multifunctional mitogenic protein known as a potent activator of the EGFR pathway in CRC (refs 54, 55).