REG4 and neoplasm: Resistance to cetuximab was also associated with expression of REG4, and featured strong epithelial (P=2 × 10−9), as well as developmental (P=1 × 10−5) signatures whereas sensitive tumours featured expression of MYC, JUN and E2F5, and of previously reported markers of cetuximab sensitivity CEACAM7 and EREG46, 56.