EGFR and colorectal carcinoma: The induction of PUMA has a vital role in apoptosis induced by a range of chemotherapy agents and may be a valuable chemosensitivity biomarker.37 Studies have shown that induction of PUMA relates closely with varying sensitivity to EGFR TKIs in neck and head cancer cells, and of the absence of PUMA induction correlates with resistance to EGFR TKIs.8, 43 Increased expression of PUMA is associated with superior prognosis in stage II and III CRC patients undergoing 5‐FU‐based therapy.44 Therefore, induction of PUMA may be a useful surrogate biomarker for CRC response to gilteritinib.