GDF15 and neoplasm: To validate that the suppression of tumor growth was a result of disruption of the GDF15 gene and downregulation of GDF15 protein expression, excised tumor tissues obtained from mice treated with SNCSS(Cas9/sgGDF15) or the 2 control formulations were examined on day 30 using 3 different techniques: T7E1 mismatch detection assay, western blot, and next‐generation sequencing (NGS).