There has been limited investigation into agents targeting the DDR in metastatic colorectal cancer (mCRC), mainly because of the lack of systematic identification of alterations in DDR genes.8 Here, we test adavosertib in RAS- and TP53-mutant (RAS/TP53-mut) mCRC, which we hypothesize would be sensitive to WEE1 inhibition. This evidence concerns the gene TP53 and metastatic colorectal cancer.