Accordingly, the alterations in genes with potential association to the T-DXd resistance in our case (GATA3, NOTCH2, CKS1B, and MCL1) could be highly relevant for multiple cancer types, primarily for breast, bladder, and gynecologic cancers as well as lung adenocarcinoma, lung squamous cell carcinoma, cholangiocarcinoma, and hepatocellular carcinoma [cBioPortal (70)]. Here, MCL1 is linked to cholangiocarcinoma.