After the administration of the second cycle of T-DXd, a progressive and significant increase in liver enzymes was recorded, in particular aspartate transaminase (AST) and alanine transaminase (ALT), up to persistent grade 3 toxicity, in the absence of associated symptoms; grade 1 hypoalbuminemia was associated, while other indices of liver function and cholestasis, including coagulation tests, showed no alterations. The gene discussed is GPT; the disease is Hypoalbuminemia.