In the multicohort DS8201-A-J101 study, including patients with HER2-positive advanced solid tumors, meaningful objective response rates (ORRs) were observed in most sub-cohorts, especially in gastric, non-small-cell lung and breast cancers, including a separate cohort for advanced pretreated HER2-low breast tumors [42]. This evidence concerns the gene ERBB2 and breast cancer.