In light of increasing evidence for a possible link between HER2-directed therapies and ILD in multiple tumor types, it is possible that patients with HER2-positive mBC at high risk for ILD were treated at lower doses or received closer monitoring than lower-risk patients which could lead to underestimation of the true incidence of treatment-related ILD in high-risk patients. This evidence concerns the gene ERBB2 and interstitial lung disease.