ERBB2 and neoplasm: Accumulating evidence from several studies indicates that tumor infiltrating lymphocytes (TILs) are associated with better survival in triple-negative breast cancer (TNBC) and to a lesser extent in ERBB2-positive BC, with fewer studies supporting the relevance of TILs in luminal (hormone receptor–positive and ERBB2-negative) BC.5,6 However, the association between TILs and ERBB2 at low levels (ERBB2-negative or ERBB2-low) is unknown.