Our previous analysis added to a growing body of evidence supporting the prognostic value of TILs in ERBB2-positive breast cancer in both the neoadjuvant4,5,6,7,8,9and adjuvant setting,10,11,12 where TILs are strongly associated with surrogate end points such as increased rates of pathological complete responses and reduced risk of relapse. This evidence concerns the gene ERBB2 and breast cancer.