ERBB2 and metastatic neoplasm: Interestingly, the concept that the immune phenotype, whether in the periphery or in the tumor microenvironment, correlates more closely with the severity of the disease rather than the breast cancer molecular subtypes has also recently been described by Savas et al. (37) who found that the overall percentage of CD45+ TILs did not change according to each breast cancer subtype (TNBC, HER2+, and hormone receptor–positive (luminal)), but was significantly higher in primary than in metastatic tumor samples.