In this study, we analyzed different breast cancer cell lines and identified two types of cell lines with the constitutive surface expression of B7-H4, including SKBR3 (HER2-enriched breast cancer cells) and MDA-MB-468 (triple-negative breast cancer cells, TNBC) (Additional file 1: Fig. S1A). This evidence concerns the gene ERBB2 and triple-negative breast carcinoma.