The surface ICAM1 expression of two human TNBC cell lines (MDA-MB-231 and MDA-MB-468), ER-positive breast cancer cell line MCF-7, MDA-MB-231 ICAM1KO cell line, normal human mammary epithelial MCF10a, and HER2-amplified luminal breast cancer cell line SKBR3 were examined by FACS. This evidence concerns the gene ICAM1 and breast cancer.