Given the high ICAM1 expression in inflammatory breast cancer cell lines FC-IBC-02 and EMF-01 we generated from plural effusion33, the blood and lung microenvironment may be not only favorably selecting rare ICAM1+ tumor cells with their propensity to cluster, transmigrate, and metastasize, but also capable of providing niche-specific signals to enhance stemness/plasticity in tumor cells with ICAM1 expression for lung metastasis. This evidence concerns the gene ICAM1 and breast cancer.