Accordingly, we suggest that BC patients with tumors expressing high levels of the NK-activating ligands that would mark worse prognosis or limited OS (such as BAT3, CD58, ULBP2, MICA, ULBP3, B7-1, B7-2, CD70, MICB, TNFSF9, ULBP1 and ULBP4), would probably have tumors with low expression of NK-inhibitory ligands (which should be tested and confirmed in the tumor), making them ideal candidates for a successful NK-based immunotherapy. This evidence concerns the gene ULBP2 and breast cancer.