Therefore, preclinical studies using patient-derived breast cancer xenograft-mouse models would allow the verification of whether the high cytotoxic activity of NK-92 cells against CD56-positive breast cancer cells is maintained in vivo and the identification of potential combinatory treatment in addition to NK-92 adoptive transfer to counteract any possible inhibitory effect of the tumor microenvironment. Here, NCAM1 is linked to breast carcinoma.