In contrast, among the NK-92-resistant breast cancer cells, only a small portion of the HCC1954 cell line (approximately 14.5%) express CD56 on their surface while all other resistant cells (MCF-7, MDA-MB-231, SKBR3, T47D, BT20 and BT474) are negative for CD56 protein expression. The gene discussed is NCAM1; the disease is breast cancer.