Interestingly, the percentage of early apoptotic CD56+ NK cells obtained from PBMCs co-cultured with cancer cells increased only at 24 h (P < 0.05), while the increase of late apoptotic CD56+ NK cells occurred at both 48 and 72 h of co-culture (P < 0.01, P < 0.001 vs CD56+ NK cells obtained from PBMCs cultured alone, Fig. 6B). The gene discussed is NCAM1; the disease is cancer.