Since NK cells are the main effectors of antibody-dependent cellular cytotoxicity (ADCC), we evaluated the overall density of CD56+ NK cells on breast cancer tissues and found that tumors with both high numbers of apoptotic cells and a high percentages of IgG-stained tumor cells were more infiltrated by CD56+ NK than tumors with high numbers of apoptotic cells but low percentages of IgG-stained tumor cells (Figure 5C). Here, NCAM1 is linked to breast cancer.