In the absence of 2B4, NK cells not only lyse hematopoietic tumor cells more efficiently but also begin to target other NK cells (Taniguchi et al., 2007) as well as activated CD8 T cells (Waggoner et al., 2010), suggesting that 2B4 is involved in the maintenance of self-tolerance (McNerney et al., 2005a). Here, CD244 is linked to neoplasm.