KLRD1 and neoplasm: A number of soluble factors [25–28], as well as different tumor associated regulatory/suppressive immune cells [29, 30], Tumor Associated Fibroblasts (TAFs) [31], and tumor cells [32, 33], have been shown to profoundly alter the expression and/or the function of several NK cell receptors and affect the ability of NK cells to reach, recognize, and kill tumor cells at the tumor site (Table 1).