CXCR4 and hematologic disorder: These and previously published data showing that CXCR4 expression is reduced on the NK cell surface shortly after activation with IL-2 (9) have led our group to hypothesize that modification of NK cells to express higher levels of CXCR4, including CXCR4 receptor variants associated with a gain-of-function (GOF), may represent a method to improve the clinical efficacy of adoptive NK cell immunotherapy for hematological malignancies.