To further evaluate the functions of TMIGD2 and HHLA2 in leukemia cells, we next performed small hairpin RNA (shRNA)-mediated knockdown of TMIGD2 (shTMIGD2) or HHLA2 (shHHLA2) in Kasumi-1, HEL and K562 cell lines (Fig. 2a, b and Supplementary Fig. 2c, d). Here, HHLA2 is linked to leukemia.