We found that binding of Angptls to PirB/LILRB2 induces activation of tyrosine phosphatase SHP-1/SHP-2 and calcium/calmodulin-dependent protein kinase CAMKIV [1], both known to be critical for HSC repopulation and stimulation of leukemia development [1, 2, 8–10]. Here, CAMK4 is linked to leukemia.