PTK2 and acute lymphoblastic leukemia: Furthermore, blocking antibodies to ICAM-1 and VCAM-1 in co-cultures of T-ALL and myeloid cells reduced the frequency of T-ALL cells with activated FAK and PYK2 (Supplementary Fig. 8e, f), confirming a link between integrin signaling and FAK/PYK2 activation in T-ALL cells upon ICAM-1 and VCAM-1 dependent interactions with myeloid cells.