IGF1 and acute lymphoblastic leukemia: However, at least in human T-ALL cell lines, PI3K/Akt signaling was dominant over MEK/ERK in mediating cell proliferation and/or survival [81], although in the article by Triplett et al. [85], MEK/ERK activation by IGF1/IGF1R was detected in T-ALL cells co-cultured with thymic DCs.