SOS1 and chronic myelogenous leukemia, BCR-ABL1 positive: To confirm the oncogenic property of SOS1 in CML, protein and mRNA levels of SOS1 were detected in leukemia cells (K562, KCL-22, BV173, Jurkat, and peripheral blood mononuclear cells [PBMCs] of CML patients) and several normal human cells (293T, LO2, JCG, and PBMCs from normal subjects) by qPCR and western blotting (WB) assay.