Given previous studies reporting the impact of SOS1 on the sensitivity of CML to the BCR–ABL inhibitor imatinib (30, 33), it would be interesting to explore whether targeting SOS1 by SIAIS562055 synergizes with TKIs to inhibit the proliferation of CML cells. Here, SOS1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.