Splenomegaly and, less frequently, hepatomegaly are also often described as pathological alterations associated with CML [41,42]; thus, we also wished to test and compare the effect of SOS1/2 genetic ablation on the size and histological structure of these hematopoietic organs in our non-transgenic and transgenic p210BCR/ABL mice (Figure 4). The gene discussed is SOS1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.