We also noticed that the structural histological organization of the spleen was significantly altered as a consequence of the CML development in our control transgenic mice expressing normal levels of both SOS1 and SOS2 (WT (both −TAM and +TAM) and SOS1FL/fl kept in the absence of TAM (Figure 4), which displayed significantly more disorganized and less defined red pulp and white pulp areas within this hematopoietic organ. Here, SOS1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.