VAV1 and myeloproliferative neoplasm: H&E staining revealed extensive disruption of liver architecture and replacement with mononuclear infiltrates in VAV1-Cre DKO mice (Figure 2A–2C).Interestingly, in contrast to prominent splenomegaly that accompanies hepatomegaly in the MMTV-Cre-based CBL/CBL-B DKO model of MPD [23, 24], the splenic size was significantly reduced in VAV1-Cre-based DKO mice with paler spleens, which showed reduced red and white pulp cellularity upon H&E staining (Figure 2A–2C).