KRAS and acute myeloid leukemia: We performed western blotting in NRAS mutant (OCI-AML3, THP-1 and HL60), KRAS mutant (NB4) and RAS WT (OCI-AML2 and MOLM13) human AML cell lines, and demonstrated that SOCS2 protein levels were significantly lower in NRAS and KRAS mutant cells than RAS wild-type AML cells (Fig. 4A).