KRAS and acute lymphoblastic leukemia: To determine whether KRAS4A is expressed in blood cancer cells harboring KRAS mutations, we checked the KRAS4A protein levels with a KRAS4A specific antibody in acute myeloid leukemia cell lines SHI-1 and NB4, T cell acute lymphoblastic leukemia cell line CCRF-CEM, as well as diffuse large B cell lymphoma cell line Toledo.