VAV1 and T-cell leukemia: Other notable mutations in Vav1 were shown to cluster at several hotspot amino acids in the acidic (Tyr 174 and Glu175), PH (Lys404), C1 (Glu556), and SH3 (Arg798 and Arg822) domains, 18% of them identified in T cell leukemia/lymphoma, but again both the functional activity of these mutants and their potential oncogenic activity remain to be tested28.