Gain of function mutations and fusions, such as VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7 have been found in adult T cell leukemia (77) and in PTCLs (78) with dismal overall survival and results in a constitutive active conformation of Vav1 and a consequent transcriptional increase of chemokines (78). Here, VAV1 is linked to adult T-cell leukemia/lymphoma.