Kataoka et al. [14] conducted a comprehensive genomic study of 426 patients with ATLL in Japan and identified 50 frequently altered genes enriched in the T-cell receptor (TCR)/nuclear factor (NF)-κB pathway (CD28, FYN, VAV1, RHOA, PLCG1, PRKCB, CARD11, and IRF4), the T-cell trafficking pathway (CCR4, CCR7, and GPR183), immune-related genes (HLA-A, HLA-B, CD58), and other T-cell-related genes (TBL1XR1, GATA3, NOTCH1, and STAT3). Here, VAV1 is linked to adult T-cell leukemia/lymphoma.