Interestingly, the virally transformed HTLV-1 T-cell leukemia/lymphoma cell lines MT2 and Hut102 displayed JAK3-Y841 phosphorylation, while the non-HTLV-1-positive parental cell line of Hut102, Hut78, did not (Figure 4c, lane a). Here, JAK3 is linked to T-cell leukemia.