JAK2 and acute lymphoblastic leukemia: So, in total, we identified JAK2 mutations in 2 of 46 (4%) T-ALL samples and in 0 of 18 T-ALL cell lines and JAK3 mutations in 2 of 46 (4%) T-ALL samples and in 2 of 18 T-ALL cell lines (Table S5, Figure 3.A-B).