FGFR1 and T-cell acute lymphoblastic leukemia: By frequency, pediatric soft tissue sarcoma had the highest percentage of FGFR1-4 gene alterations, followed by atypical teratoid-rhabdoid tumors (ATRT), pediatric T-cell acute lymphoblastic leukemia (T-ALL), and B-cell lymphoblastic ALL (B-ALL), [Figure 1B and C].