PTPN11 mutation with additional somatic alteration indicates unfavorable outcome in juvenile myelomonocytic leukemia: a retrospective clinical study from a single center.

Juvenile myelomonocytic leukemia (JMML) is a heterogeneous childhood leukemia. The management of patients with JMML requires accurate assessment of genetic and clinical features to help in patient risk stratification. This study aimed to investigate the association between genomic alterations and prognosis in children with JMML. Genomic DNA was extracted from a total of 93 patients with JMML for targeted sequencing. Univariable and multivariable analysis were used to evaluate the correlation between gene mutations and prognosis of the patients. Patients with PTPN11 mutation exhibited significantly lower event-free survival (EFS) compared with non-PTPN11 mutations (P = 0.005). Patients without or with one somatic alteration at diagnosis showed significantly better prognosis in comparison with those with more than two alterations (P = 0.009). PTPN11 mutation with additional alterations showed significantly the poorest outcome in comparison with those with only one non-PTPN11 mutation, only one PTPN11 mutation, and combined mutations without PTPN11, respectively (P < 0.0001).Conclusion: Both PTPN11 mutation and the number of somatic alterations detected at diagnosis are likely to be the major determinant of outcome in JMML. The subgroup of patients with PTPN11 mutation showed the shortest survival which was even worsened when a secondary mutation was present.