Somatic Mutations Predict Poor Prognosis in Myelodysplastic Syndrome Patients with Normal Karyotypes

Purpose: Somatic mutations are common in myelodysplastic syndrome (MDS), but its risk stratification is mainly based on cytogenetics. This study was to explore the prognostic significance of somatic mutations in MDS patients with normal karyotypes.

Patients and Methods: Three hundred and four patients with MDS were enrolled in this retrospective study. A genomic panel of 127 gene targets were detected by next-generation sequencing.

Results: Two hundred and Eighty-one (92.4%) patients carried at least one somatic mutation, while cytogenetics identified abnormalities in 140 (46.1%) patients. The 5 most frequently mutated genes were TET2, ASXL1, EZH2, TET1, FAT1, and TET2, TP53, TET1, EP300, SF3B1 in the patients with normal karyotypes and aberrant karyotypes, respectively. When mutations detected in >5% of the whole cohort, they were included in analysis and the results showed that the frequency of TET2, TP53, ASXL1, CD101, KDM6A, SH2B3 and IL-3RA mutations was different between two groups(all P<0.05). ASXL1, CD101, KDM6A, SH2B3, IL-3RA mutations were more common in normal karyotype group, while TET2 and TP53 were more common in aberrant karyotype group. Multivariable analysis showed that age (HR 1.02; P=0.027), IPSS-R(HR 1.80; P<0.0001), TP53(HR 2.36; P<0.0001) and DNMT3A (HR 1.83, P=0.044) were the risk factors while allo-HSCT(HR 0.50; P=0.001) was a protect factor for OS in the whole cohort. For sub-group analysis, IPSS-R(HR 1.54; P=0.005; HR 1.80; P<0.0001, respectively), TP53 mutation(HR 2.49; P=0.030; HR 2.13; P=0.005, respectively) and allo-HSCT(HR 0.52; P=0.040; HR 0.37; P<0.0001, respectively) retained the prognostic significance in both the normal karyotype and aberrant karyotype group. FAT1(HR 2.32; P=0.019), DNMT3A(HR 3.32; P=0.006) and IL-7R(HR 4.35; P=0.002) mutations were unfavorable factors for OS only in the normal karyotype group.

Conclusion: FAT1, IL-7R and DNMT3A mutations pretict poor prognosis in MDS patients with normal karyotypes.

Key words: Somatic mutation, Next-generation sequencing, Prognosis, Myelodysplastic syndrome