Reclassification of Myelodysplastic Neoplasms According to the 2022 World Health Organization Classification and the 2022 International Consensus Classification Using Open-Source Data: Focus on SF3B1- and TP53-mutated Myelodysplastic Neoplasms.

Background: In 2022, the WHO and International Consensus Classification (ICC) published diagnostic criteria for myelodysplastic neoplasms (MDSs). We examined the influence of the revised diagnostic criteria on classifying MDSs in a large population.

Methods: We retrieved an open-source pre-existing dataset from cBioPortal and included 2,454 patients with MDS in this study. Patients were reclassified based on the new diagnostic 2022 WHO and ICC criteria. Survival analysis was performed using Cox regression to validate the new criteria and to assess risk factors.

Results: Based on the 2022 WHO criteria, 1.4% of patients were reclassified as having AML. The 2022 WHO criteria provide a superior prognostic/diagnostic model to the 2017 WHO criteria (Akaike information criterion, 14,152 vs. 14,516; concordance index, 0.705 vs. 0.681). For classifying MDS with low blast counts and SF3B1 mutation, a variant allele frequency cut-off of 5% (2022 WHO criteria) and the absence of RUNX1 co-mutation (2022 ICC criteria) are diagnostically relevant. For classifying MDSs with mutated TP53, a blast count cut-off of 10% (2022 ICC criteria) and multi-hit TP53 (2022 WHO criteria) are independent risk factors in cases with ≥10% blasts.

Conclusions: Our findings support the refinements of the new WHO criteria. We recommend the complementary use of the new WHO and ICC criteria in classifying SF3B1- and TP53-mutated MDSs for better survival prediction.