Characteristics and clinical outcomes of patients with myeloid malignancies and cohesin mutations.

Background: The prognostic impact of cohesin mutations in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) is controversial.

Methods: In patients with AML and MDS who underwent next-generation sequencing at the authors' center during 2017-2023, the authors assessed the landscape of cohesin mutations and the impact of co-occurring mutations on overall survival (OS) and compared outcomes between patients with cohesin mutations and those with wild-type (WT) cohesin genes.

Results: The study included 83 patients, 36 with cohesin mutations (STAG2, n = 28; SMC1A, n = 7; SMC3, n = 3; co-expression of cohesin mutations, n = 2) and 47 with WT cohesin genes. Of the 36 patients with cohesin mutations, 17 (47%) had AML (six de novo and 11 secondary), and 19 (53%) had MDS. Patients who had STAG2 mutations had better median OS than patients who had only SMC1A and SMC3 mutations (26 vs. 10 months; p = .043). SRSF2 mutation was the most frequent co-occurring mutation (n = 12; 33%) and was associated with worse median OS than WT SRSF2 (13 vs. 43 months; p = .016). Seven patients (19%) with cohesin mutations underwent hematopoietic transplantation; their median OS was 70 months. Compared with the WT cohesin group, patients who had cohesin mutations were more likely to have adverse-risk AML (82% vs. 53%). The median OS was similar among patients with adverse-risk AML in the cohesin-mutation and WT cohesin groups (10 vs. 14 months, respectively; p = .9).

Conclusions: The current study provides insight into the prognostic impact of cohesin mutations and co-occurring mutations in patients with myeloid malignancies.