Mutations in the cohesin complex in acute myeloid leukemia: clinical and prognostic implications

Mutations in the cohesin complex are novel, genetic lesions in acute myeloid leukemia (AML) that are not well characterized. In this study, we analyzed the frequency, clinical, and prognostic implications of mutations in STAG1, STAG2, SMC1A, SMC3, and RAD21, all members of the cohesin complex, in a cohort of 389 uniformly treated AML patients by next generation sequencing. We identified a total of 23 patients (5.9%) with somatic mutations in 1 of the cohesin genes. All gene mutations were mutually exclusive, and STAG1 (1.8%), STAG2 (1.3%), and SMC3 (1.3%) were most frequently mutated. Patients with any cohesin complex mutation had lower BAALC expression levels. We found a strong association between mutations affecting the cohesin complex and NPM1. Mutated allele frequencies were similar between NPM1 and cohesin gene mutations. Overall survival (OS), relapse-free survival (RFS), and complete remission rates (CR) were not influenced by the presence of cohesin mutations (OS: hazard ratio HR 0.98; 95% confidence interval CI, 0.56-1.72 P = .94; RFS: HR 0.7; 95% CI, 0.36-1.38 P = .3; CR: mutated 83% vs wild-type 76% P = .45). The cohesin complex presents a novel pathway affected by recurrent mutations in AML. This study is registered at www.clinicaltrials.gov as #NCT00209833.