RAD21 mutations in acute myeloid leukemia

The cohesin complex is a ring-shaped protein structure involved in DNA repair and chromosomal segregation. Studies have showed that genomic alterations in the cohesin complex members are among the initial occurrences in the development of acute myeloid leukemia (AML). STAG2 is the most commonly mutated and best-studied member of the cohesin complex in AML and mutations in this gene have been associated with adverse outcomes and are diagnostically relevant. However, the exact role of mutations in other members of the cohesin complex in the development of myeloid neoplasia is controversial. In this single institution study, we retrospectively reviewed data from the molecular profiles of 1,381 AML patients and identified 14 patients with mutations in RAD21, another member of the cohesin complex. We evaluated the frequency, mutational profile, clinico-pathologic features, and prognostic impact of RAD21 in this cohort. This study showed that RAD21-mutated AML often associates with monocytic differentiation, CD7 expression, co-existing mutations in epigenetic regulators, a normal karyotype, and poor prognosis. Our findings provide additional insights into the morphologic, immunophenotypic, and genomic profile of RAD21 mutation-positive AML and suggest that RAD21 mutations should be evaluated for independent prognostic significance in AML.