Prognostic relevance of NPM1, CEBPA, and FLT3 mutations in cytogenetically normal adult AML patients.

Background: Acute myeloid leukemia with normal cytogenetics (CN-AML) is the largest group of AML patients with very heterogenous patient outcomes. The revised World Health Organization classification of the hematolymphoid tumours, 2022, has incorporated AML with Nucleophosphmin1 (NPM1) and CCAAT/enhancer binding protein-alpha (CEBPA) mutations as distinct entities. Despite the existing evidence of the prognostic relevance of FMS-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD) in AML, it has not been included in the revised classification.

Method: In this prospective study, we determined the prevalence of NPM1, CEBPA, and FLT3 gene mutations in 151 de novo CN-AML adult patients (age ≥18 years) in a tertiary care hospital in north India. Additionally, the prognostic relevance of these mutations was also evaluated.

Results: NPM1, FLT3-ITD, and CEBPA mutations were found in 33.11%, 23.84%, and 15.77% of CN-AML patients, respectively. CEBPA mutations were found at 3 domains: transactivation domain 1 (TAD1) in 10 (6.62%), transactivation domain 2 (TAD2) in 5 (3.31%), and basic leucine zipper domain (bZIP) in 11 (7.82%) patients. Patients with NPM1 mutation had better clinical remission rate (CR) (P=0.003), event-free survival (P=0.0014), and overall survival (OS) (P=0.0017). However, FLT3-ITD and CEBPA mutations did not show any association with CR (P=0.404 and 0.92, respectively). Biallelic CEBPA mutations were found in 12 (7.95%) patients and were associated with better OS (P=0.043).

Conclusions: These findings indicate that NPM1 and CEBPA mutations can be precisely used for risk stratification in CN-AML patients.