Prognostic Value of Recurrent Mutations in a Prospective Cohort of Myelodysplasia and Secondary Acute Myeloid Leukemias

Myelodysplastic syndromes (MDS) are a heterogeneous group of stem cell disorders characterized by ineffective hematopoiesis with dysplasia and a propensity to acute myeloid leukemia. Patients are affected in the elderly with a global incidence of 10/100,000/year.

During the past 3 years, a significant progress has been made in the understanding of molecular pathogenesis through identification of mutations in epigenetic genes like TET2, ASXL1, EZH2, RUNX1, DNMT3A, IDH1/2, transcription factors, signalling molecules, cohesion and splicing regulators. Inactivating mutations targeting the hematopoietic stem cell may alter its gene expression pattern and could be an early mechanism of clonal selection. However, a single genetic alteration does not readily recapitulate the apoptotic and dysplastic phenotype. Several clones may co-exist, but their architecture is still unclear.

This study aims at prospectively enrolling a cohort of 350 incident cases at diagnosis, to identify evaluate the impact of recurrent mutations on overall survival and event-free survival, using next generation sequencing.

Considering the current knowledge, investigators propose to:

• perform whole exome sequencing to identify new mutations in a subset of 30 patients at diagnosis and in 10/30 samples at follow-up, and validate the recurrence of the new mutations in a training set.
• validate a high throughput technology for extensive genotyping to determine the mutational status of 54 target genes in the entire prospective cohort.
• analyze the frequency and impact on phenotype, OS and EFS of the most frequent mutations including SF3B1, SRSF2, ZRSR2, U2AF1, TET2, ASXL1, EZH2, IDH1/2, DNMT3A, NRAS, TP53, and RUNX1 and possibly of the newly discovered new mutations. Individual follow-up will be 36 months.