ANALYSIS OF COOPERATING PATHOGENIC GENE VARIANTS IN PATIENTS WITH MYELOFIBROSIS

CAMACHO, MARIA FERNANDA; MOIRAGHI, BEATRIZ; BENDEK, GEORGINA; DE LUCA, GERALDINE; LARRIPA, IRENE; HELLER, PAULA; CASTRO RIOS, MIGUEL; VALLEJO, VERONICA; BELLI, CAROLINA; ENRICO, ALICIA; SACKMANN, FEDERICO ; VARELA, ANA; GUTIÉRREZ, MARINA

Ciudad Autónoma de Buenos Aires

Jornada; Reunión Anual de Sociedades de Biociencias 2020; 2020

CONSEJO NACIONAL DE INVESTIGACIONES CIENTÍFICAS Y TÉCNICAS

The myelofibrosis (MF) is a myeloproliferative neoplasm derived from a clonal hematopoietic stem-cell associated with bone marrow fibrosis. The Dynamic International Prognostic Scoring System(DIPSS) enables prognosis assessment at any point during clinical disease follow-up. This model considers the age, hemoglobin level, leukocyte count, circulating blasts and constitutional symptoms to predict survival. Most of patient present one driver mutations in JAK2, CALR or MPL genes, and the majority acquire others affecting epigenetic (ASXL1, IDH1/2) and splicing (SRSF2) genes, often in multiple combinations.In the current study, we screened hot-spot regions of ASXL1, IDH1/2 and SRSF2 to identify pathogenic variants and to describe their prevalence in the context of the DIPSS classification.The series included 67 patients (61% females) with MF diagnosed according to the 2016 WHO criteria. At the time of testing, the median age was 65 years old (range 20?88) and laboratory characteristics included a median hemoglobin level of 10 g/dL (3-16), leukocyte counts of 11x109/L (16-124) and circulating blast of 0% (0-15). The distribution according to the DIPSS was: 18% low, 18% intermediate-1, 30% intermediate-2, and 34% high risk. Driver mutational status revealed 49% JAK2, 30% CALR, 9% MPL and 12% triple-negatives.Genomic DNA samples was amplified using allele-specific-primers for IDH1/2 (exon 4), Sanger sequencing for ASXL1 (exon 12-13) and high-resolution melting confirmed by Sanger sequencing for SRSF2 (exon 1). Fifteen patients (22%) presented pathogenic variants in ASXL1, 2 (3%) in IDH2, 1 (1.5%) in SRSF2 and 6 (9%) combined two of them. Overall mutational frequencies according to the DIPSS were 3% for low, 6% intermediate-1, 9% intermediate-2 and 18% high risk patients.Of all the subclonal cooperating pathogenic variants found, 50% were identified in the DIPSS high risk patients associated with a more aggressive disease with clinical and therapeutic implications.