Ambrus Gángó1, Péter Attila Király1-2, Szilvia Krizsán1, Csaba Bödör1
1 MTA-SE Momentum Molecular Oncohematology Research Group, 1st Department of Pathology and Experimental Cancer Research, Semmelweis University
2 1st Department of Internal Medicine, Semmelweis University
Introduction: Philadelphia negative myeloproliferative neoplasms (MPNs) are clonal hematopoietic disorders comprising essential thrombocythaemia, polycythaemia vera and primary myelofibrosis. Despite their relatively indolent clinical course, transformation into more aggressive MPNs (myelofibrosis) or acute myeloid leukemia (AML) might occur in a subset of patients conferring adverse prognosis and treatment failure. Revealing the genetic background of transformation offers the opportunity for improved risk stratification and therapy tailoring.
Aims: By analyzing the main driver genes involved in MPN transformation, we aimed to establish the genetic composition of a transformed MPN patient cohort.
Methods: To reveal the genetic changes leading to transformation of MPNs, we performed an amplicon-based ultra-deep next-generation sequencing (NGS) of 26 peripheral blood- or bone marrow-derived DNA samples collected at MPN diagnosis or transformation. Library preparation was carried out using a custom 11-gene panel covering the main mutational hotspots or regions affected in the following genes: JAK2, CALR, MPL, DNMT3A, EZH2, ASXL1, IDH1, SH2B3, SRSF2, TET2, TP53. Sequencing was performed on Ion Torrent platform (Thermo Fisher Scientific), followed by bioinformatic analysis (Ion Reporter software).
Results: Sixty-eight mutations were identified in 26 patients (median: 2, range: 0-11). JAK2 V617F and CALR indel mutations occurred most frequently among transformed MPN cases (65% and 31%, respectively). We detected TET2, TP53 and ASXL1 mutations in 27%, 23% and 23% of the cases, respectively. Mutations in the remaining genes occurred at following frequencies: DNMT3A (12%), EZH2 (12%), SH2B3 (8%), SRSF2 (4%), IDH1 (4%). MPL gene mutations were absent this cohort. The probability of AML transformation increased with the mutation load reflected by the number of affected target genes.
Conclusion: By determining the genetic composition of transformed MPN, a molecular-based risk stratification can be established for a reliable prognostication and personally tailored therapy.
Doctoral School: Pathological Sciences
Program: Experimental Oncology
Supervisor: Csaba Bödör