Cytogenetic evolution in myeloproliferative neoplasms with different molecular abnormalities

Area of Science:

• Hematology
• Oncology
• Genetics

Background:

• Myeloproliferative neoplasms (MPN) are a group of blood cancers characterized by the overproduction of myeloid cells.
• Chromosomal abnormalities play a crucial role in the pathogenesis and progression of MPNs.
• Long-term monitoring of cytogenetic changes is essential for understanding disease evolution.

Purpose of the Study:

• To investigate the dynamic changes in chromosomal abnormalities in MPN patients during long-term follow-up.
• To identify the frequency and types of cytogenetic abnormalities at diagnosis and during disease progression.
• To correlate cytogenetic evolution with specific mutations and patient prognosis.

Main Methods:

• Analysis of serial bone marrow biopsies from 28 MPN patients (22 primary myelofibrosis, 6 polycythemia vera).
• JAK2, CALR, and MPL mutation analysis, with targeted sequencing in 11 patients.
• Cytogenetic analysis to detect chromosomal abnormalities at diagnosis and during follow-up.

Main Results:

• 75% of MPN patients exhibited cytogenetic abnormalities, either at diagnosis or during follow-up.
• The median time to developing additional chromosomal abnormalities was 8.4 years.
• Del(20q) and +1q were the most frequent abnormalities overall (28.6%), followed by del(6p) (14.3%) and trisomy 8 (10.7%).
• Del(20q) was significantly more frequent in CALR-mutated patients compared to JAK2-mutated patients (P=0.016).
• Initial cytogenetic abnormalities were associated with a poor prognosis.

Conclusions:

• Cytogenetic abnormalities are common and evolve over time in MPN patients.
• Specific chromosomal changes, like del(20q), show differential frequencies based on underlying mutations (e.g., CALR vs. JAK2).
• Monitoring cytogenetic evolution offers valuable insights into MPN disease course and prognosis.