MPN Frequently Asked Questions

Myelofibrosis FAQs

What is the hallmark genetic mutation in patients with myelofibrosis?
In contrast to some other malignancies (eg, chronic myelogenous leukemia), no single hallmark mutation has been identified in patients with myelofibrosis.1,2 Notably, 50% to 60% of affected patients have a mutation of the JAK2 gene, but several other mutations have been reported in patients with myelofibrosis as well.3,4
What percentage of patients with myelofibrosis have genetic mutations other than JAK2V617F?
The MPLW515L/K (TpoR) mutation and casitas B-lineage (CBL) lymphoma mutations are found in 5% to 10% of patients with myelofibrosis.5-7 The SH2B3 (LNK) mutation is found in 3% to 6% of patients.8 The JAK2 exon 12 mutation is seen rarely in patients with myelofibrosis.9
How common is splenomegaly in myelofibrosis, and how does it affect patients?
Eighty-five percent or more of patients with myelofibrosis present with splenomegaly at the time of diagnosis.10 Symptoms related to splenomegaly include abdominal fullness, early satiety, and pain under the left ribs that may be indicative of spontaneous splenic infarction.11 New or increasing splenomegaly is considered to be a marker of disease progression in MF.12
What is the risk for progression to acute myelogenous leukemia for patients with myelofibrosis?
Leukemic transformation occurs in 8% to 23% of patients with myelofibrosis during the first decade after diagnosis.13

Essential Thrombocythemia FAQs

What are the main characteristics of essential thrombocythemia (ET)?
ET is characterized by thrombocytosis with bone marrow megakaryocytic hyperplasia and a tendency to develop thrombotic and hemorrhagic complications.14-16
What prognostic variables are associated with shortened survival in essential thrombocythemia (ET)?

Prognostic variables associated with shortened survival in patients with ET include16:

  • Age ≥60 years
  • History of arterial thrombosis
  • Occurrence of any major thrombosis at or after diagnosis
  • Hypertension
  • Leukocyte count of ≥15 × 109/L at diagnosis
  • Tobacco use
  • Diabetes mellitus

1. Verstovsek S. Clin Cancer Res. 2010;16(7):1988-1996. 2. Kralovics R. Leukemia. 2008;22(10):1841-1848. 3. Quintás-Cardama A, Vaddi K, Liu P, et al. Blood. 2010;115(15):3109-3117. 4. Cross NC. Hematology Am Soc Hematol Edu Program. 2011;2011:208-214. 5. Pikman Y, Lee BH, Mercher T, et al. PLoS Medicine. 2006;3(7):e270. 6. Tefferi A, Lasho TL, Jimma T, et al. Mayo Clin Proc. 2012;87(1):25-33. 7. Vannucchi AM, Lasho TL, Guglielmelli P, et al. Leukemia. 2013;27(9):1861-1869. 8. Oh ST, Simonds EF, Jones C, et al. Blood. 2010;116(6):988-992. 9. Scott LM. Am J Hematol. 2011;86(8):668-676. 10. Barosi G. J Clin Oncol. 1999;17(9):2954-2970. 11. Abdel-Wahab OI, Levine RL. Annu Rev Med. 2009;60:233-245. 12. Tefferi A, Cervantes F, Mesa R, et al. Blood. 2013;122(8):1395-1398. 13. Mesa RA, Li CY, Ketterling RP, Schroeder GS, Knudson RA, Tefferi A. Blood. 2005;105(3):973-977. 14. Tefferi A, Barbui T. Leukemia. 2013;27(8):1617-1620. 15. Cervantes F. Hematology. 2011;2011:215-221. 16. Wolanskyj AP, Schwager SM, McClure RF, Larson DR, Tefferi A. Mayo Clin Proc. 2006;81(2):159-166.

By: World Health Organization (WHO)
A diagnostic worksheet from the WHO for primary MF, PV, and ET.
By: International Working Group for Myeloproliferative Neoplasms Research and Treatment (IWG-MRT)
Diagnostic criteria from the IWG-MRT.