Tag Archives: JAK2

Organ Systems, Bone Marrow, WHO Classification, Hematopathology, Acute Leukemia

Myeloid/Lymphoid Neoplasms Associated with Eosinophilia

November 7, 2017 peferguson

PDGFA
- Eosinophilia with increased tryptase and marrow mast cells
- Cryptic deletion in chromosome 4q12
- FIP1L1-PDGFA, many other partners
- Responsive to tyrosine kinase inhibitors (e.g. imatimib/Gleevec®)
PDGFB
- Eosinophilia combined with monocytosis that mimics CMML
- t(5;12)(q31;33;p12) ETV6-PDGFB, many other partners
- Responsive to TKIs
FGFR1
- Eosinophilia combined with AML or T-ALL
- Associated with 8p11 translocations, FGFR1 with multiple partners
- Not responsive to TKIs (poor prognosis)
PCM1-JAK2 (provisional entity)
- Eosinophilia along with acute lymphoblastic leukemia (B-cell) or lymphoma (T-cell)
- Bone marrow with lymphoid aggregates and increased/left shifted erythroid precursors (mimics PMF)
- May respond to JAK2 inhibitors (e.g ruxolitinib/Jakafi®)

References

Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016;127: 2391–2405. doi:10.1182/blood-2016-03-643544

Swerdlow SH, Campo E, Harris, NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds): WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017

Bone Marrow, WHO Classification, MPN

Polycythemia Vera (PV)

October 27, 2017 peferguson

Major Criteria

One of the following
- Hgb. > 16.5 g/dL or Hct. > 49% in men
- Hgb. > 16.0 g/dL or Hct. >48% in women
- Elevated RBC mass (at least 25% above the mean predicted value)
BM with trilineage hyerpcellularity (panmyelosis) including pleomorphic megakaryocytes (variability in size)
JAK2 V617F or JAK2 exon 12 mutation

Minor Criteria

Low serum EPO level

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PathMD Blog, Bone Marrow, WHO Classification

JAK2, CALR, & MPL Testing in Myeloproliferative Neoplasms (MPN)

October 15, 2017 peferguson

Molecular Testing Specimen Adequacy Summary

JAK2, CALR, and MPL testing is often performed on peripheral blood specimens in an outpatient setting.
JAK2 mutations are preferably analyzed in granulocytes.
Peripheral blood and bone marrow specimens are equally adequate for the identification of JAK2 mutations.
By extrapolation, CALR and MPL testing on peripheral blood specimens should be equally adequate.

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