Hematopoietic neoplasms with 9p24/JAK2 rearrangement: a multicenter study

Mod Pathol. 2019 Apr;32(4):490-498. doi: 10.1038/s41379-018-0165-9. Epub 2018 Nov 6.


The purpose of this study is to examine hematopoietic neoplasms with 9p24/JAK2 rearrangement including neoplasms associated with t(8;9)(p22;p24)/PCM1-JAK2 fusion neoplasm as well as cases with translocations involving 9p24/JAK2 and other partner genes. From seven large medical centers, we identified ten patients with t(8;9)(p22;p24) /PCM1-JAK2 and 3 with t(9p24;v)/JAK2 at diagnosis. Majority of the cases showed myeloproliferative neoplasm (MPN) associated features (n = 7) characterized by variable degrees of eosinophilia, myelofibrosis, frequent proliferations of early erythroblasts in bone marrow and extramedullary sites, and infrequent/absent somatic mutations. Other less common presentations included myelodysplastic syndromes (MDS) or MDS/MPN (one each). Four patients presented with B-lymphoblastic leukemia (B-ALL), and of them, two patients with t(8;9)(p22;p24.1) were proven to be B-lymphoblastic crisis of MPN; and the other two cases with t(9p24;v) both were de novo B-ALL, BCR-ABL1-like (Ph-like). We show that the hematopoietic neoplasms with 9p24/JAK2 rearrangement are extremely rare, and most of them are associated with t(8;9)(p22;p24)/PCM1-JAK2, a recent provisional World Health Organization entity under "myeloid/lymphoid neoplasm with a specific gene rearrangement". Cases of t(8;9)(p22;p24)/PCM1-JAK2, though heterogeneous, do exhibit some common clinicopathological characteristic features. Cases with t(9p24;v)/JAK2 are extremely rare; while such cases with a MPN presentation may resemble t(8;9)(p22;p24.1)/PCM1-JAK2, B-ALL cases presenting de novo B-ALL might belong to Ph-like B-ALL.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Chromosomes, Human, Pair 9 / genetics*
  • Female
  • Gene Rearrangement
  • Hematologic Neoplasms / genetics*
  • Humans
  • Janus Kinase 2 / genetics*
  • Male
  • Middle Aged
  • Oncogene Proteins, Fusion / genetics*


  • Oncogene Proteins, Fusion
  • PCM1-JAK2 fusion protein, human
  • JAK2 protein, human
  • Janus Kinase 2