Clinical characteristics of Japanese patients with polycythemia vera: results of the JSH-MPN-R18 study

Yoko Edahiro, Tomoki Ito, Akihiko Gotoh, Mika Nakamae, Fumihiko Kimura, Michiaki Koike, Keita Kirito, Hideho Wada, Kensuke Usuki, Takayuki Tanaka, Takehiko Mori, Satoshi Wakita, Toshiki I. Saito, Akiko Kada, Akiko M. Saito, Kazuya Shimoda, Yuka Sugimoto, Toshiro Kurokawa, Akihiro Tomita, Yoshinori HashimotoKoichi Akashi, Itaru Matsumura, Katsuto Takenaka, Norio Komatsu

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The presence of a JAK2 V617F or JAK2 exon 12 mutation is one of the three major criteria listed for the diagnosis of polycythemia vera (PV) in the 2017 World Health Organization Classification. However, a nationwide study has not yet been conducted in Japan since the discovery of JAK2 mutations. Therefore, the Japanese Society of Hematology (JSH) retrospectively analyzed the clinical characteristics of 596 Japanese patients with PV diagnosed between April 2005 and March 2018. Among the 473 patients with complete data on JAK2 mutations available, 446 (94.3%) and 10 (2.1%) were positive for the JAK2 V617F and JAK2 exon 12 mutations, respectively. During a median follow-up of 46 months (range: 0–179 months), 47 (7.9%) deaths occurred. The major causes of death were secondary malignancies (23.4%), acute leukemia (12.8%), non-leukemic progressive disease (10.6%) and thrombotic (6.4%) and hemorrhagic complications (6.4%). Thrombotic and hemorrhagic events occurred during the clinical course in 4.0% (n = 24) and 3.5% (n = 21) of patients, respectively. These results show that the international PV prognostic score (age, venous thrombosis and leukocytosis) is applicable to Japanese patients with PV.

Original languageEnglish
Pages (from-to)696-711
Number of pages16
JournalInternational Journal of Hematology
Issue number5
Publication statusPublished - 11-2022

All Science Journal Classification (ASJC) codes

  • Hematology


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