Endoplasmic Reticulum Stress and Resistance to Treatments in Ph-negative Myeloproliferative Neoplasms

• ET or PV patients diagnosed before acceleration phase and treated by hydroxyurea with a follow up period of at least 6 months following treatment start.

• Diagnosis criteria of PV :

  • WHO criteria of PV with :

    • Acquired JAK2V617F mutation > 5%
    • Absence of evident cause of secondary polycythemia

• Diagnosis criteria of ET :

  • Platelet count > 450 G/L
  • Absence of PV or Chronic Myeloid Leukemia
  • Bone marrow biopsy preferred but not necessary in absence of reactional causes (CRP and ferritin levels normal) and/or presence of acquired JAK2V617F, CALR exon 9 or MPL exon 10
• Availability of RNA sample of total leukocytes before start of treatment.

Exclusion Criteria:

In absence of clonality marker, presence of secondary cause of :

• Thrombocytosis :

  • Inflammatory syndrom (CRP or SV increased)
  • Iron deficiency (decreased ferritin level or increased soluble transferrin receptor level)

• Polycythemia :

  • Increased or normal level of EPO in context of :

    • Hypoxia, respiratory insufficiency
    • Sleep apnea syndrome
    • Hyperaffin hemoglobin
• Absence of treatment by hydroxyurea
• Treatment by anagrelide, P32, pipobroman, interferon without subsequent hydroxyurea treatment.
• Concommitant treatment by other cancer chemotherapy (in a context of solid cancer for example).
• Diagnostic during transformation to acute leukemia
• Treatment by hydroxyurea during less than 6 months
• Bad observance of the cytotoxic treatment