GATA1 Expression in BCR/ABL1-negative Myeloproliferative Neoplasms

Background: This study aimed to determine GATA1 expression levels to better characterize subgroups in BCR/ABL1-negative myeloproliferative neoplasms (MPNs). Methods: This study enrolled 49 patients diagnosed as having BCR/ABL1-negative MPN on the basis of the 2016 World Health Organization classification : nine polycythemia vera (PV), 17 essential thrombocythemia (ET), 12 prefibrotic primary myelofibrosis (prePMF), and 11 overt primary myelofibrosis (PMF). Relevant clinical and laboratory data were retrieved from the medical records. The molecular analysis of CALR and MPL mutations and quantification of JAK2 V617F allele burden were performed. GATA1 expression was assessed by an immunohistochemical assay on bone marrow biopsy. GATA1 expression was analyzed serially in 18 patients. Results: GATA1 expression decreased significantly in PMF compared with that in other subtypes, while no statistical difference was identified between ET and prePMF. GATA1 expression did not differ according to the mutation profiles or the allele burden of JAK2 V617F, but it decreased significantly in patients with overt fibrosis or leukemic transformation. Conclusions: Our results suggest that GATA1 expression is significantly low in PMF and decreases with progressive fibrosis and possibly with leukemic transformation, although our attempt to accurately distinguish between subgroups using GATA1 immunohistochemical approach did not achieve statistical significance. A large patient cohort with long term follow-up is required to evaluate the prognostic value of GATA1 expression.