Primary myelofibrosis and its targeted therapy.

Primary myelofibrosis is a unique entity among BCR-ABL-negative myeloproliferative diseases, manifesting as bone marrow fibrosis and pancytopenia. Considerable evidence indicates that genetic and epigenetic abnormalities can result in defective clonal hematopoietic stem cell proliferation in addition to bone marrow microenvironment alteration. The "bad seeds in bad soil" theory illustrates the orchestrating efforts of hematopoietic stem cells, stromal cells, and their surrounding signaling molecules in myelofibrosis progression and malignancy transformation, though the exact mechanism of myelofibrosis is still not clear. This study reviews current concepts and questions regarding the pathogenesis of primary myelofibrosis and discusses the emerging targeted therapy aimed at restoring normal bone marrow environment and halting bone marrow fibrotic deterioration.