JAK2 and myeloproliferative neoplasm: On one hand, the cooperation of the JAK2V617F-bearing MPN clone with its surrounding (JAK2 wild type) stroma sets off a progressive remodeling of the hematopoietic microenvironment in the bone marrow and spleen [44], and it is conceivable that this may lead to gradually reduced dependency on the JAK2V617F initiating event.