Risk factors for myelofibrotic progression have been reported and include older age; longer disease period; greater disease burden (as defined by leucocytosis, thrombocytopenia, anemia, palpable splenomegaly); higher JAK2 allele burden (for PV); detection of SRSF2, U2AF1, and ASXL1 mutations; and cytogenetic abnormalities (12p abnormality, acquired loss of heterozygosity of chromosome 1p) [19,20,21,37,38,39,40,41,42,43]. Here, JAK2 is linked to Splenomegaly.