ABL1 and myeloproliferative neoplasm: Myeloproliferative neoplasms (MPN) are heterogeneous group of disorders arising from transformation in a haemopoietic stem cell and characterised by proliferation of one or more cell lines such as granulocytes, platelets or erythroid cells.8 Traditionally MPN have been classified on the basis of Philadelphia chromosome presence.9,10 Philadelphia positive MPN include chronic myeloid leukaemia which has molecular lesion, the BCR-ABL fusion gene, resulting from Philadelphia translocation.11