There are six types of chronic myeloproliferative neoplasms and Chronic Myeloid Leukemia (CML) is probably the most representative disorder, due to the well-known and widely investigated Philadelphia chromosome, which is an abnormal version of chromosome 22, containing the BCR/ABL, a novel gene made by the fusion of the ABL gene and the BCR gene. The gene discussed is ABL1; the disease is myeloproliferative neoplasm.