However, there are several examples of gains associated with gene mutations on the chromosomes involved, such as KIT mutations and trisomy 4 and internal tandem duplications of KMT2A and trisomy 11 in acute myeloid leukemia, MET mutations and trisomy 7 in hereditary papillary renal carcinomas, and JAK2 mutations and trisomy 9 in polycythemia vera[46–49]. The gene discussed is JAK2; the disease is acquired polycythemia vera.