Both patients were found to be negative for mutations in erythropoietin, erythropoietin receptor, HIF-1α, janus kinase 2, prolyl hydroxylase, succinate dehydrogenase B/C/D, and von Hippel-Lindau genes in circulating leukocytes and resected tumor tissues (Table 1). The gene discussed is JAK2; the disease is neoplasm.