JAK2 (Janus Kinase 2): JAK2 is a gene encoding a kinase enzyme that is part of the Janus kinase (JAK) family. JAK2 is involved in cytokine signaling pathways and is crucial for the activation of immune and hematopoietic cells. Mutations in JAK2 are associated with blood disorders such as polycythemia vera and myeloproliferative neoplasms....