JAK1 and hematopoietic and lymphoid cell neoplasm: JAK family members, consisting of JAK1, JAK2, JAK3, and TYK2, are deregulated in immune response disorders, such as systemic lupus erythematosus, and in hematological cancers, and JAK inhibitors are used in the treatment of these diseases [22]. JAK1 frameshift mutations mediate immune response evasion via inhibition of antigen presentation in microsatellite unstable EC.