XIST and myeloproliferative disorder: For example, genetic deletion of XIST in mouse hematopoietic and human mammary epithelial cells promotes the formation of highly aggressive myeloproliferative neoplasm and HRASG12V-driven mammary carcinoma respectively [22, 23], suggesting a role of XIST expression from the inactive X chromosome (Xi) in protecting somatic cells from oncogenesis.