ERVW-1 and myeloid sarcoma: According to the Antony et al. study, elevated HERV-W env RNA expression in MS brain tissue originates mainly from the HERV-W env elements amplified by the HERV-Wdeg env primers and (somewhat less) from HERV-W env 7q21.2, while HERV-W env 15q21.3 expression was similar in patients and controls [20].