Importantly, a significant contribution on the HERV-W group presence in the human genome was recently provided in a study in which the cDNA obtained from HERV-W RNA transcripts in MS patients and controls brain samples was amplified in the env region and assigned to single HERV-W loci by Genome Browser BLAT on the NCBI36/hg18 assembly (March 2006) [20]. Here, ERVW-1 is linked to myeloid sarcoma.