MiR-17-5p, a microRNA associated with autoimmunity, was found to be up-regulated in CD4(+) cells from individuals with MS, as reported by Lindberg et al. This up-regulation was linked to changes in the expression of its predicted target genes—phosphatase and tensin homolog (PTEN) and phosphatidylinositol-3-kinase regulatory subunit 1 (PIK3R1)—both of which were down-regulated following in vitro stimulation of CD4(+) cells with anti-CD3/CD28. The gene discussed is PTEN; the disease is myeloid sarcoma.