In the meta-analysis conducted to explain the existence of a relationship between the MMP-9-1562C/T polymorphism and MS incidences, covering 10 studies on MMP-9-1562C/T SNP with 1,757 MS patients and 1,702 control subjects, a strong positive correlation was shown between the discussed polymorphism and the risk of MS incidence. The gene discussed is MMP9; the disease is myeloid sarcoma.