We estimated the IL-2R in the serum of 78 women, of whom 30 were diagnosed as having malignant ovarian tumours, five had non ovarian tumours, one had a negative second look laparotomy, 11 had benign ovarian tumours, three had uterine fibroids and 28 were age-matched controls. This evidence concerns the gene IL2RA and ovarian benign neoplasm.