We establish that the WID-OC signature is not driven by tumour DNA, is high in healthy women with a BRCA1 mutation as well as in women with poor prognostic breast cancer and furthermore has a very high sensitivity and specificity for identifying women with endometrial cancer, which like ovarian cancer also arises from Müllerian Duct epithelial cells. The gene discussed is BRCA1; the disease is ovarian cancer.