BRCA1 and ovarian cancer: We did not observe a striking association between the WID-OC-index and any of the known epidemiological risk factors for ovarian cancer (apart from age and a BRCA1 germline mutation), and neither did we find any evidence that the WID-OC-index is triggered by tumour DNA draining from the peritoneal cavity via the uterine cavity and detected by the cervical smear.