1. Department of Gynecologic Oncology, Medical University-Pleven, 5800 Pleven, Bulgaria
2. Department of General and Clinical Pathology, Heart and Brain Center of Clinical Excellence, 5800 Pleven, Bulgaria
3. Research Institute, Medical University Pleven, 5800 Pleven, Bulgaria
4. Department of Breast Surgery, Shterev Hospital, 1000 Sofia, Bulgaria
5. Department of Obstetrics and Gynecology, University Hospital “Sofiamed”, 1750 Sofia, Bulgaria
6. Department of Gynecology, Hospital “Saint Anna”, Medical University—“Prof. Dr. Paraskev Stoyanov”, 9002 Varna, Bulgaria