1. Department of General Surgery, University Hospital “Sofiamed”, Sofia, Bulgaria
2. Department of Gastroenterology, University Hospital “Sofiamed”, Sofia, Bulgaria
3. Department of Clinical Pathology and Cytology, First Specialized Obstetrics and Gynecological Hospital “St Sofia”, Sofia, Bulgaria
4. Department of Transmembrane Signalization, Bulgarian Academy of Sciences, Institute of Biophysics and Biomedical Engineering, Sofia, Bulgaria