The role of human papillomavirus in ductal hyperplasia of the epithelium in breast fibroade- nomatosis

   Benign breast papilloma is considered a lesion with uncertain malignant potential and, in most cases, it is recommended to be removed. The molecular pathology of ductal hyperplasia of the epithelium in fibroadenomatosis is under intensive study, but at the moment there is no strong enough evidence of diagnostically significant causes of its occurrence.   The aim of the study was to determine the presence of E6 and L1 proteins of the human papillomavirus (HPV) in biopsy specimens of breast tissue in fibroadenomatosis.   Material and methods. Viral proteins were detected using an immunohistochemical method with primary polyclonal antibodies to the E6 protein of HPV types 16 and 18 and capsid protein L1 of HPV types 1, 6, 11, 16, 18, and 31.   Results. In biopsy specimens with fibroadenomatosis of the mammary gland, ductal hyperplasia without atypical proliferation of luminal epithelial cells (NOS 65 %) was most often detected, while atypical ductal hyperplasia (ADH) was detected in 35 %. Viral proteins E6 and L1 were found in more than 90 % of biopsies, with no significant difference between the synthesis of these proteins depending on the type of epithelial proliferation. There was a moderate correlation between the level of intensity of the capsid protein L1 and proliferation marker Ki-67 syntheses in biopsies with atypical epithelial proliferation. The simultaneous presence of the viral proteins E6, L1 synthesis and the index of Ki-67 cell proliferation in breast tissues with fibroadenomatosis increased under transition of epitheliocytes from typical proliferation to atypical ductal hyperplasia.   Conclusion. As demonstrated, there is a correlation between the presence of HPV types 16/18 and atypical changes in the epithelium in breast fibroadenomatosis. The analysed intensity of the E6, L1 and Ki-67 protein syntheses and their simultaneous expression in tissues in benign tumors allows evaluating the risk of epithelial cell malignancy.