HPV-16 and HPV-18 Affects Viability and Proliferation in Normal Breast Tissue Cells

Introduction and Aims: Recently HPV-16 and 18 have been found in the oral cavity and have been significantly linked as causative agents of oral cancer. Research has also shown the effects of HPV on breast cancer cells. More recently, HPV-16 and 18 have been found in normal breast tissue. The carcinogenic effects of HPV on oral and breast tissues have been demonstrated; however, the effect of HPV on non-cancerous breast tissue cells has not yet been studied. Based upon this information, the objective of this study was to evaluate the effects of HPV on normal breast tissue.

Study Design: This is an observational laboratory-based study of human cell cultures.

Place and Duration of Study: This study was conducted in the Department of Biomedical Sciences at the University of Nevada, Las Vegas – School of Dental Medicine between May 2017 and May 2019.

Methodology: HPV16 and HPV18 strains were used to infect normal, non-cancerous breast tissue cell lines Bst-Hs578 and 18485 in vitro. Cellular growth and viability was evaluated to determine if HPV mediated any of these cellular phenotypes. Cells were plated into 96-well assay plates to measure proliferation. Viability was measured using a BioRad TC20 automated cell counter.

Results: The addition of HPV-16 and HPV-18 had significant effects on cellular phenotypes in both Bst-Hs578 and 184B5 cells. For example, cell viability increased between 21% and 41% in Bst-Hs578 cells and 23% to 53% in 184B5 cells over three days. In addition, cellular proliferation was also significantly altered with both HPV strains in each of the cell lines, increasing approximately two-fold at each of the three-day assay time points. Each of these phenotypes was sustained over the course of one week and three week assays.

Conclusion: Although studies have demonstrated that HPV can modulate oral and breast cancer cells, no studies to date have demonstrated that HPV has the potential to mediate the growth or viability of normal, non-cancerous breast tissue. This study may be among the first to demonstrate that HPV is capable of modulating these phenotypes in normal, non-cancerous breast tissue – which will be important for dentists, oral healthcare professionals and epidemiologists who are interested in HPV prevention and vaccination.