Systematic review and meta-analysis of the papillomavirus prevalence in breast cancer fresh tissues.

BACKGROUND Although widely studied, the role of HPV in the genesis of breast carcinomas remains elusive due to the diversity of results across studies, possibly caused by the wide methodological heterogeneity, some of them with inadequate methods. OBJECTIVE To verify the association between HPV and breast cancer through the meta-analysis of studies that used the best-recognized techniques for viral detection and tissue conservation. METHODS A systematic review and meta-analysis restricted to studies that detected HPV by PCR in fresh and frozen tissue from breast cancer were conducted to obtain greater homogeneity. PubMed, Scopus, Science Direct, Cochrane Library, and SciELO were searched until December 14, 2019. Search terms included "breast cancer" and "HPV" without language restrictions. Eleven studies were included in the meta-analysis. The pooled relative risks and 95% confidence interval (95% CI) were calculated, and heterogeneity was assessed using the I-squared (I2). RESULTS The selected studies had very low heterogeneity (2%). There is a 2.15 times higher combined relative risk (95% CI = 1.60-2.89) of detecting HPV in breast cancer than in cancer-free breast controls with a statistically significant p-value (p < 0.0001). CONCLUSION Our data support the association of DNA-HPV with breast carcinomas. Further studies are needed to find out which breast cancer subtypes this association is most frequent.