Absence of high-risk human papillomavirus in breast cancer tissues from young BRCA1/BRCA2-negative women.

Human papillomavirus (HPV) has been investigated as a potential risk factor in breast cancer, but the literature remains inconsistent. Although biological mechanisms involving HPV E6/E7 oncogene activity provide biological plausibility for viral involvement, reproducible evidence in breast tumors is lacking. This study aimed to determine whether high-risk HPV is detectable or transcriptionally active in breast cancer tissues from young women negative for BRCA1/BRCA2 mutations. This retrospective, single-center study included women younger than 50 years with confirmed BRCA1/BRCA2-negative breast cancer. Formalin-fixed, paraffin-embedded tumor specimens were analyzed for high-risk HPV DNA using a PCR-based assay targeting HPV-16, HPV-18, and pooled high-risk genotypes. A subset of tumors with sufficient residual FFPE material and laboratory acceptance for FFPE-based RNA testing also underwent high-risk HPV E6/E7 mRNA analysis to assess transcriptional activity. Ninety women contributed 91 breast cancer specimens. Demographic, reproductive, and pathological features were consistent with typical early-onset breast cancer. High-risk HPV DNA was not detected in any tumor specimen. All mRNA analyses were also negative, indicating absence of transcriptionally active viral oncogene expression. High-risk HPV was neither detectable nor transcriptionally active in breast cancer tissues from young BRCA1/BRCA2-negative women. These findings do not support a role for high-risk HPV in breast carcinogenesis in this population.