Exposure to bovine leukemia virus linked to increased risk of breast cancer and cell proliferation

BUEHRING, GC; KRISHNAMURTY S; HUDEN M; BALTZELL K; MARTINEZ CUESTA, LUCIA; CERIANI, M.C; JENSEN HM; SWARTZ DA; BLOCK G; LENDEZ, P.A; DOLCINI, G. L; SHEN H; JENSEN HM; SISON J; LAWSON J; NIETO FARIAS, M.V

Hollywood, California

Encuentro; Advances in Breast Cancer Research; 2017

American Association for Cancer Research

The purpose of this study was to compare recent epidemiologic studies to determine frequency of bovine leukemia virus (BLV) detection in breast tissue in different human populations, and association of BLV with a confirmed diagnosis of breast cancer and outcome of commonly used clinical biomarkers. umerous risk factors are associated with breast cancer, but what causes the initial molecular and cellular changes from normal to malignant is not well understood. Six types of human cancer are caused by viruses, and several viruses have been studied for their possible role in breast cancer. Bovine leukemia virus (BLV) is a common virus of US cattle, (38% of beef herds, 89% of dairy herds, 90-100% of large dairy operations). BLV DNA and protein have been identified in human tissues. Breast tissue specimens were formalin fixed, paraffin embedded archived tissue sections obtained from the sources listed in the table. In situ PCR (IS-PCR) was performed on intact deparaffinized sections on glass slides, using primers from the tax region (transforming gene), highly conserved and rarely deleted, as are most regions of BLV genome as tumor progression occurs. tax primer specificity was confirmed by NCBI (nucleotide BLAST), indicating highest homology with BLV, and extremely low homology with human genomic sequences, including human endogenous retroviral sequences. Sections were semi-quantitatively scored for density of the IS-PCR product within mammary epithelial cells upon microscopic examination by two independent examiners.