Bovine Leukemia Virus Presence in Breast Tissue of Argentinian Females and Its Association With Cell Proliferation and Prognosis Markers

Abstract

Introduction: Bovine leukemia virus (BLV) causes enzootic bovine leukemia, andis closely related to human T-lymphotropic virus type 1. It expresses microRNAs ofunknown function and codes Tax, the protein that mediates malignant transformation.BLV is capable of infecting B- and T-lymphocytes, endothelial cells, and mammaryepithelial cells of cattle. Several studies demonstrated the presence of BLV DNA inhuman tissue, and it is significantly associated with breast cancer in case-control studiesusing in situ PCR, a highly sensitive and specific technique. The current study was thefirst report of BLV DNA detection by in situ PCR in tissue from Argentinian femaleswith a diagnosis of breast cancer.Methods: In situ PCR was done to detect BLV DNA in 85 human FFPE breast cancertissue samples. The association of BLV DNA and expression of Ki67 and Her-2 wasassessed.Results: BLV DNA presence could be determined in 22.6% of the analyzed samples, andits presence was associated with an increase of the expression and prognosis markers Ki67(P=0.009) and HER-2 (P=0.044) determined by conventional immunohistochemistry.No statistical significance was observed between the presence or absence of hormonalreceptors and the presence of BLV DNA.Conclusions: The obtained results support the idea that BLV might play a role inmalignant tissue transformation.