bovine leukemia virus presence in breast tissue of argentinian females and its association with cell proliferation and prognosis markers

Introduction: bovine leukemia virus (blv) causes enzootic bovine leukemia, and is closely related to human t-lymphotropic virus type 1. it expresses micrornas of unknown function and codes tax, the protein that mediates malignant transformation. blv is capable of infecting b- and t-lymphocytes, endothelial cells, and mammary epithelial cells of cattle. several studies demonstrated the presence of blv dna in human tissue, and it is significantly associated with breast cancer in case-control studies using in situ polymerase chain reaction (pcr), a highly sensitive and specific technique. the current study was the first report of blv dna detection by in situ pcr in tissue from argentinian females with a diagnosis of breast cancer. methods: in situ pcr was done to detect blv dna in 85 human ffpe breast cancer tissue samples. the association of blv dna and expression of ki67 and her-2 was assessed. results: blv dna presence could be determined in 22.6% of the analyzed samples, and its presence was associated with an increase of the expression and prognostic 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 hormonal receptors and the presence of blv dna. conclusions: the obtained results support the idea that blv might play a role in malignant tissue transformation.