Viruses and breast cancer

Abstract

Viruses are the accepted cause of many important cancers including cancers of the cervix and anogenital area, the liver, some lymphomas, head and neck cancers and indirectly human immunodeficiency virus associated cancers. For over 50 years, there have been serious attempts to identify viruses which may have a role in breast cancer. Despite these efforts, the establishment of conclusive evidence for such a role has been elusive. However, the development of extremely sophisticated new experimental techniques has allowed the recent development of evidence that human papilloma virus, Epstein-Barr virus, mouse mammary tumor virus and bovine leukemia virus may each have a role in the causation of human breast cancers. This is potentially good news as effective vaccines are already available to prevent infections from carcinogenic strains of human papilloma virus, which causes cancer of the uterine cervix.

Figure 1

Human papilloma virus associated koilocytes (see arrows for selected koilocytes) in a ductal carcinoma in situ breast cancer specimen [18].

Figure 2

Histological characteristics of MMTV-associated mouse mammary tumors (magnification 600×) compared with human IDC breast cancer specimens. Left (top and bottom): mouse mammary tumor specimens; right (top and bottom): human IDC breast cancer specimens. The histological characteristics of these mouse mammary tumors are virtually identical to the human breast cancer specimens [19,92].