Abstract
IntroductionBreast cancer is the most common malignancy affecting females worldwide but conventional risk factors are able to explain only a small proportion of these cases. A possible viral etiology for breast cancer has been proposed and Epstein-Barr Virus (EBV) is a widely researched candidate virus. The aim of the present study, first one of its kind from India, was to determine if there is a greater association of EBV infection with breast cancer patients as compared to patients with benign breast diseases.MethodsWe looked for expression of Epstein-Barr Virus Nuclear Antigen-1 (EBNA-1) in breast cancer tissue specimens by employing immunohistochemistry (IHC). We also measured levels of anti-EBNA-1 Immunoglobulin (IgG) antibodies in stored sera of these patients using commercial Enzyme linked Immunosorbent Assay (ELISA) kit. Patients with benign breast diseases were used as a comparison group for both immunohistochemical and serological analysis.Results58 cases of malignant breast disease and 63 of benign breast disease (controls) were included in the study. Using manufacturer determined cut-off of 3 IU/ml, 50/55 tested (90.9%) cases and 27/33 tested (81.8%) controls were seropositive for anti-EBNA-1 IgG. Mean antibody levels were significantly higher for cases (54.22 IU/ml) as compared to controls (18.68 IU/ml). IHC for EBNA-1 was positive in 28/51 cases (54.9%). No IHC positivity was noted in the tested 30 controls. Our results show that EBNA-1 expression is seen in a significant proportion of breast cancer tissue specimens from rural India and as compared to patients with benign breast diseases these patients also have a higher immunological response against EBNA-1.
Highlights
Breast cancer is the most common malignancy affecting females worldwide but conventional risk factors are able to explain only a small proportion of these cases
In the current study we found that about 55% of breast cancer cases showed Epstein-Barr Virus Nuclear Antigen-1 (EBNA-1) expression in tumor cells by IHC, while all the controls with benign breast disease were negative
On the other hand both cases as well as controls had a high seroprevalence of Epstein-Barr Virus (EBV) infection, but IgG levels were significantly higher in cases as compared to controls
Summary
Breast cancer is the most common malignancy affecting females worldwide but conventional risk factors are able to explain only a small proportion of these cases. A possible viral etiology for breast cancer has been proposed and Epstein-Barr Virus (EBV) is a widely researched candidate virus. Breast cancer is the most common malignancy affecting women world-wide with an annual incidence of around 800,000 cases.[1,2] Though various reproductive and hormonal factors have been identified as risk factors for breast cancer, but even together these factors do not explain more than fifty percent of all cases of breast cancer.[1,3] This prompted the researchers to look for other risk factors including a possible viral etiology for breast cancer. If a causal association of EBV with breast cancer is established, it would have therapeutic significance because of the possible role of EBV specific cytotoxic T cells in targeting EBV associated tumor cells.[7]
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