Background: Breast cancer is the malignancy in humans and other mammals. Several risk factors are involved in their appearance such as higher hormone levels and obesity. Identification of a mouse mammary tumor virus supports a viral etiology for breast tumors in animals. Viruses have been implicated in the development of various cancers, but viral induction for formation breast cancer is controversial. The purpose of this study was investigation of the presence of human papillomavirus (HPV) & Epstein-Barr virus (EBV), in Iranian patients with breast cancer.  As the etiology and progression of breast cancer remain incompletely understood, novel routes of disease pathogenesis are important to consider. Some researchers have been found Human papillomavirus (HPV) and Epstein Barr virus (EBV) in breast carcinomas (BCs).
Materials and Methods: Paraffin-embedded sections from 65 female patients with breast carcinoma and 53 breast tissues from patients with fibrocystic disease as control were selected. After DNA extraction and amplification of housekeeping gene (beta-globin), all suitable samples were evaluated for presence of DNA-EBV and DNA-HPV by using PCR (Polymerase Chain Reaction).
Results: HPV DNA sequences were detected in 3 of the 53 benign breast tissue samples but none of the breast carcinoma samples was identified. EBV was detected by PCR in 23 of 65 (35.38%) cases of breast cancer specimens and 11 of 53 (20.75%) control samples ( fibroadenoma 7 of 26 (26.92%) and fibrocystic 4 of 27 (14.81%)). A total of 118 samples from 34 cases (81/28%) were positive. Statistically, crammer indicator analysis for EBV infection in tumor samples and normal samples was 0.46 which indicates a significant relationship.
Conclusion: Our analysis could not confirm a role of HPV in breast cancer but statistically, significant correlation between EBV infection and breast cancer exists. To demonstrate the possible relationship between viral load and breast cancer, need for epidemiological, biological and molecular mechanisms to clear the virus is involved in the process of carcinogenesis.