Cmar_a_294584 2835..2848

1Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt; 2Surgical Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt; 3Surgical Oncology Department, Materia Teaching Hospital, Cairo, Egypt; 4Biostatistics and Epidemiology Department, National Cancer Institute, Cairo University, Cairo, Egypt; 5Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt; 6Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, CA, USA; 7Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt; 8Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA; 9Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA; 10Moores Cancer Center, University of California, San Diego, La Jolla, CA, 92093, USA Background: Mouse mammary tumor virus (MMTV) is thought to have a role in human breast cancer (BC) pathogenesis. BRCA1 and 2 genes mutations are well-established risk factors for BC. The purpose of this study was to evaluate the presence of MMTV in familial and non-familial Egyptian breast cancer patients. We also aimed to establish a correlation between BRCAs genes mutations and MMTV infection in those patients. Patients and Methods: The study was included 80 BC patients and 10 healthy women were included as a control group. We used PCR to amplify a 250-bp MMTV-like env sequence. We also used PCR followed by direct sequencing to identify the genetic variation of exons 2, 13, 19 of BRCA1 gene and exon 9 and region f of exon 11 of BRCA2 gene. High resolution melting (HRM) analysis was used to screen the selected exons of BRCA1/2 genes in order to detect different variants. Results: MMTV DNA-like env sequences were detected in 70%, 76% of familial and nonfamilial BC patients, respectively, and it was not detected in any of the control subjects. The presence of viral sequences was associated with larger tumor size in the sporadic patients. Seventy BC patients showed variations in BRCA1/2 genes according to HRM analysis and sequencing analysis showed two different sequences of polymorphism among 22 familial and non-familial BC patients. Conclusion: MMTV DNA was present among BC patients and it was associated with increased tumor growth. This indicates a potential role for MMTV in BC patients with and without deleterious mutation in BRCA1/2 genes.