downregulation of mir-143/145 cluster in breast carcinoma specimens: putative role of dna oncoviruses

Background: the dna oncoviruses, including human papillomavirus (hpv) and epstein-barr virus (ebv) are among the most important infectious agents involved in breast carcinogenesis. these oncoviruses have a broad disrupting effect on cellular mirnas and their functions, by which they contribute to carcinogenesis. objectives: in this investigation, we evaluated the correlation between hpv and ebv and the expression level of tumor suppressor mirnas (mir-143 and 145), clinical outcomes, and their association with stimulating inflammatory cytokines in patients with breast carcinoma. methods: in our case-control study, 35 cancerous tissues and 35 adjacent non-cancerous tissues were collected from 35 patients. nested-pcr was set up for the detection of hpv and ebv genomes, and rt-qpcr was used for mirna expression in the case and control groups. in addition, serum specimens were obtained from all patients (n = 35) and healthy controls (n = 35) to determine the il-8 serum concentration. results: we found hpv and ebv in 14.2% (10/70) and 7% (5/70) of all samples, respectively. the distributions of positive samples in the case and control groups were 25.7% (9/35) and 2.9% (1/35) (p = 0.006) for hpv and 11.4% (4/35) and 2.9% (1/35) (p = 0.164) for ebv, respectively. besides, rt-qpcr showed that mir-143 and mir-145 were significantly downregulated in hpv and ebv-infected cases compared to non-infected ones (p < 0.05). data also indicated that the promotion of metastasis status was related to mir-143/145 downregulation and hpv infection (p = 0.003). no significant difference was found in serum il-8 concentration concerning viral infections. conclusions: our results suggested the possible involvement of viral infections in breast carcinogenesis and adverse clinical outcomes by downregulating mir-143/145.