Inflammatory breast cancer: Mixed viral infections within carcinoma tissues and the expression of Ki-67 proliferation marker.

Abstract

Background: Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. Our previous results showed that IBC carcinoma tissues possess mixed human cytomegalovirus genotypes than non-IBC carcinoma tissues. However, the role of viral infection in breast cancer is poorly understood.

Methods: We enrolled 135 women diagnosed breast cancer (91 Non-IBC and 44 IBC). The incidence of different viral DNA (Herpes viruses and HPV) was performed using nested and multiplex PCR and DNA sequencing. The expression of Ki-67 proliferation index was assessed by immunohistochemistry.

Results: DNA of HCMV and HPV-16 were the most detected in breast tissues of both IBC and non-IBC patients. However, as a single infection the incidence of HCMV-DNA and HHV-8 DNA were significantly higher in carcinoma tissues of IBC in comparison with non-IBC (p = 0.035, p= 0.039, respectively). Moreover, the prevalence of mixed infection of different viral DNA was higher in IBC than non-IBC carcinoma tissues (P= 0.003). HCMV and HPV-16 were the dominant mixed infection in both non-IBC and IBC tissues. Interestingly, although no significant difference in expression of Ki67 has been detected in tissues of IBC and non-IBC, we found that Ki-67 was significantly higher in mixed than single viral infected tissues of both non-IBC and IBC (p = 0.04 and p = 0.03 respectively).

Conclusions: The incidence of mixed viral DNA detected in carcinoma tissues of IBC is higher than non-IBC. Moreover, mixed viral DNA is positively correlated with upregulation of Ki67 expression in breast carcinoma tissues.