Investigating the role of HCMV in cancer etiology was recommended following the development of advanced and sensitive laboratory techniques that can detect virus genomic, protein and secretome products in cancer tissues 
. Studies have shown that HCMV-DNA can be detected in colorectal cancer tissues but not in normal tissues of the colon 
, and in carcinoma tissue of malignant glioma 
and prostate cancer 
. Moreover, HCMV infection was implicated as a key determinant of clinical outcome in glioblastoma. For example, patients with HCMV microinfection were found to have higher survival rates compared with patients with detectably higher levels of HCMV infection in cancer tissue 
High levels of antibody titers to herpes viruses have been previously detected in human cancers, including HCMV in newly diagnosed 
and metastatic breast cancer patients 
. Furthermore, HCMV proteins and viral DNA were detected in breast ductal carcinoma in situ and infiltrating ductal carcinomas, suggesting a correlation if not a role for HCMV in breast cancer 
. That said, the effect off HCMV infection on breast cancer development and progression has been poorly investigated at best.
IBC is considered to be a unique phenotype of breast cancer characterized by rapid dissemination, poor prognosis and low survival rate 
. Moreover, the biological mechanisms underlying IBC disease biology are poorly understood. Our studies show that IBC tissues are characterized by over expression of proteases such as cysteine protease cathepsin B 
, membrane type matrix metalloproteinase-1 (MT1-MMP) and matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) 
. Infection of HCMV was found to induce the expression of different cytokines and chemokines among which were TNF-α, IL10, IL-8 and MCP-1 
. Furthermore, studies suggested that HCMV infection induces overexpression of MMPs in mesenchymally transformed renal tubular cells 
. Therefore, based on published results and other studies cited above, we suggest that HCMV may be involved in the etiology and progression of IBC.
In the present study we screened for HCMV infection in non-IBC and IBC patients. Serological diagnosis indicated that the HCMV antibody titer was higher in IBC patients than in non-IBC cases. In addition, a high antibody titer for HCMV has been detected in patients newly diagnosed with breast cancer 
. Furthermore, there was a significant difference in HCMV-DNA detected in carcinoma tissue of IBC compared with versus non-IBC patients, suggesting a possible role for HCMV in the pathobiology of IBC; this role now needs to be examined closely to assess possible causality. Data that are most compelling for an association between HCMV and IBC are sequence analysis data of the detected HCMV-DNA, for which our findings show that HCMV infected IBC tissues possess multiple and different strains of viral DNA than that observed in non-IBC breast cancer tissues.
IBC was associated with HCMV strains AL, NT and AD169, whereas in infected non-IBC tissues we only found HCMV strain AL and at a considerably lower frequency. In our positive control HCMV infected patients that did not have breast cancer we found only HCMV strain AD169. There is a need to explore polymorphism differences among HCMV strains which may provide additional information possibly implicating involvement of HCMV in IBC disease etiology.
HCMV infection was previously shown to augment angiogenesis and lymphangiogenesis 
, to induce cancer cell motility, invasion and adhesion to endothelial cells 
, to stimulate NF-κB signaling pathways 
and to promote resistance of cancer cells to chemotherapy 
, all of which are also properties that characterize IBC disease 
. Thus, we suggest that HCMV may contribute to the specific phenotype of IBC, either directly or indirectly, by activating specific cellular pathways such as that of transcription factor NF-κ
B, which itself is associated with poor prognosis in breast cancer. Molecular studies indicate that genes activated by the NF-κ
B signaling pathway are over-expressed and activated in IBC versus non-IBC 
. Now having shown that NF-κ
B is strongly activated in IBC, it is very likely that its activation and sustained high activity contribute to IBC disease aggressiveness. Most interestingly, when we tested the level of expression and cellular localization of total and phospho-NF-κ
B/p65 in HCMV-infected and non-infected tissues of IBC and non-IBC patients, we found a significant increase in the expression and activity of NF-κ
B/p65 in HCMV-infected IBC carcinoma tissue compared with non-infected carcinoma tissue. In fact, in the non-IBC breast carcinoma tissue samples there was no difference in the level of expression or activity of NF-κ
B/p65 in the non-infected compared with infected carcinoma tissue. Increased expression and activation of NF-κ
B molecules following HCMV infection have been found to be regulated by different mechanisms, including transactivation by HCMV IE genes such as IE1-72, IE2-86 and IE2-55, and increased DNA binding activity of transcription factor SP1 
A significant increase in the expression of NF-κ
B/p65 in infected IBC carcinoma tissue may be due to the secondary involvement of biological molecules such as cytokines and chemokines that characterize IBC tumor biology, but which could be elevated due to HCMV infection of immune cells, fibroblasts or epithelial cells, and in which HCMV induces oncomodulatory proteins through activating NF-κ
B/p65 signaling pathways 
. Currently, we are establishing in-vitro
tissue culture models with and without HCMV infection to identify candidate molecules that result from HCMV infection, an area that has received very little attention.
In conclusion, our results suggest that HCMV infection correlates with IBC pathogenic phenotype and may contributes to the etiology of IBC, directly or indirectly. If this is true additional therapeutic targeting of HCMV may be warranted in the treatment of IBC. It will be important to determine whether HCMV infection either enhances disease severity or whether IBC disease is more susceptible to HCMV infection.