Detection of cytomegalovirus DNA in colorectal tissue from Swedish and Vietnamese patients with colorectal cancer.

Background: Human cytomegalovirus (HCMV) has been implicated as a factor, which might be associated with colorectal cancer (CRC) progression. Data from studies with HCMV-infected tumour cell lines have highlighted an oncomodulatory potential of HCMV. In the present study, we aimed to evaluate the prevalence of HCMV DNA in CRC tissue compared to matched normal tissue, and its association with clinical factors. Patients and Methods: We used quantitative real-time polymerase chain reaction assay to detect HCMV DNA in 202 cancerous and paired normal tissue from Swedish (n=119) and Vietnamese (n=83) CRC patients. Results: Overall, the HCMV DNA rate was significantly higher in cancerous in relation to paired normal tissue. Furthermore, a significantly higher frequency (39.8%) of HCMV DNA was observed in cancer tissues from the Vietnamese patients compared to the Swedish patients (15.1%). The prevalence of HCMV DNA in CRC tissue of 50% of those with disseminated disease tended to be higher compared to those with localized disease, with a prevalence of 33.3% in Vietnamese patients. Conclusion: Our observations indicate that the prevalence of HCMV DNA differs significantly between cancer and matched normal tissues. Thus, these data support a possible role of CMV in CRC. Moreover, we noted differences between Swedish and Vietnamese patients, indicating a role of ethnicity.