Cytomegalovirus is not associated with progression and metastasis of colorectal cancer

Recently, it was hypothesized that human cytomegalovirus (HCMV) might be associated with colorectal cancer progression. However, the role of HCMV infection in colorectal cancer remains controversial. We aimed to assess whether nucleic acids and/or gene products of HCMV could be detected in primary and metastatic colorectal carcinomas. Fresh-frozen biopsy specimens from 77 primary and metastatic colorectal carcinomas of randomly selected patients were analyzed by PCR and immunohistochemistry. We investigated 57 primary tumors and 20 metastases, comprising 13 tumor pairs from the same patient. In PCR, four primary tumors showed a positive CMV result whereas all investigated metastases were negative including three paired samples from positive primaries. In immunohistochemistry, no specific staining could be determined in all neoplastic epithelial cells. In summary, we think that there is no association between CMV infection and tumor progression or metastasis formation of colorectal cancer.