The aim of this study was to evaluate whether parvovirus B19, a common infectious pathogen in humans, also was involved in human colon carcinoma.
A total of 119 paraffin-embedded specimens of colon polyps, adenocarcinomas, carcinoma-adjacent tissues, and normal controls were processed for nested polymerase chain reaction (PCR), in situ
hybridization (ISH), immunohistochemistry (IHC), and laser capture micro dissection detection of B19 DNA and protein. The expression of cyclo-oxygenase-2 (COX-2) in the colon- cancer cells (Lovo) transfected by inducible vector for VP1u was determined by western-blot analysis.
B19 DNA was detected in 94.6% (35/37) of colon adenocarcinomas, 67.6% (25/37) of adjacent noncancerous tissues, 85.6% (30/35) of polyps, and 60.0% (6/10) of normal controls by nested PCR, respectively. Analysis of the microdissected material confirmed the presence of viral DNA in colonic neoplastic epithelium. ISH detected B19 DNA in 81.1% (30/37) of colon adenocarcinomas, 43.2% (16/37) of adjacent noncancerous tissues, 74.3% (26/35) of polyps, and 50.0% (5/10) of normal controls, respectively. B19 protein VP1/VP2 was found in 78.4% (29/37), 32.4% (12/37), and 57.1% (20/35) of colon adenocarcinomas, tumor-adjacent tissues, and polyps, respectively, but not in normal colons (none of 10). There were significant differences in nested PCR, ISH, and IHC between adenocarcinoma and non-neoplastic adjacent tissues, and between adenocarcinoma and normal controls. Transfection of colon-cancer cells (Lovo) by inducible vector for VP1u resulted in marked upregulation of cyclo-oxygenase-2 proteins.
Parvovirus B19 nucleic acids commonly exist in human colon tissues and VP1/VP2 antigen is preferentially located in colon polyps and adenocarcinomas lesions. B19 viral products VP1u may induce important oncogenic pathways in colon-cancer cells.