Specific localisation of human cytomegalovirus nucleic acids and proteins in human colorectal cancer.
BACKGROUND
Colorectal cancer is the second most frequent cause of death from cancer in the USA, and most tumours arise sporadically with no clear cause or genetic predisposition. Human cytomegalovirus is a beta-herpesvirus that is endemic in the human population and can cause life-threatening disease in immunosuppressed adults. In vitro, human cytomegalovirus can transform cells and dysregulate many cellular pathways relevant to colon adenocarcinoma pathogenesis, especially those affecting the cell cycle, mutagenesis, apoptosis, angiogenesis, and cyclo-oxygenase-2 (COX-2) expression. We aimed to assess whether gene products of human cytomegalovirus could be detected in colorectal cancers.


METHODS
We obtained formalin-fixed, paraffin-embedded pathological specimens of colorectal polyps, adenocarcinomas, and adjacent normal mucosa from 29 patients. To detect human cytomegalovirus proteins and nucleic acids, we used immunohistochemistry with two different monoclonal antibodies, in-situ hybridisation, and PCR with DNA sequencing.


RESULTS
Human cytomegalovirus proteins IE1-72 and pp65 were detected in a tumour cell-specific pattern in 14 (82%) of 17 and seven (78%) of nine colorectal polyps, respectively, and 12 (80%) of 15 and 11 (92%) of 12 adenocarcinomas, respectively, but not in adjacent non-neoplastic colon biopsy samples from the same patients (none of seven and none of two, respectively). Human cytomegalovirus infection of colon-cancer cells (Caco-2) in vitro resulted in specific induction of Bcl-2 and cyclo-oxygenase-2 proteins, both of which are thought to contribute to progression of colon cancer.


CONCLUSIONS
Human cytomegalovirus nucleic acids and proteins can be found that specifically localise to neoplastic cells in human colorectal polyps and adenocarcinomas, and virus infection can induce important oncogenic pathways in colon-cancer cells.
Harkins
Lualhati
L
Pathology Service, Birmingham Veterans Affairs Hospital, Birmingham, AL, USA.
Volk
Andrea L
AL
Samanta
Minu
M
Mikolaenko
Ivan
I
Britt
William J
WJ
Bland
Kirby I
KI
Cobbs
Charles S
CS
D000230:Adenocarcinoma / Q000821:virology; D018938:Caco-2 Cells; D003111:Colonic Polyps / Q000821:virology; D015179:Colorectal Neoplasms / Q000821:virology*; D051546:Cyclooxygenase 2; D003587:Cytomegalovirus / Q000302:isolation & purification*; D006801:Humans; D017874:Immediate-Early Proteins / Q000032:analysis*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000032:analysis; D008565:Membrane Proteins; D009696:Nucleic Acids / Q000032:analysis*; D016133:Polymerase Chain Reaction; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis; D014763:Viral Matrix Proteins / Q000032:analysis*; D014764:Viral Proteins
C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; D009696:Nucleic Acids; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C047015:cytomegalovirus matrix protein, pp 64-69; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases