Oncogenic T-antigen of JC virus is present frequently in human gastric cancers.
BACKGROUND
JC virus (JCV) is a polyomavirus that commonly infects humans and is the causative agent of progressive multifocal leukoencephalopathy in immune-compromised patients. An association between JCV and human cancers long has been suspected, because this virus induces brain tumors in several animal models. The oncogenic potential of JCV is mediated by a transforming protein, the T-antigen (T-Ag), which is a multifunctional protein that transforms cells through interactions with various growth-regulatory genes, including p53 and pRb, and by stabilizing beta-catenin. Previously, the laboratory at the authors' institution demonstrated that JCV is present frequently in the human gastrointestinal tract and may play a role in colorectal carcinogenesis. However, to date, no studies have determined whether JCV sequences are present specifically in gastric cancers. The current study was designed to investigate whether JCV sequences and expression are found in human gastric cancers.


METHODS
DNA was extracted from 23 paraffin embedded and 14 frozen gastric cancer specimens. For the detection of JCV gene sequences, polymerase chain reaction amplifications were performed using gene-specific primers for T-Ag, VP-1 (a JCV capsid gene), and the viral regulatory region (or transcriptional control region). Immunohistochemical staining was performed with an anti-T-Ag monoclonal antibody to detect protein expression.


RESULTS
Twenty-one of 37 gastric cancers (57%) harbored JCV T-Ag sequences, and 13 of 37 gastric cancers (30%) contained VP-1 sequences. T-Ag sequences also were found in adjacent nonneoplastic mucosa. In addition, JCV regulatory region sequences were present frequently in gastric cancers and adjacent nonneoplastic mucosa. T-Ag protein expression was found in 9 of 23 gastric cancers (39%), whereas no expression was observed in any of the nonneoplastic tissues.


CONCLUSIONS
To the authors' knowledge, this is the first demonstration of the presence of JCV T-Ag expression in human gastric cancers. These findings suggest a possible role for this polyomavirus in gastric carcinogenesis.
Shin
Sung Kwan
SK
Division of Gastroenterology, Department of Internal Medicine, Baylor University Medical Center, Dallas, Texas 75206, USA.
Li
Mei-Shu
MS
Fuerst
Florentine
F
Hotchkiss
Erin
E
Meyer
Richard
R
Kim
Il Tae
IT
Goel
Ajay
A
Boland
C Richard
CR
D000952:Antigens, Polyomavirus Transforming / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D043171:Chromosomal Instability; D006801:Humans; D007577:JC Virus / Q000235:genetics* / Q000276:immunology; D016133:Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000737:chemistry / Q000235:genetics / Q000821:virology*
D000952:Antigens, Polyomavirus Transforming