Detection of Epstein-barr virus by PCR and expression of LMP1, p53, CD44 in gastric cancer

Lee, Myung Ah; Hong, Young Seon; Kang, Jin Hyung; Lee, Kyung Shik; Yoo, Jin Young; Lee, Kyo Young

Abstract

BACKGROUND: Epstein-Barr virus (EBV) is associated with various lymphoproliferative disorders and nasopharyngeal carcinoma. Recently some of the tumor cells of gastric cancer were observed to contain EBV sequence. We detected EBV using PCR to determine the frequency of EBV associated gastric cancer, which is the most common cancer in Korea. We also performed immunohistochemical staining for the latent membrane protein (LMP1), p53 and CD44 to investigate the possible mechanism in EBV-associated gastric cancer.
METHODS
Eighty-seven formalin-fixed and paraffin-embedded blocks (40 gastric adenocarcinomas, 34 adjacent normal tissues, 13 metastatic lymph nodes) from 40 surgically resected gastric specimens were studied. All patients were diagnosed as having gastric cancer at the Kang-Nam St. Mary's Hospital during the period of April 1995 to April 1997. DNA was extracted from each paraffin block and then we performed PCR and immunohistochemical staining for the LMP1, p53 and CD44. We reviewed the patients' charts for clinical information.
RESULTS
EBV was detected in 4 cases (10%) by EBV-PCR among the 40 patients. It was also detected in a metastatic lymph node in 1 patient. The immunohistochemical staining for the LMP1, p53 and CD44 was negative in all the EBV-positive cancer patients. Of the patients having these cancers, 2 had a poorly differentiated adenocarcinoma with a lymphoepithelioma-like morphology.
CONCLUSION
The frequency of EBV-associated gastric cancer may be about 10% in Korea. Considering the negative result of the immunohistochemical staining for the LMP1, p53 and CD44, EBV-associated gastric cancer seems to have a different mechanism of tumorigenesis from ordinary gastric cancer or other EBV-associated cancers. This must be determined by further large scale studies.