Open AccessIn situ mRNA Hybridization Technique for Analysis of Human Telomerase RNA in Gastric Precancerous and Cancerous Lesions
Author(s) -
Hiyama Toru,
Yokozaki Hiroshi,
Kitadai Yasuhiko,
Tahara Eiji,
Tahara Hidetoshi,
Ide Toshinori,
Haruma Ken,
Yasui Wataru,
Kajiyama Goro,
Tahara Eiichi
Publication year - 1998
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1998.tb00514.x
Subject(s) - telomerase , in situ hybridization , intestinal metaplasia , biology , carcinogenesis , pathology , telomerase reverse transcriptase , microbiology and biotechnology , hyperplastic polyp , cancer , cancer research , gene expression , colorectal cancer , gene , medicine , biochemistry , genetics , colonoscopy
Telomerase, the ribonucleoprotein enzyme that elongates telomeres, is repressed in normal somatic cells but is reactivated during tumor progression. The purpose of this study was to investigate the localization of human telomerase RNA (hTR) expression in human gastric precancerous and cancerous lesions by using in situ mRNA hybridization (ISH) with avidin‐biotin staining. We also examined telomerase activity in these lesions by using hybridization protection assay connected with a telomeric repeat amplification protocol (TRAP/HPA). Analyzed tissue samples were as follows; 132 cases of chronic atrophic gastritis without intestinal metaplasia, 115 incomplete‐type intestinal metaplasias, 40 complete‐type intestinal metaplasias, 23 hyperplastic polyps, 23 tubular adenomas and 26 adenocarcinomas. In ISH analysis, high levels of hTR expression were observed preferentially in the nuclei at the single‐cell level. hTR‐expressing cells in carcinomas and adenomas were significantly more frequent than those of the other lesions ( P <0.001). The expression pattern of hTR in carcinoma and adenoma tissues was heterogeneous and similar intratumor heterogeneity was detected in Ki‐67 immunoreactivity. Infiltrating lymphocytes in tissues also exhibited high levels of hTR expression. In TRAP/HPA analysis, carcinomas had significantly more frequent positivity for telomerase activity and a higher level of telomerase activity than the other lesions ( P <0.05). However, the amount of telomerase activity did not parallel the expression level of hTR. Our data suggest that hTR expression increases in the early stages of stomach carcinogenesis and that sufficient synthesis of hTR is a prerequisite for telomerase reactivation in tumorigenesis.