Overexpression of human telomerase RNA in Helicobacter pylori-infected human gastric mucosa

Telomerase, an enzyme associated with cellular immortality and malignancy, plays an important role in cellular immortalization and tumorigenesis, Furt hermore, overexpression of the RNA component of the telomerase, called huma n telomerase RNA (hTR), has been demonstrated in various human cancers as a n early event. The pattern of hTR expression following Helicobacter pylori (H, pylori) infection in human gastric mucosa was investigated by a radioac tive irt situ hybridization (ISH) assay. Paraffin-embedded sections of 50 b iopsy specimens taken from the gastric antrum of individual patients infect ed to different extents with H. pylori, as well as normal gastric mucose, w ere studied. In normal gastric mucosa, only weak hTR expression was noted a nd the expression was limited to basal cells of the gastric glands. However , the degree of hTR expression gradually increased in parallel with the deg ree of H. pylori infection. The mean scores of gastric mucosa with mild, mo derate and severe degrees of H. pylori infection were 2.3, 2.8, and 3.7 tim es higher than that of normal gastric mucosa, respectively. The results of this study suggested that up-regulation of hTR expression is a frequent and early event associated with H. pylori infection in the gastric mucosa and may play some role in gastric carcinogenesis. Sufficient synthesis of hTR d uring this early stage may be a prerequisite for telomerase reactivation to occur in gastric cancer.