[Study on expression of ING1, human telomerase reverse transcriptase and telomerase-associated protein 1 genes in human gliomas].

OBJECTIVE: To investigate the relationship between expressions of ING1 gene and genes of human telomerase reverse transcriptase (hTERT) and telomerase-associated protein 1 (hTP1) in human gliomas. METHODS: The expressions of ING1 mRNA and p33(ING1) protein, hTERT mRNA and protein, and hTP1 mRNA and protein in seventy human glioma specimens with different malignant grades were studied using in situ hybridization and immunohistochemistry. RESULTS: All of the 70 gliomas collected expressed hTP1 mRNA and protein and among them, 62 (88.6%) and 58 (82.9%) out of 70 expressed hTERT mRNA and protein respectively. The quantities of the four kinds of positive cells were correlated positively with one another (r = 0.758 - 0.882, P < 0.000 5), and all of them were significantly fewer in gliomas of WHO grade I - II than in grade III gliomas and the most in grade IV gliomas (P < 0.05 approximately 0.01). 66 (94.3%) and 62 (88.6%) out of 70 gliomas expressed ING1 mRNA and p33(ING1) protein respectively. The quantities of their positive cells were also correlated positively with each other (r = 0.831, P < 0.000 5), but the positive cells were more in gliomas of WHO grade I - II than in grade III gliomas and the fewest in grade IV gliomas (P < 0.01). The quantities of positive cells of ING1 mRNA and p33(ING1) protein were correlated negatively with those of hTERT mRNA and protein as well as hTP1 mRNA and protein respectively (r = -0.211 to -0.384, P < 0.05 approximately 0.001). CONCLUSIONS: The results suggest that all of the parameters concerned are valuable in evaluating the biological behavior of gliomas. In glioma cells, overexpressions of hTERT and hTP1 genes might be significant in inhibiting the expression of ING1 gene. The abnormal expressions of the three genes play possibly the important roles in the development and malignant progression of gliomas.