Quantitative analysis of hTERT mRNA expression in colorectal cancer

OBJECTIVES: Telomerase is highly activated in a variety of malignant neoplasms including colon cancer. Among the major components of telomerase, human telomerase reverse transcriptase (hTERT) is thought to regulate telomerase activity. To assess the importance of telomerase for the diagnosis of colorectal cancer, we measured the expression of hTERT mRNA and telomerase activity in a large series of 140 colorectal cancers, 140 adjacent normal tissues, and 20 adenomas. METHODS: The expression level of hTERT was measured quantitatively by competitive reverse transcriptase-polymerase chain reaction (RT-PCR), and telomerase activity was examined by telomeric repeat amplification protocol (TRAP) assay in the same samples. RESULTS: The median expression level of hTERT mRNA in carcinomas was significantly higher than that in either adenomas or normal tissues. The median level of hTERT in adenomas was significantly higher than that in normal tissues. Telomerase activities in carcinomas were significantly higher than those in either adenomas or normal tissues. Telomerase activities in adenomas were also significantly higher than those in normal tissues. Furthermore, the relative expression levels of hTERT mRNA in adenomas and carcinomas were significantly correlated with the relative telomerase activities; the Spearman rank correlation was 0.53 (p = 0.021) and 0.18 (p = 0.031), respectively. CONCLUSIONS: Our data suggest that determination of hTERT mRNA by competitive RT-PCR is superior in quantitative accuracy and sensitivity and would support the importance of telomerase activity for the diagnosis of colorectal cancer. (C) 2001 by Am. Cell. of Gastroenterology.