Real-time PCR quantification of human telomerase reverse transcriptase (hTERT) in colorectal cancer

Aims: Human telomerase reverse transcriptase (hTERT) is believed to a reliable marker for telomerase activity. The expression of telomerase activity has not been investigated in a consecutive series of patients with colorectal adenocarcinoma in North Queensland. The objective of this study was to evaluate the significance of hTERT mRNA expression in colorectal adenocarcinoma in North Queensland. Methods: Matched samples of tumour and adjacent non-tumorous mucosa samples from 53 colorectal carcinomas and nine colorectal adenomas were collected. In all these samples, RNA was extracted and then transcribed to cDNA. Real-time polymerase chain reaction (RT-PCR) was used to quantitate expression the level of hTERT mRNA. The findings were correlated with the clinicopathological features of patients with these tumours prospectively collected into a computerised database. Results: hTERT mRNA was expressed in all tumour samples. The level of expression in the colorectal adenocarcinomas was significantly higher than the corresponding non-tumorous mucosa (p=0.009, t-test). The level of expression in the adenocarcinomas was slightly higher than those of adenomas, but the difference was not statistically significant. A higher level of hTERT expression was often noted in the adenocarcinomas arising from the left colon and rectum when compared with those from the right colon (p=0.029). Conclusions: Colorectal adenocarcinoma revealed expression of telomerase hTERT mRNA, which was detected quantitatively by real-time PCR. hTERT could be a potential biomarker for colorectal cancer. The difference between proximal and distal colorectum in hTERT expression could account for their known different clinical behaviour.