Real time quantification in plasma of human telomerase reverse transcriptase (hTERT) mRNA in patients with colorectal cancer.

BACKGROUND: Increased telomerase activity can be found in almost 90% of colorectal tumours. We aim to describe the preliminary results for quantification in plasma of hTERT mRNA in colorectal cancer patients.

MATERIALS AND METHODS: Fifty patients undergoing surgery for colorectal cancer and a control group of 50 healthy volunteers were prospectively studied. Pre-operative venous blood samples were taken from all cancer patients and volunteers. Plasma hTERT expression was determined from peripheral blood based on real-time quantitative RT-PCR (qRT-PCR) method normalized to the amount of RNA input using 18S rRNA gene expression. Plasma pre-operative CEA levels were also determined.

RESULTS: Median values for normalized hTERT (hTERT(N)) gene expression were higher in colorectal cancer patients (11.62, range 0.23-47.67) than healthy volunteers (0.29, range 0.00-4.63) (P < 0.001). Individual data showed that 82% of colorectal cancer patients had hTERT(N) expression values superior to the maximum value observed in the control group. Sensitivity and specificity of the assay for colorectal cancer detection were 98% and 64%, respectively. No significant differences in hTERT(N) expression between gender or with age (P > 0.05). No significant correlation was found between hTERT(N) expression and CEA values (Spearman's rank test = 0.136, P = 0.348).

CONCLUSIONS: These results show that detection of mRNA based on the qRT-PCR of the telomerase hTERT(N) gene in plasma clearly differentiates between healthy and colorectal cancer patients and that hTERT(N) can be detected and quantified in plasma. This opens up a new field as a noninvasive blood test for colorectal cancer diagnosis.