Telomerase activity determined by conventional telomeric repeat amplification protocol and reverse transcriptase-polymerase chain reaction assay in ovarian lesions: a comparison of assays.
OBJECTIVE: Telomerase is capable of restoring telomeric sequence lost during replication. No or low levels of telomerase activity are present in normal somatic cells, whereas up to 85-90% of all cancer cells express telomerase activity, suggesting telomerase as a possible tumor marker. The catalytic subunit, hTERT, correlates with the activity of the enzyme. MATERIAL AND METHODS: Telomerase activity in ovarian tissue was measured by the functional telomeric repeat amplification protocol (TRAP)eze assay, and a quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) assay measuring the expression of the telomerase catalytic subunit, hTERT. RESULTS: A weakly positive correlation was found between telomerase activity and severity of ovarian disease using the results of the TRAP assay, compared to a strongly positive correlation considering the results obtained in the RT-PCR assay. A statistically significant difference between the benign and borderline groups was present using the RT-PCR assay, allowing for screening for both borderline and primary malignant conditions with a specificity of 97% and a sensitivity of 68%. No significant statistical difference was found between telomerase activity in benign and borderline conditions when using the TRAP assay. When screening for primary malignancy, the specificity and sensitivity rates were 94% and 21%, respectively. CONCLUSIONS: The RT-PCR assay allowed discrimination between benign and borderline and malignant cases, and thereby proved superior to the TRAP assay, which could not discriminate the benign cases from the borderline cases. This suggests that the RT-PCR assay may be useful in screening for both borderline and primary malignancy in ovarian lesions.