Is the telomerase assay useful for screening of endometrial lesions?

Telomerase activation is specifically observed in most cancers but not in normal tissues with some exceptions, such as germ cells or certain tissues with regenerative potential, suggesting a diagnostic opportunity for cancers involving measurement of telomerase activity. Cytologic screening for endometrial cancer has not been well established, due to the complexity of diagnostic criterion. In the present study, we investigated the utility of the telomerase assay for screening endometrial lesions. A total of 100 patients with or without endometrial lesions were examined for telomerase activity by the telomeric repeat amplification protocol (TRAP) assay using endometrial scraping samples and the correlation with cytology was investigated. The TRAP assay revealed frequent telomerase activation in normal endometria at reproductive age, particularly in 67% of proliferative-phase endometria, suggesting that the telomerase assay is not suitable for screening women of reproductive age. However, in postmenopausal women, telomerase activity was rarely detected (8%) in normal endometria, while it was observed in >80% of endometrial cancers or hyperplasias. Interestingly, some cases of endometrial cancer and hyperplasia were misdiagnosed by cytology but correctly detected by the TRAP assay. The sensitivity of the TRAP assay to screen endometrial lesions was 87%, equivalent to that of cytology. Combination of cytology and the TRAP assay increased sensitivity to 100%. We thus concluded that measuring telomerase activity in endometrial scrapings is a useful diagnostic tool for the screening of endometrial lesions in postmenopausal women, particularly when used with cytology to increase screening sensitivity.