Telomerase activity in oral cancer.

Telomerase activity can be detected in most human cancers. This is consistent with the telomere hypothesis, which predicts upregulation of telomerase expression after a number of mitotic divisions to prevent the progressive and catastrophic loss of telomeres. However, telomerase has not been fully analyzed in oral cancers. In this report, telomerase activity was analyzed in 31 human oral malignant tumors, 11 leukoplakias, three pleomorphic adenomas, and 40 samples taken from normal tissues of the oral cavity, using a polymerase chain reaction (PCR)-based telomeric repeat amplification protocol assay. Telomerase activity was detected in most oral cancers [squamous cell carcinoma (SCC), non-Hodgkin's lymphoma, adenoid cystic carcinomas, mucoepidermoid carcinoma, osteosarcoma, acinic cell carcinoma, rhabdomyosarcoma]. None of the normal tissues or pleomorphic adenomas displayed telomerase activity. In leukoplakia, telomerase activity was seen in moderate or severe dysplastic tissue and carcinoma in situ. Mild dysplasia did not reveal telomerase activity. In SCC, there was no clear association between relative telomerase activity and grade or stage. These results suggest that detection of telomerase activity in oral tissues could be used to differentiate malignant from benign or normal tissues.