TELOMERASE EXPRESSION IN HUMAN BREAST-CANCER WITH AND WITHOUT LYMPH-NODE METASTASES

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DN A onto the ends of chromosomes, thereby preventing the replication-dep endent shortening of these ends. Telomerase activity is detected in a wide range of cancers of various tissues, and its expression may be a critical step in tumor progression The telomeric repeat amplification protocol was used to compare telomerase activity in breast cancers wit h and without lymph node metastases, as well as in fibroadenomas and n ormal breast tissue. Expression of telomerase was detected in 22 (79%) of 28 primary breast cancers, which included 16 (73%) of 22 cancers p ositive and 6 (100%) of 6 cancers negative for axillary lymph node met astases. It was detected in 1 (11%) of 9 fibroadenomas but was negativ e in 13 normal breast tissues. There was no statistical difference in expression of telomerase between axillary node-negative primary breast cancers and similar tumors with nodal metastasis (P = .289). Further, no statistical association was found between telomerase activity and tumor size (P = .679) or hormonal status (P = .178). The difference in telomerase activity among breast cancers vs fibroadenomas and normal breast tissues, however, was statistically significant (P < .001). Alt hough normal breast tissue does not express telomerase, both node-posi tive and node-negative breast cancers express telomerase. The possible significance of telomerase expression in fibroadenomas remains open t o further investigation.