TELOMERASE ACTIVITY IN HUMAN BREAST-CANCER AND BENIGN BREAST-LESIONS - DIAGNOSTIC APPLICATIONS IN CLINICAL SPECIMENS, INCLUDING FINE-NEEDLEASPIRATES

We analysed telomerase activity in normal, benign and malignant breast tissues and in fine needle aspirates by a PCR-based assay. The tissue samples we used in this assay consisted of 20 cryostat sections, 10 m u m thick, from each breast biopsy. This method was used to obtain eff ective extraction from small samples and to confirm the histological i dentity of the specimen by microscopical examination of serial section s. Fifty-two of 71 breast carcinomas were positive for telomerase acti vity, and the intensity of this was strong in most cases, whereas all 6 samples of normal breast tissue and 17 of fibrocystic disease were n egative and only 1 of 15 fibroadenomas was positive. Invasive ductal c arcinomas were more frequently positive than invasive lobular carcinom as. There was no correlation of telomerase activity with tumour size o r the occurrence of lymph node metastasis. Evaluation of our assay sys tem showed that a signal of telomerase activity was detectable in extr acts from single cryostat sections (<1 mm(2)) of a cancer specimen and from as few as 4 cells of a human breast cancer cell line. On the bas is of the above data, we applied this assay to fine needle aspirates o f breast lesions. Ten of 15 aspirates which had been cytopathologicall y diagnosed as cancer were strongly positive, while 26 of 29 benign as pirates were totally negative and the remaining 3 showed only borderli ne activity. In 3 cases, the telomerase result could have helped estab lish a diagnosis when the cytological observations were inconclusive. Our results indicate that this sensitive assay could become a useful n ew modality for supplementing microscopic cytopathology in the detecti on of cancer cells in small tissue biopsies and fine needle aspirates. (C) 1996 Wiley-Liss, Inc.