ANALYSIS OF TELOMERASE ACTIVITY LEVELS IN BREAST-CANCER - POSITIVE DETECTION AT THE IN-SITU BREAST-CARCINOMA STAGE

Telomerase activity has been implicated to be associated with most hum an malignant tumors, including breast cancer, To evaluate possible ass ociations with well-known prognostic factors in breast cancer, we perf ormed a semiquantitative analysis of telomerase activity levels using the very sensitive PCR-mediated telomeric repeat amplification protoco l, Telomerase activity was detected in 99 of 104 breast cancer samples analyzed (95.2%), whereas no activity was detected in 10 of 10 adjace nt nonmalignant breast tissues, Analysis of five breast fibroadenoma s amples revealed telomerase activity in one (20%), In contrast to previ ous observations, we observed that 100% of stage I breast tumors were positive for telomerase activity, More interestingly, we detected telo merase activity in six of six ductal carcinoma in situ samples (i,e,, stage 0), In our semiquantitative analysis of levels of enzymatic acti vity, we found no statistically significant correlation at the P < 0.0 5 level between telomerase levels and lymph node metastasis status, es trogen and progesterone receptor status, tumor size, S-phase fraction, and ploidy, The only statistically significant correlation was found with patient age (rho = -0.3; P = 0.03), We observed no statistically significant difference in the telomerase activity levels of early tumo rs (stages 0 and I) versus more advanced lesions (stages II to IV), Ne vertheless, stage IV tumors displayed a tendency for higher telomerase activity levels, In summary, no clear association was observed betwee n telomerase levels and known breast cancer prognostic indicators, How ever, telomerase detection by the telomeric repeat amplification proto col method, due to its high sensitivity, may be of value in early brea st cancer diagnosis and detection, because our data indicate that telo merase reactivation appears to constitute a relatively early event in breast carcinogenesis.