Telomerase activity in ductal carcinoma in situ of the breast

Telomerase plays an important role in maintaining the stability of the chro mosomes. Activity of telomerase has been detected in proliferating and immo rtalized cell lines and in a number of malignant tumors including invasive breast cancer. The aim of the study was to examine telomerase activity in d uctal carcinoma in situ (DCIS), which is considered to be a precursor lesio n of infiltrating breast carcinoma, using a PCR-based telomerase activity p rotocol (TRAP). We examined 35 samples obtained from histologically confirm ed breast biopsies, including 13 normal breast tissues, 11 infiltrating duc tal carcinoma (IDC), nine DCIS, and two DCIS with microinvasion. Telomerase activity was demonstrated in 8/9 samples of DCIS, both samples of DCIS wit h microinvasion, and all but one sample of IDC. Normal breast tissue had no demonstrable telomerase activity. Our results indicate that telomerase is activated frequently in early breast carcinogenesis, although its utilizati on as a biomarker in DCIS is questionable.