Telomerase activity in ductal carcinoma in situ of the breast.

Telomerase plays an important role in maintaining the stability of the chromosomes. Activity of telomerase has been detected in proliferating and immortalized cell lines and in a number of malignant tumors including invasive breast cancer. The aim of the study was to examine telomerase activity in ductal carcinoma in situ (DCIS), which is considered to be a precursor lesion of infiltrating breast carcinoma, using a PCR-based telomerase activity protocol (TRAP). We examined 35 samples obtained from histologically confirmed breast biopsies, including 13 normal breast tissues, 11 infiltrating ductal carcinoma (IDC), nine DCIS, and two DCIS with microinvasion. Telomerase activity was demonstrated in 8/9 samples of DCIS, both samples of DCIS with 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 utilization as a biomarker in DCIS is questionable.