Telomerase activity in normal human breast and cancer, association with Bcl-2, estrogen receptors (α-, β-) and clinical parameters

Abstract

9675 Background: Telomerase has been shown to be specifically expressed in immortal cells. Bcl-2 overexpression has been found to be associated with estrogen receptor (ER) positivity. There is controversy with respect to use telomerase activity (TA) as prognostic marker or even more if TA could be associated with other breast molecular markers. Methods: Using a fluorometric detection for detect TA by the use of FRET primers was determined in 44 core central biopsies of infiltrating breast carcinoma and by immunohistochemistry were determined Bcl-2 and estrogen receptors (α-, β-). A semiquantitative method was use to analyze the protein expression. Clinical data were available for statistical analysis. Results: 52% of all patients were post-menopausal, the average age was 49.3+ SD 11.6 years, 70% of cases were stage III and IV, and 72.7% were moderately and high differentiated. TA was scored since 0 to 49.9 units of total generated product. ERα were detected in 39/44(88.6%); ERβ in 16/44(36.44%). Bcl-2 immunoreactivity was observed in 36/44 (82%). We found a strong association between TA and moderately and high differentiated tumors (p=0.033). Bcl-2 protein expression was associated with clinical stage I and II (p=0.02). Bcl-2 protein expression correlated directly with the expression of ERα (p=0.024). Conclusions: It was clear that TA was positive and correlated with high grade malignancy. It seems that TA is not regulated by the anti-apoptotic protein bcl-2 because we did not find an association between them. The expression of the protein bcl-2 shows a significant increase in breast tumors within early stage and also with the absence or early relapse. We were not able to find the expected relation between the expression of the estrogen receptors and the TA. The ERα is associated with the expression of Bcl-2 in 82% but it was not found a positive correlation with ERβ. Our results suggest a possible role of ERα in the regulation of Bcl-2 protein expression in Breast cancer. No significant financial relationships to disclose.