Prostate-Specific Antigen Gene Expression and Telomerase Activity in Breast Cancer Patients: Possible Relationship to Steroid Hormone Receptors

Abstract

Breast cancer, the most prevalent cancer among women, is a steroid hormone receptor-dependent cancer. Recently, it has been shown that telomerase and prostate-specific antigen (PSA) gene expressions are under control of steroid hormone receptors. The aim of this study was to investigate the relationship between telomerase activity and PSA gene expression with steroid hormone receptors in breast cancer patients. This study consisted of 50 women with breast benign tumors and 50 malignant (invasive) tumors. Telomerase activity was measured in tumor cytosol of samples by telomeric repeat amplification protocol (TRAP) assay. PSA protein and its mRNA expression were measured using ultrasensitive immunoassay and RT-PCR technique in all tumor tissues, respectively. Estrogen and progesterone receptors were stained using immunohistochemistry in tumor tissues. Telomerase activity was detected in all of the invasive breast cancer tissues. The difference of relative telomerase activity (RTA) values between stages and grades were statistically significant (p < 0.05). The PSA mRNA was detected only in benign tumors and stage I and grade I malignant tumor cytosol. Difference of tumor cytosol PSA levels between the cases and control groups and also between all grades and stages of diseases were significant (p < 0.05). There was an inverse significant correlation between the RTA and PSA protein levels in the case groups (r = -0.42, p < 0.05). There was a statistically significant difference between ER/PR with PSA level and telomerase activity in tumor tissues (p < 0.05). It is speculated that differential expression of PSA and telomerase genes in breast tumors are under control of steroid hormone receptors and could be used as a target for treatment in the future.