Abstract LB-63: Expression of α+β+ splice variant of human telomerase reverse transcriptase (hTERT) in cytokeratin 19 (CK-19) positive circulating tumor cells (CTCs) of breast cancer patients

Abstract

Abstract Introduction: Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase. The α+β+ splice variant is the functional variant of hTERT. Circulating tumor cells (CTCs) have already been established as strong predictors of prognosis in patients with metastatic breast cancer. Our group has previously shown the prognostic significance of cytokeratin 19 (CK-19) mRNA-positive CTCs in early breast cancer. The aim of our study was to study the expression of hTERT α+β+ splice variant in CK-19 positive CTCs in breast cancer samples by qRT-PCR. Materials and Methods: Peripheral blood (20 ml in EDTA) was obtained from 25 patients with early breast cancer before the administration of adjuvant chemotherapy, 14 patients with verified metastasis who were all tested positive for CK-19 expression by real time PCR (Stathopoulou et al, Int J Cancer 2006), and 17 female healthy volunteers. CTCs were isolated after ficoll density gradient centrifugation, following enrichment with immunomagnetic Ber-EP4 coated capture beads, mRNA was isolated using oligo (dT)25 coated magnetic beads, followed by cDNA synthesis. The expression of hTERT α+β+ splice variant was tested in both CTCs and PBMCs fractions by quantitative real-time PCR in the LightCycler, (Mavroyiannou et al, Clin Chem, 2007). Results: hTERT α+β+ splice variant was expressed in 4/14 (29%) of CK-19 mRNA positive CTCs samples from patients with metastasis and in 5/24 (21%) of CK-19 mRNA positive CTCs samples from patients with early breast cancer. None of the 17 female healthy volunteers CTCs fraction was tested positive for hTERT α+β+ splice variant, while the corresponding PBMCs fraction was positive in all cases. Conclusions: To our knowledge this is the first report on the expression of hTERT α+β+ splice variant in CTCs of patients with early breast cancer and verified metastasis. Further studies are needed to evaluate and confirm our findings in a larger number of patients. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-63.