Detection of circulating carcinoma cells by telomerase activity

Abstract

Summary Telomerase has been shown to be a marker of epithelial cancer cells. We developed a method that allows the detection of circulating carcinoma cells in the blood of cancer patients. Circulating epithelial cells are harvested from peripheral blood mononuclear cells by immunomagnetic separation using BerEP4-coated beads. A telomeric repeat amplification protocol (TRAP)-ELISA is then used to measure telomerase in harvested epithelial cells. This method is specific and sensitive as demonstrated by experiments using BerEP4-positive and negative cell lines. Whereas we never found telomerase activity in harvested epithelial cells (HEC) samples from 30/30 healthy donors, we have detected telomerase activity in HEC from 11/15 (73%) patients with stage IIIB or IV non-small cell lung cancer (NSCLC) patients and from 8/11 (72%) stage C or D (Dukes classification) colon cancer patients. This non-invasive method could be of great value as a diagnostic or prognostic marker, or for monitoring cancer progression.

Preoperative Circulating Tumor Cell Detection Using the Isolation by Size of Epithelial Tumor Cell Method for Patients with Lung Cancer Is a New Prognostic Biomarker

“…Different methods have been applied in the past to detect occult CTC in patients with NSCLC (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Indeed, most of the previous studies have used indirect methods based on RT-PCR or quantitative RT-PCR before, during, and after surgery (21,23,24,(27)(28)(29) or nested RT-PCR (25) or used BErEP4-coated beads (22), magnetic bead enrichment, and laser scanning cytometric (26) and immunocytologic methods (CellSearch System; ref.…”

“…30). Different biomarkers such as the telomerase activity (22), the cytokeratin 19/ carcinoembryonic antigen and c-met mRNAs (25,27,31), epidermal growth factor receptor (21,32), and other different molecules of interest (23) have been used in these studies to specifically identify CTC. However, contrasting results have been obtained in all these previous studies because of technical characteristics such as marker-and method-related specificity and sensitivity and limitations such as the high cost and labor needed, which are not adapted for use in large cohorts of patients…”

Telomere Maintenance Mechanisms: Prognostic and Therapeutic Implications for the Pathologist and Oncologist

“…Although not as widely validated, blood samples may be used. Here, cancerous cells are first separated from leukocytes before the telomerase activity is assessed [48]. However, blood samples are only applicable if cancerous cells are in circulation.…”

Μεταγραφική Έκφραση Της Ανάστροφης Μεταγραφάσης Της Τελομεράσης Και Της 23-Διοξυγονάσης Της Ινδολεαμίνης Στον Καρκίνο Του Πνεύμονα

“…πλευριτικό υγρό [80], [105], [107], [108], [109], [110] [111], [112] περιφερικό αίμα [116] [117], [118], [119], [131] Εικόνα 9: Α. Επίστρωση βρογχικής έκπλυσης (χρώση κατά Παπανικολάου x 800) Β. Αντίστοιχη in situ TRAP assay όπου φαίνονται τα καρκινικά κύτταρα με έντονη πυρηνική αντιδραστικότητα, στο πλακώδες ΚΠ (1) και στο αδενοκαρκίνωμα (2) [96].…”

“…Η Τa ανιχνεύτηκε στο 73% των ασθενών με ΚΠ και σε κανέναν υγιή μάρτυρα [116], ενώ σε μια άλλη μελέτη, παρόλο που η hTERT εκφράστηκε στο αίμα μόνο ενός μικρού ποσοστού ασθενών (12%), σημαντική ήταν η απουσία της σε όλους τους μάρτυρες [117]. Σε μια πρόσφατη μελέτη, με τη βοήθεια ποσοτικού προσδιορισμού του mRNA της hTERT, αναφέρθηκε υψηλή ευαισθησία και ειδικότητα (89% και 72,7% αντίστοιχα) και σημαντικά μεγαλύτερος αριθμός αντιγράφων mRNA-hTERT στον ορό ασθενών με ΚΠ, έναντι των υγιών μαρτύρων, ενώ βρέθηκε επίσης συσχέτιση μεταξύ των επίπεδων έκφρασης της hTERT στον ορό και στον καρκινικό ιστό [118].…”