The quantification of the catalytic subunit of telomerase in plasma is a prognostic factor in advanced non-small cell lung cancer (NSCLC) patients

Abstract

7052 Background: Qualitative and quantitative analysis of circulating DNA in blood is a promising non-invasive diagnostic and prognostic tool. Our aim was to study the association between the free amount in plasma of the catalytic subunit of telomerase (hTERT) and several clinical variables in advanced NSCLC patients. Methods: We examined 451 NSCLC patients in stage IIIB and IV, treated with cisplatin and docetaxel. Blood samples were collected before chemotherapy, and circulating DNA was extracted from the serum using commercial adsorption columns. The amount of free hTERT in plasma was quantified by using RT-PCR. Results: Median age was 61 years [35–82] and 84% were males. 99% had performance status 0–1. 84% were in stage IV and 16% in stage IIIB. The histological subtypes were: 32% squamous cell carcinoma, 50% adenocarcinoma, 14% anaplastic large cell, and 4% undifferentiated. 41% of the patients received second line chemotherapy. 1% achieved complete response (CR), 36% partial response (PR), 35% had stable disease (SD) and 28% progressive disease (PD). Median hTERT value was 4856 ng/ml; for patients in IIIB was 4847 ng/ml [263–964826] and 4886 ng/ml [67–4373520] in stage IV (p = 0.75). There was not association between hTERT values and response to therapy, 20588 ng/ml [122–317251] in the CR+PR group vs 50204 ng/ml [67–4373520] in the SD+PD group (p = 0.09). hTERT values were not related with the localization of the metastasis. Dividing the cohort in two sets according to hTERT median we found two significantly different groups in terms of Overall Survival (OS) and Time To Progression (TTP). Patients with hTERT <4856 ng/ml had a median TTP of 5.3 months (m) [4.4–6.1] while for hTERT >4856 ng/ml was 4.1 m [3.5–4.6], (p = 0.0009). OS when hTERT <4856 ng/ml was 10.1m [4.9–11.3] and for hTERT >4856 ng/ml was 8.4 m [7.2–9.5], (p = 0.01). In the multivariate analysis, hTERT was an independent predictive variable for TTP (HR 1.39, CI 95% 1.1–1.7, p = 0.002) and OS (HR 1.27, CI 95% 1.1–1.6, p = 0.04). Conclusions: In advanced NSCLC patients, the quantification of free circulating hTERT in plasma is an affordable and valuable prognostic marker. High plasma hTERT levels are a poor prognostic indicator for TTP and OS. No significant financial relationships to disclose.