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Poster display

3661 - Prognostic relevance of molecular characterization of circulating tumor cells (CTC) in head and neck squamous cell carcinoma (HNSCC)


09 Oct 2016


Poster display


George Koutsodontis


Annals of Oncology (2016) 27 (6): 328-350. 10.1093/annonc/mdw376


G. Koutsodontis1, A. Strati2, G. Papaxoinis3, N. Charalambakis1, I. Kotsantis1, P. Oikonomopoulou1, L. Hoxhallari1, E. Lianidou2, A. Psyrri1

Author affiliations

  • 1 Oncology Unit, Attikon University Hospital, 12462 - Athens/GR
  • 2 Chemistry, National and Kapodistrian University of Athens, Athens/GR
  • 3 Medical Oncology, The Christie NHS Foundation Trust, M20 4BX - Manchester/GB


Abstract 3661


CTCs are considered indicators of residual disease and thus are associated with an increased risk of metastasis. Moreover, hypoxic microenviroment, a major feature of HNSCC, plays a pivotal role in the emergence of CTCs and cancer stem cells. Although rare and exposed to immune mediated destruction, these cells manage to evade the immune system of the host. Therefore, a better understanding of the immunogenicity of these cells and their cross talk with immune cells may shed light to potential immunotherapy opportunities in HNSCC.


We quantified by RT-qPCR TWIST1, Stem Cell (SC) markers (CD24, CD44, ALDH1) and PD-L1 in immunomagnetically positively selected CTCs from 90 locally advanced (LA) HNSCC, 33 recurrent/metastatic (R/M) HNSCC and 20 healthy individuals. Patients (pts) with LA disease were treated with cisplatin chemoradiotherapy +/- TPF induction chemotherapy (IC). We assessed the expression of TWIST1, SC markers and PD-L1 at baseline, after completion of IC, at end of chemoradiotherapy and at relapse in pts with LA disease and at baseline in pts with R/M HNSCC. To assess univariate differences of study parameters according to gene expression chi-square test was used for the categorical clinicopathological variables, while patients' survival curves according to gene expression were generated by Kaplan-Meier analysis and tested for significance using the Mantel-Cox log-rank test.


Pts with PD-L1 positive CTCs at the end of treatment had shorter Progression Free Survival (PFS) (p 


Liquid biopsies could identify pts at high risk for relapse after adjuvant chemoradiation that may derive benefit from adjuvant therapy in LA disease. PD-L1 expression in CTCs at the end of treatment is a potential biomarker for pt selection for treatment with adjuvant PD1 checkpoint inhibitors.

Clinical trial identification

Legal entity responsible for the study

Attikon General University Hospital, National and Kapodistrian University of Athens


National and Kapodistrian University of Athens


All authors have declared no conflicts of interest.

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