@article {44733,
	title = {Prognostic significance of PD-L1 expression on circulating tumor cells in patients with head and neck squamous cell carcinoma},
	journal = {Annals of Oncology},
	volume = {28},
	number = {8},
	year = {2017},
	note = {Strati, AKoutsodontis, GPapaxoinis, GAngelidis, IZavridou, MEconomopoulou, PKotsantis, IAvgeris, MMazel, MPerisanidis, CSasaki, CAlix-Panabieres, CLianidou, EPsyrri, AengEngland2017/08/26 06:00Ann Oncol. 2017 Aug 1;28(8):1923-1933. doi: 10.1093/annonc/mdx206.},
	month = {Aug 1},
	pages = {1923-1933},
	abstract = {BACKGROUND: Successful application of programmed death 1 (PD1) checkpoint inhibitors in the clinic may ultimately benefit from appropriate patient selection based upon predictive biomarkers. Molecular characterization of circulating tumor cells (CTC) is crucial for the investigation of molecular-targeted therapies while predictive biomarkers for response to PD1 checkpoint inhibitors are lacking. We sought to assess whether overexpression of PD-L1 in CTCs could be detected at baseline and at different timepoints during treatment in a prospective cohort of head and neck squamous cell carcinoma (HNSCC) patients and used to predict clinical outcome after treatment with curative intent. PATIENTS AND METHODS: We developed a highly sensitive, specific and robust RT-qPCR assay for PD-L1 mRNA expression in EpCAM(+) CTCs. In a prospective cohort of 113 locally advanced HNSCC patients treated with curative intent we evaluated PD-L1 expression in the EpCAM(+) CTC fraction at baseline, after 2 cycles of induction chemotherapy (week 6) and at the end of concurrent chemoradiotherapy (week 15). RESULTS: PD-L1 overexpression was found in 24/94 (25.5\%) patients at baseline, 8/34 (23.5\%) after induction chemotherapy and 12/54 (22.2\%) patients at the end of treatment. Patients with CTCs overexpressing PD-L1 at end of treatment had shorter progression-free survival (P = 0.001) and overall survival (P \&lt; 0.001). Multivariate analysis revealed that PD-L1 overexpression at end of treatment was independent prognostic factor for progression-free survival and overall survival. The absence of PD-L1 overexpression at the end of treatment was strongly associated with complete response with an odds ratio = 16.00 (95\% CI = 2.76-92.72, P = 0.002). CONCLUSIONS: We demonstrate that detection of CTCs overexpressing PD-L1 is feasible and may provide important prognostic information in HNSCC. Our results suggest that adjuvant PD1 inhibitors deserve evaluation in HNSCC patients in whom PD-L1(+) CTCs are detected at the end of curative treatment.},
	keywords = {Aged, B7-H1 Antigen/genetics/*metabolism, cancer immunotherapy, Carcinoma, Squamous Cell/*blood/pathology, checkpoint inhibitors, circulating tumor cells, Female, Head and Neck Neoplasms/*blood/pathology, head and neck squamous cell carcinoma, Humans, Limit of Detection, liquid biopsy, Male, Middle Aged, Neoplastic Cells, Circulating/*metabolism, Pd-l1, polymerase chain reaction, Prognosis, Reproducibility of Results, Squamous Cell Carcinoma of Head and Neck, Survival Analysis},
	isbn = {1569-8041 (Electronic)0923-7534 (Linking)},
	author = {Strati,A. and Koutsodontis,G. and Papaxoinis, G. and Angelidis, I. and Zavridou, M. and Economopoulou, P. and Kotsantis,I. and Avgeris, M. and Mazel, M. and Perisanidis, C. and Sasaki, C. and Alix-Panabieres, C. and Lianidou,E. and Psyrri, A.}
}
