Purpose: To investigate the impact of hypoxia-induced gene expression and cancer stem cell (CSC) marker expression on outcome of postoperative cisplatin-based radiochemotherapy (PORT-C) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC).Experimental Design: Expression of the CSC markers CD44, MET, and SLC3A2, and hypoxia gene signatures were analyzed in the resected primary tumors using RT-PCR and nanoString technology in a multicenter retrospective cohort of 195 patients. CD44 protein expression was further analyzed in tissue microarrays. Primary endpoint was locoregional tumor control.Results: Univariate analysis showed that hypoxia-induced gene expression was significantly associated with a high risk of locoregional recurrence using the 15-gene signature (P ¼ 0.010) or the 26-gene signature (P ¼ 0.002). In multivariate analyses, in patients with HPV16 DNA-negative but not with HPV16 DNA-positive tumors the effect of hypoxia-induced genes on locoregional control was apparent (15-gene signature: HR 4.54, P ¼ 0.006; 26-gene signature: HR 10.27, P ¼ 0.024). Furthermore, MET, SLC3A2, CD44, and CD44 protein showed an association with locoregional tumor control in multivariate analyses (MET: HR 3.71, P ¼ 0.016; SLC3A2: HR 8.54, P ¼ 0.037; CD44: HR 3.36, P ¼ 0.054; CD44 protein n/a because of no event in the CD44-negative group) in the HPV16 DNA-negative subgroup.Conclusions: We have shown for the first time that high hypoxia-induced gene expression and high CSC marker expression levels correlate with tumor recurrence after PORT-C in patients with HPV16 DNA-negative HNSCC. After validation in a currently ongoing prospective trial, these parameters may help to further stratify patients for individualized treatment de-escalation or intensification strategies.

We examined the prognostic role of PD-1+ and CD8+ tumor infiltrating lymphocytes (TILs), and PD-L1+ cells in patients with squamous cell carcinoma of the head and neck (SCCHN) treated with surgery and postoperative chemoradiotherapy (CRT). FFPE samples from 161 patients were immunohistochemically stained for PD-1, CD8 and PD-L1. The immune marker expression was correlated with clinicopathologic characteristics, and overall survival (OS), local progression-free survival (LPFS) and distant metastases free-survival (DMFS), also in the context of HPV16 DNA/p16 status. The median follow-up was 48 months (range: 4-100). The 2-year-OS was 84.1% for the entire cohort. High PD-1 and PD-L1 expression were more common in patients with positive HPV16 DNA (p < 0.001 and p = 0.008, respectively) and high infiltration by CD8+ TILs (p < 0.001 for both markers). High PD-L1 expression correlated with superior OS (p = 0.025), LPFS (p = 0.047) and DMFS (p = 0.048) in multivariable analysis, whereas no significance could be demonstrated for PD-1. Patients with CD8 /PD-L1 expression had favorable outcome (p < 0.001 for all endpoints) compared to other groups. We validated the superior OS data on CD8 /PD-L1 using the Cancer Genome Atlas TCGA dataset (n = 518; p = 0.032). High PD-L1 expression was a favorable prognostic marker in HPV16-negative but not HPV16-positive patients. In conclusion, HPV-positive tumors showed higher expression of immune markers. PD-L1 expression constitutes an independent prognostic marker in SCCHN patients post-adjuvant CRT. In conjunction with CD8 status, these data provide an important insight on the immune contexture of SCCHN and are directly relevant for future treatment stratification with PD-1/PD-L1 immune checkpoint inhibitors to complement CRT.

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(2013) A strategy for multimodal deformable image registration to integrate PET/MR into radiotherapy treatment planning,

We and others have demonstrated already that TRAIL (TNF-related apoptosis-inducing ligand) is a very promising candidate for molecular targeted anticancer therapy, especially when combined with ionizing radiation or other DNA-damaging agents. Agonist monoclonal antibodies that activate and are specific for the death signaling TRAIL receptors are an alternative method to stimulate the programmed cell death pathway. Phase 1 clinical trials have subsequently been conducted and shown a very good tolerability of these antibodies. In order to assess the efficacy of TRAIL receptor stimulation to induce cell death by this alternate method, we studied the combination of the agonistic-TRAIL receptor antibodies HGS-ETR1 and HGS-ETR2 with radiation in vitro and in vivo. Induction of apoptosis after combined treatment with TRAIL receptor antibodies HGS-ETR1 and/or HGS-ETR2 (0.01, 0.1, 1.0 mg/ml) and irradiation with 2, 5 or 10 Gy was determined by fluorescence microscopy and Western blot analysis of caspase-8 and PARP. The colorectal tumour cell lines Colo 205, HCT 116 and HCT-15 were used for in vitro experiments. Growth delay experiments were performed with combined treatment with fractionated irradiation (days 1-5 and 3 Gy single dose/day) and the receptor antibodies (intraperitonially, three different concentrations, application on days 1, 4 and 8) on Colo 205 xenograft-bearing NMRI (nu/nu) nude mice. HGS-ETR1 and HGS-ETR2 induced apoptotic cell death in a dose-dependent fashion and significantly increased cell death in combination with irradiation in vitro when compared to either irradiation or antibody treatment alone. The efficacy of the combined treatment seems to be at least partially Bax-dependent. Similar to the results from cell culture experiments, in vivo experiments demonstrated a dose-dependent delay in tumour growth after combined treatment. In vivo, in the Colo205 xenograft model, HGS-ETR2 revealed a higher activity than HGS-ETR1. This is the first study to demonstrate significant efficacy of combined treatment with the monoclonal agonistic TRAIL receptor antibodies HGS-ETR1 and HGS-ETR2 and ionising radiation in in vitro and in vivo models. We postulate that HGS-ETR1 and HGS-ETR2 will be very promising new agents in the field of molecular targeted multi-modality anticancer therapy.

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