OX40 expression enhances the prognostic significance of CD8 positive lymphocyte infiltration in colorectal cancer

// Benjamin Weixler 1 , Eleonora Cremonesi 2 , Roberto Sorge 3 , Manuele Giuseppe Muraro 2 , Tarik Delko 1 , Christian A. Nebiker 1 , Silvio Däster 1 , Valeria Governa 2 , Francesca Amicarella 2 , Savas D. Soysal 1,2 , Christoph Kettelhack 1 , Urs W. von Holzen 1,4 , Serenella Eppenberger-Castori 5 , Giulio C. Spagnoli 2 , Daniel Oertli 1 , Giandomenica Iezzi 2 , Luigi Terracciano 5 , Luigi Tornillo 5 , Giuseppe Sconocchia 6,* and Raoul A. Droeser 1,2,* 1 Department of Surgery, University Hospital Basel, Basel, Switzerland 2 Institute of Surgical Research and Hospital Management (ICFS) and Department of Biomedicine, University Hospital Basel, Basel, Switzerland 3 Department of Systems Medicine, University of Rome “Tor Vergata”, Rome, Italy 4 IU Health Goshen Center for Cancer Care, Goshen, IN, USA 5 Institute of Pathology, University Hospital Basel, Basel, Switzerland 6 Institute of Translational Pharmacology, National Research Council, Rome, Italy * These authors have contributed equally to this work Correspondence to: Raoul A. Droeser, email: // Keywords : OX40, CD8, colorectal cancer, prognosis, microenvironment Received : August 15, 2015 Accepted : September 18, 2015 Published : September 30, 2015 Abstract Background: OX40 is a TNF receptor family member expressed by activated T cells. Its triggering by OX40 ligand promotes lymphocyte survival and memory generation. Anti-OX40 agonistic monoclonal antibodies (mAb) are currently being tested in cancer immunotherapy. We explored the prognostic significance of tumor infiltration by OX40+ cells in a large colorectal cancer (CRC) collective. Methods: OX40 gene expression was analyzed in 50 freshly excised CRC and corresponding healthy mucosa by qRT-PCR. A tissue microarray including 657 clinically annotated CRC specimens was stained with anti-OX40, -CD8 and -FOXP3 mAbs by standard immunohistochemistry. The CRC cohort was randomly split into training and validation sets. Correlations between CRC infiltration by OX40+ cells alone, or in combination with CD8+ or FOXP3+ cells, and clinical-pathological data and overall survival were comparatively evaluated. Results: OX40 gene expression in CRC significantly correlated with FOXP3 and CD8 gene expression. High CRC infiltration by OX40+ cells was significantly associated with favorable prognosis in training and validation sets in univariate, but not multivariate, Cox regression analysis. CRC with OX40 high /CD8 high infiltration were characterized by significantly prolonged overall survival, as compared to tumors with OX40 low /CD8 high , OX40 high /CD8 low or OX40 low /CD8 low infiltration in both uni- and multivariate analysis. In contrast, prognostic significance of OX40+ and FOXP3+ cell infiltration was not enhanced by a combined evaluation. Irrespective of TNM stage, CRC with OX40 high /CD8 high density infiltrates showed an overall survival similar to that of all stage I CRC included in the study. Conclusions: OX40 high /CD8 high density tumor infiltration represents an independent, favorable, prognostic marker in CRC with an overall survival similar to stage I cancers.