Human Cancer Biology Tumor-Expressed B7-H1 and B7-DC in Relation to PD-1+ T-Cell Infiltration and Survival of Patients with Cervical Carcinoma

Purpose: The interaction between programmed cell death 1 (PD-1), expressed by activated effector or regulatory T cells, and B7-H1 (PD-L1) and B7-DC (PD-L2) results in the inhibition of T-cell function. The aim of this study was to determine B7-H1, B7-DC, and PD-1 expression in cervical carcinoma. Experimental Design: A tissue microarray of a well-defined group of 115 patients was stained with antibodies against B7-H1 and B7-DC. Three-color fluorescent immunohistochemistry was used to study the number and phenotype of tumor-infiltrating T cells expressing PD-1. Additional analyses consisted of in vitro T-cell suppression assays. Results: B7-H1 was expressed in 19%, and B7-DC was expressed by 29% of the 115 tumors. PD-1 was expressed by more than half of both the infiltrating CD8+ T cells and CD4+Foxp3+ T cells, irrespective of B7-H1 or B7-DC expression by tumors. The expression of B7-H1 did not show a direct impact on patient survival. However, subgroup analysis revealed that patients with a relative excess of infiltrating regulatory T cells displayed a better survival when the tumor was B7-H1 positive (P = 0.033). Additional studies showed that the presence of B7-H1 during the activation of CD4+Foxp3+ regulatory T cells impaired their suppressive function in a functional in vitro assay. Conclusions: B7-H1 is expressed on only a minority of cervical cancers and does not influence the survival of patients with cervical cancer. PD-1 is expressed by a vast number of infiltrating CD8 T cells, suggesting that blocking of PD-1 could have therapeutic potential in cervical cancer patients. (Clin Cancer Res 2009;15(20):6341–7) Cervical cancer is the second most common cancer in women worldwide (1). It develops as a result of an uncontrolled persistent infection with a high-risk type of human papilloma virus (HPV), in particular, types HPV16 and HPV18 (2). The occurrence of HPV-induced cancer is strongly associated with failure to mount a strong HPV-specific type 1 T-helper and cytotoxic Tlymphocyte response (3–5), the lack of CD8+ T cells migrating into the tumor cell nests, the induction of HPV16-specific regulatory T cells, and the influx of regulatory T cells into the tumor (6, 7). Moreover, the ratio between the tumor-infiltrating CD8+ T cells and coinfiltrating CD4+Foxp3+ regulatory T cells is an independent prognostic factor for overall survival (8), indicating the key role of these different types of T cells in cervical cancer. Activated T cells can express the programmed cell death 1 (PD-1) receptor, which can bind B7-H1 (PD-L1) and B7-DC (PD-L2). B7-H1 could be induced to express by a wide variety of immune cells and nonhematopoetic cell types, whereas B7DC is expressed mainly on activated macrophages and dendritic cells (9). Upon simultaneous engagement of both, the T-cell receptor and PD-1–negative immunoregulatory signals are transferred to the T cells, resulting in a decreased effector response and T-cell tolerance (10). PD-1/B7-H1 interactions have been shown to inhibit a wide range of immune responses against pathogen, tumor, and self-antigens (11, 12). More recently, it has been reported that B7-H1 and B7-DC are exploited by tumors to evade immune responses. B7-H1 is found to express on cell surface in most human cancers, and this expression was correlated with poor clinical prognosis in renal, gastric, ovarian, breast, and esophageal carcinomas (13–17). The role of B7-DC in the suppression of immune responses remains controversial (18). Because of the strong association between tumor-infiltrating lymphocytes (TIL) and the prognosis of cervical cancer (6, 8) and the fact that PD-1 has been reported to be expressed by tumor-infiltrating CD8+ Authors' Affiliations: Departments of Center for Human and Clinical Genetics, Immunohematology and Blood Transfusion, Clinical Oncology, Pathology, and Gynecology, Leiden University Medical Center, The Netherlands; and Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland Received 6/29/09; revised 7/22/09; accepted 7/28/09; published OnlineFirst 10/13/09. Grant support: Centre for Medical Systems Biology, a Centre of Excellence supported by the Netherlands Genomics Initiative (C.J.M. Melief; J.M. Boer), and grants fromNetherlandsOrganisation for Scientific Research (NWOZon/ Mw) 917.56.311 and Dutch Cancer Society UL2007-3848 (S.H. van der Burg). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Requests for reprints: Sjoerd H. van der Burg, Department of Clinical Oncology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands. Phone: 31-71-5261180; Fax: 31-71-5266760; E-mail: [email protected]. F 2009 American Association for Cancer Research. doi:10.1158/1078-0432.CCR-09-1652 6341 Clin Cancer Res 2009;15(20) October 15, 2009 www.aacrjournals.org Published Online First on October 13, 2009 as 10.1158/1078-0432.CCR-09-1652 Research. on May 1, 2017. © 2009 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Published OnlineFirst October 13, 2009; DOI: 10.1158/1078-0432.CCR-09-1652