HLA Class I Antigen Down-Regulation in Primary Ovary Carcinoma Lesions: Association with Disease Stage Marco Vitale, 1,2 Giuseppe Pelusi, 3 Beatrice Taroni, 3 Giuliana Gobbi, 1 Cristina Micheloni, 1 Rita Rezzani, 4 Francesco Donato, 5 Xinhui Wang, 6 and Soldano Ferrone 6 1 Department of Anatomy, Pharmacology and Forensic Medicine, University of Parma; 2 Institute Trapianti d’Organo e Immunocitologia-Consiglio Nazionale delle Ricerche, Unit of Bologna; 3 Department of Obstetrics and Gynaecology, University of Bologna, Bologna, Italy; Departments of 4 Biomedical Sciences and Biotechnologies and 5 Experimental and Applied Medicine, University of Brescia, Brescia, Italy; and 6 Department of Immunology, Roswell Park Cancer Institute, Buffalo, New York ABSTRACT Purpose: To investigate TAP1, TAP2, and HLA class I antigen expression in primary ovarian carcinoma lesions and to assess the clinical significance of defects in the expression of these molecules. Experimental Design: Fifty-one formalin-fixed, paraffin- embedded primary ovarian carcinoma lesions were stained with affinity-purified rabbit anti-TAP1 and anti-TAP2 anti- bodies and with anti-HLA class I heavy chain monoclonal antibody (mAb) HC-10 using the immunoperoxidase reaction. The results of immunohistochemical staining were correlated with the histopathologic characteristics of the lesions and with patients’ survival. Results: Ovarian surface epithelium, thecal cells of follicles, and stromal cells were stained by anti-TAP1, anti- TAP2, and anti-HLA class I antigen xenoantibodies with a homogeneous pattern. In contrast, no staining of lutheinic cells by these antibodies was detected. Forty-one and 32 out of 51 primary ovarian carcinoma lesions were stained by anti- TAP1 and anti-TAP2 xenoantibodies and by anti-HLA class I antigen mAb HC-10, respectively. The staining patterns by anti-TAP1 and anti-TAP2 xenoantibodies were completely concordant, but did not correlate with that by anti-HLA class I heavy chain mAb HC-10. TAP1 and TAP2 expression was associated neither with the histopathologic characteristics of the lesions nor with clinical variables. On the other hand, HLA class I antigen down-regulation was associated with disease stage: the odds ratio of stage III for HLA class I antigen negative patients was 7.6 (95% confidence interval, 1.9-30.5; P = 0.007), whereas for TAP negative patients was 5.1 (95% confidence interval, 0.9-28.4; P = 0.07). Follow up was available for 39 out of the 51 patients. Multivariate analysis showed that both grading and staging were associated with a higher risk of death, whereas TAP and HLA class I antigen phenotypes were not. Conclusions: The lack of association between TAP and HLA class I antigen expression is compatible with the possibility that multiple mechanisms underlie HLA class I antigen down-regulation in primary ovarian carcinoma lesions. The potential role of immunologic events in the clinical course of ovarian carcinoma suggests that the association between HLA class I antigen down-regulation and disease progression may reflect the escape of tumor cells from immune recognition and destruction. INTRODUCTION The limited efficacy of conventional chemotherapy in most malignant diseases has provided the impetus to develop and implement alternative strategies for the treatment of malignant diseases. Among them, immunotherapy has attracted much attention in recent years because of the revival of the role of immune surveillance in the control of tumor growth (1) and because of the significant progress in the identification of human tumor-associated antigens (TAA; ref. 2) and in the characteriza- tion of the molecular steps leading to an immune response (3). The emphasis has been on T cell–based immunotherapy, because T cells are generally believed to play the major, if not the only role in the control of tumor growth (4). The outcome of T cell – based immunotherapy of malignant diseases is influenced by many variables. Among them, an important role is played by HLA class I antigen-TAA–derived peptide complexes expressed on tumor cells, because they mediate the recognition of tumor cells by CTL. In humans, like in other animal species, HLA class I antigen-TAA –derived peptide complexes are generated, trans- ported to the cell membrane, and presented to CTL through a series of sequential steps. The latter include (i) cleavage in the cytoplasm of proteins by proteasome, which modulates its activity by replacing the constitutive subunits h1, h2, and h5 with the immunosubunits LMP2, LMP10, and LMP7, respec- tively, upon exposure to IFN-g (5); (ii) transport by the transporter associated with antigen processing TAP1-TAP2 complex of peptides to the endoplasmic reticulum (6), and (iii) loading of peptides on h 2 microglobulin (h 2 m)-HLA class I heavy chain complex (7, 8). The peptide-h 2 m-HLA class I heavy chain complex then travels to the cell membrane and peptides are presented to CTL. Therefore, abnormalities in the expression and/or function of antigen processing machinery components and/or HLA class I antigens may lead to defects in the expression of HLA class I antigen-peptide complexes and eventually in the recognition of targets by CTL. This mechanism Received 4/2/04; revised 10/6/04; accepted 10/14/04. Grant Support: Associazione Italiana per la Ricerca sul Cancro and Fondazione Cassa di Risparmio di Parma & Piacenza grants and Public Health Service grant CA67108 (National Cancer Institute, Department of Health and Human Services). 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: Soldano Ferrone, Department of Immunology, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263. Phone: 845-8534; Fax: 845-7613; E-mail: soldano.ferrone@roswellpark.org. I2005 American Association for Cancer Research. Vol. 11, 67–72, January 1, 2005 Clinical Cancer Research 67 Research. on October 6, 2021. © 2005 American Association for Cancer clincancerres.aacrjournals.org Downloaded from