CT7 (MAGE-C1) antigen expression in normal and neoplastic tissues

Langerhans dendritic cell vaccines bearing mRNA-encoded tumor antigens induce anti-myeloma immunity after autotransplant

Triple antigen–bearing mRNA-electroporated autologous LC vaccines after ASCT for MM are safe and immunogenic.

Posttransplant vaccination targeting residual disease is an immunotherapeutic strategy to improve antigen-specific immune responses and prolong disease-free survival after autologous stem cell transplantation (ASCT) for multiple myeloma (MM). We conducted a phase 1 vaccine trial to determine the safety, toxicity, and immunogenicity of autologous Langerhans-type dendritic cells (LCs) electroporated with CT7, MAGE-A3, and Wilms tumor 1 (WT1) messenger RNA (mRNA), after ASCT for MM. Ten patients received a priming immunization plus 2 boosters at 12, 30, and 90 days, respectively, after ASCT. Vaccines contained 9 × 10⁶ mRNA-electroporated LCs. Ten additional patients did not receive LC vaccines but otherwise underwent identical ASCT and supportive care. At 3 months after ASCT, all patients started lenalidomide maintenance therapy. Vaccinated patients developed mild local delayed-type hypersensitivity reactions after booster vaccines, but no toxicities exceeded grade 1. At 1 and 3 months after vaccines, antigen-specific CD4 and CD8 T cells increased secretion of proinflammatory cytokines (interferon-γ, interleukin-2, and tumor necrosis factor-α) above prevaccine levels, and also upregulated the cytotoxicity marker CD107a. CD4 and CD8 T-cell repertoire analysis showed a trend for increased clonal expansion in the vaccine cohort, which was more pronounced in the CD4 compartment. Although not powered to assess clinical efficacy, treatment responses favored the vaccine arm. Triple antigen–bearing mRNA-electroporated autologous LC vaccination initiated at engraftment after ASCT, in conjunction with standard lenalidomide maintenance therapy for MM, is safe and induces antigen-specific immune reactivity. This trial was registered at www.clinicaltrials.gov as #NCT01995708.

Immunohistochemical Detection of Cancer-Testis Antigen PRAME

Cancer-testis (CT) antigens were identified by their ability to elicit T- or B-cell immune responses in the autologous host. They are typically expressed in a wide variety of neoplasms and in normal adult tissues are restricted to testicular germ cells. PReferentially expressed Antigen of Melanoma (PRAME) is a member of the family of nonclassical CT antigens being expressed in a few other normal tissues besides testis. Interestingly, knowledge about the protein expression of many CT antigens is still incomplete due to the limited availability of reagents for their immunohistochemical detection. Here, we tested several commercially available serological reagents and identified a monoclonal antibody suitable for the immunohistochemical detection of PRAME in formalin-fixed paraffin-embedded specimens. We also tested a wide array of normal and neoplastic tissues. PRAME protein expression in normal tissues is congruent with original molecular data being present in the testis, and at low levels in the endometrium, adrenal cortex, and adult as well as fetal ovary. In tumors, there is diffuse PRAME immunoreactivity in most metastatic melanomas, myxoid liposarcomas, and synovial sarcomas. Other neoplasms such as seminomas and carcinomas of various origins including endometrial, serous ovarian, mammary ductal, lung, and renal showed an intermediate proportion of cases and variable extent of tumor cells positive for PRAME protein expression. As seen with other CT antigens, hepatocellular and colorectal carcinoma, Leydig cell tumors, mesothelioma, and leiomyosarcoma are poor expressers of PRAME.

Expression of cancer/testis antigens in cutaneous melanoma: a systematic review

The cancer/testis antigen (CTA) family is a group of antigens whose expression is restricted to male germline cells of the testis and various malignancies. This expression pattern makes this group of antigens potential targets for immunotherapy. The aim of this study was to create an overview of CTA expressed by melanoma cells at mRNA and protein level. A systematic literature search was performed in Medline (PubMed) and Embase from inception up to and including February 2018. Studies were screened for eligibility by two independent reviewers. A total of 65 full-text articles were included in the final analysis. A total of 48 CTA have been studied in melanoma. Various CTA show different expression rates in primary and metastatic tumours. Of the 48 CTA, the most studied were MAGE-A3, MAGE-A1, NY-ESO-1, MAGE-A4, SSX2, MAGE-A2, MAGE-C1/CT7, SSX1, MAGE-C2/CT10 and MAGE-A12. On average, MAGE-A3 mRNA is present in 36% of primary tumours, whereas metastatic tumours have an expression rate of 55-81%. The same applies to the protein expression rate of MAGE-A3 in primary tumours, which is reported to be at 15-37%, whereas metastatic tumours have a higher expression rate of 25-70%. This trend of increased expression in metastases compared with primary tumours is observed with MAGE-A1, MAGE-A2, MAGE-A4, MAGE-A12 and NY-ESO-1. Many CTA are expressed on melanoma. This review provides an overview of the expression frequency of CTAs in melanoma and may aid in identifying CTA as the therapeutic target for immunotherapy.

[Expression of cancer testis (CT) antigens in pediatric and adolescent melanomas]

BACKGROUND

One of the main problems in the diagnostics of pediatric melanomas is the differentiation from benign dermal lesions typical for this age group, such as Spitz nevus. The biological behavior of pediatric melanomas differs considerably from that of melanomas in adults.

MATERIAL AND METHODS

Cancer testis (CT) antigens are named after their typical expression pattern since they are present in various types of malignant tumors but in normal adult tissues are solely expressed in testicular germ cells. Because of this tumor-associated expression pattern, CT antigens are regarded as potential targets for vaccine-based immunotherapy of cancer and might be used as diagnostic tools in surgical pathology. In adults, melanoma is among the tumors showing a high incidence of CT antigen expression; however, while there is ample knowledge about adult melanomas, little is known about the presence of CT antigens in pediatric melanomas. Consequently, the expression of CT antigens MAGE-A1, MAGE-A4, CT7/MAGE-C1, NY-ESO-1, and GAGE was analyzed in a series of pediatric melanomas. The study was restricted to cases of metastatic disease and/or fatal outcome. A total of 12 cases were available and immunohistochemically analyzed with monoclonal antibodies (mAb).

RESULTS

The expression of CT antigens was generally low and present in only 4 of 12 cases. This is in stark contrast to the expression of these antigens in adult melanomas. Moreover, the extent of expression was very limited with most cases showing only a focal CT antigen expression and only marked in very small tumor areas (<5%).

CONCLUSION

Despite the low case numbers this study indicates that CT antigens are most likely not useful as diagnostic markers in pediatric melanomas or as targets for vaccine-based immunotherapy. It supports the notion that pediatric melanomas show a different biological behavior than their adult counterparts.

Expression of cancer/testis antigens MAGE-A, MAGE-C1, GAGE and CTAG1B in benign and malignant thyroid diseases

Despite considerable advances in the understanding of thyroid gland biology, correctly diagnosing thyroid nodules and treating high-grade thyroid carcinoma remains challenging. Cancer/testis (CT) antigens have emerged as potential diagnostic tools as well as targets of potential cancer vaccinations. In the present study, a total of 117 patients who underwent surgical therapy for thyroid disease were available for analysis. The expression levels of melanoma-associated antigen (MAGE) A, MAGE-C1/CT7, cancer/testis antigen 1B (CTAG1B) and G antigen (GAGE) were analyzed by immunohistochemistry. None of the CT antigens were expressed in the normal thyroid or goiter. In papillary and follicular carcinoma, MAGE-A was present in 8.1% of cases, GAGE in 10.8% and CT/7MAGE-C1 and CTAG1B in 2.7% each. In medullary carcinoma, CT antigen expression was as follows: MAGE-A in 42.9% of patients; MAGE-C1/CT7 in 46.5%; GAGE in 92.9%; and CTAG1B in 3.6%. A statistically significant association was observed between the expression of G MAGE-C1/CT7 and patient gender as well as patient clinical stage (P=0.029 and 0.031, respectively). In poorly differentiated and anaplastic carcinoma cases, CT antigen expression was as follows: MAGE-A in 61.8% of cases; MAGE-C1 in 57.1%; GAGE in 66.7%; and CTAG1B in 14.4%. There was a statistically significant association between expression of GAGE and gender (P=0.043). However, there was no association between CT antigen expression and patient survival in any of the tumor entities analyzed. The current study identified a distinct expression pattern of CT antigens in malignant thyroid tumors indicating that CT antigens have the potential to outperform existing thyroid cancer biomarkers. The prevalence of CT antigens in high-grade carcinomas suggests that they serve an important biological role within malignant tumors.

A Comprehensive Guide to the MAGE Family of Ubiquitin Ligases

Melanoma antigen (MAGE) genes are conserved in all eukaryotes and encode for proteins sharing a common MAGE homology domain. Although only a single MAGE gene exists in lower eukaryotes, the MAGE family rapidly expanded in eutherians and consists of more than 50 highly conserved genes in humans. A subset of MAGEs initially garnered interest as cancer biomarkers and immunotherapeutic targets due to their antigenic properties and unique expression pattern that is primary restricted to germ cells and aberrantly reactivated in various cancers. However, further investigation revealed that MAGEs not only drive tumorigenesis but also regulate pathways essential for diverse cellular and developmental processes. Therefore, MAGEs are implicated in a broad range of diseases including neurodevelopmental, renal, and lung disorders, and cancer. Recent biochemical and biophysical studies indicate that MAGEs assemble with E3 RING ubiquitin ligases to form MAGE-RING ligases (MRLs) and act as regulators of ubiquitination by modulating ligase activity, substrate specification, and subcellular localization. Here, we present a comprehensive guide to MAGEs highlighting the molecular mechanisms of MRLs and their physiological roles in germ cell and neural development, oncogenic functions in cancer, and potential as therapeutic targets in disease.

The MAGE protein family and cancer

The Melanoma Antigen Gene (MAGE) protein family is a large, highly conserved group of proteins that share a common MAGE homology domain. Intriguingly, many MAGE proteins are restricted in expression to reproductive tissues, but are aberrantly expressed in a wide variety of cancer types. Originally discovered as antigens on tumor cells and developed as cancer immunotherapy targets, recent literature suggests a more prominent role for MAGEs in driving tumorigenesis. This review will highlight recent developments into the function of MAGEs as oncogenes, their mechanisms of action in regulation of ubiquitin ligases, and outstanding questions in the field.

Intratumoral Heterogeneity of MAGE-C1/CT7 and MAGE-C2/CT10 Expression in Mucosal Melanoma

Mucosal melanoma is a rare disease, which differs from its cutaneous counterpart genetically and for its clinical behaviour. Moreover this is a heterogeneous disease based on the tissue of origin. As CT7 and CT10 are highly expressed in cutaneous melanoma and are immunogenic in this disease, we analysed their expression throughout the different subtypes of mucosal melanoma and tumor development. We detected a frequent expression of CT7 in primaries and corresponding metastases (55%) as well as for CT10 (30%). This expression resulted to be heterogeneous in the same tumor specimen and moreover influenced by the tissue of origin. Our results support the role of these antigens in immunotherapy for mucosal melanoma.

Epigenetic mechanisms underlying the dynamic expression of cancer-testis genes, PAGE2, -2B and SPANX-B, during mesenchymal-to-epithelial transition

Cancer-testis (CT) genes are expressed in various cancers but not in normal tissues other than in cells of the germline. Although DNA demethylation of promoter-proximal CpGs of CT genes is linked to their expression in cancer, the mechanisms leading to demethylation are unknown. To elucidate such mechanisms we chose to study the Caco-2 colorectal cancer cell line during the course of its spontaneous differentiation in vitro, as we found CT genes, in particular PAGE2, -2B and SPANX-B, to be up-regulated during this process. Differentiation of these cells resulted in a mesenchymal-to-epithelial transition (MET) as evidenced by the gain of epithelial markers CDX2, Claudin-4 and E-cadherin, and a concomitant loss of mesenchymal markers Vimentin, Fibronectin-1 and Transgelin. PAGE2 and SPAN-X up-regulation was accompanied by an increase in Ten-eleven translocation-2 (TET2) expression and cytosine 5-hydroxymethylation as well as the disassociation of heterochromatin protein 1 and the polycomb repressive complex 2 protein EZH2 from promoter-proximal regions of these genes. Reversal of differentiation resulted in down-regulation of PAGE2, -2B and SPANX-B, and induction of epithelial-to-mesenchymal transition (EMT) markers, demonstrating the dynamic nature of CT gene regulation in this model.

MAGE-specific T cells detected directly ex-vivo correlate with complete remission in metastatic breast cancer patients after sequential immune-endocrine therapy

Studies suggest that conventional cancer therapies given after immunotherapy (IT) can boost antitumor immunity and possibly improve response rates and progression-free survival. We report two cases of metastatic breast cancer with durable complete responses (CRs) after sequential IT and endocrine therapy. Immune analyses of these long-term disease-free breast cancer patients previously treated with imiquimod (IMQ) suggest in-situ vaccination is achieved by topical application of the TLR-7 agonist directly onto tumors. Furthermore, IT-induced antigen-specific T cells were expanded by subsequent endocrine therapy and correlated with response, persisting > 2 years. Our findings therefore suggest that the induction/boosting of polyfunctional tumor antigen-specific T in response to sequential immune endocrine therapy and detected directly ex-vivo can serve as a peripheral blood biomarker for true clinical benefit.

Cancer-testis antigen 7 expression and immune responses following allogeneic stem cell transplantation for multiple myeloma

Cancer-testis antigen 7 (CT7) is the most frequently and consistently expressed MAGE antigen in multiple myeloma, exhibits tissue-restricted expression, and is an independent negative prognostic factor for multiple myeloma. We sought to characterize CT7 protein expression in the bone marrow of patients with multiple myeloma undergoing allogeneic T cell-depleted hematopoietic stem cell transplantation (alloTCD-HSCT), and to examine the significance of CT7-specific cellular immune responses. We further aimed to determine CT7-derived immunogenic epitopes and their associated allelic restrictions. CT7 protein expression in neoplastic CD138(+) plasma cells was evaluated by immunohistochemistry in bone marrow biopsies from 10 patients. CT7 was present in 8 of 10 patients. Longitudinal analyses of the 10 patients revealed an association between CT7 expression and prognosis. Longitudinal monitoring of CT7-specific T cells revealed an association between increased frequencies of CT7-specific T cells and reductions in specific myeloma markers. Epitope-specific reactivity to the nonamer FLAMLKNTV was detected by intracellular IFNγ assay in peripheral blood (PB) and bone marrow-derived T cells from HLA-A*0201(+) patients. Serial monitoring of PB CT7-specific T-cell frequencies in 4 HLA-A*0201(+) patients by HLA-A*0201-CT7(1087-1095) tetramer staining revealed an association with disease course. Phenotypic analyses revealed bone marrow enrichment for central memory CT7-specific T cells, while effector memory cells dominated the PB. Together, these findings support the development of immunotherapeutic strategies that aim to enhance CT7-directed immune responses for the treatment of multiple myeloma.

The clinical value of the quantitative detection of four cancer-testis antigen genes in multiple myeloma

BACKGROUND

Cancer-testis (CT) antigen genes might promote the progression of multiple myeloma (MM). CT antigens may act as diagnostic and prognostic markers in MM, but their expression levels and clinical implications in this disease are not fully understood. This study measured the expression levels of four CT antigen genes in Chinese patients with MM and explored their clinical implications.

METHODS

Real-time quantitative polymerase chain reaction (qPCR) was used to quantify the expression of MAGE-C1/CT7, MAGE-A3, MAGE-C2/CT10 and SSX-2 mRNA in 256 bone marrow samples from 144 MM patients.

RESULTS

In the newly diagnosed patients, the positive expression rates were 88.5% for MAGE-C1/CT7, 82.1% for MAGE-C2/CT10, 76.9% for MAGE-A3 and 25.6% for SSX-2. The expression levels and the number of co-expressed CT antigens correlated significantly with several clinical indicators, including the percentage of plasma cells infiltrating the bone marrow, abnormal chromosome karyotypes and the clinical course.

CONCLUSION

MAGE-C1/CT7, MAGE-A3, MAGE-C2/CT10 and SSX-2 expression levels provide potentially effective clinical indicators for the auxiliary diagnosis and monitoring of treatment efficacy in MM.

Centrosomal localisation of the cancer/testis (CT) antigens NY-ESO-1 and MAGE-C1 is regulated by proteasome activity in tumour cells

The Cancer/Testis (CT) antigen family of genes are transcriptionally repressed in most human tissues but are atypically re-expressed in many malignant tumour types. Their restricted expression profile makes CT antigens ideal targets for cancer immunotherapy. As little is known about whether CT antigens may be regulated by post-translational processing, we investigated the mechanisms governing degradation of NY-ESO-1 and MAGE-C1 in selected cancer cell lines. Inhibitors of proteasome-mediated degradation induced the partitioning of NY-ESO-1 and MAGE-C1 into a detergent insoluble fraction. Moreover, this treatment also resulted in increased localisation of NY-ESO-1 and MAGE-C1 at the centrosome. Despite their interaction, relocation of either NY-ESO-1 or MAGE-C1 to the centrosome could occur independently of each other. Using a series of truncated fragments, the regions corresponding to NY-ESO-1_91-150 and MAGE-C1_900-1116 were established as important for controlling both stability and localisation of these CT antigens. Our findings demonstrate that the steady state levels of NY-ESO-1 and MAGE-C1 are regulated by proteasomal degradation and that both behave as aggregation-prone proteins upon accumulation. With proteasome inhibitors being increasingly used as front-line treatment in cancer, these data raise issues about CT antigen processing for antigenic presentation and therefore immunogenicity in cancer patients.

Expression of MAGE-C1/CT7 and selected cancer/testis antigens in ovarian borderline tumours and primary and recurrent ovarian carcinomas

MAGE-C1/CT7, NY-ESO-1, GAGE and MAGE-A4 are members of the cancer/testis (CT) antigen family, which have been proposed as potential targets for cancer immunotherapy. To determine the prevalence and biologic relevance of the novel CT antigen MAGE-C1/CT7 and other antigens, 36 ovarian borderline tumours (BTs), 230 primary ovarian carcinomas (OCs) and 80 recurrent OCs were immunohistochemically analysed using the monoclonal antibodies CT7-33 (MAGE-C1/CT7), E978 (NY-ESO-1), clone 26 (GAGE) and 57B (MAGE-A4). Positivity of at least one CT antigen was present in 39.5 % (81/205) of primary OC and in 50 % (26/52) of all recurrences. Expression of the novel CT antigen MAGE-C1/CT7 was most commonly seen with positivity in 24.5 % of primary and 35.1 % of recurrent OC. MAGE-A4, GAGE and NY-ESO-1 expressions were seen in 22.7, 13.9 and 7.1 % of primary and 22.6, 17.5 and 8.9 % of recurrent OC, respectively. Analysis of histological subtypes (serous, endometrioid, clear cell, mucinous and transitional) exhibited variable expression with negativity in all mucinous OC. High-grade serous OC revealed CT antigen expression in 5.6 to 28 % with MAGE-C1/CT7 being the most frequent, but without correlation with stage or overall survival. MAGE-C1/CT7 expression and coexpression of CT antigens were significantly correlated with grade of endometrioid OC. None of the BT showed CT antigen expression. No significant correlation was seen with stage, overall survival or response to chemotherapy. In summary, CT antigens are expressed in a certain subset of OC with no expression in BT or OC of mucinous histology. These findings may have implications for the design of polyvalent vaccination strategies for ovarian carcinomas.

MAGE-C2 promotes growth and tumorigenicity of melanoma cells, phosphorylation of KAP1, and DNA damage repair

Melanoma-associated antigen-encoding (MAGE) genes are expressed in melanoma and other cancers but not in normal somatic cells. MAGE expression is associated with aggressive tumor growth, poor clinical outcome, and resistance to chemotherapy, but the mechanisms have not been completely elucidated. In this study, we show that downregulation of MAGE-C2 in A375 melanoma cells and low-passage cultures from human metastatic melanomas (MRA cells) results in increased apoptosis and decreased growth of tumor xenografts in athymic nude mice. Previously, we showed that MAGE-C2 binds KAP1, a scaffolding protein that regulates DNA repair. Phosphorylation of KAP1-Serine 824 (Ser824) by ataxia-telangiectasia-mutated (ATM) kinase is necessary for repair of DNA double-strand breaks (DSBs); now we show that MAGE-C2 knockdown reduces, whereas MAGE-C2 overexpression increases, ATM kinase-dependent phosphorylation of KAP1-Ser824. We demonstrate that MAGE-C2 increases co-precipitation of KAP1 with ATM and that binding of MAGE-C2 to KAP1 is necessary for increased KAP1-Ser824 phosphorylation. Furthermore, ectopic expression of MAGE-C2 enhances repair of I-SceI endonuclease-induced DSBs in U-2OS cells. As phosphorylation of KAP1-Ser824 facilitates relaxation of heterochromatin, which is necessary for DNA repair and cellular proliferation, our results suggest that MAGE-C2 can promote tumor growth by phosphorylation of KAP1-Ser824 and by enhancement of DNA damage repair.

Cancer-testis antigen expression and immunogenicity in AL amyloidosis

Light-chain amyloidosis (AL) is a plasma cell dyscrasia closely related to multiple myeloma. In multiple myeloma, the cancer-testis antigens (CTAs) CT7 (MAGE-C1), CT10 (MAGE-C2) and MAGE-A CTAs are expressed in up to 80% of cases. In this study, we investigated the expression and immunogenicity of several CTAs in patients with AL amyloidosis in a total of 38 bone marrow specimens by employing standard immunohistochemistry techniques on paraffin-embedded archival tissues. Plasma samples from 35 patients (27 with matched bone marrow samples) were also analyzed by ELISA for sero reactivity to a group of full-length CTA proteins. CT7 was present in 25/38 (66%) while CT10 was demonstrated in 3/38 and GAGE in 1/38 AL amyloid cases. The expression pattern was mostly focal. There were no significant differences with regard to organ involvement, response to treatment, or prognosis in CTA positive compared to negative cases. None of the specimens showed spontaneous humoral immunity to CT7, but sero reactivity was observed in individual patients to other CTAs. This study identifies CT7 as the prevalent CTA in plasma cells of patients with AL amyloidosis. Further analyses determining the biology of CTAs in AL amyloidosis and their value as potential targets for immunotherapy are warranted.

A cancer/testis antigen microarray to screen autoantibody biomarkers of non-small cell lung cancer

Cancer/testis antigens (CTAs) are highly immunogenic in many tumors, especially in non-small cell lung cancer (NSCLC). A low-density protein microarray, which consisted of 72 CTAs and six non-CTAs, was used to screen for lung cancer-related autoantibodies. The CTA panel of NY-ESO-1, XAGE-1, ADAM29 and MAGEC1, had sensitivity and specificity values of 33% and 96%, respectively. When examined in a test set, this panel of markers had sensitivity and specificity values of 36% and 89%, respectively. This array of markers preferentially detected NSCLC, but did not detect breast cancer, and non-cancer lung disease.

Targeting MAGE-C1/CT7 expression increases cell sensitivity to the proteasome inhibitor bortezomib in multiple myeloma cell lines

The MAGE-C1/CT7 encodes a cancer/testis antigen (CTA), is located on the chromosomal region Xq26–27 and is highly polymorphic in humans. MAGE-C1/CT7 is frequently expressed in multiple myeloma (MM) that may be a potential target for immunotherapy in this still incurable disease. MAGEC1/CT7 expression is restricted to malignant plasma cells and it has been suggested that MAGE-C1/CT7 might play a pathogenic role in MM; however, the exact function this protein in the pathophysiology of MM is not yet understood. Our objectives were (1) to clarify the role of MAGE-C1/CT7 in the control of cellular proliferation and cell cycle in myeloma and (2) to evaluate the impact of silencing MAGE-C1/CT7 on myeloma cells treated with bortezomib. Myeloma cell line SKO-007 was transduced for stable expression of shRNA-MAGE-C1/CT7. Downregulation of MAGE-C1/CT7 was confirmed by real time quantitative PCR and western blot. Functional assays included cell proliferation, cell invasion, cell cycle analysis and apoptosis. Western blot showed a 70–80% decrease in MAGE-C1/CT7 protein expression in inhibited cells (shRNA-MAGE-C1/CT7) when compared with controls. Functional assays did not indicate a difference in cell proliferation and DNA synthesis when inhibited cells were compared with controls. However, we found a decreased percentage of cells in the G2/M phase of the cell cycle among inhibited cells, but not in the controls (p<0.05). When myeloma cells were treated with bortezomib, we observed a 48% reduction of cells in the G2/M phase among inhibited cells while controls showed 13% (empty vector) and 9% (ineffective shRNA) reduction, respectively (p<0.01). Furthermore, inhibited cells treated with bortezomib showed an increased percentage of apoptotic cells (Annexin V+/PI-) in comparison with bortezomib-treated controls (p<0.001). We found that MAGE-C1/CT7 protects SKO-007 cells against bortezomib-induced apoptosis. Therefore, we could speculate that MAGE-C1/CT7 gene therapy could be a strategy for future therapies in MM, in particular in combination with proteasome inhibitors.

Identification of MAGE-C1 (CT-7) epitopes for T-cell therapy of multiple myeloma

Multiple myeloma is incurable with standard therapies but is susceptible to a T-cell-mediated graft versus myeloma effect after allogeneic stem cell transplantation. We sought to identify myeloma-specific antigens that might be used for T-cell immunotherapy of myeloma. MAGE-C1 (CT-7) is a cancer-testis antigen that is expressed by tumor cells in >70% of myeloma patients and elicits a humoral response in up to 93% of patients with CT-7(+) myeloma. No CD8(+) T-cell epitopes have been described for CT-7, so we used a combination of reverse immunology and immunization of HLA-A2 transgenic mice with a novel cell-based vaccine to identify three immunogenic epitopes of CT-7 that are recognized by human CD8(+) T-cells. CT-7-specific T-cells recognizing two of these peptides are able to recognize myeloma cells as well as CT-7 gene-transduced tumor cells, demonstrating that these epitopes are naturally processed and presented by tumor cells. This is the first report of the identification of immunogenic CD8(+) T-cell epitopes of MAGE-C1 (CT-7), which is the most commonly expressed cancer-testis antigen found in myeloma, and these epitopes may be promising candidate targets for vaccination or T-cell therapy of myeloma or other CT-7(+) malignancies.

Expression of MAGE-C1/CT7 and MAGE-C2/CT10 predicts lymph node metastasis in melanoma patients

MAGE-C1/CT7 and MAGE-C2/CT10 are members of the large MAGE family of cancer-testis (CT) antigens. CT antigens are promising targets for immunotherapy in cancer because their expression is restricted to cancer and germ line cells and a proportion of cancer patients presents with immune responses against CT antigens, which clearly demonstrates their immunogenicity. This study investigates the expression of MAGE-C1/CT7 and MAGE-C2/CT10 in primary and metastatic melanoma. Immunohistochemical staining of tissue microarrays that consisted of 59 primary malignant melanomas of the skin, 163 lymph node and distant melanoma metastases and 68 melanoma cell lines was performed. We found MAGE-C1/CT7 expression in 15 out of 50 (24%) primary melanomas and 15 out of 50 (24%) cell lines, whereas MAGE-C2/CT10 was detected in 17 out of 51 (33%) primary melanomas and 14 out of 68 (17%) cell lines. MAGE-C1/CT7 and MAGE-C2/CT10 were both detected in 40% of melanoma metastases. Patients with MAGE-C1/CT7 or MAGE-C2/CT10 positive primary melanoma had significantly more lymph node metastases (p = 0.005 and p<0.001, resp.). Prediction of lymph node metastasis by MAGE-C1/CT7 and MAGE-C2/CT10 was independent of tumor cell proliferation rate (Ki67 labeling index) in a multivariate analysis (p = 0.01). Our results suggest that the expression of MAGE-C1/CT7 and MAGE-C2/CT10 in primary melanoma is a potent predictor of sentinel lymph node metastasis.

Expression of cancer testis antigens in human BRCA-associated breast cancers: potential targets for immunoprevention?

INTRODUCTION

Novel breast cancer risk-reducing strategies for individuals with germline mutations of the BRCA1 and/or BRCA2 genes are urgently needed. Identification of antigenic targets that are expressed in early cancers, but absent in normal breast epithelium of these high-risk individuals, could provide the basis for the development of effective immunoprophylactic strategies. Cancer testis (CT) antigens are potential candidates because their expression is restricted to tumors, and accumulating data suggest that they play important roles in cellular proliferation, stem cell function, and carcinogenesis. The objective of this study was to examine the expression of CT antigens and their frequency in BRCA-associated breast cancers.

METHODS

Archived breast cancer tissues (n = 26) as well as morphologically normal breast tissues (n = 7) from women carrying deleterious BRCA 1 and/or 2 mutations were obtained for antigen expression analysis by immunohistochemistry. Expression of the following CT antigens was examined: MAGE-A1, MAGE-A3, MAGE-A4, MAGE-C1.CT7, NY-ESO-1, MAGE-C2/CT10, and GAGE.

RESULTS

CT antigens were expressed in 16/26 (61.5%, 95% CI 43-80%) of BRCA-associated cancers, including in situ tumors. Thirteen of twenty-six (50%) breast cancers expressed two or more CT antigens; three cancers expressed all seven CT antigens. MAGE-A was expressed in 13/26 (50%) of cancers, NY-ESO-1 was expressed in 10/26 (38%) of tumors. In contrast, none of the CT antigens were expressed in adjacent or contralateral normal breast epithelium (P = 0.003).

CONCLUSIONS

We report a high CT antigen expression rate in BRCA-associated breast cancer as well as the lack of expression of these antigens in benign breast tissue of carriers, identifying CT antigens as potential vaccine targets for breast cancer prevention in these high-risk individuals.

Multiple cancer/testis antigens are preferentially expressed in hormone-receptor negative and high-grade breast cancers

Background

Cancer/testis (CT) antigens are protein antigens normally expressed only in germ cells of testis, and yet are expressed in a proportion of a wide variety of human cancers. CT antigens can elicit spontaneous immune responses in cancer patients with CT-positive cancers, and CT antigen-based therapeutic cancer vaccine trials are ongoing for “CT-rich” tumors. Although some previous studies found breast cancer to be “CT-poor”, our recent analysis identified increased CT mRNA transcripts in the ER-negative subset of breast cancer.

Methodology/Principal Findings

In this study, we performed a comprehensive immunohistochemical study to investigate the protein expression of eight CT genes in 454 invasive ductal carcinomas, including 225 ER/PR/HER2-negative (triple-negative) carcinomas. We found significantly more frequent expression of all eight CT antigens in ER-negative cancers, and five of them—MAGEA, CT7, NY-ESO-1, CT10 and CT45, were expressed in 12–24% of ER-negative cancers, versus 2–6% of ER-positive cancers (p<0.001 to 0.003). In comparison, GAGE, SAGE1 and NXF2 were only expressed in 3–5% of ER-negative and 0–2% of ER-positive cancers. ER-negative cancers were also more likely to simultaneously co-express multiple CT antigens, with 27% (34/125) of ER-negative, CT-positive tumors expressing three or more CT antigens. HER2 status had no consistent effect on CT expression, and triple-negative carcinomas showed similar frequencies of MAGEA and NY-ESO-1 expression as ER-negative/HER2-positive carcinomas. More frequent CT expression was also found in tumors with higher nuclear grade (p<0.001 to p = 0.01) and larger in size (>2 cm).

Conclusions/Significance

CT antigens are preferentially expressed in hormone receptor-negative and high-grade breast cancer. Considering the limited treatment options for ER/PR/HER2 triple-negative breast cancer, the potential of CT-based immunotherapy should be explored.

Identification of novel small molecules that inhibit protein-protein interactions between MAGE and KAP-1

The Class I MAGE proteins are normally expressed only in developing germ cells but are often aberrantly expressed in malignancies, particularly melanoma, making them good therapeutic targets. MAGE proteins promote tumor survival by binding to the RBCC region of KAP-1 and suppressing p53. Although, suppression of MAGE expression, by RNA interference, relieves p53 suppression and inhibits tumor growth, its therapeutic uses are limited by lack of methods for systemic delivery of small interfering RNA. To overcome this barrier, we sought to discover chemical compounds that inhibit binding between MAGE and KAP-1 proteins. Based on previously published effects of MAGE suppression, we developed a strategy for screening a small molecule library based on selective death of MAGE positive cells, activation of p53 and lack of caspase activity. We screened the Maybridge HitFinder library of compounds and eight compounds fulfilled these criteria. Seven of these compounds interfered with co-precipitation of MAGE and KAP-1, and three interfered with binding of MAGE and KAP-1 in a mammalian two hybrid assay. We now report identification of three potential compounds that interfere with MAGE/KAP-1 binding and can be developed as novel chemo-therapeutic agents for treatment of advanced melanoma and other cancers.

Expression of MAGE-A4 and MAGE-C1 tumor-associated antigen in benign and malignant thyroid diseases

BACKGROUND

A subset of thyroid tumors characterized by a follicular growth pattern can represent a serious diagnosis. Immunohistochemistry and molecular pathology for genetic profiling have been used in an attempt to resolve some of these issues.

METHODS

Tumor tissue samples of thyroid were obtained from 70 patients who underwent surgical therapy. They were divided into 4 groups: 20 adenomatous goiters, 10 follicular adenomas, 24 papillary carcinomas, and 16 follicular carcinomas. Immunohistochemical analysis was carried out using antibodies for MAGE-A4 (melanoma antigen-encoding gene A4) and MAGE-C1 (melanoma antigen-encoding gene C1).

RESULTS

Standard histologic analysis and immunohistochemistry analysis of MAGE-A4 and MAGE-C1 expression were performed in all patients. The antigens examined were not expressed in any of the tissues.

CONCLUSIONS

The malignant degeneration of normal tissues is a multifactorial process, varying considerably both among tumor types and among individual patients. The present study showed that there was no immunolabeling of the MAGE-A4 and MAGE-C1 antigens.

High expression of cancer testis antigens MAGE-A, MAGE-C1/CT7, MAGE-C2/CT10, NY-ESO-1, and gage in advanced squamous cell carcinoma of the larynx

BACKGROUND

Despite diagnostic and therapeutic advances in head and neck cancer, the 5-year survival of patients with laryngeal cancer has not improved in the last 30 years. Several recent studies indicate that specific targets for immunotherapeutic approaches can be useful in the control of cancer. There is considerable interest in the expression of cancer testis antigens in human cancers since they may serve as the basis for an immunologic approach to therapy.

METHODS

We evaluated by immunohistochemical analysis the expression of cancer testis antigens MAGE-A4 (57B), MAGE-C1 (CT7-33), MAGE-A1 (MA454), MAGE-A3 (M3H67), MAGE-C2 (CT10.5), NY-ESO-1 (E978), and GAGE (GAGE) in squamous cell carcinoma (SCC) of the larynx.

RESULTS

A total of 63 cases (57 men and 6 women) of laryngeal SCC were available for this study. The findings were correlated with the clinical course and laboratory data. Expression of at least 1 cancer testis antigen was detected in 42 of 63 of the laryngeal SCCs (67%). In 34 of 42 of the positive cases (81%) there was simultaneous expression of ≥2 cancer testis antigens. There was significant correlation between antigen expression and advanced tumor stage (stage III/IV) in cases with reactivity to only 1 antibody (p = .01) as well as in the cases with reactivity to ≥2 primary antibodies (≥2 mAbs, p = .04). There was no association between survival and expression of any of the analyzed antigens.

CONCLUSIONS

We find a high incidence of cancer testis antigen expression in SCCs of the larynx, which was correlated with advanced clinical stage. Our data indicate that cancer testis antigens could be valuable vaccine targets in laryngeal tumors, especially in those with a worse prognosis.

Fine analysis of spontaneous MAGE-C1/CT7-specific immunity in melanoma patients

Cancer/testis (CT) antigens represent prime candidates for immunotherapy in cancer patients, because their expression is restricted to cancer cells and germ cells of the testis. MAGE-C1/CT7 is a CT antigen that is highly expressed in several types of cancers. Spontaneous occurrence of CT7-specific antibodies was previously detected by SEREX screen in a melanoma patient. However, naturally occurring CT7-specific T-cell responses have thus far not been detected. Peripheral blood mononuclear cells (PBMCs) from 26 metastatic melanoma patients expressing CT7 in their tumor lesions (CT7(+)) were analyzed for CT7-specific T-cell responses using overlapping peptides. CT7-specific CD4(+) T-cell responses were detected in three patients (11.5%). These CT7-specific CD4(+) T-cell responses were detectable in melanoma patients' PBMCs exclusively from preexisting CD45RA(-) memory CD4(+) T-cell pool. Additional CT7-specific memory CD4(+) T-cell responses were detected in CT7(+) melanoma patients after depletion of CD4(+)CD25high Treg cells showing that Treg cells impact on CT7-specific CD4(+) T cells in melanoma patients. CT7-specific CD4(+) T-cell clones were generated and used to define minimal epitopes, restriction elements, and confirm the recognition of naturally processed antigen. Surprisingly, these clones were able to secrete perforin and exert cytotoxicity. This study shows that CT7 can induce specific cellular immunity in melanoma patients. Based on these findings, CT7 will be further explored as a potential vaccine for melanoma immunotherapy.

Expression and prognostic relevance of MAGE-C1/CT7 and MAGE-C2/CT10 in osteolytic lesions of patients with multiple myeloma

Cancer-testis (CT) antigens are promising targets for antigen-specific therapy of multiple myeloma (MM). Osteolytic lesions represent the most common clinical manifestation of myeloma and it is possible that osseous myeloma lesions differ from bone-infiltrating tumor cells with regard to the extent of CT antigen expression based on the epigenetic regulation of these genes. We, therefore, performed the first analysis of CT antigen expression in osteolytic lesions of myeloma patients to further define the diagnostic, prognostic, and therapeutic value of these proteins. Lytic bone samples were obtained from MM patients during surgical interventions and a tissue microarray was constructed. 105 bone samples and 24 bone marrow biopsies were stained immunohistochemically with antibodies against CT antigens MAGE-C1/CT7 and MAGE-C2/CT10 and Ki-67. MAGE-C1/CT7 and MAGE-C2/CT10 were frequently expressed in osteolytic lesions (46% and 54%) and bone marrow (75% and 54%). Expression of MAGE-C1/CT7 was significantly more frequent in patients with advanced stage of disease (p=0.023) and with a chromosomal deletion 17p13 (p53) (p=0.047). Samples with more than 75% MAGE-C1/CT7 expressing myeloma cells showed a higher proliferative rate (indicated by the expression of Ki67) than those with less than 25% MAGE-C1/CT7 expressing cells (p=0.011). Moreover, a content of ≥50% MAGE-C1/CT7 expressing myeloma cells in a sample was associated with reduced overall survival (p=0.013). Our results, therefore, suggest that expression of MAGE-C1/CT7 and MAGE-C2/CT10 in osteolytic lesions of myeloma patients can be used for diagnostic, prognostic, as well as immunotherapeutic purposes.

Cancer/testis antigens can be immunological targets in clonogenic CD133+ melanoma cells

"Cancer stem cells" that resist conventional treatments may be a cause of therapeutic failure in melanoma. We report a subpopulation of clonogenic melanoma cells that are characterized by high prominin-1/CD133 expression in melanoma and melanoma cell lines. These cells have enhanced clonogenicity and self-renewal in vitro, and serve as a limited in vitro model for melanoma stem cells. In some cases clonogenic CD133(+) melanoma cells show increased expression of some cancer/testis (CT) antigens. The expression of NY-ESO-1 in an HLA-A2 expressing cell line allowed CD133(+) clonogenic melanoma cells to be targeted for killing in vitro by NY-ESO-1-specific CD8(+) T-lymphocytes. Our in vitro findings raise the hypothesis that if melanoma stem cells express CT antigens in vivo that immune targeting of these antigens may be a viable clinical strategy for the adjuvant treatment of melanoma.

Frequent expression of the novel cancer testis antigen MAGE-C2/CT-10 in hepatocellular carcinoma

Cancer testis (CT) antigens are attractive targets for immunotherapy in cancer patients. Immunohistochemistry was used to study the expression of the CT antigens MAGE-C2/CT-10, MAGE-C1/CT-7, GAGE, MAGE-A4 and NY-ESO-1 in 146 hepatocellular carcinomas, 13 intrahepatic cholangiocarcinomas, 37 extrahepatic cholangiocarcinomas and 32 gallbladder carcinomas. Immunopositivity was correlated with clinicopathological parameters, MHC Class 1 expression, intratumoral CD4+, CD8+ and FOXP3+ T cells and CD163+ antigen-presenting cells. Of the 146 hepatocellular carcinomas, 34% were positive for MAGE-C2/CT-10, 12% for MAGE-C1/CT-7, 11% for GAGE and 2% for NY-ESO-1, respectively. MHC Class 1 coexpression was identified in almost all CT antigen-positive tumors. The number of intratumoral FOXP3+ regulatory T cells was increased in CT antigen-positive hepatocellular carcinomas (p<0.004), suggesting inhibition of immune response in such tumors. Furthermore, MAGE-C1/CT-7 and GAGE positivity was correlated with reduced overall survival in patients with hepatocellular carcinoma (p=0.03 and 0.01, respectively). Four (13%) gallbladder carcinomas stained positive for MAGE-C2/CT-10, of which 1 tumor (3%) was also positive for NY-ESO-1 and GAGE. CT antigens were not expressed in intra- and extrahepatic cholangiocarcinomas. Our results suggest that MAGE-C2/CT-10 may be a good candidate for peptide vaccination in patients with hepatocellular carcinoma.

Cancer testis antigen expression in gastrointestinal stromal tumors: new markers for early recurrence

Cancer testis antigens (CTAs) are expressed in a variety of malignant tumors but not in any normal adult tissues except germ cells and occasionally placenta. Because of this tumor-associated pattern of expression, CTAs are regarded as potential vaccine targets. The expression of CTAs in gastrointestinal stromal tumors (GIST) has not been analyzed systematically previously. The present study was performed to analyze the expression of CTA in GIST and to determine if CTA expression correlates with prognosis. Thirty-five GIST patients were retrospectively analyzed for their expression of CTAs by immunohistochemistry using the following monoclonal antibodies (mAb/antigen): MA454/MAGE-A1, M3H67/MAGE-A3, 57B/MAGE-A4, CT7-33/MAGE-C1 and E978/NY-ESO-1. Fourteen tumors (40%) expressed 1 or more of the 5 CTAs tested. Fourteen percent (n = 5/35) were positive for MAGE-A1, MAGE-A3 or MAGE-A4, respectively. Twenty-six percent (n = 9/35) stained positive for MAGE-C1 and 20% (n = 7/35) for NY-ESO-1. A highly significant correlation between CTA expression and tumor recurrence risk was observed (71% vs. 29%; p = 0.027). In our study population, the high-risk GIST expressed CTAs more frequently than low-risk GIST (p = 0.012). High-risk GISTs which stained positive for at least 1 CTA, recurred in 100% (n = 25) of the cases. This is the first study analyzing CTA expression in GIST and its prognostic value for recurrence. The CTA staining could add information to the individual patient prognosis and represent an interesting target for future treatment strategies.

Expression and significance of cancer testis antigens in primary mucosal melanoma of the head and neck

BACKGROUND

Cancer testis antigens (CTAs) are T-cell-defined tumor-associated antigens encoded by the genes and gene families such as MAGE, NY-ESO-1, and others. Their expression in a wide variety of malignant neoplasms but absence in all normal adult tissue except testicular germ cells makes them attractive targets for immunotherapy of cancer. Primary mucosal melanomas of the head and neck (HNMM) are rare aggressive malignant tumors that are usually difficult to treat. CTAs may provide useful targets for therapy; however, their expression in HNMM is not known.

METHODS

We analyzed 40 initial, 15 recurrent, and 15 metastatic HNMM to nonmucosal locations from 64 patients (oral, n = 30; sinonasal, n = 34). Immunohistochemistry was performed on archival tissue with monoclonal antibodies 57B, CT7-33, and ES121 to the following CTAs: MAGE-A4, CT7 (MAGE-C1), and NY-ESO-1, respectively.

RESULTS

CT7, MAGE-A4, and NY-ESO-1 expression was seen in 73%, 61%, and 24% of tumors, respectively, with 81% of the tumors expressing at least one of the CTAs. CT7 and MAGE-A4 were significantly more frequently expressed in tumors composed of epithelioid cells than spindle cells (p = .05). CTA expression did not correlate with disease progression, overall survival, and disease-specific survival.

CONCLUSIONS

CT7, MAGEA4, and NY-ESO-1 are frequently expressed in HNMM and may be potential targets for CTA-based immunotherapy. The expression does not seem to have prognostic significance.

MAGE-A, mMage-b, and MAGE-C proteins form complexes with KAP1 and suppress p53-dependent apoptosis in MAGE-positive cell lines

The MAGE-A, MAGE-B, and MAGE-C protein families comprise the class-I MAGE/cancer testes antigens, a group of highly homologous proteins whose expression is suppressed in all normal tissues except developing sperm. Aberrant expression of class I MAGE proteins occurs in melanomas and many other malignancies, and MAGE proteins have long been recognized as tumor-specific targets; however, their functions have largely been unknown. Here, we show that suppression of class I MAGE proteins induces apoptosis in the Hs-294T, A375, and S91 MAGE-positive melanoma cell lines and that members of all three families of MAGE class I proteins form complexes with KAP1, a scaffolding protein that is known as a corepressor of p53 expression and function. In addition to inducing apoptosis, MAGE suppression decreases KAP1 complexing with p53, increases immunoreactive and acetylated p53, and activates a p53 responsive reporter gene. Suppression of class I MAGE proteins also induces apoptosis in MAGE-A-positive, p53wt/wt parental HCT 116 colon cancer cells but not in a MAGE-A-positive HCT 116 p53-/- variant, indicating that MAGE suppression of apoptosis requires p53. Finally, treatment with MAGE-specific small interfering RNA suppresses S91 melanoma growth in vivo, in syngenic DBA2 mice. Thus, class I MAGE protein expression may suppress apoptosis by suppressing p53 and may actively contribute to the development of malignancies and by promoting tumor survival. Because the expression of class I MAGE proteins is limited in normal tissues, inhibition of MAGE antigen expression or function represents a novel and specific treatment for melanoma and diverse malignancies.

Expression of cancer-testis antigen CT7 (MAGE-C1) in breast cancer: an immunohistochemical study with emphasis on prognostic utility

High expression of the cancer-testis antigen CT7, also referred to as MAGE-C1, has been recently described in a variety of malignant tumors, including breast carcinoma. To our knowledge, no data concerning the prognostic utility of CT7 expression in breast cancer are available. In this retrospective study, we evaluated the relationship between CT7 immunoreactivity and clinicopathological parameters as well as relapse-free survival (RFS) and metastasis-free survival (MFS) of 124 women with invasive breast cancer. A positive CT7 status, defined as immunoreactivity in more than 50% of tumor cells, was found in 18% of cases and correlated significantly with high tumor grade (p=0.004), but with no other clinicopathological parameter. In a univariate analysis, CT7 status showed an association with RFS by trend (p=0.107; relative risk [RR]: 1.85) and a significant association with MFS (p=0.043; RR: 2.02). In a multivariate analysis, tumor grade, stage, nodal status, angioinvasion, HER2 expression as well as estrogen and progesterone receptor expression were identified as significant independent prognostic factors of RFS and/or MFS. In this respect, CT7 expression showed a weak, statistically not significant trend towards an independent prognostic relevance concerning prediction of MFS (p=0.147; RR: 1.95). Our data suggest that estimation of CT7 immunoreactivity is of limited prognostic usefulness in breast cancer. It may provide additional information concerning assessment of MFS in selected cases.

MAGE-A9 mRNA and protein expression in bladder cancer

In a previous analysis, we showed that MAGE-As were the most frequently expressed cancer-testis antigens in human bladder tumours. Here, we further characterized by RT-PCR the expression of this family of genes by analyzing specifically MAGE-A3, -A4, -A8 and -A9 mRNAs in 46 bladder tumours and 10 normal urothelia. We found that they were expressed in 30, 33, 56 and 54% of tumours, respectively. Although MAGE-A8 was the most frequent, its expression was low and was also found in most normal urothelia. The other MAGE-A mRNAs were all tumour-specific but MAGE-A9 mRNA was expressed at a higher level and was two times more frequent in superficial than in invasive tumours. To study the expression of the protein, we produced 2 MAGE-A9-specific monoclonal antibodies (mAbs) presenting no cross-reactivity with other MAGE-A proteins. MAb 14A11, was used to analyse the expression of the antigen in testis and tumour samples by immunohistochemistry. In testis, MAGE-A9 expression was restricted to primary spermatocytes. Most bladder tumours that expressed the MAGE-A9 transcript were positive with mAb 14A11. Staining was heterogeneous but half of the tumours showed over 75% positive cells. Finally, we showed that treatment of bladder cancer cells with the methylation inhibitor, 5-aza-2'-deoxycytidine, alone or in combination with the histone deacetylase inhibitors MS-275 and 4-phenylbutyrate could strongly induce the expression of MAGE-A9. These results show that MAGE-A9 is frequently expressed in superficial bladder cancer and could be a relevant target for immunotherapy or chemoimmunotherapy because its expression can be induced by chemotherapeutic drugs.

Epigenetic control of MAGE gene expression by the KIT tyrosine kinase

The Class I MAGE proteins include the MAGE-A, MAGE-B, and MAGE-C antigens, which are normally expressed only in male germ cells but may be aberrantly expressed in melanomas and other tumors. It is known that MAGE gene expression is epigenetically repressed by promoter region methylation in most cells but factors controlling MAGE gene promoter methylation have not been identified. Using transcript microarray analysis and immunoblotting we found that MAGE-A and MAGE-C mRNA and protein are selectively downregulated by pharmacologic inhibition of KIT in KIT-dependent mast cell lines. Methylation-specific polymerase chain reaction studies showed that the MAGE-A3 and MAGE-C2 gene promoter regions were de-methylated in the presence of activated KIT but became methylated on inhibition of KIT, consistent with the downregulation of mRNA and protein. This is early evidence of a tyrosine kinase affecting MAGE gene promoter region methylation and expression, and represents early evidence of a tyrosine kinase in the epigenetic control of gene expression. MAGE proteins suppress apoptosis and promote tumor survival, and are novel targets for functional manipulation and immunotherapy. Understanding the factors controlling MAGE gene expression may allow more effective therapeutic strategies targeting MAGE antigens.

Cancer-testis antigens: expression and correlation with survival in human urothelial carcinoma

PURPOSE

Vaccination against human cancer is a promising therapeutic approach but the optimal antigen or antigens remain undefined. Cancer-testis antigens (CTA), a family of tumor-associated antigens, have both potent immunogenicity and restricted expression patterns in normal adult tissues, highly desirable characteristics for targets of anticancer vaccines. These antigens were evaluated for both the degree of expression and prognostic value in cancer of the urothelium.

EXPERIMENTAL DESIGN

The expression patterns of nine CTAs (NY-ESO-1, LAGE-1, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7, CT10, and GAGE) were examined by immunohistochemistry and reverse transcription-PCR in a panel of high-grade urothelial carcinomas of the urinary bladder. Also assessed were correlations between the expression of CTAs by immunohistochemistry and both disease-free and overall survival.

RESULTS

At least one CTA was expressed in 77% of samples and 61% of these tumors expressed more than one CTA. Additionally, patients with CT10-positive tumors had an improved disease-free survival (P=0.008) and overall survival (P=0.037) compared with patients with CT10-negative tumors.

CONCLUSIONS

These findings establish CTAs as potential prognostic markers and as target candidates for vaccine development for patients with urothelial carcinoma.

Preferential nuclear and cytoplasmic NY-BR-1 protein expression in primary breast cancer and lymph node metastases

PURPOSE

NY-BR-1 is a recently isolated differentiation antigen, which is expressed in normal mammary tissue and in breast cancer. However, current data are based on RT-PCR analysis and nothing is known about the presence of NY-BR-1 on a protein level. We previously generated a monoclonal antibody to NY-BR-1 to study the protein expression of NY-BR-1.

METHODS

In our immunohistochemical study, NY-BR-1 was analyzed in normal tissues, various tumor types, 124 primary breast cancers, and 37 paired lymph node metastases.

RESULTS

Among normal tissues, NY-BR-1 was present solely in ductal epithelium of the breast. In tumors, carcinoma in situ and invasive carcinoma of the breast were NY-BR-1 positive whereas other tumors and normal tissues were negative. Sixty percent of invasive breast carcinomas were NY-BR-1 positive, displaying cytoplasmic and/or nuclear immunoreactivity. This coexpression was verified by confocal microscopy. Although the monoclonal antibody identified intratumoral heterogeneity, a majority (72%) of NY-BR-1-positive carcinomas revealed immunoreactivity in >50% of the tumor cells. NY-BR-1 expression was more frequent in estrogen receptor-positive and lymph node-negative primary carcinomas (P < 0.05 each) and was more common in grade 1 (77%) than in grade 2 (63%) or grade 3 (50%) carcinomas (P < 0.05). This suggests that NY-BR-1 expression is lost with tumor progression. Forty-nine percent of lymph node metastases were NY-BR-1 positive.

CONCLUSION

This study supports the notion that NY-BR-1 is a differentiation antigen of the breast, which is present in normal and tumorous mammary epithelium. The organ-specific expression of NY-BR-1 and its high prevalence in metastases indicate that it could be a valuable target for cancer immunotherapy.

Expression of Y-box-binding protein dbpC/contrin, a potentially new cancer/testis antigen

Y-box-binding proteins are members of the human cold-shock domain protein superfamily, which includes dbpA, dbpB/YB-1, and dbpC/contrin. dbpC/contrin is a germ cell-specific Y-box-binding protein and is suggested to function as a nuclear transcription factor and RNA-binding protein in the cytoplasm. Whereas ubiquitous dbpB/YB-1 expression has been well studied in various types of human carcinomas as a prognostic or predictive marker, the dbpC/contrin expression in human tumour cells has not been reported. In this report, we provide the first evidence showing that dbpC was highly expressed in human testicular seminoma and ovarian dysgerminomas, and in carcinomas in other tissues and that its expression in normal tissues is nearly restricted to germ cells and placental trophoblasts. These results indicate that dbpC/contrin would be a potentially novel cancer/testis antigen.

An evaluation of molecular markers for improved detection of breast cancer metastases in sentinel nodes

BACKGROUND AND OBJECTIVES

In patients with breast cancer (BC), the sentinel node (SN) is the first node in the axillary basin that receives the primary lymphatic flow and can be used to accurately assess the axillary nodal status without removal of the axillary contents. Currently, histology and/or immunohistochemistry are the routine methods of SN analysis. The primary objective of this study was to develop a reproducible reverse transcription (RT) PCR assay, with emphasis on achieving high specificity for accurate detection of BC micrometastases in the SN. To correct for the heterogeneity of BC cells, a multimarker approach was followed, with the further aim of improving the detection rate of the assay.

METHODS

In total, 73 markers were evaluated, of which 7 were breast epithelial markers and 66 were either cancer testis or tumour associated antigens. Twelve BC cell lines and 30 SNs (from 30 patients) were analysed using RT-PCR to determine the in vitro and in vivo detection rates for each of the markers. In addition, 20 axillary nodes obtained from a patient with brain death were used as controls to optimise the PCR cycle numbers for all the markers.

RESULTS

Of the 30 SNs, 37% (11/30) were positive on haematoxylin and eosin analysis. Extensive immunohistochemical (IHC) analyses of the haematoxylin and eosin negative nodes confirmed the presence of very small numbers of BC cells in an additional 40% (12/30) of SNs. Molecular analysis with the hMAM-A alone identified metastases in 70% (21/30) of SNs. Using MAGE-A3 in combination with hMAM-A identified metastases in 90% (27/30) of patients. Seven SNs (23%) were negative for micrometastases (with haematoxylin and eosin and IHC) but RT-PCR positive for either hMAM-A or MAGE-A3.

CONCLUSIONS

As IHC analysis resulted in a 77% detection rate compared with 37% for haematoxylin and eosin analysis, we consider that IHC is essential in order not to miss SN micrometastases. Molecular analysis with hMAM-A and MAGE-A3 allows detection of BC micrometastases with a 90% detection rate. However, the clinical value of histologically negative but RT-PCR positive SNs can only be determined with long term follow up.

Expression of MHC class I, MHC class II, and cancer germline antigens in neuroblastoma

BACKGROUND

Neuroblastoma is the most common solid extracranial tumor in childhood, still with poor survival rates for metastatic disease. Neuroblastoma cells are of neuroectodermal origin and express a number of cancer germline (CG) antigens. These CG antigens may represent a potential target for immunotherapy such as peptide-based vaccination strategies.

OBJECTIVE

The purpose of this study was to analyze the presence of MAGE-A1, MAGE-A3/A6, and NY-ESO-1 on an mRNA and protein level and to determine the expression of MHC class I and MHC class II antigens within the same tumor specimens.

METHODS

A total of 68 tumors were available for RT-PCR, and 19/68 tumors were available for immunohistochemical (IHC) analysis of MAGE-A1, MAGE-A3/A6, and NY-ESO-1. In parallel, the same tumors were stained with a panel of antibodies for MHC class I and MHC class II molecules.

RESULTS

Screening of 68 tumor specimens by RT-PCR revealed expression of MAGE-A1 in 44%, MAGE-A3/A6 in 21%, and NY-ESO-1 in 28% of cases. Immunohistochemistry for CG antigens of selected tumors showed good agreement between protein and gene expression. However, staining revealed a heterogeneous expression of CG antigens. None of the selected tumors showed MHC class I or MHC class II expression.

CONCLUSIONS

mRNA expression of MAGE-A1, MAGE-A3/A6, and NY-ESO-1 is congruent with the protein expression as determined by immunohistochemistry. The heterogeneous CG-antigen expression and the lack of MHC class I and II molecules may have implications for T-cell-mediated immunotherapy in neuroblastoma.

The cancer-testis antigens CT7 (MAGE-C1) and MAGE-A3/6 are commonly expressed in multiple myeloma and correlate with plasma-cell proliferation

Multiple myeloma is a malignancy of plasma cells. Vaccine immunotherapy is among the novel therapeutic strategies under investigation for this disease. To identify myeloma-associated antigens as potential targets for vaccine immunotherapy, we surveyed a comprehensive panel of bone marrow specimens from patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma for expression of cancer-testis (CT) antigens. Immunohistochemistry (IHC) demonstrated that 82% of stage-III myeloma specimens expressed the CT antigen CT7 (also known as melanoma antigen C1 [MAGE-C1]) and 70% expressed MAGE-A3/6. Messenger RNA for CT7 and MAGE-A family members was detected in 87% and 100% of stage-III samples, respectively. CT7 protein expression increased with advanced stage of disease. Higher levels of CT7 and MAGE-A3/6 proteins also correlated with elevated plasma-cell proliferation. These results show that CT7 and MAGE-A3/6 are promising myeloma-associated antigens for application in vaccine immunotherapy. Furthermore, the common expression and correlation with proliferation suggest a possible pathogenic role for these proteins in myeloma.

Cancer/testis antigens and gametogenesis: a review and "brain-storming" session

Genes expressed both in normal testis and in malignancies (Cancer/ Testis associated genes - CTA) have become the most extensively studied antigen group in the field of tumour immunology. Despite this, many fundamentally important questions remain unanswered: what is the connection between germ-cell specific genes and tumours? Is the expression of these genes yet another proof for the importance of genome destabilisation in the process of tumorigenesis?, or maybe activation of these genes is not quite random but instead related to some programme giving tumours a survival advantage?This review collates most of the recent information available about CTAs expression, function, and regulation. The data suggests a programme related to ontogenesis, mostly to gametogenesis. In the "brain-storming" part, facts in conflict with the hypothesis of random CTA gene activation are discussed. We propose a programme borrowed from organisms phylogenetically much older than humans, which existed before the differentiation of sexes. It is a programme that has served as a life cycle with prominent ploidy changes, and from which, as we know, the germ-cell ploidy cycle - meiosis - has evolved. Further work may show whether this hypothesis can lead to a novel anti-tumour strategy.

Immunohistochemical analysis of the expression of FATE/BJ-HCC-2 antigen in normal and malignant tissues

FATE/BJ-HCC-2 is a newly identified cancer/testis (CT) antigen, which was detected in tumor tissues and testis. As previous studies of FATE/BJ-HCC-2 expression pattern were mainly based on messenger RNA (mRNA) analysis, it is necessary to investigate its actual protein expression pattern in tumor tissues for the evaluation of its application value. In this study, we produced specific polyclonal antibody (pAb) to the recombinant FATE/BJ-HCC-2 protein and analyzed the FATE/BJ-HCC-2 antigen expression in normal and malignant tissues by the immunohistochemical approach. The results showed that there was no detectable FATE/BJ-HCC-2 antigen expressed in normal tissues except testis. In hepatocellular carcinoma (HCC) tissues, the FATE/BJ-HCC-2 antigen was detected in 20% (7/35) specimens. All samples that expressed the FATE/BJ-HCC-2 antigen were of poorly or moderately differentiated HCC. The stained antigen was located in the cytoplasm and the staining pattern showed heterogeneity from focal to more than 40% of the tumor cells. The FATE/BJ-HCC-2 antigen was also expressed in other tumor tissues. The results of [3H]thymidine incorporation showed that FATE/BJ-HCC-2 protein enhanced tumor cell proliferation after transfection of FATE/BJ-HCC-2 gene in HCC cell line (P<0.01). This effect could be specifically blocked by anti-FATE/BJ-HCC-2 pAb. Serological screening showed that the antibody specific to the FATE/BJ-HCC-2 antigen was detected in 7.7% (4/52) patients. Notably, the four positive patients bore poorly or moderately differentiated HCC. FATE/BJ-HCC-2 mRNA transcript was detected in the peripheral blood mononuclear cells (PBMCs) of 46.67% patients whose resected HCC tissue samples were positive for FATE/BJ-HCC-2 mRNA, which implicated tumor cell dissemination in blood circulation and may relate to the metastasis of HCC. Thus, FATE/BJ-HCC-2 may be a valuable candidate CT antigen for polyvalent vaccines in tumor immunotherapy and an assisting diagnostic marker for prognosis of the disease.

Expression of cancer-testis antigens in endometrial carcinomas using a tissue microarray

Cancer-testis (CT) antigens are expressed in a variety of malignant tumors, but in normal adult tissue, they are only expressed in testicular germ cells. Owing to this tumor-associated expression pattern, these antigens are of major interest as potential targets for immunotherapy and possibly for diagnostic purposes. This study was performed to analyze the expression of four CT antigens, NY-ESO-1, MAGE-A3, MAGE-A4, and CT7/MAGE-C1, in endometrial carcinoma using immunohistochemistry, and to correlate expression with histologic subtypes, grade, and expression of WT1 and p53. Formalin-fixed paraffin-embedded tissues of 130 endometrial carcinomas of the following types and grades were analyzed using a tissue microarray: 85 endometrioid carcinomas (FIGO grade 1, 39; grade 2, 11; and grade 3, 35), 18 papillary serous carcinomas, 12 clear cell carcinomas, 13 malignant mixed mullerian tumors, one mucinous adenocarcinoma, and one undifferentiated carcinoma. The following anti-CT monoclonal antibodies/antigens were studied by immunohistochemistry: monoclonal antibody ES121/NY-ESO-1, monoclonal antibody M3H67/MAGE-A3, monoclonal antibody 57B/MAGE-A4, and monoclonal antibody CT7-33/CT7. The CT expression data were compared to WT1 and p53 protein expression as analyzed in a previous study. Positive staining with anti-CT monoclonal antibodies was graded as follows: focal, <5% positive cells; 1+, 5-25% cells; 2+, 26-50% cells; 3+, 51-75%; and 4+, >75% cells. The 3+ and 4+ staining patterns were considered homogeneous patterns of potential clinical significance and were scored positive for statistical analysis. In low-grade tumors, the most immunoreactivity was seen with mAb M3H67 but little labeling was observed with the other monoclonal antibodies. In high-grade tumors, monoclonal antibodies M3H67 (25%), 57B (23%), and CT7-33 (20%) showed the highest reactivity, while ES121 showed the lowest immunoreactivity (6%). The staining pattern was mostly heterogeneous. Statistical significance was found solely for the correlation of monoclonal antibody 57B staining and p53 expression. No correlation was found for any anti-CT monoclonal antibody staining and clinical stage or for anti-CT staining and WT1 expression. CT antigens CT7, MAGE-A3 and MAGE-A4, but not NY-ESO-1, are expressed in high-grade endometrial carcinomas, and expression of MAGE-A4 is correlated with the presence of overexpressed p53.

Melanoma or not? Cancer testis antigens may help

BACKGROUND

Cancer testis antigens (CTAs) are expressed in a variety of malignant tumours. No CTA expression is found in normal adult tissues, except in male germ cells and occasionally placenta. To date, more than 20 CTAs or antigen families have been identified.

OBJECTIVES

Owing to their tumour-associated expression pattern, CTAs may be useful for making a distinction between benign and malignant neoplasms. The present study was done to analyse the value of CTAs for the discrimination of cutaneous melanoma and naevi.

PATIENTS AND METHODS

Primary melanomas (38) and 19 naevi were analysed for their expression of CTAs by immunohistochemistry using the following monoclonal antibodies (mAb) to the following antigens (mAb/antigen): MA454/MAGE-A1, 57B/MAGE-A4, ES121/NY-ESO-1. In a subset of melanomas (n = 26), the CTA panel was extended to three additional CTAs (mAb/antigen): CT7-33/MAGE-C1, M3H67/MAGE-A3 and GAGE/GAGE.

RESULTS

All 19 naevi were negative for the mAbs MA454, M3H67, 57B, ES121, CT7-33 and GAGE. In melanoma, the immunoreactivity was as follows: MA454: 8/38 (21%), 57B 11/38 (29%), ES121 9/38 (24%). However, 19/38 (50%) were positive for at least one CTA. When 26 melanomas were tested for the expression of six different CTAs 20/26 (77%) were positive for at least one CTA.

CONCLUSIONS

CTAs may be useful in the determination of suspected malignancy in cutaneous melanomas. The low incidence of particular CTAs can be overcome by increasing the number of CTAs analysed.

Biological functions of melanoma-associated antigens

To date, dozens of melanoma-associated antigens (MAGEs) have been identified and classified into 2 subgroups, I and II. Subgroup I consists of antigens which expression is generally restricted to tumor or germ cells, also named as cancer/testis (CT) antigen. Proteins and peptides derived from some of these antigens have been utilized in promising clinical trials of immunotherapies for gastrointestinal carcinoma, esophageal carcinoma, pulmonary carcinoma and so on. Various MAGE family members play important physiological and pathological roles during embryogenesis, germ cell genesis, apoptosis, etc. However, little is known regarding the role of MAGE family members in cell activities. It is reasonable to speculate that the genes for subgroup I MAGEs, which play important roles during embryogenesis, could be later deactivated by a genetic mechanism such as methylation. In the case of tumor formation, these genes are reactivated and the resultant proteins may be recognized and attacked by the immune system. Thus, the subgroup I MAGEs may play important roles in the immune surveillance of certain tumor types. Here, we review the classifications of MAGE family genes and what is known of their biological functions.

Immunohistochemistry in melanocytic proliferative lesions

Melanoma incidence is rising worldwide. Early diagnosis is very important, as the most effective treatment for melanoma still consists of excision of the tumour before onset of the metastatic growth phase. Immunohistochemistry is a valuable tool for (dermato)pathologists to aid establishing diagnosis. Melanoma markers can be classified into two main categories: melanocytic differentiation markers and melanoma progression markers. Melanocytic differentiation markers are mostly used to distinguish poorly differentiated melanomas from non-melanocytic tumours and for staging of melanocytic proliferative lesions. Melanoma progression markers are most suitable to determine the level of malignancy and/or aggressiveness of tumour cells. This review describes the classification of melanoma markers, including commonly used and recently identified antigens with potential marker function. We characterize their expression profile in melanocytic proliferative lesions and their potential usefulness for diagnosis, prognosis, microstaging, immunotherapeutic purposes and evaluation of therapies.