NY-ESO-1 and CTp11 expression may correlate with stage of progression in melanoma

Oncolytic attenuated measles virus encoding NY-ESO-1 induces HLA I and II presentation of this tumor antigen by melanoma and dendritic cells

Antitumor virotherapy stimulates the antitumor immune response during tumor cell lysis induced by oncolytic viruses (OVs). OV can be modified to express additional transgenes that enhance their therapeutic potential. In this study, we armed the spontaneously oncolytic Schwarz strain of measles viruses (MVs) with the gene encoding the cancer/testis antigen NY-ESO-1 to obtain MVny. We compared MV and MVny oncolytic activity and ability to induce NY-ESO-1 expression in six human melanoma cell lines. After MVny infection, we measured the capacity of melanoma cells to present NY-ESO-1 peptides to CD4 + and CD8 + T cell clones specific for this antigen. We assessed the ability of MVny to induce NY-ESO-1 expression and presentation in monocyte-derived dendritic cells (DCs). Our results show that MVny and MV oncolytic activity are similar with a faster cell lysis induced by MVny. We also observed that melanoma cell lines and DC expressed the NY-ESO-1 protein after MVny infection. In addition, MVny-infected melanoma cells and DCs were able to stimulate NY-ESO-1-specific CD4 + and CD8 + T cells. Finally, MVny was able to induce DC maturation. Altogether, these results show that MVny could be an interesting candidate to stimulate NY-ESO-1-specific T cells in melanoma patients with NY-ESO-1-expressing tumor cells.

T-cell-engaging Therapy for Solid Tumors

T-cell engagers (TCE) are a rapidly evolving novel group of treatments that have in common the concurrent engagement of a T-cell surface molecule and a tumoral cell antigen. Bispecific antibodies and genetically engineered adoptive cell therapies, as chimeric antigen receptors or T-cell receptors, have similarities and differences among their mechanisms of action, toxicity profiles, and resistance pathways. Nevertheless, the success observed in the hematologic field has not been obtained with solid tumors yet, as they are biologically more complex and have few truly tumor-specific cell surface antigens that can be targeted with high avidity T cells. Different strategies are under study to improve their short-term perspective, such as new generations of more active TCEs, multi-target or combination of different treatments approaches, or to improve the manufacturing processes. A comprehensive review of TCEs as a grouped treatment class, their current status, and research directions in their application to solid tumors therapeutics are discussed here.

Adoptive T cell therapy: Boosting the immune system to fight cancer

Cellular therapies have shown increasing promise as a cancer treatment. Encouraging results against hematologic malignancies are paving the way to move into solid tumors. In this review, we will focus on T-cell therapies starting from tumor infiltrating lymphocytes (TILs) to optimized T-cell receptor-modified (TCR) cells and chimeric antigen receptor-modified T cells (CAR-Ts). We will discuss the positive preclinical and clinical findings of these approaches, along with some of the persisting barriers that need to be overcome to improve outcomes.

Unleashing the immune response to NY-ESO-1 cancer testis antigen as a potential target for cancer immunotherapy

INTRODUCTION

Cancer Immunotherapy has recently emerged as a promising and effective modality to treat different malignancies. Antigenic profiling of cancer tissues and determination of any pre-existing immune responses to cancer antigens may help predict responses to immune intervention in cancer. NY-ESO-1, a cancer testis antigen is the most immunogenic antigen to date. The promise of NY-ESO-1 as a candidate for specific immune recognition of cancer comes from its restricted expression in normal adult tissue but frequent occurrence in multiple tumors including melanoma and carcinomas of lung, esophageal, liver, gastric, prostrate, ovarian, and bladder.

MAIN BODY

This review summarizes current knowledge of NY-ESO-1 as efficient biomarker and target of immunotherapy. It also addresses limitations and challenges preventing a robust immune response to NY-ESO-1 expressing cancers, and describes pre-clinical and clinical observations relevant to NY-ESO-1 immunity, holding potential therapeutic relevance for cancer treatment.

CONCLUSION

NY-ESO-1 induces strong immune responses in cancer patients but has limited objective clinical responses to NY-ESO-1 expressing tumors due to effect of competitive negative signaling from immune-checkpoints and immune-suppressive tumor microenvironment. We propose that combination therapy to increase the efficacy of NY-ESO-1 specific immunotherapeutic interventions should be explored to unleash the immune response against NY-ESO-1 expressing tumors.

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.

MAGE-A4 and MAGE-A1 Immunohistochemical Expression in High-grade Endometrial Cancer

The aim was to investigate MAGE-A4 and MAGE-A1 protein expression in high-grade endometrial cancer and determine its correlation with histologic subtype, FIGO stage, presence of vascular invasion, disease free, and overall survival. Immunohistochemical staining was performed by using 77B (MAGE-A1) and 57B (MAGE-A4) monoclonal antibodies on paraffin-embedded sections from high-grade endometrial cancers diagnosed in University Hospital Split between 1998 and 2011 (n=77). Median follow-up time for survivors was 48 mo. MAGE-A4 was found to be expressed in 33% of endometrioid type endometrial cancers grade 3 and in 27% of serous and clear cell carcinomas. MAGE-A1 was found to be expressed in 93% endometrioid endometrial cancer grade 3 and 86% of serous and clear cell carcinomas. Univariate analysis showed that positive immunohistochemical staining for MAGE-A4 was associated with decreased disease free and overall survival in patients with high-grade endometrial cancer. Multivariate analysis showed an association between MAGE-A4 overexpression and decreased disease free but not overall survival in high-grade endometrial cancer. No correlation was found between MAGE-A1 immunohistochemical expression and patient survival. There was no significant correlation between MAGE-A4 and MAGE-A1 expression and histologic subtype, FIGO stage, lymph node metastasis, muscular infiltration, and lymphovascular invasion. MAGE-A4 immunohistochemical expression is associated with decreased disease free and overall survival in patients with high-grade endometrial cancer. Our findings suggest that MAGE-A1 may be expressed in the epithelial cells of the normal endometrium. MAGE-A1 is highly expressed in high-grade endometrial cancer, with no impact on survival.

Therapeutic Targets for Bone and Soft-Tissue Sarcomas

Due to the rarity and heterogeneity of bone and soft-tissue sarcomas, investigation into molecular targets and new treatments has been particularly challenging. Although intensive chemotherapy and establishment of surgical procedures have improved the outcomes of patients with sarcoma, the curative rate of recurrent and metastatic sarcomas is still not satisfactory. Recent basic science research has revealed some of the mechanisms of progression and metastasis of malignancies including proliferation, apoptosis, angiogenesis, tumor microenvironment, migration, invasion, and regulation of antitumor immune systems. Based on these basic studies, new anticancer drugs, including pazopanib, trabectedin, eribulin, and immune checkpoint inhibitors have been developed and the efficacies and safety of the new drugs have been assessed by clinical trials. This review summarizes new molecular therapeutic targets and advances in the treatment for bone and soft tissue sarcomas.

Adoptive cellular therapies: the current landscape

For many cancer types, the immune system plays an essential role in their development and growth. Based on these rather novel insights, immunotherapeutic strategies have been developed. In the past decade, immune checkpoint blockade has demonstrated a major breakthrough in cancer treatment and has currently been approved for the treatment of multiple tumor types. Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TIL) or gene-modified T cells expressing novel T cell receptors (TCR) or chimeric antigen receptors (CAR) is another strategy to modify the immune system to recognize tumor cells and thus carry out an anti-tumor effector function. These treatments have shown promising results in various tumor types, and multiple clinical trials are being conducted worldwide to further optimize this treatment modality. Most successful results were obtained in hematological malignancies with the use of CD19-directed CAR T cell therapy and already led to the commercial approval by the FDA. This review provides an overview of the developments in ACT, the associated toxicity, and the future potential of ACT in cancer treatment.

Isolation and characterization of NY-ESO-1-specific T cell receptors restricted on various MHC molecules

Tumor-specific T cell receptor (TCR) gene transfer enables specific and potent immune targeting of tumor antigens. Due to the prevalence of the HLA-A2 MHC class I supertype in most human populations, the majority of TCR gene therapy trials targeting public antigens have employed HLA-A2-restricted TCRs, limiting this approach to those patients expressing this allele. For these patients, TCR gene therapy trials have resulted in both tantalizing successes and lethal adverse events, underscoring the need for careful selection of antigenic targets. Broad and safe application of public antigen-targeted TCR gene therapies will require (i) selecting public antigens that are highly tumor-specific and (ii) targeting multiple epitopes derived from these antigens by obtaining an assortment of TCRs restricted by multiple common MHC alleles. The canonical cancer-testis antigen, NY-ESO-1, is not expressed in normal tissues but is aberrantly expressed across a broad array of cancer types. It has also been targeted with A2-restricted TCR gene therapy without adverse events or notable side effects. To enable the targeting of NY-ESO-1 in a broader array of HLA haplotypes, we isolated TCRs specific for NY-ESO-1 epitopes presented by four MHC molecules: HLA-A2, -B07, -B18, and -C03. Using these TCRs, we pilot an approach to extend TCR gene therapies targeting NY-ESO-1 to patient populations beyond those expressing HLA-A2.

Melanoma: a prototype of cancer-testis antigen-expressing malignancies

Melanoma is the first malignancy in which expression and immunogenicity of cancer-testis antigens (CTAs) have been documented. Several CTAs have been shown to be expressed in melanoma samples especially those with metastatic potential. Many of them have been shown to exert oncogenic effects through modulation of essential pathways involved in melanoma. The crucial role of CTAs in the pathogenesis of melanoma, the high prevalence of expression of CTA panels in melanoma and the presence of spontaneous as well as inducible immune responses against CTAs in melanoma patients potentiate CTAs as immunotherapeutic targets. Numerous clinical trials are now ongoing to evaluate CTA-based immunotherapeutic effects in melanoma patient's survival. NY-ESO-1 and MAGE antigens have the most promising results up to now.

NY-ESO-1 Based Immunotherapy of Cancer: Current Perspectives

NY-ESO-1 or New York esophageal squamous cell carcinoma 1 is a well-known cancer-testis antigen (CTAs) with re-expression in numerous cancer types. Its ability to elicit spontaneous humoral and cellular immune responses, together with its restricted expression pattern, have rendered it a good candidate target for cancer immunotherapy. In this review, we provide background information on NY-ESO-1 expression and function in normal and cancerous tissues. Furthermore, NY-ESO-1-specific immune responses have been observed in various cancer types; however, their utility as biomarkers are not well determined. Finally, we describe the immune-based therapeutic options targeting NY-ESO-1 that are currently in clinical trial. We will highlight the recent advancements made in NY-ESO-1 cancer vaccines, adoptive T cell therapy, and combinatorial treatment with checkpoint inhibitors and will discuss the current trends for future NY-ESO-1 based immunotherapy. Cancer treatment has been revolutionized over the last few decades with immunotherapy emerging at the forefront. Immune-based interventions have shown promising results, providing a new treatment avenue for durable clinical responses in various cancer types. The majority of successful immunotherapy studies have been reported in liquid cancers, whereas these approaches have met many challenges in solid cancers. Effective immunotherapy in solid cancers is hampered by the complex, dynamic tumor microenvironment that modulates the extent and phenotype of the antitumor immune response. Furthermore, many solid tumor-associated antigens are not private but can be found in normal somatic tissues, resulting in minor to detrimental off-target toxicities. Therefore, there is an ongoing effort to identify tumor-specific antigens to target using various immune-based modalities. CTAs are considered good candidate targets for immunotherapy as they are characterized by a restricted expression in normal somatic tissues concomitant with a re-expression in solid epithelial cancers. Moreover, several CTAs have been found to induce a spontaneous immune response, NY-ESO-1 being the most immunogenic among the family members. Hence, this review will focus on NY-ESO-1 and discuss the past and current NY-ESO-1 targeted immunotherapeutic strategies.

Melanoma: tumor microenvironment and new treatments

In the recent past years, many discoveries in the tumor microenvironment have led to changes in the management of melanoma and it is rising up hopes, specially, to those in advanced stages. FDA approved seven new drugs from 2011 to 2014. They are: Vemurafenib, Dabrafenib and Trametinib, kinases inhibitors used for patients that have BRAFV600E mutation; Ipilimumab (anti-CTLA4), Pembrolizumab (anti-PD-1) and Nivolumab (anti-PD-1), monoclonal antibodies that stimulate the immune system; and Peginterferon alfa-2b, an anti-proliferative cytokine used as adjuvant therapy. In this article, we will review the molecular bases for these new metastatic melanoma therapeutic agents cited above and also analyze new molecular discoveries in melanoma study, as Cancer-Testis antigens (CT). They are capable of induce humoral and cellular immune responses in cancer patients and because of this immunogenicity and their restrict expression in normal tissues, they are considered an ideal candidate for vaccine development against cancer. Among CT antigens, NY-ESO-1 is the best characterized in terms of expression patterns and immunogenicity. It is expressed in 20-40% of all melanomas, more in metastatic lesions than in primary ones, and it is very heterogeneous inter and intratumoral. Breslow index is associate with NY-ESO-1 expression in primary cutaneous melanomas, but its relation to patient survival remains controversial.

Lack of XAGE-1b and NY-ESO-1 in metastatic lymph nodes may predict the potential survival of stage III melanoma patients

The cancer-testis antigens (CTA) are a large family of tumor-associated antigens expressed by a variety of cancer cells and primitive germ cells of the adult testis and placenta. These tumor-restricted expressing patterns suggest that CTA would be ideal targets for tumor-specific immunotherapy. XAGE-1 is a CTA that was originally identified by computer-based screening, and four transcription variants, XAGE-1a, -1b, -1c and -1d, have been characterized to date. Although the presence of XAGE-1 transcripts has been reported in various cancers, the expression of XAGE-1b in melanoma has not been fully characterized. In this study, we performed immunohistochemical staining of XAGE-1b together with NY-ESO-1, a well-known CTA, in 113 melanoma samples obtained from 84 patients and evaluated their expression in tumor cells. The effects of expression on tumor progression and patient prognosis were analyzed. Both XAGE-1b and NY-ESO-1 were expressed at high levels in lymph node metastasis and skin metastasis samples compared with the primary site (P < 0.01 in XAGE-1b and P < 0.05 in NY-ESO-1). In a subgroup analysis of 22 patients with stage III lymph node metastasis, overall survival was significantly higher in the XAGE-1b and NY-ESO-1 double-negative group than in the other groups (P < 0.05). These results suggest that lack of XAGE-1b and NY-ESO-1 expression could have a positive influence on clinical outcome in patients with melanoma.

New York esophageal squamous cell carcinoma-1 and cancer immunotherapy

New York esophageal squamous cell carcinoma 1 (NY-ESO-1) is a known cancer testis gene with exceptional immunogenicity and prevalent expression in many cancer types. These characteristics have made it an appropriate vaccine candidate with the potential application against various malignancies. This article reviews recent knowledge about the NY-ESO-1 biology, function, immunogenicity and expression in cancers as well as and the results of clinical trials with this antigen.

Increased NY-ESO-1 expression and reduced infiltrating CD3+ T cells in cutaneous melanoma

NY-ESO-1 is a cancer-testis antigen aberrantly expressed in melanomas, which may serve as a robust and specific target in immunotherapy. NY-ESO-1 antigen expression, tumor features, and the immune profile of tumor infiltrating lymphocytes were assessed in primary cutaneous melanoma. NY-ESO-1 protein was detected in 20% of invasive melanomas (16/79), rarely in in situ melanoma (1/10) and not in benign nevi (0/20). Marked intratumoral heterogeneity of NY-ESO-1 protein expression was observed. NY-ESO-1 expression was associated with increased primary tumor thickness (P = 0.007) and inversely correlated with superficial spreading melanoma (P < 0.02). NY-ESO-1 expression was also associated with reduced numbers and density of CD3+ tumor infiltrating lymphocytes (P = 0.017). When NY-ESO-1 protein was expressed, CD3+ T cells were less diffusely infiltrating the tumor and were more often arranged in small clusters (P = 0.010) or as isolated cells (P = 0.002) than in large clusters of more than five lymphocytes. No correlation of NY-ESO-1 expression with gender, age, tumor site, ulceration, lymph node sentinel status, or survival was observed. NY-ESO-1 expression in melanoma was associated with tumor progression, including increased tumor thickness, and with reduced tumor infiltrating lymphocytes.

Broadening the repertoire of melanoma-associated T-cell epitopes

Immune therapy has provided a significant breakthrough in the treatment of metastatic melanoma. Despite the remarkable clinical efficacy and established involvement of effector CD8 T cells, the knowledge of the exact peptide-MHC complexes recognized by T cells on the tumor cell surface is limited. Many melanoma-associated T-cell epitopes have been described, but this knowledge remains largely restricted to HLA-A2, and we lack understanding of the T-cell recognition in the context of other HLA molecules. We selected six melanoma-associated antigens (MAGE-A3, NY-ESO-1, gp100, Mart1, tyrosinase and TRP-2) that are frequently recognized in patients with the aim of identifying novel T-cell epitopes restricted to HLA-A1, -A3, -A11 and -B7. Using in silico prediction and in vitro confirmation, we identified 127 MHC ligands and analyzed the T-cell responses against these ligands via the MHC multimer-based enrichment of peripheral blood from 39 melanoma patients and 10 healthy donors. To dissect the T-cell reactivity against this large peptide library, we used combinatorial-encoded MHC multimers and observed the T-cell responses against 17 different peptide-MHC complexes in the patient group and four in the healthy donor group. We confirmed the processing and presentation of HLA-A3-restricted T-cell epitopes from tyrosinase (TQYESGSMDK) and gp100 (LIYRRRLMK) and an HLA-A11-restricted T-cell epitope from gp100 (AVGATKVPR) via the cytolytic T-cell recognition of melanoma cell lines and/or K562 cells expressing the appropriate antigen and HLA molecule. We further found T-cell reactivity against two of the identified sequences among tumor-infiltrating lymphocytes from melanoma patients, suggesting a potential clinical relevance of these sequences.

A pilot trial using lymphocytes genetically engineered with an NY-ESO-1-reactive T-cell receptor: long-term follow-up and correlates with response

PURPOSE

Although adoptive cell therapy can be highly effective for the treatment of patients with melanoma, the application of this approach to the treatment of other solid tumors has been limited. The observation that the cancer germline (CG) antigen NY-ESO-1 is expressed in 70% to 80% and in approximately 25% of patients with synovial cell sarcoma and melanoma, respectively, prompted us to perform this first-in-man clinical trial using the adoptive transfer of autologous peripheral blood mononuclear cells that were retrovirally transduced with an NY-ESO-1-reactive T-cell receptor (TCR) to heavily pretreated patients bearing these metastatic cancers.

EXPERIMENTAL DESIGN

HLA-*0201 patients with metastatic synovial cell sarcoma or melanoma refractory to standard treatments and whose cancers expressed NY-ESO-1 received autologous TCR-transduced T cells following a lymphodepleting preparative chemotherapy. Response rates using Response Evaluation Criteria in Solid Tumors (RECIST), as well as immunologic correlates of response, are presented in this report.

RESULTS

Eleven of 18 patients with NY-ESO-1(+) synovial cell sarcomas (61%) and 11 of 20 patients with NY-ESO-1(+) melanomas (55%) who received autologous T cells transduced with an NY-ESO-1-reactive TCR demonstrated objective clinical responses. The estimated overall 3- and 5-year survival rates for patients with synovial cell sarcoma were 38% and 14%, respectively, whereas the corresponding estimated survival rates for patients with melanoma were both 33%.

CONCLUSIONS

The adoptive transfer of autologous T cells transduced with a retrovirus encoding a TCR against an HLA-A*0201 restricted NY-ESO-1 epitope can be an effective therapy for some patients bearing synovial cell sarcomas and melanomas that are refractory to other treatments.

A case of spontaneous systemic immunity to melanoma associated with cure after amputation for extensive regional recurrence

PURPOSE

Survival after amputation for melanoma is short; however, rare long-term survivors are reported. The mechanism for durable systemic tumor control in patients with regional failure is not known. To explore whether systemic tumor immunity may be implicated, tumor and circulating immune responses were examined in a patient who survived disease-free 14 years after hip disarticulation.

METHODS

A 71-year-old female with extensive regional metastases of melanoma in the left lower extremity underwent amputation for palliative reasons. Tumor was collected at surgery, and blood was collected during follow-up. Tumor sections were evaluated for lymphocytic infiltration and NY-ESO-1 expression by immunohistochemistry. Cellular immune responses to defined tumor antigens were evaluated by ELISPOT assay, and antibody responses to a panel of tumor antigens were assayed by ELISA.

RESULTS

The patient's tumor had minimal lymphocytic infiltrate (immunotype A). NY-ESO-1 was strongly expressed by the melanoma cells. Circulating T-cell responses to NY-ESO-1 peptides were observed 6 and 12 years postoperatively, and antibodies to NY-ESO-1 were detected 2-6 years after surgery.

CONCLUSION

The patient described in this report experienced relentless regional tumor progression, with intravascular metastases, and then 14-year systemic disease-free survival after palliative resection, without evidence of melanoma recurrence before death from other causes. Her immune response to NY-ESO-1 likely failed to control established regional metastases because T cells were unable to infiltrate them. It is possible, however, that among other factors, the host immune response may have contributed to systemic protection.

Cancer/testis antigens expression and autologous serological response in a set of Brazilian non-Hodgkin's lymphoma patients

BACKGROUND

Based on their tumor-associated expression pattern, cancer/testis antigens (CTAs) are considered potential targets for cancer immunotherapy. We aim to evaluate the expression of CTAs in non-Hodgkin's lymphoma (NHL) samples and the ability of these patients to elicit spontaneous humoral immune response against CTAs.

METHODS

Expression of MAGE-A family, CT7/MAGE-C1, CT10/MAGE-C2, GAGE and NY-ESO-1 was analyzed by immunohistochemistry in a tissue microarray generated from 106 NHL archival cases. The humoral response against 19 CTAs was tested in 97 untreated NHL serum samples using ELISA technique.

RESULTS

11.3 % of NHL tumor samples expressed at least 1 CTA. MAGE-A family (6.6 %), GAGE (5.7 %) and NY-ESO-1(4.7 %) were the most frequently expressed antigens. We found no statistically significant correlation between CTA positivity and clinical parameters such as NHL histological subtype, Ann Arbor stage, international prognostic index score, response to treatment and overall survival. Humoral response against at least 1 CTA was observed in 16.5 % of NHL serum samples. However, overall seroreactivity was low, and strong titers (>1:1000) were observed in only two diffuse large B-cell lymphomas patients against CT45.

CONCLUSION

Our findings are in agreement with most of published studies in this field to date and suggest an overall low expression of CTAs in NHL patients. However, as many new CTAs have been described recently and some of them are found to be highly expressed in NHL cell lines and tumor samples, further studies exploring the expression of different panels of CTAs are needed to evaluate their role as candidates for immunotherapy in NHL patients.

Germ cell proteins in melanoma: prognosis, diagnosis, treatment, and theories on expression

Germ cell protein expression in melanoma has been shown to correlate with malignancy, severity of disease and to serve as an immunologic target for therapy. However, very little is known about the role that germ cell proteins play in cancer development. Unique germ cell pathways include those involved in immortalization, genetic evolution, and energy metabolism. There is an ever increasing recognition that within tumors there is a subpopulation of cells with stem-cell-like characteristics that play a role in driving tumorgenesis. Stem cell and germ cell biology is intertwined. Given the enormous potential and known expression of germ cell proteins in melanoma, it is possible that they represent a largely untapped resource that may play a fundamental role in tumor development and progression. The purpose of this paper is to provide an update on the current value of germ cell protein expression in melanoma diagnosis, prognosis, and therapy, as well as to review critical germ cell pathways and discuss the potential roles these pathways may play in malignant transformation.

Exclusion of the 750-kb genetically unstable region at Xq27 as a candidate locus for prostate malignancy in HPCX1-linked families

Several linkage studies provided evidence for the presence of the hereditary prostate cancer locus, HPCX1, at Xq27-q28. The strongest linkage peak of prostate cancer overlies a variable region of ~750 kb at Xq27 enriched by segmental duplications (SDs), suggesting that the predisposition to prostate cancer may be a genomic disorder caused by recombinational interaction between SDs. The large size of SDs and their sequence similarity make it difficult to examine this region for possible rearrangements using standard methods. To overcome this problem, direct isolation of a set of genomic segments by in vivo recombination in yeast (a TAR cloning technique) was used to perform a mutational analysis of the 750 kb region in X-linked families. We did not detect disease-specific rearrangements within this region. In addition, transcriptome and computational analyses were performed to search for nonannotated genes within the Xq27 region, which may be associated with genetic predisposition to prostate cancer. Two candidate genes were identified, one of which is a novel gene termed SPANXL that represents a highly diverged member of the SPANX gene family, and the previously described CDR1 gene that is expressed at a high level in both normal and malignant prostate cells, and mapped 210 kb of upstream the SPANX gene cluster. No disease-specific alterations were identified in these genes. Our results exclude the 750-kb genetically unstable region at Xq27 as a candidate locus for prostate malignancy. Adjacent regions appear to be the most likely candidates to identify the elusive HPCX1 locus.

An overview of cancer/testis antigens expression in classical Hodgkin's lymphoma (cHL) identifies MAGE-A family and MAGE-C1 as the most frequently expressed antigens in a set of Brazilian cHL patients

ABSTRACT: BACKGROUND: Cancer/testis antigens are considered potential targets for immunotherapy due to their tumor-associated expression pattern. Although recent studies have demonstrated high expression of CT45 in classical Hodgkin's lymphomas (cHL), less is known about the expression pattern of other families of CTAs in cHL. We aim to evaluate the expression of MAGE-A family, MAGE-C1/CT7, MAGE-C2/CT10, NY-ESO1 and GAGE family in cHL and to correlate their expression with clinical and prognostic factors in cHL. METHODS: Tissue microarray was generated from 38 cHL archival cases from Pathology Department of Universidade Federal de Sao Paulo. Immunohistochemistry (IHC) was done using the following panel of antibodies: MAGE-A family (MA454, M3H67, 57B and 6C1), GAGE (#26), NY-ESO-1 (E978), MAGE-C1/CT7 (CT7-33) and MAGE-C2/CT10 (CT10#5). RESULTS: We found CTA expression in 21.1% of our cHL series. Among the tested CTAs, only MAGE-A family 7/38 (18.4%) and MAGE-C1/CT7 5/38 (13.2%) were positive in our cHL samples. We found higher CTA positivity in advanced stage (28.6%) compared to early stage (11.8%) disease, but this difference was not statistically significant. Analysis of other clinicopathological subgroups of cHL including histological subtypes, EBV status and response to treatment also did not demonstrate statistical significant differences in CTA expression. CONCLUSION: We found CTA expression in 21.1% of cHL samples using our panel. Our preliminary findings suggest that from all CTAs included in this study, MAGE-A family and MAGE-C1/CT7 are the most interesting ones to be explored in further studies.

Tumor regression in patients with metastatic synovial cell sarcoma and melanoma using genetically engineered lymphocytes reactive with NY-ESO-1

PURPOSE

Adoptive immunotherapy using tumor-infiltrating lymphocytes represents an effective cancer treatment for patients with metastatic melanoma. The NY-ESO-1 cancer/testis antigen, which is expressed in 80% of patients with synovial cell sarcoma and approximately 25% of patients with melanoma and common epithelial tumors, represents an attractive target for immune-based therapies. The current trial was carried out to evaluate the ability of adoptively transferred autologous T cells transduced with a T-cell receptor (TCR) directed against NY-ESO-1 to mediate tumor regression in patients with metastatic melanoma and synovial cell sarcoma.

PATIENTS AND METHODS

A clinical trial was performed in patients with metastatic melanoma or metastatic synovial cell sarcoma refractory to all standard treatments. Patients with NY-ESO-1-positive tumors were treated with autologous TCR-transduced T cells plus 720,000 iU/kg of interleukin-2 to tolerance after preparative chemotherapy. Objective clinical responses were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Objective clinical responses were observed in four of six patients with synovial cell sarcoma and five of 11 patients with melanoma bearing tumors expressing NY-ESO-1. Two of 11 patients with melanoma demonstrated complete regressions that persisted after 1 year. A partial response lasting 18 months was observed in one patient with synovial cell sarcoma.

CONCLUSION

These observations indicate that TCR-based gene therapies directed against NY-ESO-1 represent a new and effective therapeutic approach for patients with melanoma and synovial cell sarcoma. To our knowledge, this represents the first demonstration of the successful treatment of a nonmelanoma tumor using TCR-transduced T cells.

Cancer-testis antigen expression in primary cutaneous melanoma has independent prognostic value comparable to that of Breslow thickness, ulceration and mitotic rate

To determine the effect of Cancer-Testis Antigen (CTAg) expression on the natural history of primary cutaneous melanoma we compared its impact on prognosis with that of known prognostic factors and its relationship with other clinicopathologic characteristics. The immunohistochemical expression of three CTAgs (MAGE-A1, MAGE-A4 and NY-ESO-1) in 348 cases of stage I and stage II primary cutaneous melanoma was analysed and correlated with clinicopathologic characteristics, relapse free survival (RFS) and overall survival (OS). A Cox proportional hazards regression model was used to analyse factors which independently predicted RFS. All three CTAgs were significantly co-expressed with each other (p < 0.001). The median RFS for patients with CTAg-negative tumours and CTAg-positive tumours was 72 months and 45 months, respectively, (P = 0.008). Univariate analysis demonstrated that the impact of CTAg expression on RFS was comparable in magnitude to that of Breslow thickness, ulceration and tumour mitotic rate. Multivariate Cox regression analysis indicated that CTAg expression was a powerful independent predictor of RFS (risk ratio (RR) = 1.715, 95% confidence interval (CI) = 0.430-0.902, P = 0.010). In contrast, CTAg expression was demonstrated to have no prognostic impact on overall survival. This study demonstrates that CTAg expression in primary cutaneous melanoma is a strong independent predictor of RFS and it is comparable to other known important prognostic factors. CTAg expression has no relationship with overall survival, suggesting anti-melanoma immunity directed towards CTAg expression may contribute to the natural history of the disease. In view of these results, further investigation of the function of CTAgs and their potential use in therapeutic targeting is warranted.

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.

Cancer-germline antigen vaccines and epigenetic enhancers: future strategies for cancer treatment

IMPORTANCE OF THE FIELD

Immunotherapy holds great potential for disseminated cancer, and cancer-germline (CG) antigens are among the most promising tumor targets. They are widely expressed in different cancer types and are essentially tumor-specific, since their expression in normal tissues is largely restricted to immune-privileged sites. Although the therapeutic potential of these antigens may be compromised by their highly heterogeneous expression in many tumors and low frequency in some cancers, recent developments suggest that tumor-cell-selective enhancement of CG antigen gene expression can be achieved using epigenetic modifiers.

AREAS COVERED IN THIS REVIEW

We provide an overview of the potential of CG antigens as targets for cancer immunotherapy, including advantages and disadvantages. We also discuss the current state of development of CG antigen vaccines, and the potential synergistic effect of combining CG antigen immunotherapeutic strategies with epigenetic modifiers.

WHAT THE READER WILL GAIN

The reader will gain an overview of the past, present and future role of CG antigens in cancer immunotherapy.

TAKE HOME MESSAGE

Chemoimmunotherapy using epigenetic drugs and CG antigen vaccines may be a useful approach for treating cancer.

Expression of cancer-testis antigen SPANX-C mRNA in human hepatocellular carcinoma and prediction of HLA-A2-restricted CTL epitopes of SPANX-C

AIM: To investigate the expression of SPANX-C (sperm protein associated with the nucleus mapped to the X chromosome-C) gene in hepatocellular carcinoma (HCC) and to predict the HLA-A2-restricted cytotoxic T lymphocyte (CTL) epitopes of SPANX-C to find new targets for specific immunotherapy of HCC.

METHODS: The expression of SPANX-C mRNA was characterized by RT-PCR in tumor tissue and adjacent liver tissue specimens from 115 HCC patients and liver tissue specimens from 20 non-HCC patients (10 with liver cirrhosis and 10 without liver disease). The positive PCR products (297 bp) obtained from 5 tumor tissue specimens were randomly selected for sequencing to confirm the detecting results. HLA-A2-restricted CTL epitopes of SPANX-C were predicted by peptide supermotif prediction method in combination with quantitative motif method.

RESULTS: Seventy (60.9%) of 115 tumor tissue specimen from HCC patients expressed SPANX-C mRNA. In contrast, SPANX-C mRNA was not detected in tumor-adjacent tissue and liver tissue from non-HCC patients. There was no discernable correlation between SPANX-C expression and tumor stage, differentiation degree or serum α-fetoprotein level (all P > 0.05). Five CTL epitope candidates (nonamers) derived from the antigen SPANX-C were found by peptide supermotif prediction, of them, SPANX-C_51-59 (LVVRYRRNV) may have stronger binding potential with HLA-A2 molecule.

CONCLUSION: SPANX-C mRNA is highly expressed in HCC tumor tissue in Chinese patients. SPANX-C may provide potential HLA-A2-restricted CTL epitopes as specific targets for immunotherapy of HCC.

Cancer/testis (CT) antigens: potential targets for immunotherapy

Cancer/testis (CT) antigens are protein antigens with normal expression restricted to adult testicular germ cells, and yet are aberrantly activated and expressed in a proportion of various types of human cancer. At least a subset of this group of antigens has been found to elicit spontaneous humoral and cell-mediated immune responses in cancer patients, raising the possibility that these antigens could be cancer vaccine targets. More than 100 CT antigen genes have been reported in the literature, with approximately 30 being members of multigene families on the X chromosome, so-called CT-X genes. Most CT-X genes are expressed at the spermatogonia stage of spermatogenesis, and their functions are mostly unknown. In cancer, the frequency of CT antigen expression is highly variable among different tumor types, but is more often expressed in high-grade late-stage cases in general. Cancer vaccine trials based on CT antigens MAGE-A3 and NY-ESO-1 are currently ongoing, and these antigens may also play a role in antigen-specific adoptive T-cell transfer and in the immunomodulation approach of cancer therapy.

Evolutionary diversification of SPANX-N sperm protein gene structure and expression

The sperm protein associated with nucleus in the X chromosome (SPANX) genes cluster at Xq27 in two subfamilies, SPANX-A/D and SPANX-N. SPANX-A/D is specific for hominoids and is fairly well characterized. The SPANX-N gave rise to SPANX-A/D in the hominoid lineage ∼7 MYA. Given the proposed role of SPANX genes in spermatogenesis, we have extended studies to SPANX-N gene evolution, variation, regulation of expression, and intra-sperm localization. By immunofluorescence analysis, SPANX-N proteins are localized in post-meiotic spermatids exclusively, like SPANX-A/D. But in contrast to SPANX-A/D, SPANX-N are found in all ejaculated spermatozoa rather than only in a subpopulation, are localized in the acrosome rather than in the nuclear envelope, and are expressed at a low level in several nongametogenic adult tissues as well as many cancers. Presence of a binding site for CTCF and its testis-specific paralogue BORIS in the SPANX promoters suggests, by analogy to MAGE-A1 and NY-ESO-1, that their activation in spermatogenesis is mediated by the programmed replacement of CTCF by BORIS. Based on the relative density of CpG, the more extended expression of SPANX-N compared to SPANX-A/D in nongametogenic tissues is likely attributed to differences in promoter methylation. Our findings suggest that the recent duplication of SPANX genes in hominoids was accompanied by different localization of SPANX-N proteins in post-meiotic sperm and additional expression in several nongonadal tissues. This suggests a corresponding functional diversification of SPANX gene families in hominoids. SPANX proteins thus provide unique targets to investigate their roles in the function of spermatozoa, selected malignancies, and for SPANX-N, in other tissues as well.

Epitope clustering in regions undergoing efficient proteasomal processing defines immunodominant CTL regions of a tumor antigen

Identification of immunodominant CD8(+) T cell responses to frequently expressed tumor antigens across MHC class I polymorphism is essential for the implementation of cancer immunotherapy. However, the key factors that determine immunodominance are not fully understood. Because of its frequent expression in tumors and its spontaneous immunogenicity, NY-ESO-1 is a prime target of cancer vaccines and an ideal model antigen for elucidating the molecular basis of immunodominant tumor-specific CD8(+) T cell responses. Here, we have assessed CD8(+)T cell responses to full-length NY-ESO-1 in cancer patients. We identified 3 immunodominant regions of the protein located within 3 distinct clusters of MHC class I binding sequences that co-localize with previously defined clusters of MHC class II binding sequences, are predicted to be hydrophobic and undergo efficient proteasomal processing. Our results support the concept that epitope clustering within defined protein regions identifies tumor antigen immunodominant regions and suggest a general strategy for their identification.

Directions in the immune targeting of cancer: lessons learned from the cancer-testis Ag NY-ESO-1

Since the early 1990s, numerous cancer Ag have been defined and for a handful of these there is now some clinical experience, which has made it possible to assess their value as targets for cancer immunotherapy. The cancer-testis Ag have been particularly attractive because their expression is limited to cancer and virtually no non-malignant cells apart from germ cells and trophoblast. Among these, NY-ESO-1 has been the focus of our attention. The exceptional immunogenicity of this Ag coupled with its widespread distribution among many cancer types make it a very good vaccine candidate, with the potential to be used in vaccines against many types of malignancies. This article reviews emerging knowledge about the biology of NY-ESO-1 and experience with the early clinical development of vaccines directed against NY-ESO-1. These early studies have yielded a wealth of information about the immunology of NY-ESO-1 and set the scene for future clinical strategies for immune targeting of cancer.

Tumor antigen expression in melanoma varies according to antigen and stage

PURPOSE

Melanoma cells express antigens that can induce T-cell and antibody responses. Obtaining a detailed understanding of antigen expression in primary and metastatic melanoma is essential if these molecules are to be useful targets for immunotherapy of melanoma.

EXPERIMENTAL DESIGN

Malignant melanomas (n = 586) from 426 patients were typed for antigen expression. Multiple samples were available from 86 individuals, enabling analysis of antigen expression patterns over time. Paraffin-embedded samples were tested by immunohistochemistry for the presence of the differentiation antigens: gp100, Melan-A, tyrosinase, and the "cancer/testis" antigens MAGE-A1, MAGE-A4, and NY-ESO-1.

RESULTS

Samples were primary tumors (n = 251), lymph node metastases (n = 174), s.c. metastases (n = 71), and distant metastases (n = 90). The differentiation antigens were strongly expressed in 93% to 95% of tumors regardless of stage. In contrast, the frequency of cancer/testis antigen expression in primary tumors for MAGE-A1, MAGE-A4, and NY-ESO-1 was lower (20%, 9%, and 45%, respectively). MAGE-A1 and MAGE-A4 were acquired with advancing disease (to 51% and 44% in distant metastases, respectively) but not NY-ESO-1, which remained positive in 45%. MAGE-A1 expression was twice as prevalent in ulcerated primaries as in nonulcerated primaries (30% versus 15%; P = 0.006) and in thicker as opposed to thin melanomas (26% versus 10%; P = 0.1).

CONCLUSIONS

This large series describes patterns of antigen expression in melanoma and their evolution over time. This will help inform decisions about selection of patients and target antigens for melanoma immunotherapy clinical trials.

Dynamic structure of the SPANX gene cluster mapped to the prostate cancer susceptibility locus HPCX at Xq27

Genetic linkage studies indicate that germline variations in a gene or genes on chromosome Xq27-28 are implicated in prostate carcinogenesis. The linkage peak of prostate cancer overlies a region of approximately 750 kb containing five SPANX genes (SPANX-A1, -A2, -B, -C, and -D) encoding sperm proteins associated with the nucleus; their expression was also detected in a variety of cancers. SPANX genes are >95% identical and reside within large segmental duplications (SDs) with a high level of similarity, which confounds mutational analysis of this gene family by routine PCR methods. In this work, we applied transformation-associated recombination cloning (TAR) in yeast to characterize individual SPANX genes from prostate cancer patients showing linkage to Xq27-28 and unaffected controls. Analysis of genomic TAR clones revealed a dynamic nature of the replicated region of linkage. Both frequent gene deletion/duplication and homology-based sequence transfer events were identified within the region and were presumably caused by recombinational interactions between SDs harboring the SPANX genes. These interactions contribute to diversity of the SPANX coding regions in humans. We speculate that the predisposition to prostate cancer in X-linked families is an example of a genomic disease caused by a specific architecture of the SPANX gene cluster.

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.

A phenotype based approach for the immune monitoring of NY-ESO-1-specific CD4+ T cell responses in cancer patients

Because of its frequent expression in tumors and spontaneous immunogenicity in advanced cancer patients, NY-ESO-1 is presently viewed as a prototype tumor antigen for the development of cancer vaccines. A prerequisite for the analysis of NY-ESO-1-specific T cell responses in vaccinated patients is the assessment of the complete T cell repertoire available for the antigen. Here, we have assessed frequency and fine specificity of CD4+ T cells reactive against NY-ESO-1-derived sequences in circulating lymphocytes from cancer patients with spontaneous responses to the antigen. We found that, relative to healthy donors, this frequency was only moderately increased in cancer patients. The reactivity of these cells, however, was directed against the same immunodominant regions previously identified for healthy donors. On account of these data, we developed an approach for the immune monitoring of NY-ESO-1-specific CD4+ T cell responses based on the assessment of CD4+ T cell populations of defined phenotype. Using this approach, a similar frequency of NY-ESO-1-specific CD4+ T cells was found among naive T cells of healthy donors and cancer patients. In contrast, among antigen-experienced T cells, NY-ESO-1-specific CD4+ T cells were exclusively detectable in cancer patients. We anticipate that this phenotype-based approach will be useful for the immune monitoring of vaccine-induced responses in vaccination trials using NY-ESO-1 as well as other tumor antigens.

Cancer-Testis Genes Are Coordinately Expressed and Are Markers of Poor Outcome in Non–Small Cell Lung Cancer

PURPOSE

Cancer-testis genes mapping to the X chromosome have common expression patterns and show similar responses to modulators of epigenetic mechanisms. We asked whether cancer-testis gene expression occurred coordinately, and whether it correlated with variables of disease and clinical outcome of non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Tumors from 523 NSCLC patients undergoing surgery were evaluated for the expression of nine cancer-testis genes (NY-ESO-1, LAGE-1, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7/MAGE-C1, SSX2, and SSX4) by semiquantitative PCR. Clinical data available for 447 patients were used to correlate cancer-testis expression to variables of disease and clinical outcome.

RESULTS

At least one cancer-testis gene was expressed by 90% of squamous carcinoma, 62% of bronchioloalveolar cancer, and 67% of adenocarcinoma samples. Statistically significant coexpression was observed for 34 of the 36 possible cancer-testis combinations. Cancer-testis gene expression, either cumulatively or individually, showed significant associations with male sex, smoking history, advanced tumor, nodal and pathologic stages, pleural invasion, and the absence of ground glass opacity. Cox regression analysis revealed the expression of NY-ESO-1 and MAGE-A3 as markers of poor prognosis, independent of confounding variables for adenocarcinoma of the lung.

CONCLUSIONS

Cancer-testis genes are coordinately expressed in NSCLC, and their expression is associated with advanced disease and poor outcome.

Quantitative and qualitative assessment of circulating NY-ESO-1 specific CD4+ T cells in cancer-free individuals

The germ cell antigen NY-ESO-1 is characterized by its frequent expression in patients bearing cancers of various histological types, that positively correlates with stage of disease, together with its frequent spontaneous immunogenicity in patients with advanced cancer. Because of these features, NY-ESO-1 is presently viewed as a prototype antigen for the development of cancer vaccines aimed at preventing disease progression. To gain a global view of the CD4+ T cell repertoire available for NY-ESO-1 in individuals of different genetic background, in this study, we have addressed the presence, frequency, and fine specificity of CD4+ T cells reactive against NY-ESO-1-derived sequences among circulating lymphocytes from healthy donors. NY-ESO-1 specific CD4+ T cells were present among circulating lymphocytes at a frequency between 0.5 and 5 precursors per million CD4+ T cells. In the majority of the cases, the reactivity of NY-ESO-1 specific CD4+ T cells was directed towards immunodominant regions located in the carboxyl-terminal half of the protein. Interestingly, immunodominant regions were confined to parts of the NY-ESO-1 protein containing hotspot sequences with predicted high binding for multiple frequently expressed MHC class II molecules. In contrast, no reactivity was found against the amino-terminal part of the protein, which was concomitant with the paucity, in this region, of sequences with predicted high binding to MHC class II molecules.

Quantification of SSX mRNA expression in human bone and soft tissue tumors using nucleic acid sequence-based amplification

The SSX family proteins have been considered new members of the cancer/testis antigens because of the restricted expression in testis among normal tissues and the activation in a wide range of cancers. Thus, they would be potential molecular targets for immunotherapeutic strategies. We have developed a competitive nucleic acid sequence-based amplification (NASBA) assay to analyze SSX mRNA expression in 211 bone and soft tissue tumors. The copy numbers of SSX mRNA per mug of total RNA in tumor tissues were widely distributed, ranging logarithmically from 0.6 to 6.6. We found that malignant tumors showed significantly higher expression of SSX mRNA than benign tumors (P < 0.0001). Further, SSX mRNA expression in stage III tumors was significantly higher than that in stage I or II tumors (P < 0.005). This NASBA assay was also more sensitive compared to immunohistochemistry using newly affinity-purified polyclonal antibody against SSX. Collectively, these results suggest that the SSX quantitative NASBA assay could provide useful information to select eligible patients for SSX-specific cancer vaccines.

NY-ESO-1 expression and immunogenicity in esophageal cancer

PURPOSE

Although NY-ESO-1 was isolated from an esophageal carcinoma patient, its expression in this type of cancer and its immunogenicity in esophageal cancer patients have not yet been fully elucidated. We report here the frequency of NY-ESO-1 mRNA and protein expression in esophageal cancer and the presence of NY-ESO-1-specific immune response in patients.

EXPERIMENTAL DESIGN

One hundred twenty three esophageal squamous cell carcinoma specimens were analyzed for the expression of NY-ESO-1 mRNA by conventional and real-time reverse transcription-PCR and the expression of protein by immunohistochemistry and Western blot. Sera and peripheral blood lymphocytes from 51 patients were analyzed for the NY-ESO-1 antibody production by enzyme-linked immunosorbent assay and NY-ESO-1 T cell response by enzyme-linked immunospot assay. Survival analyses were also performed.

RESULTS

NY-ESO-1 mRNA was expressed in 41 of 123 (33%) esophageal squamous cell carcinoma specimens, and its expression was found at higher frequency in well-differentiated and moderately differentiated type of cancer. No mRNA copy was detected in any of the adjacent normal tissues. Twenty-one of 24 (87.5%) NY-ESO-1 mRNA-positive tumors were stained positively by immunohistochemistry. Correlation between the level of NY-ESO-1 mRNA expression and the degree of immunohistochemistry positivity was observed. Antibody production was observed in 2 patients with tumors that showed protein expression. Furthermore, a CD8 T-cell response against NY-ESO-1 was observed in 1 of the 2 seropositive patients.

CONCLUSIONS

The high expression frequency of NY-ESO-1 mRNA and protein indicates NY-ESO-1 as a feasible vaccine target in esophageal cancer.

Expression Profile of Cancer-Testis Genes in 121 Human Colorectal Cancer Tissue and Adjacent Normal Tissue

PURPOSE

Among tumor antigens identified to date, cancer-testis (CT) antigens, which are coded by CT genes, are identified as a group of highly attractive targets for cancer vaccines. This study is the first to analyze the mRNA expression and possible correlation with pathologic characteristics of multiple CT genes in a large cohort of colorectal cancer (CRC) patients.

EXPERIMENTAL DESIGN

The expression of 10 individual CT genes in 121 CRC and adjacent tissues were analyzed by RT-PCR method. The presence of autologous antibodies against NY-ESO-1 was examined in serum samples by ELISA. To confirm the protein expression, immunohistochemistry was done for detecting the NY-ESO-1 antigen in mRNA-positive CRC tissues.

RESULTS

The CT genes were detected with various frequencies in CRC tissue, SCP-1, 1.7%; SSX-2, 2.5%; SSX-4, 2.5%; SSX-1, 5.0%; CT10, 6.6%; NY-ESO-1, 9.9%; MAGE-1, 11.6%; LAGE-1, 15.7%; MAGE-4, 22.3%; and MAGE-3, 27.3%. In 56.2% of tumor tissues examined in this study, at least one CT gene was detected. In contrast, no CT gene expression was found in cancer adjacent tissues. Among 10 CT genes investigated, NY-ESO-1 and LAGE-1 are of particular interest because their mRNA expression in CRC was rarely reported before. In our study, NY-ESO-1 mRNA was found to express in 9.9% of the samples, and also correlated significantly with stages (P = 0.041) and local lymph node metastasis (P = 0.002). In addition, we also identified one NY-ESO-1 antibody-positive serum sample. MAGE-4 mRNA was expressed at a high frequency in tumor tissues with vessel emboli samples (P = 0.025).

CONCLUSIONS

These results suggested that CT genes, especially NY-ESO-1 and LAGE-1, do express in CRC. More than 50% of the CRC patients in this study express at least one CT gene, making them eligible for CT vaccination. NY-ESO-1 gene may serve as a marker for local metastasis and advanced disease. MAGE-4 gene is significantly associated with the vessel emboli.

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.

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.

Genomic Organization, Incidence, and Localization of the SPAN-X Family of Cancer-Testis Antigens in Melanoma Tumors and Cell Lines

PURPOSE

Members of the SPAN-X (sperm protein associated with the nucleus mapped to the X chromosome) family of cancer-testis antigens are promising targets for tumor immunotherapy because they are normally expressed exclusively during spermiogenesis on the adluminal side of the blood-testis barrier, an immune privileged compartment.

EXPERIMENTAL DESIGN AND RESULTS

This study analyzed the human SPANX genomic organization, as well as SPAN-X mRNA and protein expression in somatic and cancer cells. The SPANX family consists of five genes, one of which is duplicated, all located in a gene cluster at Xq27.1. From the centromere, the arrangement of the five SPANX genes mapped on one contiguous sequence is SPANXB, -C, -A1, -A2, and -D. Reverse transcription-PCR analyses demonstrated expression of SPAN-X mRNA in melanoma and ovarian cell lines, and virtual Northern analysis established SPANX gene expression in numerous cancer cell lines. Immunoblot analysis using polyclonal antisera raised against recombinant SPAN-X confirmed the translation of SPAN-X proteins in melanoma and ovarian tumor cell lines. The immunoreactive proteins migrated between M(r) 15,000 and M(r) 20,000 similar to those observed in spermatozoa. Immunoperoxidase labeling of melanoma cells and tissue sections demonstrated SPAN-X protein localization in the nucleus, cytoplasm, or both. Ultrastructurally, in melanoma cells with nuclear SPAN-X, the protein was associated with the nuclear envelope, a localization similar to that observed in human spermatids and spermatozoa. Significantly, the incidence of SPAN-X-positive immunostaining was greatest in the more aggressive skin tumors, particularly in distant, nonlymphatic metastatic melanomas.

CONCLUSIONS

The data herein suggest that the SPAN-X protein may be a useful target in cancer immunotherapy.

HCA587 antigen expression in normal tissues and cancers: correlation with tumor differentiation in hepatocellular carcinoma

The HCA587 gene, identified by serological analysis of recombinant cDNA expression library (SEREX) from a hepatocellular carcinoma (HCC) patient, encodes a new member of cancer-testis antigens. HCA587 mRNA expression in normal tissues and cancers has been previously reported. To estimate its immunogenicity to induce immune response, it is essential to analyze HCA587 expression at the protein level. In this study anti-HCA587 polyclonal antibody, termed "TC-1," was generated, and the expression of HCA587 protein was assessed by immunohistochemical staining in a panel of normal and tumor tissue sections. No HCA587 protein was shown in normal tissues except germ cells in testis and Purkinji cells in cerebellum. In HCC specimens the HCA587 protein was expressed in 37.1% (26 of 70) samples. The expressed protein was either located in the cytoplasm or nucleus depending on the individual samples. More importantly, there appears to be correlation between the tumor differentiation of HCC and HCA587 protein expression, ie, the lower differentiation, the higher percentage of protein expression. Coincidentally, seroreactivity showed that the Ab specific to recombinant HCA587 protein was detected only in the sera of three patients with poorly differentiated HCCs. HCA587 antigen was also expressed in different proportions in melanoma, lymphoma, pancreatic cancer, and lung cancer.

The human SPANX multigene family: genomic organization, alignment and expression in male germ cells and tumor cell lines

Multigenicity is one of the features of cancer/testis-associated genes. In the present study we analyzed the number and expression of genes of the SPANX(CTp11) family of cancer/testis-associated genes. Genomic database analysis, next to the four previously described SPANX genes, revealed the presence of a novel gene: SPANXE. Moreover, we detected an allelic variant of SPANXB resulting in one amino acid substitution in the encoded protein: SPANXB'. Most SPANX genes are present on contig NT_011574 located at Xq26.3-Xq27.1. Based on expressed sequence tag databases and RT-PCR analysis three additional novel SPANX sequences were identified, though not represented so far in the human genome sequence. Sequence alignments justify a subdivision of this gene family based on the absence (SPANXA-likes) or presence (SPANXB) of an 18 base pair sequence stretch in the open reading frame. The alignments also reveal an unusually high level (99%) of intron homology. Furthermore, the nucleotide variations in the open reading frame almost all lead to amino acid substitutions. Southern blot and database analyses indicate that SPANX sequences are exclusively present in primates. With RT-PCR analysis on human sperm cell precursors and tumor cell lines most family members could be detected. SPANXB was only found in sperm cell precursors and could not be detected in the tumor cell lines tested. Overall SPANXA was the most frequently expressed SPANX variant in melanoma and glioblastoma cell lines.

Cancer/testis-associated genes: identification, expression profile, and putative function

Cancer/testis-associated genes (CTAs) are a subgroup of tumor antigens with a restricted expression in testis and malignancies. During the last decade, many of these immunotherapy candidate genes have been discovered using various approaches. Most of these genes are localized on the X-chromosome, often as multigene families. Methylation status seems to be the main, but not the only regulator of their specific expression pattern. In testis, CTAs are exclusively present in cells of the germ cell lineage, though there is a lot of variation in the moment of expression during different stages of sperm development. Likewise, there is also a lot of heterogeneity in the expression of CTAs in melanoma samples. Clues regarding functionality of CTAs for many of these proteins point to a role in cell cycle regulation or transcriptional control. Better insights in the function of these genes may shed light on the link between spermatogenesis and tumor growth and could be of use in anti-tumor therapies. This review outlines the CTA family and focuses on their expression and putative function during male germ cell development and melanocytic tumor progression.

Cancer/testis antigens: an expanding family of targets for cancer immunotherapy

Cancer/testis (CT) antigens are a category of tumor antigens with normal expression restricted to male germ cells in the testis but not in adult somatic tissues. In some cases, CT antigens are also expressed in ovary and in trophoblast. In malignancy, this gene regulation is disrupted, resulting in CT antigen expression in a proportion of tumors of various types. Since their initial identification by T-cell epitope cloning, the list of CT antigens has been greatly expanded through serological expression cloning (SEREX) and differential mRNA expression analysis, and approximately 20 CT antigens or antigen families have been identified to date. Characteristics commonly shared by CT antigens, aside from the highly tissue-restricted expression profile, include existence as multigene families, frequent mapping to chromosome X, heterogeneous protein expression in cancer, likely correlation with tumor progression, induction of expression by hypomethylation and/or histone acetylation, and immunogenicity in cancer patients. Spontaneous humoral and cell-mediated immune responses have been demonstrated against several CT antigens, including NY-ESO-1, MAGE-A, and SSX antigens. Since CT antigens are immunogenic and highly restricted to tumors, their discovery has led directly to the development of antigen-specific cancer vaccines, and clinical trials with MAGE-A and NY-ESO-1 are in progress.

The cancer-testis gene, NY-ESO-1, is expressed in normal fetal and adult testes and in spermatocytic seminomas and testicular carcinoma in situ

Cancer/testis genes are potential targets for therapeutic genetic and immunologic approaches, and are highly expressed in a large variety of human cancers. However, they are not expressed in normal tissues, with the exception of the testis. The NY-ESO-1 gene is the most recently identified member of the cancer/testis family and its product is one of the most immunogenic tumor antigens. We used immunohistochemistry to investigate the expression of NY-ESO-1 in healthy human prenatal and adult testes and in 59 human testicular tumors of different subtypes. We found that NY-ESO-1 was expressed from 18 weeks until birth in human fetal testes. In the adult testis, NY-ESO-1 was strongly expressed in spermatogonia and in primary spermatocytes, but not in post-meiotic cells or in testicular somatic cells. NY-ESO-1 was not expressed in the Sertoli cells, Leydig cells, classical seminomas, or nonseminomatous germ cells in the 59 testicular tumors. In contrast, NY-ESO-1 was expressed both in carcinomas in situ, which are the earliest stage of testicular tumors (7 of 15 cases), and in spermatocytic seminomas, which are believed to be derived from spermatogonia or primary spermatocytes (8 of 16 cases). We conclude that NY-ESO-1 is a marker that can be used to follow the early progression of testicular tumorigenesis when the tumors present a similar pattern of expression to the cells from which they originated, although the later tumors cease to express NY-ESO-1.