Expression of MAGE genes in human colorectal carcinoma

Cross-reactive CD8+ T cell responses to tumor-associated antigens (TAAs) and homologous microbiota-derived antigens (MoAs)

BACKGROUND

We have recently shown extensive sequence and conformational homology between tumor-associated antigens (TAAs) and antigens derived from microorganisms (MoAs). The present study aimed to assess the breadth of T-cell recognition specific to MoAs and the corresponding TAAs in healthy subjects (HS) and patients with cancer (CP).

METHOD

A library of > 100 peptide-MHC (pMHC) combinations was used to generate DNA-barcode labelled multimers. Homologous peptides were selected from the Cancer Antigenic Peptide Database, as well as Bacteroidetes/Firmicutes-derived peptides. They were incubated with CD8 + T cells from the peripheral blood of HLA-A*02:01 healthy individuals (n = 10) and cancer patients (n = 16). T cell recognition was identified using tetramer-staining analysis. Cytotoxicity assay was performed using as target cells TAP-deficient T2 cells loaded with MoA or the paired TuA.

RESULTS

A total of 66 unique pMHC recognized by CD8+ T cells across all groups were identified. Of these, 21 epitopes from microbiota were identified as novel immunological targets. Reactivity against selected TAAs was observed for both HS and CP. pMHC tetramer staining confirmed CD8+ T cell populations cross-reacting with CTA SSX2 and paired microbiota epitopes. Moreover, PBMCs activated with the MoA where shown to release IFNγ as well as to exert cytotoxic activity against cells presenting the paired TuA.

CONCLUSIONS

Several predicted microbiota-derived MoAs are recognized by T cells in HS and CP. Reactivity against TAAs was observed also in HS, primed by the homologous bacterial antigens. CD8+ T cells cross-reacting with MAGE-A1 and paired microbiota epitopes were identified in three subjects. Therefore, the microbiota can elicit an extensive repertoire of natural memory T cells to TAAs, possibly able to control tumor growth ("natural anti-cancer vaccination"). In addition, non-self MoAs can be included in preventive/therapeutic off-the-shelf cancer vaccines with more potent anti-tumor efficacy than those based on TAAs.

Expression of cancer-testis antigens in the immune microenvironment of non-small cell lung cancer

The antigenic repertoire of tumors is critical for successful anti-cancer immune response and the efficacy of immunotherapy. Cancer-testis antigens (CTAs) are targets of humoral and cellular immune reactions. We aimed to characterize CTA expression in non-small cell lung cancer (NSCLC) in the context of the immune microenvironment. Of 90 CTAs validated by RNA sequencing, eight CTAs (DPEP3, EZHIP, MAGEA4, MAGEB2, MAGEC2, PAGE1, PRAME, and TKTL1) were selected for immunohistochemical profiling in cancer tissues from 328 NSCLC patients. CTA expression was compared with immune cell densities in the tumor environment and with genomic, transcriptomic, and clinical data. Most NSCLC cases (79%) expressed at least one of the analyzed CTAs, and CTA protein expression correlated generally with RNA expression. CTA profiles were associated with immune profiles: high MAGEA4 expression was related to M2 macrophages (CD163) and regulatory T cells (FOXP3), low MAGEA4 was associated with T cells (CD3), and high EZHIP was associated with plasma cell infiltration (adj. P-value < 0.05). None of the CTAs correlated with clinical outcomes. The current study provides a comprehensive evaluation of CTAs and suggests that their association with immune cells may indicate in situ immunogenic effects. The findings support the rationale to harness CTAs as targets for immunotherapy.

Genome instability-derived genes as a novel prognostic signature for lung adenocarcinoma

Background: An increasing number of patients are being diagnosed with lung adenocarcinoma, but there remains limited progress in enhancing prognostic outcomes and improving survival rates for these patients. Genome instability is considered a contributing factor, as it enables other hallmarks of cancer to acquire functional capabilities, thus allowing cancer cells to survive, proliferate, and disseminate. Despite the importance of genome instability in cancer development, few studies have explored the prognostic signature associated with genome instability for lung adenocarcinoma. Methods: In the study, we randomly divided 397 lung adenocarcinoma patients from The Cancer Genome Atlas database into a training group (n = 199) and a testing group (n = 198). By calculating the cumulative counts of genomic alterations for each patient in the training group, we distinguished the top 25% and bottom 25% of patients. We then compared their gene expressions to identify genome instability-related genes. Next, we used univariate and multivariate Cox regression analyses to identify the prognostic signature. We also performed the Kaplan-Meier survival analysis and the log-rank test to evaluate the performance of the identified prognostic signature. The performance of the signature was further validated in the testing group, in The Cancer Genome Atlas dataset, and in external datasets. We also conducted a time-dependent receiver operating characteristic analysis to compare our signature with established prognostic signatures to demonstrate its potential clinical value. Results: We identified GULPsig, which includes IGF2BP1, IGF2BP3, SMC1B, CLDN6, and LY6K, as a prognostic signature for lung adenocarcinoma patients from 42 genome instability-related genes. Based on the risk score of the risk model with GULPsig, we successfully stratified the patients into high- and low-risk groups according to the results of the Kaplan-Meier survival analysis and the log-rank test. We further validated the performance of GULPsig as an independent prognostic signature and observed that it outperformed established prognostic signatures. Conclusion: We provided new insights to explore the clinical application of genome instability and identified GULPsig as a potential prognostic signature for lung adenocarcinoma patients.

Autoimmune alleles at the major histocompatibility locus modify melanoma susceptibility

Autoimmunity and cancer represent two different aspects of immune dysfunction. Autoimmunity is characterized by breakdowns in immune self-tolerance, while impaired immune surveillance can allow for tumorigenesis. The class I major histocompatibility complex (MHC-I), which displays derivatives of the cellular peptidome for immune surveillance by CD8+ T cells, serves as a common genetic link between these conditions. As melanoma-specific CD8+ T cells have been shown to target melanocyte-specific peptide antigens more often than melanoma-specific antigens, we investigated whether vitiligo- and psoriasis-predisposing MHC-I alleles conferred a melanoma-protective effect. In individuals with cutaneous melanoma from both The Cancer Genome Atlas (n = 451) and an independent validation set (n = 586), MHC-I autoimmune-allele carrier status was significantly associated with a later age of melanoma diagnosis. Furthermore, MHC-I autoimmune-allele carriers were significantly associated with decreased risk of developing melanoma in the Million Veteran Program (OR = 0.962, p = 0.024). Existing melanoma polygenic risk scores (PRSs) did not predict autoimmune-allele carrier status, suggesting these alleles provide orthogonal risk-relevant information. Mechanisms of autoimmune protection were neither associated with improved melanoma-driver mutation association nor improved gene-level conserved antigen presentation relative to common alleles. However, autoimmune alleles showed higher affinity relative to common alleles for particular windows of melanocyte-conserved antigens and loss of heterozygosity of autoimmune alleles caused the greatest reduction in presentation for several conserved antigens across individuals with loss of HLA alleles. Overall, this study presents evidence that MHC-I autoimmune-risk alleles modulate melanoma risk unaccounted for by current PRSs.

Development of novel self-assembled vaccines based on tumour-specific antigenic peptide and TLR2 agonist for effective breast cancer immunotherapy via activating CD8+ T cells and enhancing their function

Vaccines based on tumour-specific antigens are a promising approach for immunotherapy. However, the clinical efficacy of tumour-specific antigens is still challenging. Twelve conjugates with self-assembly properties were designed and synthesized using MAGE-A1 peptide and TLR2 agonist, combined with different covalent bonds. All the developed conjugates formed spherical nanoparticles with a diameter of approximately 150 nm, and enhanced the efficacy of the peptide vaccines with the better targeting of lymph nodes. All the conjugates could well bind to serum albumin and improve the plasma stability of the individual antigenic peptides. In particular, conjugate 6 (N-Ac PamCS-M-6) had a more significant ability to promote dendritic cell maturation, CD8⁺ T cell activation, and subsequent killing of tumour cells, with an in vivo tumour inhibition rate of 70 ± 2.9%. The interaction between specific response and the different conjugation modes was further explored, thereby providing a fundamental basis for novel immune anti-tumour molecular platforms.

The Melanoma-Associated Antigen Family A (MAGE-A): A Promising Target for Cancer Immunotherapy?

Early efforts to identify tumor-associated antigens over the last decade have provided unique cancer epitopes for targeted cancer therapy. MAGE-A proteins are a subclass of cancer/testis (CT) antigens that are presented on the cell surface by MHC class I molecules as an immune-privileged site. This is due to their restricted expression to germline cells and a wide range of cancers, where they are associated with resistance to chemotherapy, metastasis, and cancer cells with an increasing potential for survival. This makes them an appealing candidate target for designing an effective and specific immunotherapy, thereby suggesting that targeting oncogenic MAGE-As with cancer vaccination, adoptive T-cell transfer, or a combination of therapies would be promising. In this review, we summarize and discuss previous and ongoing (pre-)clinical studies that target these antigens, while bearing in mind the benefits and drawbacks of various therapeutic strategies, in order to speculate on future directions for MAGE-A-specific immunotherapies.

High expression of MAGE-C1 gene in colorectal cancer is associated with its poor prognosis

BACKGROUND

The aim of this study was to explore the relationship between melanoma antigen gene C1 (MAGE-C1) expression and the prognosis for colorectal cancer (CRC), and to establish a mathematical model to comprehensively evaluate the prognosis of patients with CRC.

METHODS

MAGE-C1 was selected by bioinformatics for its greater expression differences in CRC patients. Immunohistochemistry (IHC) was used to detect the expression level of MAGE-C1 in tissue samples of 156 patients with CRC. Kaplan-Meier analysis was employed to assess the relationship between MAGE-C1 and the prognosis of patients with CRC. Univariate and multivariate Cox regression models analyzed the factors affecting the prognosis of CRC patients. Also, the clinicopathological characteristics of patients and genes with clinical concern were integrated to establish a model to comprehensively predict the prognosis of patients with CRC.

RESULTS

MAGE-C1 was found to be highly expressed in 28.8% of CRC patients. MAGE-C1 expression was associated with tumor size, number, and metastasis. Survival analysis showed that CRC patients with high expression of MAGE-C1 had a poor prognosis. Regression analysis demonstrated that MAGE-C1 protein status, T stage, differentiation, Kirsten rat sarcoma (KRAS) status, and v-RAF murine sarcoma viral oncogene homolog B1 (BRAF) status were the independent factors influencing the overall survival of patients with CRC. Meanwhile, MAGE-C1 combined with clinicopathological characteristics and hotspot gene mutations could be used to evaluate the prognosis of CRC.

CONCLUSIONS

Our study shows that MAGE-C1 is differentially expressed in patients with CRC and affects the prognosis of patients. The combination of MAGE-C1, clinicopathological characteristics, and genes with clinical concern can be used to assess the prognosis of CRC.

MAGEA10 expression is a predictive marker of early hepatic recurrence after curative gastrectomy for gastric and gastroesophageal junction cancer

BACKGROUND

Resection for hepatic recurrence after gastrectomy in patients with gastric cancer may be curative; however, the prediction of hepatic recurrence remains intractable. Therefore, we aimed to explore predictive markers for hepatic recurrence in gastric and gastroesophageal junction cancer based on genetic information.

METHODS

This study recruited 154 patients who underwent curative gastrectomy for pathological stage II or III primary gastric and gastroesophageal junction adenocarcinoma. Genes associated with hepatic recurrence were comprehensively analyzed using whole-exome sequencing and gene expression profiling (GEP), followed by immunohistochemistry analysis for MAGEA10. The cumulative incidences of hepatic recurrence, relapse-free survival, and overall survival were evaluated.

RESULTS

A total of 12 patients with early hepatic recurrences were found within 2 years of surgery. Although there were no distinct gene mutations in recurrent patients, upregulation of MAGEA10 was identified in patients with early hepatic recurrence using GEP analysis. Immunostaining for MAGEA10 stained the cell nuclei in 29 (18.8%) of 154 samples. Furthermore, protein expression of MAGEA10 on immunohistochemistry was significantly related to a high MAGEA10 mRNA expression, high cumulative incidences of hepatic recurrence, and poor relapse-free survival. Overall survival did not differ significantly between positive and negative immunohistochemical staining for MAGEA10. The sensitivity and specificity of MAGEA10 staining for early hepatic recurrence were 58.3% and 84.5%, respectively.

CONCLUSIONS

MAGEA10 represents a promising predictive marker for early hepatic recurrence after curative gastrectomy for gastric and gastroesophageal junction cancer.

Immunological and functional aspects of MAGEA3 cancer/testis antigen

Identification of ectopic gene activation in cancer cells serves as a basis for both gene signature-guided tumor targeting and unearthing of oncogenic mechanisms to expand the understanding of tumor biology/oncogenic process. Proteins expressed only in germ cells of testis and/or placenta (immunoprivileged organs) and in malignancies are called cancer testis antigens; they are antigenic because of the lack of antigen presentation by those specific cell types (germ cells), which limits the exposure of the proteins to the immune cells. Since the Cancer Testis Antigens (CTAs) are immunogenic and expressed in a wide variety of cancer types, CT antigens have become interesting target for immunotherapy against cancer. Among CT antigens MAGEA family is reported to have 12 members (MAGEA1 to MAGEA12). The current review highlights the studies on MAGEA3 which is a CT antigen and reported in almost all types of cancer. MAGEA3 is well tried for cancer immunotherapy. Recent advances on its functional and immunological aspect warranted much deliberation on effective therapeutic approach, thus making it a more interesting target for cancer therapy.

Expression of Cancer Testis Antigens in Colorectal Cancer: New Prognostic and Therapeutic Implications

Background. While cancer/testis antigens (CTAs) are restricted in postnatal tissues to testes and germ line-derived cells, their role in cancer development and the clinical significance of their expression still remain to be better defined. Objective. The aim of this study was to investigate the level of CTA expression in colon samples from patients with colorectal cancer (CRC) in relation to patient clinical status. Methods. Forty-five patients with newly diagnosed colorectal cancer were included in the study. We selected a panel of 18 CTAs that were previously detected in CRC as well as some new gene candidates, and their expression was detected at the mRNA level by employing RQ-PCR. Additionally, we evaluated CTA expression in three colon cancer cell lines (CL-188, HTB-39, and HTB-37) after exposure to the DNA methylation-modifying drug 5-azacytidine. Results. We report that 6 out of 18 (33%) CTAs tested (MAGEA3, OIP5, TTK, PLU1, DKKL1, and FBXO39) were significantly (p < 0.05) overexpressed in tumor tissue compared with healthy colon samples isolated from the same patients. Conclusions. Moreover, we found that MAGEA3, PLU-1, and DKKL expression positively correlated with disease progression, evaluated according to the Dukes staging system. Finally, 5-azacytidine exposure significantly upregulated expression of CTAs on CRC cells, which indicates that this demethylation agent could be employed therapeutically to enhance the immune response against tumor cells.

Clinical and biological significance of circulating tumor cells in cancer

During the process of metastasis, which is the leading cause of cancer-related death, cancer cells dissociate from primary tumors, migrate to distal sites, and finally colonize, eventually leading to the formation of metastatic tumors. The migrating tumor cells in circulation, e.g., those found in peripheral blood (PB) or bone marrow (BM), are called circulating tumor cells (CTCs). CTCs in the BM are generally called disseminated tumor cells (DTCs). Many studies have reported the detection and characterization of CTCs to facilitate early diagnosis of relapse or metastasis and improve early detection and appropriate treatment decisions. Initially, epithelial markers, such as EpCAM and cytokeratins (CKs), identified using immunocytochemistry or reverse transcription polymerase chain reaction (RT-PCR) were used to identify CTCs in PB or BM. Recently, however, other markers such as human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER), and immuno-checkpoint genes also have been examined to facilitate detection of CTCs with metastatic potential. Moreover, the epithelial-to-mesenchymal transition (EMT) and cancer stem cells (CSCs) have also received increasing attention as important CTC markers owing to their roles in the biological progression of metastasis. In addition to these markers, researchers have attempted to develop detection or capture techniques for CTCs. Notably, however, the establishment of metastasis requires cancer-host interactions. Markers from host cells, such as macrophages, mesenchymal stem cells, and bone marrow-derived cells, which constitute the premetastatic niche, may become novel biomarkers for predicting relapse or metastasis or monitoring the effects of treatment. Biological studies of CTCs are still emerging. However, recent technical innovations, such as next-generation sequencing, are being used more commonly and could help to clarify the mechanism of metastasis. Additionally, biological findings are gradually being accumulated, adding to our body of knowledge on CTCs. In this review, we will summarize recent approaches to detect or capture CTCs. Moreover, we will introduce recent studies of the clinical and biological importance of CTCs and host cells.

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.

The biology of cancer testis antigens: putative function, regulation and therapeutic potential

Cancer testis antigens (CTA) are a large family of tumor-associated antigens expressed in human tumors of different histological origin, but not in normal tissues except for testis and placenta. This tumor-restricted pattern of expression, together with their strong in vivo immunogenicity, identified CTA as ideal targets for tumor-specific immunotherapeutic approaches, and prompted the development of several clinical trials of CTA-based vaccine therapy. Driven by this practical clinical interest, a more detailed characterization of CTA biology has been recently undertaken. So far, at least 70 families of CTA, globally accounting for about 140 members, have been identified. Most of these CTA are expressed during spermatogenesis, but their function is still largely unknown. Epigenetic events, particularly DNA methylation, appear to be the primary mechanism regulating CTA expression in both normal and transformed cells, as well as in cancer stem cells. In view of the growing interest in CTA biology, the aim of this review is to provide the most recent information on their expression, regulation and function, together with a brief summary of the major clinical trials involving CTA as therapeutic agents. The pharmacologic modulation of CTA expression profiles on neoplastic cells by DNA hypomethylating drugs will also be discussed as a feasible approach to design new combination therapies potentially able to improve the clinical efficacy of currently adopted CTA-based immunotherapeutic regimens in cancer patients.

Analysis of tumor antigen-specific T cells and antibodies in cancer patients treated with radiofrequency ablation

Radiofrequency (RF) ablation is a minimally invasive technique routinely applied for the treatment of primary and secondary liver tumors. It induces cell death by thermal coagulative necrosis of tumor tissues, whereas cellular metabolism can still take place in a transition zone surrounding the necrotic area. An increase in heat shock protein expression occurs shortly after treatment, suggesting that the induction of activating signals may stimulate the host immune system. In addition, various effects on immune effectors have also been observed, including stimulation of tumor-directed T lymphocytes. Here, we prospectively assessed the activation of tumor antigen-specific antibodies, as well as antigen-specific CD4(+) and CD8(+) T cells in patients suffering from primary or secondary malignancies and treated by RF ablation with or without concomitant chemotherapy. An increase of antibodies (in 4 patients of 49), CD4(+) T cells or CD8(+) T cells (in 2 patients of 49) could be detected several weeks to months following intervention. These findings suggest that in addition to the local control of tumor growth, RF ablation can provide the appropriate conditions for activating tumor-antigen specific immune responses.

Infrequent and low expression of cancer-testis antigens located on the X chromosome in colorectal cancer: implications for immunotherapy in South African populations

Cancer-testis (CT) antigens are a group of tumor antigens that are expressed in the testis and aberrantly in cancerous tissue but not in somatic tissues. The testis is an immune-privileged site because of the presence of a blood-testis barrier; as a result, CT antigens are considered to be essentially tumor specific and are attractive targets for immunotherapy. CT antigens are classified as the CT-X and the non-X CT antigens depending on the chromosomal location to which the genes are mapped. CT-X antigens are typically highly immunogenic and hence the first step towards tailored immunotherapy is to elucidate the expression profile of CT-X antigens in the respective tumors. In this study we investigated the expression profile of 16 CT-X antigen genes in 34 colorectal cancer (CRC) patients using reverse transcription-polymerase chain reaction. We observed that 12 of the 16 CT-X antigen genes studied did not show expression in any of the CRC samples analyzed. The other 4 CT-X antigen genes showed low frequency of expression and exhibited a highly variable expression profile when compared to other populations. Thus, our study forms the first report on the expression profile of CT-X antigen genes among CRC patients in the genetically diverse South African population. The results of our study suggest that genetic and ethnic variations in population might have a role in the expression of the CT-X antigen genes. Thus our results have significant implications for anti-CT antigen-based immunotherapy trials in this population.

Efficient identification of a novel cancer/testis antigen for immunotherapy using three-step microarray analysis

Advanced technology in molecular biology has provided us powerful tools for the diagnosis and treatment for cancer. We herein adopted a new methodology to identify a novel cancer/testis (CT) antigen with high frequency of expression in colorectal cancer as follows: (a) combining laser microdissection and cDNA microarray was used to analyze the gene expression profile of colorectal cancer cells; (b) genes overexpressed in testis and underexpressed in normal colon epithelium were analyzed using cDNA microarray; and (c) the gene expression profile of colorectal cancer cells was compared with that of normal testis. Using this methodology, we selected 38 candidates for CT antigen. Among these genes, we identified a novel CT antigen, serine/threonine kinase 31 (STK31), which was previously reported as a gene expressed in spermatogonia. Reverse transcription-PCR analysis showed that STK31 gene expression levels in cancer samples were significantly higher (P < 0.0001) than those in normal samples. The STK31 gene was frequently expressed not only in colorectal cancer but also in gastric and esophageal cancer. Moreover, STK31 peptide was able to elicit specific CTLs and induced CTLs lysed either peptide-loading or endogenously STK31-expressing target cells. These results showed that the new methodology in this study facilitated identification of CT antigens and that STK31 may be a candidate for cancer immunotherapy against gastrointestinal cancer.

Clinical significance of the reduced expression of G protein gamma 7 (GNG7) in oesophageal cancer

We previously cloned human G protein gamma 7 (GNG7) and demonstrated that it was downregulated in gastrointestinal cancer. The significance of GNG7 expression in oesophageal cancer is unknown. TaqMan quantitative real-time PCR was performed to determine the clinical significance of GNG7 expression in 55 cases of oesophageal cancer. Furthermore, GNG7-transfected oesophageal cancer cells were analysed in laboratory studies at genomic and epigenetic levels. Twenty-seven patients with low GNG7 expression showed significantly poorer survival than did 28 patients with high expression (P<0.05). Tumours with low GNG7 expression invaded deeper than those with high GNG7 expression (P<0.05), both in vivo and in vitro. Eight tumours retained GNG7 expression, and they did not show either promoter hypermethylation or loss of heterozygosity (LOH). In 38 tumours with GNG7 suppression, 22 (57%) showed either LOH or promoter hypermethylation. In addition, GNG7 expression was significantly associated with the presence of miR328 in oesophageal cancer cell lines, which suggests that this microRNA might be a regulator of GNG7 expression. GNG7 suppression represents a new prognostic indicator in cases of oesophageal cancer. GNG7 might be suppressed by LOH and promoter hypermethylation or by microRNA.

Vaccination of metastatic colorectal cancer patients with matured dendritic cells loaded with multiple major histocompatibility complex class I peptides

Developing a process to generate dendritic cells (DCs) applicable for multicenter trials would facilitate cancer vaccine development. Moreover, targeting multiple antigens with such a vaccine strategy could enhance the efficacy of such a treatment approach. We performed a phase 1/2 clinical trial administering a DC-based vaccine targeting multiple tumor-associated antigens to patients with advanced colorectal cancer (CRC). A qualified manufacturing process was used to generate DC from blood monocytes using granulocyte macrophage colony-stimulating factor and IL-13, and matured for 6 hours with Klebsiella-derived cell wall fraction and interferon-gamma (IFN-gamma). DCs were also loaded with 6 HLA-A*0201 binding peptides derived from carcinoembryonic antigen (CEA), MAGE, and HER2/neu, as well as keyhole limpet hemocyanin protein and pan-DR epitope peptide. Four planned doses of 35x10(6) cells were administered intradermally every 3 weeks. Immune response was assessed by IFN-gamma enzyme-linked immunosorbent spot (ELISPOT). Matured DC possessed an activated phenotype and could prime T cells in vitro. In the trial, 21 HLA-A2+ patients were apheresed, 13 were treated with the vaccine, and 11 patients were evaluable. No significant treatment-related toxicity was reported. T-cell responses to a CEA-derived peptide were detected by ELISPOT in 3 patients. T cells induced to CEA possessed high avidity T-cell receptors. ELISPOT after in vitro restimulation detected responses to multiple peptides in 2 patients. All patients showed progressive disease. This pilot study in advanced CRC patients demonstrates DC-generated granulocyte macrophage colony-stimulating factor and IL-13 matured with Klebsiella-derived cell wall fraction and IFN-gamma can induce immune responses to multiple tumor-associated antigens in patients with advanced CRC.

Lysis of human chondrosarcoma cells by cytolytic T lymphocytes recognizing a MAGE-A3 antigen presented by HLA-A1 molecules

Treatment of chondrosarcomas is limited to resection because these tumors are unresponsive to standard adjuvant treatments, such as chemotherapy and radiation. We have previously shown that high-grade chondrosarcomas express unspecified members of the Melanoma Antigen (MAGE) gene family. We show here that FS human chondrosarcoma (FS) cells express MAGE-A3 gene and HLA-A1 molecules. In vitro assays show that a cytolytic T-lymphocyte clone (CTL) specific for a MAGE-A3 peptide presented by HLA-A1 specifically lysed FS chondrosarcoma cells. Addition of antigenic peptide did not increase the susceptibility of FS cells to CTL mediated lysis, suggesting that HLA-A1 expression by the chondrosarcoma cells limited their susceptibility to lysis by the anti-MAGE-A3 CTL clone. Incubation of FS cells with 50 U/mL interferon-gamma increased surface expression of HLA class-I molecules, increased their susceptibility to lysis, and had no effect on MAGE-A3 gene expression. These results suggest that immunotherapy targeted against chondrosarcoma cells is possible.

mRNA expression of MAGE-A3 gene in leukemia cells

Leukemia-associated antigens such as proteins encoded by MAGE genes might provide tools for immunotherapy of leukemia. Positive and negative results of MAGE-A gene expression in hematological malignancies have been reported. This led us to study MAGE-A gene expression in human leukemias using RT-PCR. Among 115 leukemias from various subtypes, 14/34 (41.17%) AML were positive for one of the three genes analyzed (MAGE-A1 1/32; MAGE-A3 10/32; MAGE-B2 3/12). Expression was also detected in 23/76 (30.26%) B-cell ALL patients (MAGE-A1 2/53; MAGE-A3 20/53; MAGE-B2 1/32). One of these patients expressed both MAGE-A1 (weak signal) and -A3 (strong signal) genes. Other patient with CML were positive for MAGE-B2 (1/5, 20%). MAGE-A3 expression data were corroborated by real time RT-PCR through determination of MAGE-A3 transcript levels. We concluded that the MAGE-A3 gene is expressed at the mRNA level in a proportion of human leukemias.

Promoter Demethylation and Histone Acetylation Mediate Gene Expression ofMAGE-A1, -A2, -A3, and-A12in Human Cancer Cells

The broad range of expression of cancer-testis antigens in various tumor types makes the proteins encoded by human MAGE gene family promising targets for anticancer immunotherapy. However, a major drawback is their heterogeneous expression. In the current study, we have examined the influence of the DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) together with the histone deacetylase inhibitor trichostatin A on the expression of MAGE-A1, -A2, -A3, and -A12 genes in different cell lines. Reverse transcription-PCR, Western blot analyses, and immunocytochemical staining show that trichostatin A was able to significantly up-regulate 5-aza-CdR-induced MAGE gene expression. Transient transfection assays with methylated reporter plasmids containing promoter fragments of the different MAGE genes show that trichostatin A was able to overcome gene silencing. In addition, the methylation status of the MAGE promoters was assessed by sodium bisulfite mapping in the various cell lines before and after stimulation with 5-aza-CdR and/or trichostatin A. In contrast to the methylation patterns, which clearly correlated with the basal MAGE RNA transcripts, up-regulation of the MAGE-A mediated by both agents only resulted in a reduction in promoter methylation ranging between 1% and 19%. In conclusion, our data show for the first time that not only hypermethylation but also histone deacetylation is responsible for the mechanism underlying MAGE gene silencing.

Expression of MAGE tumor-associated antigen in thyroid carcinomas

The 12 members of the MAGE gene family encode tumor-specific antigens that are recognized by autologous cytotoxic T lymphocytes. The MAGE genes are expressed not only in melanoma but in other malignant tumors as well. There is, however, little information on their expression in thyroid carcinomas. We studied the expression of the MAGE-3 antigen in human thyroid carcinomas to explore the possibility of specific immunotherapy using MAGE peptides. Tumor tissue samples of thyroid carcinomas were obtained from 60 patients. Standard pathohistologic analysis followed by immunohistochemistry analysis of MAGE-3 expression was performed in all patients. The overall expression rate of MAGE-3 antigen in thyroid carcinomas was 65%. According to histological types of thyroid carcinomas, expression rate of MAGE-3 antigen was as follows: 0% in anaplastic, 20% in medullary, 29% in follicular, and 80% in papillary thyroid carcinomas (p < 0.01). On the other hand, significantly higher expression of MAGE-3 antigen was observed in classical subtypes of papillary thyroid carcinomas and in small papillary tumors sized to 1 cm in diameter. These findings demonstrated that MAGE-3 antigen expression seems to be particularly high in the small, typical papillary carcinomas, thus suggesting that MAGE-3 gene abnormality is an early step in thyroid cancer progression.

Immunologic Therapies for Gastrointestinal Cancers

The treatment of solid tumors has shown a dramatic change in recent years. This revolution has come from an improved understanding of the mechanisms of tumor growth and the relationship of cancers to their microenvironments. As part of this revolution, we have had a dramatic increase in our understanding of the immune system and the role it could play in the management of cancers. This article reviews the current data supporting the use of cancer immunologic therapies for gastrointestinal tract cancers. The scope is focused on the variety of approaches that have been used, citing the clinical data that have been obtained and reviewing future trials.

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.

Expression of cancer-testis antigen (CTA) genes in intrahepatic cholangiocarcinoma

BACKGROUND

Cancer-testis antigens (CTA), such as MAGE, are selectively expressed in various types of human neoplasms but not in normal tissues other than testis. This characteristic feature of CTA makes them promising antigens for cancer-specific immunotherapy.

METHODS

We investigated the expression of five genes, including MAGE-1, MAGE-3, NY-ESO-1, SCP-1, and SSX-4, in 20 surgical samples of intrahepatic cholangiocarcinomas (IHCC) using reverse transcription-polymerase chain reaction. To visualize the localization of MAGE proteins, we performed immunohistochemical studies. Furthermore, the correlation between the CTA expression and DNA methylation status was studied in three bile duct cancer cell lines.

RESULTS

Expression of MAGE-1, MAGE-3, NY-ESO-1, SCP-1, and SSX-4 was recognized in 4, 4, 2, 6, and 3 of all 20 cases, respectively. In contrast, the expressions of five genes were not recognized at all in the corresponding normal tissues. In 10 cases (50%), the tumors expressed at least one of the five CTA. An immunohistochemical analysis of MAGE proteins demonstrated homogenous or focal distributions in cytoplasm of the IHCC. Using a demethylating agent, MAGE-1, NY-ESO-1, SCP-1, and SSX-4 were induced in two of three cell lines, whereas MAGE-3 was not.

CONCLUSIONS

Half of the tumor tissues of IHCC expressed at least one of the CTA. Some of the patients with IHCC, therefore, should be candidates for potentially useful cancer-specific immunotherapy.

Expression of MAGE-A3 in intrahepatic cholangiocarcinoma and its precursor lesions

MAGE-A3 antigen is known to be neo-expressed in a large proportion of tumors but not detectable in normal tissues, and could be a target antigen recognized by autologous cytotoxic T lymphocytes. In the present study, the expression of MAGE-A3 at protein and mRNA levels was examined in intrahepatic cholangiocarcinoma (ICC) and its precursor lesions. Carcinomatous and dysplastic biliary cells expressed MAGE-A3 in their cytoplasm diffusely, although there was no MAGE-A3 expression in normal and hyperplastic biliary cells. MAGE-A3 was expressed in one of 10 cases (10%) of low-grade dysplasia, four of 13 (31%) cases of high-grade dysplasia/in situ carcinoma, and 32 of 68 invasive ICC cases (47%), respectively. The MAGE-A3 mRNA expression pattern was similar to that of MAGE-A3 protein. The incidence and intensity of MAGE-A3 expression increased along the progression of biliary neoplasia (P < 0.05). There was no correlation between MAGE-3 expression and histological differentiation or anatomical locations of invasive ICC. MAGE-A3 is a promising target molecule for the specific immunotherapy of ICC.

Tissue expression and sero-reactivity of tumor-specific antigens in colorectal cancer

The expression of 14 individual and two groups of tumor antigens was characterized for colorectal carcinoma by RT-PCR using 26 colorectal carcinoma specimens, eight cell lines, six samples of patients with inflammatory bowl diseases, and nine specimens from different locations of an individual patient with a metastasized rectal carcinoma. The most frequently detected mRNAs were MAGE-A1 (58%), GAGE-3-7 (54%), and cTAGE-5a (31%). At medium frequencies (12-19%) we found cTAGE-1, MAGE-A2, se57-1, RAGE-4, and GAGE-1,2,8, while other tumor antigens were expressed rarely (<9%). 85% of the samples were positive for at least one of the most frequently expressed antigens. Using a secondary SEREX approach and sera of eight colorectal cancer patients we found reactive antibodies against recombinant cTAGE-1 (2 sera), se57-1 (2), truncated GAGE (1), and MAGE-A1 (1). We conclude that certain cancer-germline genes can be detected in colorectal cancer and might therefore be promising targets for immunotherapy.

Epigenetic targets for immune intervention in human malignancies

Emerging evidences suggest that epigenetic events associated with tumor development and progression, such as deregulated methylation of CpG dinucleotides and aberrant histone acetylation, may impair the immunogenic potential of cancer cells. In fact, DNA hypermethylation and/or histone deacetylation contribute to the absent or downregulated expression of different components of the 'tumor recognition complex' (i.e., HLA class I antigens, cancer/testis antigens and accessory/costimulatory molecules) in solid and hemopoietic human malignancies. However, pharmacologic agents that induce DNA hypomethylation or inhibit histone deacetylation can modify these epigenetic phenomena, restoring the defective expression of selected components of the 'tumor recognition complex' in cancer cells. These antigenic modifications positively modulate the immunogenicity and the immune recognition of cancer cells, making epigenetic drugs attractive agents to design new combined chemoimmunotherapeutic strategies for the treatment of cancer patients.

Colon cancer: prevalence, screening, gene expression and mutation, and risk factors and assessment

Colon cancer detection at an early stage and identifying susceptible individuals can result in reduced mortality from this prevalent cancer. Genetic events leading to the development of this cancer involve a multistage progression of adenoma polyps to invasive metastatic carcinomas. Currently, there is no satisfactory screening method that is highly specific, sensitive, or reliable. Dietary patterns associated with the greatest increase in colon cancer risk are the ones that typify a diet rich in fat and calories, and low in vegetable, fruits, and fibers. Genetic susceptibility to environmental carcinogenesis must be factored into the risk assessment for this cancer. Many genes have been shown to be associated with increased expression and mutations in colorectal cancer patients. These genes have been reviewed; it is hoped that by carefully selecting a number of them, a molecular approach that is suitable for arriving at a tumorigenic expression index is developed, which will reliably detect this cancer at an early stage (i.e., before it metastasizes), especially in exfoliated samples (e.g., stool and blood), so that appropriate intervention strategies can be implemented. Illustrated herein is the utility of employing real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantitatively measure gene expression, and develop an index that is specific for this cancer, which if perfected may result in a reliable and sensitive screening technique for colorectal cancer detection.

MAL gene expression in esophageal cancer suppresses motility, invasion and tumorigenicity and enhances apoptosis through the Fas pathway

We isolated the MAL (T-lymphocyte maturation associated protein) gene from differentially expressed products of esophageal epithelium relative to esophageal carcinoma tissues. The Mal protein has been demonstrated as being a component of the protein machinery for apical transport in epithelial polarized cells. In this study, we describe the reduced expression of MAL in all 39 cases of esophageal carcinoma tested and 60 other human carcinomas. MAL gene transcription was induced in three out of 13 esophageal carcinoma cell lines by treatment with the demethylating agent 5-aza-2'-deoxycytidine (DAC), and in nine additional cell lines by simultaneous treatment with trichostatin A, an inhibitor of deacetylation, and DAC. We established a stable MAL gene transfectant whose expression was regulated by subcutaneous doxycycline injection in nude mice. Tumor growth was suppressed in cells expressing TE3-MAL compared with TE3 parent cells or cells not expressing TE3-MAL with doxycycline injection (20 microg/body) (P<0.01). Additionally, the TE3-MAL transfectant cells exhibited decreased cellular motility, a G1/S transition block and increased levels of apoptosis, concomitant with increased expression of Fas receptor in vitro. The apoptotic staining in MAL-expressing tumors was confirmed by TUNEL assay. Therefore, we conclude that expression of MAL was frequently decreased or diminished in gastrointestinal tract cancers, and that Mal expression confers reduced tumorigenicity in vivo to tumor TE3 cells through the induction of apoptosis via the Fas signaling pathway.

Expression spectrum and methylation-dependent regulation of melanoma antigen-encoding gene family members in pancreatic cancer cells

Human MAGE and GAGE genes encode tumor-specific antigens presented by HLA I molecules recognized on tumor cells by cytolytic T lymphocytes. To determine if pancreatic cancer patients would be suitable for MAGE- or GAGE-based immunotherapy, the expression frequency of MAGE-A1, -A2, -A3, -A4, -A6 and GAGE1-8 genes was assessed in 15 pancreatic tumor cell lines and 23 pancreatic tumor specimens using reverse transcription-polymerase chain reaction (RT-PCR). In 67% of the cell lines at least one of the MAGE-A genes was detected, 53% revealed concomitant expression of two or more genes. GAGE1-8 expression was detected in 47% of the cell lines. In the primary pancreatic tumors, MAGE-A analysis revealed exclusive MAGE-A1 and MAGE-A2 gene expression in 26 and 30% of the specimens, respectively, independent from clinicopathologic factors. Treatment of MAGE-A expression-negative pancreatic tumor cells with the demethylating agent 5-aza-2'-deoxycytidine could activate MAGE-A1, MAGE-A2, MAGE-A3, MAGE-A4 and GAGE transcription suggesting silencing due to promoter methylation. Interestingly, a metastatic lesion to the liver revealed concomittant expression of MAGE-A1, -A2, -A3 and -A6 consistent with a more pronounced genome-wide hypomethylation in metastases. Therefore, a subset of pancreatic cancer patients could be eligible for active, specific immunotherapy directed against MAGE-A antigens and demethylating agents could increase the number of candidate patients.

A new strategy for the diagnosis of MAGE-expressing cancers

The expression of melanoma antigen gene (MAGE), coding for tumor antigens recognized by cytotoxic T cell, is highly specific to cancer cells, but their use in the detection of a few cancer cells by reverse transcription-polymerase chain reaction (RT-PCR) has been limited by the low frequency of expression of individual MAGE genes. In order to increase MAGE detection rate in RT-PCR assay, here, we designed multiple MAGEs recognizing primers (MMRPs) that can bind to the sequences of cDNA of MAGE-1, -2, -3, -4a, -4b, -5a, -5b and-6 (MAGE 1-6) together. The nested RT-PCR assay using MMRPs, MAGE 1-6 assay, detected MAGE messages of 1 to 5 SNU484 cells in a background of 10(7) SNU638 cells. MAGE detection rate of MAGE 1-6 assay in cancers was higher than that of nested RT-PCR that detects single MAGE gene expression. The expressions of MAGE genes was detected by MAGE 1-6 assay in 70.4% (19/27) of head and neck cancer tissues, 91.7% (11/12) of breast cancer tissues, 75% (9/12) of lung cancer tissues. However, they were not detected in 18 benign lesions and 20 normal head and neck tissues and 30 blood samples from healthy donor. In conclusions, MAGE 1-6 assay can detect any cancer cells that express at least one of eight MAGE subtype genes, and this method may be very useful for the diagnosis of MAGE-expressing cancers.

mRNA detection of tumor-rejection genes BAGE, GAGE, and MAGE in peritoneal fluid from patients with ovarian carcinoma as a potential diagnostic tool

BACKGROUND

It has been found that the members of the BAGE, MAGE, and GAGE gene families are expressed almost exclusively in neoplastic tissues. Normal tissues, except testis and placenta, are negative. Therefore, the expression of these genes may serve as a useful diagnostic marker in detecting malignant disease. The involvement of the serous cavities by malignant neoplasms has important therapeutic and prognostic implications. Accordingly, the diagnosis of peritoneal spread of ovarian carcinoma plays an important role for both initial and second-look staging procedures. In some patients, however, a definite diagnosis cannot be established by morphologic or immunocytologic examination alone. Detection of tumor specific gene expression may be a sensitive additional tool in these settings.

METHODS

The authors studied the gene expression observed in 44 ascites specimens. Gene expression was evaluated by reverse transcription-polymerase chain reaction analysis and sequencing.

RESULTS

Of 44 ascites specimens, the expression of BAGE, MAGE-1, MAGE-3, and GAGE-1/2 was recognized in 17 specimens (63%), 2 specimens (7%), 8 specimens (30%), and 8 specimens (30%) with histologically proven ovarian carcinoma, respectively. Expression of the MAGE and GAGE genes was not observed in patients with nonneoplastic disease, whereas BAGE expression was seen in one patient with cirrhosis.

CONCLUSIONS

These findings show that testing for BAGE, GAGE-1/2, MAGE-1, and MAGE-3 transcriptional activity in ascites specimens results in high sensitivity in diagnosing malignant ascites.

MAGE-A4, a germ cell specific marker, is expressed differentially in testicular tumors

BACKGROUND

Testicular germ cell tumors are the most common malignancy in young males, and the frequency of these tumors has risen dramatically over the last century. Because it is known that the MAGE genes are expressed in a wide variety of tumors but are expressed only in the mitotic spermatogonia (germ cells) and in the primary spermatocytes in the normal testis, the authors screened the expression of MAGE-A4 in a panel of testicular germ cell tumors.

METHODS

Monoclonal antibody 57B raised against MAGE-A4 was tested immunohistochemically on 12 classical seminomas, 5 anaplastic seminomas, 10 various specimens of nonseminomatous germ cell tumors (NSGCTs), 2 combined tumors containing seminoma components, 1 Sertoli cell tumor, 2 Leydig cell tumors, and 15 carcinomas in situ (CIS). In addition, monoclonal antibody 57B was tested on embryonic gonad (age 8 weeks) and fetal gonads (ages 15 weeks, 17 weeks, and 28 weeks).

RESULTS

Classical seminomas uniformly and specifically expressed MAGE-A4 compared with anaplastic seminomas and NSGCTs, which were negative for this antigen. Specific expression of MAGE-A4 also was seen in subpopulations of CIS cells, providing additional evidence for heterogeneity of the phenotype of these cells, in which it is believed that differentiation and proliferation generate seminomas and NSGCTs. Finally, MAGE-A4 was expressed in the fetal precursors of the stem germ cells from 17 weeks of gestation onward, in accordance the fact that CIS can arise from prespermatogonia in the fetus.

CONCLUSIONS

MAGE-A4 can be considered a potential specific marker for normal premeiotic germ cells and germ cell tumors and can be used to characterize classical seminomas.

Detection of MAGE-A3 in breast cancer patients' sentinel lymph nodes

The detection of occult metastatic breast cancer cells by RT-PCR is limited by the poor specificity of most tumour mRNA markers. MAGE-A3 is a highly specific tumour mRNA marker that is not expressed in non-cancer cells. This study assesses MAGE-A3 mRNA as a molecular marker for the detection of tumour cells in the sentinel lymph nodes (SLN) of breast cancer patients. Serial frozen sections of SLN (n = 121) were obtained from 77 AJCC (American Joint Committee on Cancer) Stage I-IIIA breast cancer patients. MAGE-A3 mRNA analysis of SLN was performed by RT-PCR and Southern blot analysis. Tumour cells were detected in 48 of 121 (40%) SLN from 77 patients by H&E or IHC staining, and 35 of 77 (45%) patients, overall, had histopathologically (H&E and/or IHC) positive SLN. Among histopathologically negative SLN, 28 of 73 (38%) SLN were MAGE-A3 mRNA positive by RT-PCR. Overall, 41 of 77 (53%) patients and 50 of 121 (41%) SLN were positive for MAGE-A3. MAGE-A3 mRNA expression in the SLN occurred more frequently with infiltrating lobular carcinoma (P < 0.001) than with infiltrating ductal carcinoma, adding further evidence of possible phenotypic differences between these 2 subtypes of breast cancer. Due to its high specificity, MAGE-A3 mRNA is a potentially useful marker for detecting breast cancer cells in the SLN. One half of breast tumours expressed MAGE-A3 mRNA, which has important potential implications for antigen-specific targeted immunotherapy.

Expression of multiple cancer-testis antigen genes in gastrointestinal and breast carcinomas

Cancer-testis antigens (CTAs) such as MAGE are selectively expressed in various types of human neoplasms but not in normal tissues other than testis. This characteristic feature of CTAs makes them promising antigens for cancer-specific immunotherapy. A critical requirement for this therapy is identification of promising antigens. In this study, we investigated the expression of 6 genes recently identified by serological analysis of antigens by recombinant expression (SEREX) libraries: NY-ESO-1, LAGE-1, SCP-1, SSX-1, SSX-2, and SSX-4, in many surgical samples of gastrointestinal and breast carcinomas using reverse transcription-polymerase chain reaction. We found relatively high expression of SCP-1 (23.5%) and SSX-4 (20.6%) in gastric carcinoma, LAGE-1 (39.1%) and NY-ESO-1 (23.9%) in oesophageal carcinoma, and SCP-1 (34.1%) in breast carcinoma. We also found frequent synchronous expression with MAGE, including LAGE-1 (46.2%) in oesophageal carcinoma, SSX-4 (46.7%) in gastric carcinoma, and SCP-1 (38.3%) in breast carcinoma. Immunohistochemical analysis of the tumour samples expressing both MAGE-4 and NY-ESO-1 genes demonstrated differences in distribution between MAGE-4 and NY-ESO-1 in serial sections. We concluded that NY-ESO-1, LAGE-1, SCP-1 and SSX-4 genes may be promising candidates for cancer-specific immunotherapy in addition to MAGE, and that polyvalent cancer vaccines may be useful in cases of heterogeneous expressions of CTA genes in gastrointestinal and breast carcinomas.

Molecular staging of early colon cancer on the basis of sentinel node analysis: a multicenter phase II trial

PURPOSE

Approximately 30% of patients with American Joint Committee on Cancer stage I or II colorectal cancer (CRC) develop systemic disease. We hypothesized that multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of sentinel lymph nodes (SNs) draining a primary CRC could detect micrometastases not detected by conventional histopathologic analysis.

PATIENTS AND METHODS

In a multi-institutional study, 40 patients with primary CRC underwent dye-directed lymphatic mapping at the time of colon resection. Each dye-stained SN was tagged, and the tumor and regional nodes were resected en bloc. All lymph nodes were examined by conventional hematoxylin and eosin (HE) staining. In addition, each SN was cut into multiple sections for cytokeratin immunohistochemical (CK-IHC) staining and for RT-PCR and electrochemiluminescent detection of three markers: beta-chain human chorionic gonadotropin, hepatocyte growth factor receptor, and universal melanoma-associated antigen. Whenever possible, RT-PCR assay was also performed on primary tumor tissue. The detection sensitivity of individual markers was 10(-3) to 10(-4) microg of RNA and one to five tumor cells in 10(7) lymphocytes of healthy donors.

RESULTS

One to three SNs were identified in each patient. An average of 15 nodes were removed from each CRC specimen. No nonsentinel (untagged) node contained evidence of tumor if all tagged (sentinel) nodes in the same specimen were histopathology tumor-negative. HE staining of SNs identified tumor in 10 patients (25%), and CK-IHC of SNs identified occult micrometastases in four patients (10%) whose SNs were negative by HE. Of the remaining 26 patients with no evidence of SN involvement by HE or CK-IHC, 12 (46%) had positive RT-PCR results. The number of markers expressed in each SN correlated (P <.04) with the T stage of the primary tumor. There was 79% concordance in marker expression for the respective pairs (n = 38) of primary tumor and histopathologically positive SNs, and 86% (12 of 14) concordance between RT-PCR positive and histopathologically positive SNs.

CONCLUSION

Identification and focused examination of the SN is a novel method of staging CRC. CK-IHC and RT-PCR identified occult micrometastases in 53% of patients whose SNs were negative by conventional staging techniques. These ultrasensitive assays of the SN can identify patients who may be at high risk for recurrence of CRC and therefore are more likely to benefit from systemic adjuvant therapy.

Expression of MAGE-B genes in esophageal squamous cell carcinoma

The MAGE-B (MAGE-B1, -B2, -B3, and -B4) genes share strong homology with the MAGE-A gene family. MAGE-B1 and -B2 encode common tumor-specific peptide antigens. There is, however, still very little information about the expression of these genes in human gastro-intestinal carcinomas. We investigated the expression of MAGE-B1 and -B2 genes in 29 cell lines and 53 clinical tumor samples of esophageal squamous cell carcinoma by reverse transcription polymerase chain reaction (RT-PCR). MAGE-B1 and -B2 gene transcripts were detected by RT-PCR in 1 (3%) and 6 (21%) cell lines, and in 9 (17%) and 17 (32%) clinical samples, respectively. Among them, 7 / 29 (24%) cell lines and 19 / 53 (36%) clinical samples expressed at least either MAGE-B1 or -B2. A significant correlation was found between negative MAGE-B gene expression and vascular invasion (P = 0.008). In 45 out of 53 esophageal carcinoma RNA samples, the MAGE-A1, -A2, and -A3 genes were detected in 27 (60%), 23 (51%), and 30 (67%) samples, respectively, while the MAGE-B genes were detected in 18 (40%) samples. The frequency of MAGE-B gene expression in esophageal carcinoma was relatively higher than that observed for gastric or colorectal carcinomas (12% and 2%, respectively). Therefore, the MAGE-B genes could be used as targets in specific immunotherapy of esophageal squamous cell carcinomas.

Development of a multiple-marker RT-PCR assay for detection of micrometastases of hepatocellular carcinoma

We investigated the expression of several candidate gene markers: MAGE-1, MAGE-3, cytokeratin-20 (CK-20), and alpha-fetoprotein (AFP) in tumor tissue and blood specimens from patients with hepatocellular carcinoma to develop a multiple marker reverse transcriptase-polymerase chain reaction (RT-PCR) assay for detection of micrometastasis in circulation. In 24 tumor specimens, the positivity for MAGE-1, MAGE-3, AFP, and CK-20 genes was 71, 67, 88, and 79% respectively, and all specimens expressed at least one marker. Although AFP and CK-20 transcripts were also detected in corresponding noncancerous liver specimens, none of the 22 corresponding normal specimens or seven normal livers were positive for MAGE-1 or MAGE-3 transcripts. In addition, MAGE-1 and MAGE-3 gene transcripts were not detected in any peripheral blood specimens from 31 normal healthy volunteers. MAGE-1, MAGE-3, and AFP transcripts were detected in 9 (12.7%), 3 (4.8%), and 10 (15.9%) of 71 blood specimens from 11 hepatocellular carcinoma patients, respectively, while 19 specimens (26.8%) were positive for at least one marker. Our results indicate that a multimarker RT-PCR assay with cancer-specific markers such as MAGE-1 and MAGE-3 in combination with a liver-specific AFP marker may be a promising diagnostic tool for monitoring hepatocellular carcinoma patients with better sensitivity and specificity.

Melanoma antigen genes 1 and 2 are differentially expressed in human gastric and cardial carcinomas

BACKGROUND

MAGE genes encode for tumor-rejection antigens and are expressed in tumors of different histologic types but not in normal tissues, with the exception of testis and placenta. The aim of this study was to evaluate the frequency of MAGE-1 and -2 expression in gastric and in cardial carcinomas; these conditions have been described as two distinct diseases, having different etiologies, epidemiologic patterns, and gene mutations.

METHODS

Two groups of patients were studied: patients with distal gastric carcinoma and patients with carcinoma of the cardia. A group of patients with intestinal metaplasia in the gastric mucosa and controls were also included. All of them underwent upper GI endoscopy. Paired biopsy specimens were taken for routine histology and for RNA extraction, to study the expression of MAGE-1 and -2 genes.

RESULTS

None of the intestinal metaplastic samples or controls expressed MAGE-1 and -2 at detectable levels. Whereas 40% of the gastric cancer patients expressed either MAGE-1 or -2, 26.6% transcribed both. In the cardial cancer group, 20% of the cases expressed at least one MAGE, and only 6.6% expressed both genes. These results might reinforce the concept that cancer of the cardia is a distinct neoplastic disease with regard to esophageal and gastric (distal) carcinomas.

CONCLUSIONS

Here we show that MAGE gene expression occurs in advanced stages of gastric and cardial cancer and therefore appears to be a late event. This might point to a reconsideration of their potential role in cancer immunotherapy.

Immunoreactivity with the anti-MAGE antibody 57B in malignant melanoma: frequency of expression and correlation with prognostic parameters

The melanoma-associated antigen (MAGE) family consists of a number of antigens initially recognized by cytotoxic T lymphocytes, which are currently being investigated for immunotherapy of patients with metastatic melanoma and other tumor types. Expression of MAGE mRNA in melanocytic tumors is said to be restricted to invasive malignant tumors and absent in nevi. Recently, a monoclonal antibody (57B) has become available to examine MAGE protein expression in archival material. In this study, we performed immunohistochemical analysis on 132 melanocytic nevi and 205 melanomas (85 primary cutaneous melanomas and 120 metastatic tumors) to determine the frequency of MAGE expression and to explore a potential correlation with various prognostic parameters. None of the melanocytic nevi and none of the 20 in situ melanomas was immunopositive with the antibody 57B. Immunoreactivity was present in 17 of 65 (26%) primary invasive melanomas of the skin and in 30 of 120 (25%) metastatic tumors. Positive immunostaining did not correlate with tumor stage (P = .66), Breslow thickness (P = .39), Clark level (P = .5), or the histologic type of melanoma (P = .23) but was associated with a brisk infiltrate of lymphocytes involving the vertical growth phase of melanomas (P = .01). Because tumor-infiltrating lymphocytes in melanoma are associated with longer survival, our findings suggest a potential prognostic role for MAGE. Furthermore, the seeming restriction of immunopositivity to invasive malignant tumors suggests a potential diagnostic role for the antibody 57B in confirming the malignant potential of a melanocytic tumor.

Expression of MAGE-1 and -3 genes and gene products in human hepatocellular carcinoma

MAGE gene family encodes peptides recognized by autologous cytotoxic T lymphocytes in a major histocompatibility complex (MHC) class-I restricted fashion. In the present study, we have performed reverse-transcription polymerase chain reaction (RT-PCR) for the genes, as well as immunohistochemical analysis and Western blotting of MAGE-1 and -3 proteins in 33 surgically resected hepatocellular carcinomas (HCCs). MAGE-1 and -3 mRNAs were constitutively expressed exclusively in 78 and 42% of HCCs respectively. On immunohistochemistry with monoclonal antibodies, 77B for MAGE-1 and 57B for MAGE-3, MAGE-1 and -3 proteins were recognized in cytoplasm of only six among 33 (18%) and two of 29 HCCs (7%) respectively. The distribution pattern was mostly focal in HCC nodules. By contrast, the Western blot analysis revealed that the MAGE-1 (46 kDa) and -3 proteins (48 kDa) were expressed in 80 and 60% of 15 HCCs examined respectively. The proteins of MAGE-1 and -3 were also expressed exclusively in HCCs regardless of the histological grading and clinical staging. Our results indicate that the detection of the genes by RT-PCR or the proteins by Western blotting is useful for differentiating early HCCs from non-cancerous lesions, and that the peptides derived from MAGE-1 and -3 proteins might be suitable targets for immunotherapy of human HCC.

The potential of melanoma antigen expression in cancer therapy

A potential new therapy for cancer is active specific immunotherapy with melanoma antigen (MAGE) gene products. The MAGE gene family comprizes a series of 12 closely related genes, some of which have been shown to be expressed in a variety of tumours of different histological origin. Peptides encoded by the MAGE genes are targets for specific immunotherapy as they are presented in association with human leucocyte antigen class I molecules and are recognised by cytotoxic T lymphocytes. This article reviews the discovery, development, role and therapeutic potential of MAGE tumour-associated antigens. Knowledge in this field of study is in its early stages. Future advances can be anticipated in term of defining therapeutic relevance, antigen detection and discovery of related genes.

High frequency of expression of MAGE genes in human hepatocellular carcinoma

AIMS/BACKGROUND

Activation of human MAGE genes leads to the expression of a set of tumor rejection antigens, which are recognized by cytotoxic T lymphocytes. The antigens may become the targets of immunotherapy. The expression of MAGE genes was originally found in, but is not restricted, to melanomas. The aim of this study was to investigate the expression of MAGE genes in human hepatocellular carcinomas.

METHODS

The expression of MAGE-1, -2, -3, -4 genes in tumorous and corresponding non-tumorous liver tissue was studied using a reverse-transcription polymerase chain reaction.

RESULTS

In the 50 hepatocellular carcinomas studied, MAGE-1, -2, -3, -4 mRNA expression was detected in 23 (46%), 17 (34%), 21 (42%) and 8 (16%), respectively. Seventy-four percent of the hepatocellular carcinomas expressed at least one of the MAGE genes. MAGE mRNAs were not detected in the corresponding non-tumor liver tissues. MAGE gene expression was not significantly correlated with clinicopathological factors.

CONCLUSIONS

The MAGE genes are expressed in a high percentage of hepatocellular carcinomas; the MAGE gene products are potential targets for tumor-specific immunotherapy.

Can immunotherapy by gene transfer tip the balance against colorectal cancer?

Gene therapy, in particular the transfer of genes encoding immunostimulatory molecules (cytokines and costimulatory molecules) as well as selectively cytotoxic enzymes and DNA vaccination, has the potential of enhancing cell mediated immune responses against tumours including those of colorectal origin. Genes can be transferred using viral vectors either to cultured tumour cells in vitro that can be returned to the patient as a "cancer vaccine", or directly to tumour cells in vivo. Vaccination with DNA constructs expressing specific tumour antigens characteristic of colorectal neoplasia can trigger immune recognition and destruction of tumour cells. The aim is to tip the balance from protumour to antitumour mechanisms by generating a local immune response and systemic antitumour immune memory to destroy metastases. Studies in murine models, combined with human studies, show that such approaches could become an adjunct to current treatments for human colorectal cancer in the near future.