Human esophageal carcinomas frequently express the tumor-rejection antigens of MAGE genes

Cancer/testis antigen expression and co-expression patterns in gastroesophageal adenocarcinoma

Gastroesophageal adenocarcinoma (GEAC) poses a significant challenge due to its poor prognosis and limited treatment options. Recently, Cancer/testis antigens (CTAs) have emerged as potential therapy targets due to their high expression in tumor cells and their immunogenic nature. We aimed to explore the expression and co-expression of CTAs in GEAC. We analyzed 63 GEAC patients initially and validated our findings in 329 patients from The Cancer Genome Atlas (TCGA) database. CTA expression was measured after RNA sequencing, while clinical information, including survival outcomes and treatment details, was collected from an institutional database. Co-expression patterns among CTAs were determined using Spearman correlation analysis. The majority of the study cohort were male (87%), Caucasian (94%), and had stage IV disease (64%). CTAs were highly prevalent, ranging from 58 to 19%. The MAGE gene family showed the highest expression, consistent across both cohorts. The correlation matrix revealed a distinct cluster of significantly co-expressed genes, including MAGEA3, NY-ESO-1, and others (0.27 ≤ r ≤ 0.73). Survival analysis revealed that individual CTAs were associated with poorer survival outcomes in patients not receiving immunotherapy while showing potential for improved survival in those undergoing immunotherapy, although these findings lacked robust reliability. Our study provides a comprehensive characterization of CTA expression and co-expression in GEAC. The strong correlation among CTAs like MAGE, NY-ESO-1, and GAGE suggests a potential for therapies targeting multiple CTAs simultaneously. Further research, including prospective trials, is warranted to assess the prognostic value of CTAs and their suitability as therapeutic targets.

Cancer/testis antigen expression and co-expression patterns in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinoma (GEAC) poses a significant challenge due to its poor prognosis and limited treatment options. Recently, Cancer/testis antigens (CTAs) have emerged as potential therapy targets due to their high expression in tumor cells and their immunogenic nature. We aimed to explore the expression and co-expression of CTAs in GEAC. We analyzed 63 GEAC patients initially and validated our findings in 329 patients from The Cancer Genome Atlas (TCGA) database. CTA expression was measured after RNA sequencing, while clinical information, including survival outcomes and treatment details, was collected from an institutional database. Co-expression patterns among CTAs were determined using Pearson correlation analysis. The majority of the study cohort were male (87%), Caucasian (94%), and had stage IV disease (64%). CTAs were highly prevalent, ranging from 58-19%. The MAGE gene family showed the highest expression, consistent across both cohorts. The correlation matrix revealed a distinct cluster of significantly co-expressed genes, including MAGEA3, NY-ESO-1, and others (0.27 ≤ r ≤ 0.73). Survival analysis revealed that individual CTAs were associated with poorer survival outcomes in patients not receiving immunotherapy while showing potential for improved survival in those undergoing immunotherapy, although these findings lacked robust reliability. Our study provides a comprehensive characterization of CTA expression and co-expression in GEAC. The strong correlation among CTAs like MAGE, NY-ESO-1, and GAGE suggests a potential for therapies targeting multiple CTAs simultaneously. Further research, including prospective trials, is warranted to assess the prognostic value of CTAs and their suitability as therapeutic targets.

Cancer/testis antigens: promising immunotherapy targets for digestive tract cancers

Digestive tract cancers, including esophageal, gastric, and colorectal cancers, are the major cause of death among cancer patients worldwide due to the heterogeneity of cancer cells, which limits the effectiveness of traditional treatment methods. Immunotherapy represents a promising treatment strategy for improving the prognosis of patients with digestive tract cancers. However, the clinical application of this approach is limited by the absence of optimal targets. Cancer/testis antigens are characterized by low or absent expression in normal tissues, but high expression in tumor tissues, making them an attractive target for antitumor immunotherapy. Recent preclinical trials have shown promising results for cancer/testis antigen-targeted immunotherapy in digestive cancer. However, practical problems and difficulties in clinical application remain. This review presents a comprehensive analysis of cancer/testis antigens in digestive tract cancers, covering their expression, function, and potential as an immunotherapy target. Additionally, the current state of cancer/testis antigens in digestive tract cancer immunotherapy is discussed, and we predict that these antigens hold great promise as an avenue for breakthroughs in the treatment of digestive tract cancers.

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.

Functional and mechanistic studies reveal MAGEA3 as a pro-survival factor in pancreatic cancer cells

Background

In the era of personalized therapy, functional annotation of less frequent genetic aberrations will be instrumental in adapting effective therapeutic in clinic. Overexpression of Melanoma associated antigen A3 (MAGEA3) is reported in certain pancreatic cancer (PCA) patients. The major objective of the current study was to investigate the functional role of MAGEA3 in pancreatic cancer cells (PCCs) growth and survival.

Methods

Using overexpression (tet-on regulated system and constitutive expression system) and knockdown (by siRNA and shRNA) approach, we dissected the mechanistic role of MAGEA3 in pancreatic cancer pathogenesis. We generated MAGEA3 expressing stable PCA cell lines and mouse primary pancreatic epithelial cells. MAGEA3 was also depleted in certain MAGEA3 positive PCCs by siRNA or shRNA. The stable cells were subjected to in vitro assays like proliferation and survival assays under growth factor deprivation or in the presence of cytotoxic drugs. The MAGEA3 overexpressing or depleted stable PCCs were evaluated in vivo using xenograft model to check the role of MAGEA3 in tumor progression. We also dissected the mechanism behind the MAGEA3 role in tumor progression using western blot analysis and CCL2 neutralization.

Results

MAGEA3 overexpression in PCA cells did not alter the cell proliferation but protected the cells during growth factor deprivation and also in the presence of cytotoxic drugs. However, depletion of MAGEA3 in MAGEA3 positive cells resulted in reduced cell proliferation and increased apoptosis upon growth factor deprivation and also in response to cytotoxic drugs. The in vivo xenograft study revealed that overexpression of MAGEA3 promoted tumor growth however depleting the same hindered the tumor progression. Mechanistically, our in vitro and in vivo study revealed that MAGEA3 has tumor-promoting role by reducing macro-autophagy and overexpressing pro-survival molecules like CCL2 and survivin.

Conclusion

Our data proves tumor-promoting role of MAGEA3 and provides the rationale to target MAGEA3 and/or its functional mediators like CCL2 for PCA, which may have a better impact in PCA therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1272-2) contains supplementary material, which is available to authorized users.

Association of MAGE A1-6 Expression with Lung Cancer Progression

The melanoma-associated antigen (MAGE) genes are known to be expressed in various kinds of tumors including lung cancer. Although they are studied as targets for immunotherapy and tools for early detection of lung cancer, the correlation between MAGE expression and the prognosis in lung cancer has not been clarified. In this study, we evaluated the relationship between MAGE A1-6 gene expression and the clinical prognosis in lung cancer. Bone marrow aspirations were performed in 60 patients who were diagnosed as lung cancer and underwent lung cancer surgery between 2007 and 2008. Each bone marrow was examined using nested reverse transcription- polymerase chain reaction (RT-PCR) with the MAGE common primer to detect MAGE A1-6. Overall survival rate, disease-free survival rate, recurrence, and distant metastasis were reviewed retrospectively. Survival periods were analyzed using SPSS ver. 20.0. Of the total 60 lung cancer patients, 9 patients (15%) had MAGE A1-6. MAGE A1-6-positive patients showed poor overall survival and overall disease-free survival rates (43.8 ± 26.1, 43.2 ± 26.9 months, respectively) compared with MAGE A1-6-negative patients (54.4 ± 17.2, 44.8 ± 22.1 months, respectively). No significant difference was shown in either survival rates. In conclusion, MAGE A1-6 expression of bone marrow in lung cancer patients correlated with poor survival rates. We suggest that MAGE A1-6 may be considered as a novel prognostic factor for lung cancer which leads to effective follow-up and treatment.

An aptamer targeting shared tumor-specific peptide antigen of MAGE-A3 in multiple cancers

A DNA aptamer was identified against the shared tumor-specific MAGE-A3111-125 peptide antigen. The dissociation constant between the aptamer and the peptide was measured at 57 nM. Binding of the aptamer to seven types of cancer cells, melanoma, breast, colorectal, liver, lung, pancreas and oral cancer, was confirmed with flow cytometry and fluorescence imaging. Cy3-conjugated aptamers signals were specifically localized to the surface of those cancer cells. The results indicate that the DNA aptamer against the shared tumor-specific MAGE-A3 peptide can be used in cancer cell targeting and has the potential for developing into new modalities for the diagnosis of multiple cancers.

Inhibition of human esophageal squamous cell carcinomas by targeted silencing of tumor enhancer genes: an overview

Esophageal cancer has been reported as the ninth most common malignancy and ranks as the sixth most frequent cause of death worldwide. Esophageal cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy. Novel strategies are needed to boost the oncologic outcome. Recent advances in the molecular biology of esophageal cancer have documented the role of genetic alterations in tumorigenesis. Oncogenes serve a pivotal function in tumorigenesis. Targeted therapies are directed at the unique molecular signature of cancer cells for enhanced efficacy with low toxicity. RNA interference (RNAi) technology is a powerful tool for silencing endogenous or exogenous genes in mammalian cells. Related results have shown that targeting oncogenes with siRNAs, specifically the mRNA, effectively reduces tumor cell proliferation and induces apoptotic cell death. This article will briefly review studies on silencing tumor enhancer genes related to the induction of esophageal cancer.

Screening of genes differentially expressed between human esophageal squamous cell carcinoma and tumor-adjacent normal tissue using gene chip technology

AIM: To screen differentially expressed genes between human esophageal squamous cell carcinoma and tumor-adjacent normal tissue to lay a theoretical basis for finding molecular markers specific for esophageal squamous cell carcinoma.

METHODS: Total RNA was extracted from human esophageal squamous cell carcinoma and tumor adjacent normal tissue specimens and cDNA was synthesized by reverse transcription. Probes were prepared by labeling the synthesized cDNA with Cy3-dUTP and hybridized with gene chips to screen differentially expressed genes. Bioinformatic tools were used for characterization of differentially expressed genes obtained.

RESULTS: According to the expression ratio of >4.0 or <0.25, a total of 1 113 differentially expressed genes were identified, including 464 up-regulated and 649 down-regulated ones. Bioinformatic analysis identified a variety of known functional genes. RT-PCR analysis confirmed that three genes were differentially expressed between human esophageal squamous cell carcinoma and tumor adjacent normal tissue.

CONCLUSION: Gene chip technology is highly efficient and reliable in screening genes differentially expressed in esophageal squamous cell carcinoma. The occurrence and development of esophageal squamous cell carcinoma is the result of expression of many cancer-related genes.

MAGE-A3/4 and NY-ESO-1 antigens expression in metastatic esophageal squamous cell carcinoma

In the present study we analyzed immunohistochemical expression of MAGE-A 3/4 and NY-ESO-1 in 55 samples of esophageal squamous cell carcinomas (ESCC) and their respective lymph node metastases. To our knowledge this is the first study to assess and compare the expression of these antigens in ESCC lymph node metastases.

Fifty (90.9%) primary ESCC were positive for MAGE-A 3/4 and 53 (96.6%) were positive for NY-ESO-1. MAGE-A 3/4 was expressed in all lymph node metastases and the intensity of expression was high in a majority of cases. NY-ESO-1 was negative in 2 (7.1%) lymph nodes metastases, while the reaction was predominantly moderate in the positive group. In primary tumors MAGE-A 3/4 showed a significantly higher intensity of expression compared to NY-ESO-1 (P=0.047), while in lymph node metastases the intensity of expression was not significantly different (P=0.387). Primary tumors with and without lymph node metastases showed no significant differences in MAGE-A 3/4 (P=0.672) and NY-ESO-1 (P=0.444) expression. Intensity of MAGE-A 3/4 (P=0.461) and NY-ESO-1 (P=0.414) expression in primary tumors was not significantly different compared to the expression in their respective lymph nodes metastases. Expression of MAGE-A 3/4 in primary tumors showed significant positive correlation with primary tumor expression of NY-ESO-1 (P=0.021) but no significant correlation with the expression of MAGE-A 3/4 in lymph node metastases (P=0.056). Expression of NY-ESO-1 in primary tumors showed significant positive correlation with the expression of NY-ESO-1 in lymph node metastases (P=0.001) and significant negative correlation with patients' age (P<0.001). Expression of MAGE-A 3/4 and NY-ESO-1 in primary tumors and lymph node metastases showed no significant correlation with prognostic parameters such as tumor grade and TNM stage (P>0.05). We have shown different levels of MAGE-A 3/4 and NY-ESO-1 expression in almost all specimens of primary tumor and lymph node metastases, suggesting that ESCC may be possible target of immunotherapy and anti-tumor vaccination. High levels of expression in lymph node metastases indicate possible clinical benefit of postoperative vaccine with MAGE-A3 and NY-ESO-1 in advanced stage of disease.

Clinical significance of melanoma antigen-encoding gene-1 (MAGE-1) expression and its correlation with poor prognosis in differentiated advanced gastric cancer

BACKGROUND

Melanoma antigen-encoding gene-1 (MAGE-1), a cancer/testis antigen, has been reported to be expressed in various types of cancer. We investigated the clinicopathological features and prognostic significance of MAGE-1 expression in advanced gastric cancer (AGC).

METHODS

Immunohistochemical staining for MAGE-1 was performed on surgical specimens obtained from 135 patients with AGC.

RESULTS

Positive expression of MAGE-1 detected in cytoplasm was observed in 44 of 135 cases (32.6%) in primary tumors and 26 of 96 (27.1%) in lymph node metastases. In noncancerous gastric tissues, apparent MAGE-1 expression was not detected. MAGE-1 in primary tumor was correlated with advanced age (P < 0.001), macroscopic infiltrated type (P = 0.035), and presence of vascular invasion (P = 0.027). The 5-year cancer-specific survival rates of AGC patients with positive MAGE-1 expression were significantly lower than those of patients with negative MAGE-1 (positive: 31.6%, negative: 57.6%, P = 0.038). On multivariate analysis, MAGE-1 expression was not an independent prognostic predictor of AGC (P = 0.064). In differentiated AGC patients, MAGE-1 expression was correlated with advanced age (P = 0.003), macroscopic infiltrated type (P = 0.009), and presence of lymph node metastasis (P = 0.033). The cancer-specific survival rates of differentiated AGC patients with positive MAGE-1 were significantly lower than those of patients with negative MAGE-1 (P = 0.003). Positive MAGE-1 expression was an independent prognostic factor of differentiated AGC patients on multivariate analysis (P = 0.031).

CONCLUSIONS

These findings suggest that MAGE-1 protein expression can serve as a predictive marker of poor prognosis in differentiated AGC patients.

A newly identified MAGE-3-derived, HLA-A24-restricted peptide is naturally processed and presented as a CTL epitope on MAGE-3-expressing gastrointestinal cancer cells

PURPOSE

In order to broaden the possibility for anti-MAGE-3 immune targeting, it is important to identify HLA-A24-restricted epitopes derived from MAGE-3, since HLA-A24 is one of the most common alleles in Japanese and Asian people. In the present study, we defined a new MAGE-3 derived, HLA-A24-binding peptide presented as a CTL epitope on gastrointestinal cancer cells.

MATERIALS AND METHODS

A panel of MAGE-3-derived peptides (9mer and 10mer) with the HLA-A24-binding motif was selected, and identification of MAGE-3-derived, HLA-A24-restricted CTL epitopes was performed by a reverse immunology approach. To induce MAGE-3-peptide specific CTLs, PBMCs were repeatedly stimulated with monocyte-derived, mature DCs pulsed with the peptides. Subsequent peptide-induced T cells were tested for their specificities by ELISPOT, tetramer and cytotoxic assay. CTL clones were then obtained from the CTL line by limiting dilution.

RESULTS

The peptide-inducing CTLs revealed that MAGE-3(113)-peptide was reacted as a CTL epitope in a HLA-A24-restricted fashion, confirmed by ELISPOT and cytotoxic assays. In addition, the MAGE-3(113)-specific CTL clones, confirmed by tetramer assay, showed that the MAGE-3(113) epitope is naturally processed and presented as the CTL epitope on MAGE-3-expressing gastrointestinal cancer cells by evaluating the cold target inhibition assays.

CONCLUSION

The newly identified MAGE-3(113)-peptide epitope is naturally processed and presented as the CTL epitope on MAGE-3-expressing gastrointestinal cancer cells, indicating that anti-MAGE-3 immune targeting with the MAGE-3(113) peptide is a promising approach for treatment.

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.

Heterogeneous expression of GAGE, NY-ESO-1, MAGE-A and SSX proteins in esophageal cancer: Implications for immunotherapy

Cancer/testis antigens (CTAs) elicit immune response in cancer patients and are therefore targets of immunotherapy. Current information on CTA expression is primarily based on mRNA assays and little is known about their expression at the protein level. The objectives of our study are to analyze GAGE, NY-ESO-1, MAGE-A and SSX protein expression in esophageal cancer and to correlate their expression patterns with clinicopathologic parameters and survival. We examined CTA protein expression in 213 patients with esophageal cancer by immunohistochemistry. Antigen-positive tumors were evaluated once and antigen-negative tumors were evaluated 3 times by examining different parts of the cancer specimen. GAGE, NY-ESO-1 and MAGE-A were heterogeneously expressed in 42 (20%), 44 (21%) and 111 (52%) tumors, respectively, whereas SSX expression was not detected. Of the 126 (59%) patients expressing CTAs, 70 (33%) expressed 1, 41 (19%) expressed 2 and 15 (7%) expressed 3 antigens. The expression of MAGE-A was correlated with those of GAGE (p = 0.001) and NY-ESO-1 (p = 0.002), and the expression of GAGE was correlated with that of NY-ESO-1 (p = 0.002). One hundred fifty-six (79%) sections were positively stained in the first evaluation, whereas 37 (19%) and 4 (2%) positive sections were identified in the second and third evaluations, respectively. Particularly, MAGE and GAGE expression showed overlaps. GAGE, NY-ESO-1 and MAGE-A protein expression was not correlated with the disease progression, TNM factors or survival. The detection of immunonegative cells in every specimen suggests addition of other drugs such as 5-aza-2'-deoxycytidine to increase the therapeutic effect of CTA-specific cancer vaccines.

Expression of cancer/testis (CT) antigens in Chinese hepatocellular carcinoma and its correlation with clinical parameters

For investigating the expression of cancer/testis (CT) antigens in patients with hepatocellular carcinoma (HCC) in China, and evaluating the correlations between the expression of these CT antigens and clinical parameters, we collected tumors and adjacent non-cancerous tissues of 43 HCC patients from Beijing and 30 HCC patients from Guangxi province. Expression of the mRNA of 14 CT antigens was evaluated by reverse transcription PCR (RT-PCR). The correlation between CT antigen expression and clinical parameters was statistically analyzed. The mRNA expression frequencies of CT antigens in tumor tissue were: MAGE-A1, 69.9%; MAGE-A3, 47.9%; MAGE-A4, 20.0%; MAGE-A10, 36.7%; SSX-1, 67.4%; SSX-2, 35.6%; SSX-4, 48.8%; SSX-5, 30.2%; NY-ESO-1, 42.5%; MAGE-B1, 52.0%; MAGE-B2, 60.0%; MAGE-C1, 48.0%; MAGE-C2, 68.0%; and SCP-1, 33.3%. However, in adjacent tissues, no CT antigen mRNA expression was detected, except SSX-1 in 9.3% patients. In each HCC tissue, the expression of a minimum of one, two, or three CT antigens was in the range of 80-90, 70-80 or 50-70%, respectively. MAGE-A3 mRNA expression differed between the HCC patients in Beijing and Guangxi (P=0.002). The average age of the HCC patients bearing CT antigen positive tumors was higher than that of the HCC patients bearing CT antigen negative tumors. The expression of MAGE-A3, SSX-1, SSX-2, SSX-4, MAGE-B2, MAGE-C1, and MAGE-C2 correlated significantly with older age (P<0.05). Moreover, the expressions of MAGE-A4 and SCP-1 were related to alpha-fetoprotein abnormality (P<0.05), and the expression of NY-ESO-1 was related to early tumor stage (P<0.05). There was no correlation observed between the expression of CT antigens and the sex, HBV infection or tumor size.

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.

Novel molecular targeted therapy for esophageal cancer

Esophageal cancers are highly lethal neoplasms which are generally refractory to conventional multidisciplinary interventions. Recent elucidation of the mechanisms of esophageal carcinogenesis, as well as preclinical studies utilizing chromatin remodeling agents and inhibitors of oncogene signaling in conjunction with conventional chemotherapeutic agents provide new opportunities for the development of potentially efficacious molecular targeted therapies for these malignancies.

Immunologic analysis of a phase I/II study of vaccination with MAGE-3 protein combined with the AS02B adjuvant in patients with MAGE-3-positive tumors

In a phase I/II study, patients with solid metastatic MAGE-3-positive tumors, mainly melanoma, were vaccinated with recombinant MAGE-3 protein combined with the immunologic adjuvant AS02B comprised of MPL and QS21 in an oil-in-water emulsion. The recombinant MAGE-3 protein was made up of a partial sequence of the protein D (ProtD) antigen of Haemophilus influenzae fused to the MAGE-3 sequence. The vaccine was given intramuscularly at 3-week intervals. Patients whose tumors stabilized or regressed after 4 vaccinations received 2 additional vaccinations at 6-week intervals. MAGE-3 and ProtD antibody and cellular immune responses were monitored after vaccination. Ninety-six percent (23/24) of the patients vaccinated with MAGE-3 protein in AS02B adjuvant elicited a significant anti-MAGE-3 IgG antibody response after 4 vaccinations, and all developed anti-ProtD IgG antibodies. For the detection of T-cell activity, total peripheral blood mononuclear cells were restimulated in vitro with MAGE-3- or ProtD-loaded autologous mature dendritic cells. In 30% of the evaluable patients vaccinated with the adjuvanted recombinant protein, IFNgamma production was increased in response to MAGE-3, and 2 patients (14% of evaluable patients) had a concomitant increase in IL-5 production. In 37% and 43% of the patients, respectively, IFNgamma or IL-5 production was increased in response to ProtD. It is concluded that vaccination of advanced cancer patients with MAGE-3 self-antigen in AS02B adjuvant is able to elicit MAGE-3-specific antibody and a T-cell response.

HER-2, gp100, and MAGE-1 are expressed in human glioblastoma and recognized by cytotoxic T cells

It has recently been demonstrated that malignant glioma cells express certain known tumor-associated antigens, such as HER-2, gp100, and MAGE-1. To further determine the possible utilization of these antigens for glioma immunotherapy and as surrogate markers for specific tumor antigen cytotoxicity, we characterized the presence of mRNA and protein expression in 43 primary glioblastoma multiforme (GBM) cell lines and 7 established human GBM cell lines. HER-2, gp100, and MAGE-1 mRNA expression was detected in 81.4%, 46.5%, and 39.5% of the GBM primary cell lines, respectively. Using immunoreactive staining analysis by flow cytometry, HER-2, gp100, and MAGE-1 protein expression was detected in 76%, 45%, and 38% of the GBM primary cell lines, respectively. HLA-A1-restricted epitope specific for MAGE-1 peptide (EADPTGHSY) CTL clone B07 and HLA-A2-restricted epitope specific for HER-2 peptide (KIFGSLAFL) CTL clone A05 and gp100 peptide (ITDQVPFSV) CTL clone CK3H6 were used in this study. The specificity of CTL clone was verified by HLA/peptide tetramer staining. Three CTL clones could efficiently recognize GBM tumor cells in an antigen-specific and MHC class I-restricted manner. IFN-gamma treatment can dramatically increase MHC class I expression of GBM tumor cells and significantly increase CTL recognition of tumor cells. Treatment with the DNA hypomethylating agent 5-aza-2'-deoxycytidine induced and up-regulated the mRNA expression of MAGE-1 and epitope presentation by autologous MHC. These data indicate that HER-2, gp100, and MAGE-1 could be used as tumor antigen targets for surrogate assays for antigen-specific CTLs or to develop antigen-specific active immunotherapy strategies for glioma patients.

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.

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.

MAGE, BAGE, and GAGE gene expression in patients with esophageal squamous cell carcinoma and adenocarcinoma of the gastric cardia

BACKGROUND

The MAGE, BAGE, and GAGE gene families code for distinct, tumor specific antigens that are recognized by cytotoxic T lymphocytes in the context of HLA molecules. The purpose of this study was to analyze MAGE, BAGE, and GAGE gene expression in the two major histologic types of esophageal carcinoma, squamous carcinoma (ESCc) and adenocarcinoma (CAc), and to correlate their expression patterns with the principal prognostic parameters and long term survival.

METHODS

Gene expression was analyzed in surgical samples from 24 patients with ESCc and 24 patients with CAc by reverse transcriptase-polymerase chain reaction amplification (RT-PCR). None of the patients had received preoperative chemotherapy or radiotherapy, and all were followed until death or for a minimum of 4 years.

RESULTS

Sixteen ESCc samples (67%) and 9 CAc samples (37.5%) expressed at least one of the genes under study. The expression of each MAGE gene in the two histologic types was not significantly different, with the exception of MAGE-4, which was expressed more in ESCc samples than in CAc samples. BAGE and GAGE expression was rather low and, in every case, was associated with the expression of at least one MAGE gene.

CONCLUSIONS

In the group as a whole, and in both ESCc and CAc subgroups, no significant correlation emerged between the expression of any gene and prognostic parameters, such as pathologic tumor, lymph node, or disease stage. Nevertheless, BAGE or GAGE expression was related significantly to a poor prognosis, whereas the expression of MAGE genes (in the absence of BAGE and GAGE expression) was related significantly to a good prognosis.

Molecular Strategy for Detecting Metastatic Cancers with Use of Multiple Tumor-specific MAGE-A Genes

Background: The human melanoma-associated antigen family A (MAGE-A) has high specificity and expression in various malignancies, but individual family members are expressed at low frequency in any one particular type of cancer. We therefore developed a method to detect mRNAs from multiple MAGE-A genes in a single reaction.

Methods: Universal MAGE-A (uMAGE-A) primers and probe were designed to reverse-transcribe, amplify, and detect by electrochemiluminescence (ECL) MAGE-A mRNAs on the Origen Analyzer. The assay was performed on total RNA of melanoma (n = 9 cell lines and 24 tumors), breast cancer (n = 7 and 26), and colorectal cancer (CRC; n = 5 and 12). We also evaluated blood from melanoma (n = 50), breast cancer (n = 16), and CRC (n = 21) patients.

Results: The uMAGE-A mRNA was detectable in 0.01–1 ng of cell line RNA. The identity of the uMAGE-A cDNA products was confirmed by sequencing and polyacrylamide gel electrophoresis. The uMAGE-A assay increased detection of melanoma, breast cancer, and CRC tumor by 13%, 31%, and 25%, respectively, compared with a MAGE-A1 assay, and by 17%, 19%, and 25%, respectively, compared with a MAGE-A3 assay. The uMAGE-A assay detected circulating tumor cells in the blood of melanoma (24%), breast cancer (25%), and CRC (29%) patients.

Conclusions: The uMAGE-A reverse transcription-PCR/ECL assay provides a practical and sensitive approach for detection of various metastatic cancers in tissues and blood.

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.

Induction of MAGE-3 expression in lung and esophageal cancer cells

BACKGROUND

Although MAGE-3 has been detected in approximately 40% of lung and esophageal cancers, expression of this cancer testis antigen appears to be below the threshold for immune recognition in patients with these malignancies. The aim of this study was to determine if the demethylating agent, 5-Aza-2'-deoxycytidine (DAC) and if the histone deacetylase inhibitor Depsipeptide FR901228 (DP) could enhance MAGE-3 expression in lung and esophageal cancer cells.

METHODS

Eleven lung and esophageal cancer lines and cultured normal human bronchial epithelial (NHBE) cells were exposed to normal media (NM), DAC, DP, or combination DAC/DP at varying concentrations and exposure durations. MAGE-3 expression was evaluated by quantitative RT-PCR (TaqMan) and immunohistochemistry techniques. Trypan blue exclusion techniques were used to examine the proliferation of cancer cells after drug exposure.

RESULTS

Relative to untreated controls, MAGE-3 expression was enhanced 32-fold (range 3.9 to 110) by DAC alone (0.1 micromol/L x 72 h), 2.1-fold (0.4 to 4.2) by DP alone (25 ng/mL x 6h), and 57-fold (4.6 to 209) by sequential DAC/DP exposure. Increased MAGE-3 mRNA copy numbers coincided with enhanced protein levels in these cells. MAGE-3 expression persisted after drug exposure. Flow cytometry confirmed the presence of functional HLA class I expression in these cells. Sequential DAC/DP treatment mediated pronounced growth inhibition in cancer cells but not NHBE.

CONCLUSIONS

Sequential DAC/DP treatment may be a novel strategy to simultaneously augment MAGE-3 expression and induce growth arrest in thoracic malignancies.

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.

Expression of SART3 tumor-rejection antigen in gastric cancers

We previously reported SART3 as a tumor-rejection antigen recognized by histocompatibility leukocyte antigen (HLA)-A24-restricted cytotoxic T lymphocytes (CTLs). In this study, we investigated the expression of the SART3 antigen in gastric cancers, as a candidate for use in specific immunotherapy. The SART3 antigen was detected in 9 of 10 (90%) gastric cancer cell lines, 35 of 52 (67.3%) gastric cancer tissues, and 0 of 20 non-tumorous gastric tissues. SART3-derived peptides corresponding to positions 109- 118 and 315-323 induced HLA-A24-restricted and tumor-specific CTLs from peripheral blood mononuclear cells (PBMCs) of gastric cancer patients. These peptide-induced CTLs recognized HLA-A24(+) SART3(+) gastric cancer cells, but not HLA-A24(+) SART3(-) or HLA-A24(-) SART3(+) gastric cancer cells. Therefore, the SART3 peptides could be useful in specific immunotherapy of gastric cancer patients.

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.

Expression of MAGE genes in testicular germ cell tumors

OBJECTIVES

Some of the MAGE gene family that encode tumor-rejection antigens recognized by cytotoxic T lymphocytes are expressed at the mRNA level in various malignant tumors. However, these genes are silent in normal tissues, except in the testis and placenta. It is therefore important to understand how MAGE gene expression changes with malignant transformation of the testis. We investigated the expression of MAGE-1, -2, -3, and -4 genes at the mRNA level in testicular germ cell tumors.

METHODS

Reverse transcriptase-polymerase chain reaction for MAGE genes was performed using 32 testicular germ cell tumor specimens.

RESULTS

MAGE-1, -2, -3, and -4 mRNA was detected in 16 (72%), 15 (68%), 18 (82%), and 17 (77%) of 22 patients with pure seminoma or mixed type with seminomatous elements. MAGE-1 , -2, -3, and -4 mRNA was found in 2 (20%), 5 (50%), 4 (40%), and 4 (40%) of 10 patients with nonseminomatous germ cell tumor (NSGCT). The expression rate of MAGE-1, -3, and -4 mRNA was significantly higher in patients with seminomatous elements than that in those with NSGCT. MAGE expression did not correlate with disease progression.

CONCLUSIONS

MAGE genes are more preserved in seminoma than in NSGCT. This suggests that seminoma has traits more similar to normal testis than does NSGCT.

A MAGE-1-encoded HLA-A24-binding synthetic peptide induces specific anti-tumor cytotoxic T lymphocytes

Although several MAGE-1 peptides have already been identified, the MAGE-1-encoded peptide presented by HLA-A24, which is the most common allele in Japanese population and is also frequently present in Caucasians, might have a wide applicability for immunotherapy using these peptides. To identify this potential peptide, we examined the induction of specific cytotoxic T lymphocytes (CTL) from the peripheral-blood mononuclear cells (PBMC) in HLA-A24 healthy donors by in vitro stimulation with MAGE-1-encoded synthetic peptides with a binding affinity for HLA-A24, by a simplified method. Of the 5 peptides tested, the highest HLA binder (NYKHCFPEI) was able to elicit CTL from unseparated PBMC by stimulation with freshly isolated, peptide-pulsed PMBC as antigen-presenting cells (APC) and by also using interleukin 7 and keyhole-limpet hemocyanin for a primary culture. The induced CTL could thus lyse HLA-A24 tumor cells expressing MAGE-1, as well as the peptide-pulsed target cells, in an HLA-class-I-restricted manner. By using the MAGE-1/HLA-A24 peptide, NYKHCFPEI, we found it possible to immunize many more patients, especially Japanese patients, by means of such peptide-based immunotherapeutic approaches to MAGE-1-positive malignant tumors.

Expression of the melanoma antigen-encoding gene in human lung cancer

BACKGROUND AND OBJECTIVES

We surveyed expression of melanoma antigen-encoding genes in lung cancer because of promising implications for immunotherapy.

METHODS

We studied 57 human lung carcinoma specimens using the reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

In the samples, the expression of melanoma antigen-encoding genes 1, 2, and 3 was observed in 9/43 (20.9%), 13/43 (30.2%), and 22/48 (45.8%), respectively. In 28 cases in which all three messenger RNAs were sought, 18 (64.3%) showed expression of at least one gene, 10 (35.7%) showed expression of two or three genes, and 10 (35.7%) were negative for all three genes. In a clinicopathologic analysis, melanoma antigen-encoding genes 1 and 3 were frequently expressed in squamous cell carcinomas (P = 0.0543) and in cases with regional lymph node metastasis (P = 0.0572), respectively.

CONCLUSIONS

The high incidence of melanoma antigen-encoding gene expression in lung cancer indicates the possibility of a future specific immunotherapy for this disease.

Identification of human testis-specific transcripts and analysis of their expression in tumor cells

Tumor-specific antigens recognized by autologous T lymphocytes are encoded by genes, including those of the MAGE, BAGE, and GAGE gene families, that are expressed in a significant fraction of tumors of various types, but not in normal adult tissues, except for testis where they appear to be expressed in germ cells. Because male germ cells are known to express many genes that are not expressed in other normal adult tissues, we wished to determine whether most of these genes are occasionally activated in tumor cells. Representational difference analysis was used to obtain testis-specific transcripts. The expression of 15 testis-specific cDNA sequences was tested by RT-PCR in a series of tumor cell lines. Only one cDNA sequence showed a significant level of expression in some tumor cell lines. Remarkably, this cDNA clone proved to be a new gene of the MAGE family. These results suggest that MAGE, BAGE, and GAGE genes belong to a minor subset of testis-specific genes that is often activated in tumors of various types, whereas most testis-specific genes are either never or very rarely activated in tumors.

Two members of the human MAGEB gene family located in Xp21.3 are expressed in tumors of various histological origins

Genes of the MAGE family direct the expression of tumor antigens recognized on a human melanoma by autologous cytolytic T lymphocytes. Twelve closely related MAGE genes are located in the Xq28 region. These genes share 60-98% nucleotide identity in their coding region. The presence of homologous genes in a region of Xp21.3 has been reported previously. We obtained the complete sequence of a 42-kb stretch of this region. It contains four MAGE-related genes, which we propose to name MAGE-B1, B2, B3, and B4 (HGMW-approved symbols MAGEB1, MAGEB2, MAGEB3, and MAGEB4). The coding regions of these genes share 66-81% nucleotide identity and show 45-63% identity with those of the MAGE genes located in Xq28. Like the MAGE genes located in Xq28, the MAGE-B genes are silent in normal tissues with the exception of testis. Like MAGE-1, 2, 3, 4, 6 and 12 (HGMW-approved symbols MAGEA1, 2, 3, 4, 6, and 12), genes MAGE-B1 and MAGE-B2 are expressed in a significant fraction of tumors of various histological types. The transcription of MAGE-B1 and MAGE-B2 can be induced by 5-aza-2'-deoxycytidine, suggesting that the activation of these genes in tumors results from a demethylation process.

Expression of MAGE and BAGE genes in Japanese breast cancers

BACKGROUND

The MAGE and BAGE genes code for distinct antigens, which are recognized on melanoma cells as well as on other various tumor cells by autologous cytolytic T lymphocytes. These antigens may thus constitute useful targets for specific immunotherapy, since no expression of MAGE or BAGE genes has been recognized in normal tissue except for the testis.

PATIENTS AND METHODS

We studied the MAGE-1, MAGE-3, and BAGE gene expression observed in 49 Japanese breast cancers. Gene expression was evaluated by reverse transcription polymerase chain reaction.

RESULTS

Out of 49 tumor tissue specimens of primary breast cancers, the expression of MAGE-1, -3 and BAGE was recognized in 15 (31%), 12 (24%), and 4 (8%) tumors, respectively. The expression of MAGE and BAGE genes is not recognized in normal breast tissue. The expression of the MAGE-3 gene was frequently recognized in tumors with lymphatic and/or vascular vessel permeations. Either MAGE-1 or -3 gene expressions were induced in 1 of 3 MAGE-1 negative breast cell lines or 1 of 3 MAGE-3 negative breast cell lines by the treatment with 5-aza-2'-deoxycytidine.

CONCLUSIONS

These findings suggest that: 1) the identification of such antigens coded by MAGE or BAGE genes may thus offer the possibility of using specific immunotherapy, and 2) the use of a demethylating agent may increase the number of patients who might be candidates for MAGE specific immunotherapy.

Expression of MAGE genes in human colorectal carcinoma

OBJECTIVE

The human genes MAGE-1 and -3 encode tumor-specific peptide antigens, which are recognized by autologous cytotoxic T lymphocytes. The antigens coded by those genes may be useful for cancer immunotherapy. There is, however, little information on the expression of these genes in human colorectal carcinomas.

METHOD

The expression of MAGE-1, -2, and -3 genes in 54 pairs of tumor and corresponding normal tissue specimens of the colorectum was determined by means of reverse transcription polymerase chain reaction. The induction of MAGE-1, -2, -3, and -4 gene expression in eight colorectal carcinoma cell lines also was examined by use of a demethylating agent, 5-Aza-2'-deoxycytidine (DAC).

RESULTS

The expression of MAGE genes was not recognized in normal colorectal tissues at all. In tumor tissue specimens, the expression of MAGE-1, -2, and -3 was recognized in 16 (30%), 15 (28%), and 11 (20%) patients, respectively. The expression was seen frequently in patients with liver metastasis (p < 0.01). Although MAGE-1 or -3 genes were not induced by DAC, MAGE-2 or -4 genes were induced in three of four MAGE-2 negative cell lines or three of seven MAGE-4 negative cell lines, respectively.

CONCLUSIONS

The MAGE genes were expressed exclusively in tumor tissues of one third of patients with colorectal carcinoma. The identification of such tumor rejection antigens is considered to uncover a new possibility for the specific immunotherapy of colorectal carcinoma. The demethylating agent may increase the number of patients who might be candidates for MAGE-specific immunotherapy.