Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peptides derived from melanocyte differentiation antigens have been identified as targets for MHC class I-restricted cytolytic T lymphocytes (CTLs) in human melanoma Regression of antigen-expressing tumors as well as selection of antigen-loss variants in the presence of antigen-specific CTLs have previously been reported. In the present study, we determined the expression of the melanocyte differentiation antigens Melan A/MART-1 and tyrosinase by mRNA analysis and by immunohistochemical staining with the monoclonal antibodies (MAbs) A103 and T311. Co-expression of Melan A/MART-1 and tyrosinase was detected by both methods in 18/20 melanomas tested. However, immunohistochemistry provided additional information on intensity and microheterogeneity of antigen expression that cannot be detected by mRNA analysis as a molecular basis for the escape from CTL recognition of antigen-negative tumor cells. Comparative analysis of repeated biopsies of metastatic lesions in 5 HLA-A2+ patients showed a gradual loss of Melan A/MART-1 expression in 4/5 and of tyrosinase in 2/5 samples in association with tumor progression. However, 3 of these patients had growing antigen-positive tumors in the presence of antigen-specific CTLs. This led us to assess the expression of MHC class I, the essential restriction element for CTL recognition, and of HLA-A2. We found an unexpectedly high frequency of MHC class I-negative tumors (9/20). Loss of MHC class I expression was detected in 3/5 progressive tumors and isolated loss of HLA-A2 in 1/5 tumors. Our results suggest that strategies enhancing the expression of MHC class I and tumor-associated antigens need to be considered in attempts at making vaccination more effective.
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PMID:Immunoselection in vivo: independent loss of MHC class I and melanocyte differentiation antigen expression in metastatic melanoma. 913 33

The human immune repertoire appears to be capable of recognizing normal antigens expressed by tumor cells. Among these antigens, those of differentiation, characterized by a restricted tissue expression, could be of clinical interest since they may represent a target for immunotherapeutic protocols. In this context we have evaluated, in benign and malignant lesions of the melanocytic lineage, the expression of the Melan-A/MART-1 antigen, which has been shown to be recognized by T cells, of HLA-A2 melanoma patients. The immunohistochemical analysis conducted with a Melan-A/MART-1 monoclonal antibody demonstrated that the antigen expression does not correlate with transformation or tumor progression. At variable levels Melan-A/MART-1, differently from other differentiation antigens, is homogeneously expressed by multiple autologous metastases and by melanoma metastases at different body sites. This tissue distribution adds further biological support to the ongoing use of Melan-A/MART-1-related peptides in active immunotherapy.
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PMID:Melan-A/MART-1 antigen expression in cutaneous and ocular melanomas. 940 52

MART-1/MelanA and Pmel17/gp100 are melanoma-associated antigens (MAAs) that can be recognized by tumor-infiltrating lymphocytes (TILs) capable of mediating successful adoptive therapy in vivo. Analysis of melanoma cell lines in vitro has demonstrated that heterogeneous antigen expression in the context of class I MHC is a significant co-factor in determining the recognition of melanoma targets by cytotoxic lymphocytes (CTLs). In this study, 217 specimens from 103 patients with metastatic melanoma were examined for the expression of MART-1/MelanA (monoclonal antibody [MAb] M27C10) and Pmel17/gp100 (HMB45 MAb) by immuno-histochemistry. Marked heterogeneity in the expression of both MAAs was confirmed by analysis of the percentage of positively staining tumor cells or the average intensity of tumor staining. We also noted heterogeneity of expression among multiple lesions taken from different anatomic sites within a patient. A dissociation was noted in the detection of MART-1 and gp100 in some lesions, with gp100 being undetectable in 24% of the lesions and MART-1 being undetectable in 11%. In several cases, loss of one MAA was not associated with loss of the other MAA, suggesting that MART-1 can represent a useful additional marker for the diagnosis of melanoma in gp100 (HMB45)-negative lesions. Of the 217 specimens, 155 were obtained from HLA-A*0201 patients, of which 6% were negative for HLA-A2, 8% were negative for MART-1/MelanA and 21% were negative for Pmel17/gp100. The potential significance of our findings is illustrated by a case study in which a patient with melanoma experienced rapid tumor progression in association with loss of either MAA or HLA expression in several lesions.
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PMID:Heterogeneous expression of melanoma-associated antigens and HLA-A2 in metastatic melanoma in vivo. 946 50

Melan-A/MART-1 is a melanoma differentiation antigen that is recognized by a high proportion of cytolytic T lymphocyte (CTL) clones derived from human leukocyte antigen (HLA)-A2+ melanoma patients. Whereas peptide Melan-A/ MART-1(27-35) was originally defined as the immunodominant CTL epitope, we have previously reported that peptide Melan-A/MART-1(26-35) was recognized more efficiently by the majority of tumor-reactive CTL clones. As demonstrated here, CTL populations generated from blood lymphocytes of either melanoma patients or healthy individuals after in vitro stimulation with peptide Melan-A/MART-1(26-35) killed specifically HLA-A2+ Melan-A+ allogeneic melanoma cells, thus suggesting their potential use in adoptive immunotherapy. We characterized the surface phenotype of the circulating CTL precursors (CTLp), which respond to in vitro stimulation with peptide Melan-A/MART-1(26-35). In melanoma patients, these CTLp predominantly expressed the CD45RO memory marker. In contrast, they were mainly, although not exclusively, found in the CD45RA subpopulation of CD8 T cells in healthy individuals. The demonstration that Melan-A/MART-1-specific CTLp in peripheral blood lymphocytes from HLA-A2+ patients with metastatic melanoma express a memory phenotype provides direct evidence that in vivo priming of this antigen may occur during tumor progression.
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PMID:Circulating Melan-A/Mart-1 specific cytolytic T lymphocyte precursors in HLA-A2+ melanoma patients have a memory phenotype. 983 62

Here, we report the functional expression of CD40 on human malignant melanomas (MMs). Comparison of tumor specimen from MM precursor lesions, primary tumors, and metastases revealed that CD40 surface expression is down-regulated during tumor progression. CD40 expression was confirmed in 7 human MM cell lines established from immunogenic primary tumors or metastases, whereas 11 cell lines established from advanced stages were CD40 negative. CD40 expression could be enhanced in CD40-positive MM by stimulation with IFN-gamma and tumor necrosis factor-alpha but not by interleukin (IL)-1beta or CD40 triggering. CD40 ligation on MM by CD40L-transfected murine L-cells or by a soluble CD40L fusion protein up-regulated their expression of intercellular adhesion molecule-1 and MHC class I and class II molecules and their secretion of IL-6, IL-8, tumor necrosis factor-a, and granulocyte macrophage colony-stimulating factor and also induced a rapid activation of the transcription factor nuclear factor kappaB. Furthermore, CD40 ligation of a HLA-A2+, MelanA/MART1+ MM cell line enhanced its susceptibility to specific lysis by a HLA-A2-restricted, MelanA/MART-1-specific CTL clone. Finally, CD40 ligation induced growth inhibition and apoptosis in MM. These results indicate that CD40-CD40L interactions may play an important role in augmenting antitumor immunity and inducing apoptosis in some CD40-positive immunogenic human MMs.
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PMID:Stimulation of CD40 on immunogenic human malignant melanomas augments their cytotoxic T lymphocyte-mediated lysis and induces apoptosis. 1009 61

The biomolecules described in this article generally have been studied as possible diagnostic or clinically prognostic markers in the context of melanoma disease progression as measured by the gold standards of tumor thickness and development of metastasis. Most of the markers showed variations in expression phenotype only during the deeply invasive or metastatic stage of tumor progression and were thus predictive of clinical outcome only for these subgroups of patients. Some of the markers may have utility in identifying patients with deeply invasive primary tumors who are likely to develop metastasis and thus should receive earlier, more aggressive treatments. In addition, some of the markers may identify patients likely to respond better to a new type of therapy (e.g., anti-angiogenic therapy in a patient whose tumor is overexpressing VEGF or immunotherapy for a patient whose tumor is expressing high levels of MART-1). In the future, it will probably be possible to employ new techniques, such as laser-guided microdissection of tissues, to isolate individual melanocytes in order to identify the earliest stage-specific defects that contribute to an aggressive biological behavior. Identifying the subset of patients with superficially invasive melanomas who will develop metastatic disease will continue to provide a challenge.
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PMID:Update of diagnostic and prognostic markers in cutaneous malignant melanoma. 1041 Aug 63

The identification of circulating tumor cells in the peripheral blood of patients with malignant melanoma by detection of melanoma associated protein transcripts using the reverse transcriptase polymerase chain reaction (RT-PCR) technique has been introduced as a noninvasive and sensitive technique for early detection of tumor progression and metastatic disease. An alternative approach is the analysis of S-100 protein in the serum of melanoma patients by a luminoimmunometric assay (LIA). In this study, the sensitivities of RT-PCR and LIA were compared. Seventy-seven blood samples of 59 melanoma patients were analyzed for tyrosinase, Melan-A/MART-1, MAGE-3, gp100, and p97 expression by multimarker RT-PCR; 540 serum samples of 352 melanoma patients were analyzed for S-100 protein concentration by LIA. In stage III 23.8% and in stage IV 37.5% of the samples were positive for at least one marker in multimarker RT-PCR, versus 8.1% and 48.1% of elevated S-100 levels analyzed by LIA, respectively. In a direct comparison, 31 identical samples were analyzed by multimarker RT-PCR and by S-100 LIA. In stage III 18.2% and in stage IV 45% of the samples were positive by multimarker RT-PCR versus 45.5% and 80% by S-100 LIA, respectively. S-100 LIA was more sensitive in detection of metastatic disease in melanoma patients than multimarker RT-PCR and should be evaluated in further studies. RT-PCR might be more useful in the analysis of micrometastases in anatomic compartments other than peripheral blood.
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PMID:Tumor markers in peripheral blood of patients with malignant melanoma: multimarker RT-PCR versus a luminoimmunometric assay for S-100. 1054 77

In this review, we summarize the significant progress that has been made in the identification of melanoma-associated antigens (MAA) recognized by cytotoxic T-lymphocytes (CTL). These antigens belong to three main groups: tumor-associated testis-specific antigens (e.g. , MAGE, BAGE, and GAGE); melanocyte differentiation antigens (e.g., tyrosinase, Melan-A/MART-1); and mutated or aberrantly expressed molecules (e.g, CDK4, MUM-1, beta-catenin). Although strong CTL activity may be induced ex vivo against most of these antigens, often in the presence of excess cytokines and antigen, a clear understanding of the functional status of CTL in vivo and their impact on tumor growth, is still lacking. Several mechanisms are described that potentially contribute to tumor cell evasion of the immune response, suggesting that any antitumor efficacy achieved by immune effectors may be offset by factors that result ultimately in tumor progression. Nevertheless, most of these MAA are currently being investigated as immunizing agents in clinical studies, the conflicting results of which are reviewed. Indeed, the therapeutic potential of MAA has still to be fully exploited and new strategies have to be found in order to achieve an effective and long-lasting in vivo immune control of melanoma growth and progression.
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PMID:T-cell recognition of melanoma-associated antigens. 1065 98

The biomolecules described in this article generally have been studied as possible diagnostic or clinically prognostic markers in the context of melanoma disease progression as measured by the gold standards of tumor thickness and development of metastasis. Most of the markers showed variations in expression phenotype only during the deeply invasive or metastatic stage of tumor progression and were thus predictive of clinical outcome only for these subgroups of patients. Some of the markers may have utility in identifying patients with deeply invasive primary tumors who are likely to develop metastasis and thus should receive earlier, more aggressive treatments. In addition, some of the markers may identify patients likely to respond better to a new type of therapy (e.g., anti-angiogenic therapy in a patient whose tumor is overexpressing VEGF or immunotherapy for a patient whose tumor is expressing high levels of MART-1). In the future, it will probably be possible to employ new techniques, such as laser-guided microdissection of tissues, to isolate individual melanocytes in order to identify the earliest stage-specific defects that contribute to an aggressive biological behavior. Identifying the subset of patients with superficially invasive melanomas who will develop metastatic disease will continue to provide a challenge.
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PMID:Update of diagnostic and prognostic markers in cutaneous malignant melanoma. 1122 16

A 49-year-old patient with primary, recurrent melanoma on the lower extremity developed metastatic leptomeningeal melanoma that did not respond to treatment with radiation therapy or intrathecal interleukin 2 (IL-2). Disease was characterized by neurological symptoms, including loss of hearing, loss of short-term memory, and gait disturbance. CD8+ CTLs were generated in vitro using autologous dendritic cells pulsed with peptides from the melanoma-associated antigens tyrosinase (145-156), Melan-A/MART-1 (26-35), and gp100/Pmel 17 (209-217). The CTLs exhibited up to 74% specific lysis against peptide-pulsed autologous EBV-transformed B cells, with Melan-A-specific CTLs yielding the greatest lytic activity. CD8+ CTLs possessed a type 1 cytokine profile, expressing tumor necrosis factor alpha and IFNgamma but not IL-4. Infusions of CTLs were supported with systemic low-dose IL-2 administration. 111In labeling and computerized gamma imaging were used to monitor the distribution of CTLs up to 48 h after infusion. Intra-arterial delivery via the right carotid artery was followed by redistribution of the CTLs to the lungs, liver, and spleen within 16 h. In contrast, delivery via an indwelling Ommaya reservoir resulted in prolonged retention of CTLs within the brain for at least 48 h after infusion. Marked but transient elevations in tumor necrosis factor alpha, IFN-gamma, and IL-6 in the cerebrospinal fluid were observed within 4 h of CTL infusion. There was no evidence of tumor progression throughout the treatment period, and clinically the patient showed some resolution of neurological symptoms.
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PMID:Intrathecal cytotoxic T-cell immunotherapy for metastatic leptomeningeal melanoma. 1130 Apr 92


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