Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0025202 (melanoma)
69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence of tyrosinase mRNA in the peripheral blood cells of melanoma patients has been recently studied as a possible marker of haematogenous dissemination. However, considerable variations in the rates of detection have been noted. We determined the presence of tyrosinase mRNA-positive circulating cells using reverse transcriptase-polymerase chain reaction (RT-PCR) in 35 patients with stage I melanoma, two patients with stage II melanoma and two patients with stage III melanoma. Among the patients with stage 1, 13 were tested before and after surgery (< 1 h). Twenty healthy subjects served as negative controls. Out of the melanoma patients, the tyrosinase gene was expressed in three of the 52 samples tested. Tyrosinase mRNA was present in the circulating cells of only one patient with stage I melanoma after intra-congenital naevi resection. However, two other stage I patients developed rapidly lethal metastasis within the following 6 months, despite the lack of detectable tyrosinase mRNA. None of stage II patients were positive for the tyrosinase transcripts, while both patients with stage III melanoma showed enzyme expression. Our results confirm those of previous studies, showing that a small proportion of stage I melanoma patients have tyrosinase-positive circulating cells. Moreover, the lack of tyrosinase mRNA detection in the blood does not necessarily exclude metastatic progression. Therefore, this study indicates that the detection of tyrosinase mRNA-positive circulating cells by RT-PCR is not a predictive biomarker of a metastasis risk in patients with stage I melanoma.
Melanoma Res 2000 Apr
PMID:The detection of tyrosinase mRNA in the peripheral blood of stage I melanoma patients is not of clinical relevance in predicting metastasis risk and survival. 1080 11

The level of expression of melanoma antigens (MA) may modulate the host immunologic response. Thus, the accurate measurement of MA expression may allow proper patient selection for antigen-specific therapies and yield important information for the evaluation of clinical results. In this study, we measured the absolute levels of MA messenger ribonucleic acid (mRNA) in tumor cell lines utilizing real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). mRNA levels of MART-1, gp100, tyrosinase, TRP-1 and TRP-2 melanoma differentiation antigens and MAGE-1, MAGE-3 and ESO-1 cancer testis (CT) antigens were compared in 24 early-passage (<5 passages in culture) and 12 archival melanoma cell lines. MA mRNA expression was extremely variable among cell lines, occasionally reaching levels comparable to ribosomal RNA (rRNA). gp100 and MART-1 mRNA levels correlated with protein expression measurement obtained by FACS analysis. More significantly, a threshold of gp100 mRNA expression required for T-cell stimulation and target-cell killing was identified. This threshold level corresponded to approximately 500 mRNA copies per 10(8) copies of rRNA. Our results suggest that the measurements of MA mRNA levels may yield useful information relevant to the interpretation of clinical outcome during antigen-specific treatments.
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PMID:Threshold levels of gene expression of the melanoma antigen gp100 correlate with tumor cell recognition by cytotoxic T lymphocytes. 1084 96

We have shown previously that integrin-linked kinase (ILK) is upregulated in human HT-144 melanoma cells following TGF-beta1 stimulation. Using mRNA from TGF-beta1 stimulated HT-144 cells and reverse transcriptase polymerase chain reaction, we have isolated a cDNA encoding a protein highly homologous to ILK. Sequencing of the full-length 1359 base pair cDNA and polypeptide translation revealed that this protein, designated ILK-2, differs from the known ILK (hereafter called ILK-1) by only four amino acids, while the cDNA sequence diverges by 102 nucleotides, thus excluding that ILK-2 is an allelic variant of ILK-1. Expression of ILK-2 mRNA was observed in metastatic human HT-144 melanoma and HT-1080 fibrosarcoma cell lines, but not in normal human tissues. Moreover, stimulation of HT-144 cells with TGF-beta1, but not with EGF, PDGF-AB or insulin, induced a selective overexpression of ILK-2 mRNA as compared to ILK-1 mRNA. Bacterially-expressed GST/ILK-2 autophosphorylated and labeled myelin basic protein as well as a recombinant GST/beta3 integrin cytoplasmic tail peptide. Transfection of either ILK-2 or ILK-1 cDNA into the non-metastatic melanoma cell line SK-Mel-2, expressing exclusively ILK-1, induced anchorage independent cell growth and cell proliferation, as demonstrated by growth in soft agar. Our data provide evidence that ILK-2 is a new isoform of ILK-1 that is expressed in some highly invasive tumor cell lines but not in normal adult human tissues and whose expression is regulated by TGF-beta1.
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PMID:Cloning of an isoform of integrin-linked kinase (ILK) that is upregulated in HT-144 melanoma cells following TGF-beta1 stimulation. 1087 59

Several studies have evaluated the use of polymerase chain reaction (PCR) amplification of tyrosinase mRNA to detect melanoma cells in blood. However, contradictory results have been obtained from different groups. We therefore have developed and validated a quantitative PCR method for tyrosinase and tyrosinase-related protein-2 (TRP-2) mRNA. An important methodological finding was that high concentrations of reverse transcriptase or RNA sample inhibited the following PCR. This could be abolished by dilution of the cDNA sample before the PCR. Standard curves with a linear range over at least five logs were obtained with dilutions of melanoma cell cDNA. Controls (RNA and cDNA) consisting of melanoma cells (1000/ml) added to blood were analysed repeatedly over 3 months, resulting in means between 880 and 1074 AU/ml. The RNA controls were stable, whereas the cDNA controls, as well as the calibrators, showed a tendency to change over time. The variation in the RNA controls was 25% for tyrosinase and 22% for TRP-2. Seven stage III-IV melanoma patients were tested for tyrosinase and TRP-2 transcripts in blood drawn from a peripheral vein and from a Port-a-cath. Tyrosinase mRNA was found in three patients (0.8-12.4 AU/ml). For TRP-2, the same amount was found in the patients as in healthy donors. No differences were seen between blood from a peripheral vein and from the Port-a-cath. We here present fast and sensitive methods for the quantification of tyrosinase and TRP-2 mRNA in blood.
Melanoma Res 2000 Jun
PMID:Quantitative analysis of tyrosinase and tyrosinase-related protein-2 mRNA from melanoma cells in blood by real-time polymerase chain reaction. 1089 Mar 74

The specificity and sensitivity of the nested reverse transcriptase polymerase chain reaction (RT-PCR) on tyrosinase was studied, for the detection of micrometastases of malignant melanoma. The specificity was assessed in the blood of six healthy donors, four patients with non-melanoma cancers of which one patient was treated with granulocyte-colony stimulating factor. Lymph nodes of nine patients without malignant melanoma were tested and four cell lines of various other tumours. Six of the nine non-melanoma lymph nodes were positive in this assay. The sensitivity was tested in a spike experiment in vitro, using a melanoma cell line. The detection limit was ten melanoma cells per 10(7) peripheral blood lymphocytes.
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PMID:Limitations of the nested reverse transcriptase polymerase chain reaction on tyrosinase for the detection of malignant melanoma micrometastases in lymph nodes. 1090 68

p53 mutations are common genetic alterations in human cancer. Gene transfer of a wild-type (wt) p53 gene reverses the loss of normal p53 function in vitro and in vivo. A phase I dose escalation study of single intratumoral (i.t.) injection of a replication-defective adenoviral expression vector containing wt p53 was carried out in patients with metastatic melanoma or breast cancer with increased p53 protein immunoreactivity in pretreatment tumor biopsies. The biological activity of the injected wt p53 was assayed by reverse transcriptase-polymerase chain reaction in tumor tissue. A total of six (five melanoma and one breast adenocarcinoma) patients were treated at dose levels dependent upon tumor size/dose escalation sequence. Five of six patients became positive for the transfer of wt p53 into tumor tissue 2 days after injection of the vector. Of the four patients assayed, all developed anti-adenoviral antibodies. Adverse reactions associated with i.t. injection were mild, with no obvious correlation between the incidence, severity, or relationship of the events and drug dose. p53 gene therapy by i.t. injection of a replication-defective adenoviral expression vector is safe, feasible, and biologically effective (with respect to transduction frequency) in patients with either metastatic melanoma or breast cancer.
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PMID:Biological activity and safety of adenoviral vector-expressed wild-type p53 after intratumoral injection in melanoma and breast cancer patients with p53-overexpressing tumors. 1091 10

The detection and molecular characterisation of circulating tumour cells (CTC) and micrometastases may have important prognostic and therapeutic implications. Because their numbers are very small, these tumour cells are not easily detected using conventional methods. In the last decade, numerous groups have attempted to detect occult tumour cells in solid malignancies using the highly sensitive reverse transcriptase polymerase chain reaction (RT-PCR). These assays were in the vast majority directed against tissue-specific markers. PCR was shown to be superior to conventional techniques in detecting occult tumour cells allowing the identification of one malignant cell mixed with 1-10 million normal cells. In some tumours like melanoma and prostatic carcinoma, tissue-specific transcripts were detected with high specificity in the blood of patients with localised and advanced disease. In some reports, PCR was shown to be a strong predictor of poorer outcome. However, due to the many limitations of PCR (e.g false-positives), many groups are developing new approaches for the detection of occult tumour cells. The most attractive technique involves immunomagnetic isolation of CTC and micrometastases prior to downstream analysis. The tumour-rich magnetic fraction can be subjected to RT-PCR, immunocytochemistry and in situ hybridisation. This will lead to better quantification and molecular characterisation of these tumour cells. In conclusion, the molecular detection and characterisation of occult tumour cells offer a great opportunity for better stratifying patients with solid tumours and for developing new prognostic markers and targeted therapies.
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PMID:Molecular detection and characterisation of circulating tumour cells and micrometastases in solid tumours. 1095 54

CD34(+) cells and megakaryocyte progenitors were lower in marrow from patients after hematological recovery from the first cycle of 5-fluorouracil, leucovorin, adriamycin, cyclophosphamide (FLAC) chemotherapy plus PIXY321 (GM-CSF/interleukin 3; IL-3 hybrid) than in FLAC + GM-CSF or pre-FLAC marrows. Marrow stromal layers, an in vitro model of the marrow microenvironment, express a combination of stimulatory and inhibitory factors that modulate hematopoietic progenitor cell proliferation and differentiation. The TaqMan assay and quantitative reverse transcriptase-polymerase chain reaction were used to measure monocyte chemoattractant protein-1 (MCP-1), melanoma stimulatory growth activity, and monokine inducible by interferon-gamma (Mig) (inhibitory chemokines for primitive or megakaryocyte progenitors) mRNA levels in in vitro PIXY and GM-CSF-treated and patient post-FLAC marrow stromal layers. Chemokine mRNA was increased after in vitro GM-CSF and to a lesser extent after PIXY treatment. MCP-1 mRNA levels were fivefold higher in FLAC + PIXY than in FLAC + GM-CSF layers, and Mig mRNA was elevated in FLAC + GM-CSF layers. Thrombopoietin (TPO), insulin-like growth factor I (IGF-I), and IGF-II (stimulatory factors for primitive and megakaryocyte progenitors) mRNA were also measured. TPO mRNA levels were 30% lower in GM-CSF and PIXY-pretreated than in control layers with no decrease in IGF mRNA. TPO mRNA in stromal layers of patients who developed grade 3 thrombocytopenia (platelets < 20 x 10(9)/l) during the third cycle of FLAC was only 24% of levels in stromal layers of marrow from other post-FLAC patients. Results demonstrate that patient and in vitro treatment had modulatory effects on TPO and chemokine mRNA expression in marrow stromal layers.
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PMID:Thrombopoietin and chemokine mRNA expression in patient post-chemotherapy and in vitro cytokine-treated marrow stromal cell layers. 1100 17

The presence of lymph node metastases is the best prognostic factor for predicting relapse or survival in melanoma patients. It has been demonstrated that melanoma metastases spread through the first lymph node(s) draining the tumor (sentinel lymph node, SN) to the lymphatic system and that detection of melanoma cells in peripheral blood directly correlates with prognosis in melanoma. To identify lymph node metastases and circulating melanocytes, we developed a single-step reverse transcriptase-polymerase chain reaction assay (RT-PCR) for detection of two melanoma-specific markers: the tyrosinase gene, which encodes an enzyme associated with melanin synthesis, and melanoma antigen-related T-cells, which are present in tumor infiltrating T-lymphocytes. This method detects two tumor cells in a background of 10(7) lymphocytes. Thirty patients with stage I-IV cutaneous melanoma entered the study. Blood samples were taken preoperatively, one month after excision of the primary melanoma lesion and the SN or total lymphadenectomy, and before the start of chemotherapy and every three months thereafter in metastatic patients. SNs were collected from 22 patients, bisected and analyzed by RT-PCR and routine pathological and immunohistochemical tests. The preliminary results indicate that RT-PCR for melanoma markers is a sensitive and valuable method for the detection of micrometastases and for early diagnosis and staging of melanoma.
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PMID:Detection of melanoma cells in peripheral blood and sentinel lymph nodes by RT-PCR analysis: a comparative study with immunohistochemistry. 1101 21

Melanoma antigens (MAGE) are regarded to induce tumour-specific immune response and thought to be potential therapeutical agents for cancer immunotherapy. We hereby report the canine MAGE cDNA cloned from the testis of a beagle dog. Canine MAGE cDNA is 1,455 base pair (bp) nucleotides in length, and contains an open reading frame (ORF) of 1,137 bp nucleotides encoding a protein of 378 amino acids. The predicted amino acid sequence has 22-49% of homology with other MAGE proteins. mRNA transcripts of canine MAGE were detected only in the melanoma and testis and not in other normal tissues of adult dog by reverse transcriptase-polymerase chain reaction (RT-PCR), indicating that the expression pattern of canine MAGE mRNA is similar to that of the MAGE family genes in tumor and normal tissues.
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PMID:Cloning and sequencing of canine MAGE cDNA. 1101 19


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