Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant melanomas may develop from naevoblasts by way of the junctional naevus; from melanoblasts by way of melanocytes or by way of melanosis circumscripta praeblastomatosa. It is reasonably certain that there is no direct malignant degeneration of a naevus-cell-naevus as a result of acute or chronic irritation, but most authors reject sample excision nevertheless. Malignant melanomas from naevoblasts are relatively insensitive to radiation and dangerous, whereas those developing from melanoblasts are relatively sensitive to radiation and grow slowly. Melanomas which have developed on an unchanged skin are critical because they metastasize fast and take a rapid course. 29% of 237 stage-I patients out of a total of 680 developed metastases during the first year following surgery and irradiation, and 14% after 2-9 years. Radical removal of lymph nodes results in congestion combined with oedema, and involves the risk of melanoma cells being carried into the perilymphatic tissue. Early irradiation of regions involving metastatic risk seems to be preferable over idssection of lymph nodes. Experience has shown that surgery preceded and followed by radiotherapy, and additional surgical or radiological treatment of regional lymph-nodes should be recommended at this time. Evidence concerning the effects of endolymphatic, cytostatic, and immunotherapy is as yet incomplete. The five-year survival rate in state I is said to be 71% following surgery, up to 80% following irradiation and subsequent surgery, up to 78% following surgery and subsequent radiotherapy, and up to 72% following radiotherapy alone. Survival rates are about 14% higher following surgery and electron irradiation.
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PMID:[Indications for and results of percutaneous radiotherapy of malignant melanoma]. 112 49

Electron microscopic examination of malignant melanoma tumour tissue taken from a patient who has survived with the tumour without metastases for 13 years has shown spherical melanosomes with no internal fibrillar structure. This finding and other cell features described, suggest that this melanoma developed from Dubreuilh's melanosis rather than melanocytic change in a junctional naevus.
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PMID:Electron microscopy findings in malignant melanoma of nose. 123 44

In 21 patients with a variety of skin tumors (squamous cell carcinomas, malignant melanomas, basal cell epitheliomas and mycosis fungoides) or pre-cancerous lesions (Bowen's disease, actinic keratosis, junctional nevus cell nevus) the radioactive phosphorus uptake test demonstrates a significantly increased concentration of P32 in those tumors. There were no false negative tests. The possibility of differentiation of malignant melanoma from benign nevus cell nevus and the early recognition of cutaneous metastases is described. Furthermore recurrence of previously irradiated or excised basal cell epitheliomas can be detected without a biopsy. No hematological side-effects were observed.
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PMID:[The radiophosphorus (32P)-test in precanceroses and malignant tumors of the skin]. 127 Feb 58

Primary acquired melanosis (PAM), a disease that affects mostly middle-aged white patients, is predominantly a proliferative condition of the melanocytes that normally populate the conjunctival epithelium. Primary acquired melanosis without atypia (low risk for the development of melanoma) is typically created by increased numbers of melanocytes restricted to the basilar region of the epithelium without nuclear hyperchromasia or prominence of the nucleoli. Primary acquired melanosis with atypia, a formal precursor of melanoma, is characterized by the proliferation of small polyhedral cells, spindle cells, large dendritiform melanocytes, or epithelioid cells that may: remain restricted to the basilar region (basilar nests); form nests at all levels of the epithelium; spread individually to all levels of the epithelium (pagetoid extension); or proliferate in a sheet-like fashion approximating a melanoma in situ. Lesions composed of epithelioid cells or exhibiting intraepithelial pagetoid extension have, respectively, a 75 or 90% chance of eventuating in invasive melanoma. Primary acquired melanosis in an adult should not be confused with "a junctional nevus," which is almost always restricted to childhood. Invasive melanomas measuring less than 0.8 mm in thickness tend not to be associated with metastases; the tumor cells may be small polyhedral (in which case confusion with a compound nevus often arises), epithelioid, spindled, or ballooned. Nodules composed of spindle cells in part or in toto tend to have less metastatic potential at a given thickness measurement than comparable nodules composed of epithelioid or polyhedral cells. The clinical features, electron microscopic findings, and biologic principles underwriting clinical management are also presented.
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PMID:Clinicopathologic characteristics of premalignant and malignant melanocytic lesions of the conjunctiva. 264 38

A model for a metastasizing melanoma was developed, and its characteristics were established. Sixty-five albino guinea pigs were painted with 7,12-dimethylbenzanthracene in acetone. There was evidence that, after 18 months, 40% of the animals developed melanomas. Melanomas arose by a malignant transformation of junctional nevus cells and/or by transformation of amelanotic melanocytes. Metastases to the skin and internal organs were multiple and eventually fatal for the animals. Histology and electron microscopy of induced melanomas were reviewed in detail. Clinical and histological events leading to development of melanoma in albino guinea pigs were found to be similar to human melanomas in a number of aspects. Fragments of melanomas were successfully transplanted to "nude" mice and healthy albino guinea pigs. The described model could be used for study of the various cellular and tissue events which precede nevus, lentigo maligna, and melanoma formation. It could also be useful in studying carcinogenic potential, for studying development of metastases, and presumably for trials of treatment.
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PMID:Skin melanoma induced by 7,12-dimethylbenzanthracene in albino guinea pigs and its similarities to skin melanoma of humans. 677 35

Matrix metalloproteinase-2 (MMP-2), a member of the matrix metalloproteinase family, participates in degradation of the pericellular and extracellular matrix during neoplastic growth and metastasis. Experimental data have substantiated its role in melanoma invasion, but there is no information at present concerning its expression in histological specimens from human melanocytic tumors. This study describes the occurrence and immunolocalization of MMP-2 in human melanocytic lesions, defining distinct steps in melanoma progression. Paraffin-embedded sections from 118 melanocytic lesions were immunostained using a specific antibody to 72 kD type IV collagenase. The material included 34 common naevocellular naevi, 14 dysplastic naevi, 21 in situ melanomas, 20 primary malignant melanomas, and 29 melanoma metastases. Intracytoplasmic MMP-2 immunoreactive protein was found in the 'naevocytic nests' of common naevi, in junctional naevus cells, and in melanoma cells. The surrounding normal skin stained negatively, except for occasional macrophages, sweat glands, and hair follicles. The number of MMP-2-positive cells increased with decreasing architectural organization and increasing atypia in the melanocytic lesions. The MMP-2 positivity in the primary and subcutaneous melanoma lesions correlated with later haematogenous metastasis. The data suggest that MMP-2 expression is an early event in melanocytic tumour progression, but is nevertheless prognostic for haematogenous metastasis in melanoma.
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PMID:Matrix metalloproteinase-2 (72 kD type IV collagenase) expression occurs in the early stage of human melanocytic tumour progression and may have prognostic value. 895 6