alpha-Melanotropin immunoreactivity in human melanoma exudate is related to necrosis.
We have previously reported high immunoreactive alpha-MSH (IR-alpha-MSH) concentrations in melanoma patients' plasma, as well as significant amounts in melanoma metastases and cells grown in culture. Necrosis within the melanoma tumour leads to a massive proteolysis of intracellular proteins and release of cell content: this might significantly contribute to the elevated IR-alpha-MSH plasma levels measured in melanoma patients. To test this hypothesis, we studied the necrosis-related release of MSH from human melanoma cells, using a specific radioimmunoassay. The studies of fine-needle biopsies indicated that most of the human melanoma tumour exudates tested contained very high MSH concentrations (> 500 pg/ml; 14/15), while plasma levels were generally normal (< or = 25 pg/ml; 10/15). The level in an exudate from a non-melanoma tumour type was < 40 pg/ml. In vitro studies showed that release of the IR-alpha-MSH was time- and temperature-dependent, and related to cell death.
Loir
B
B
Laboratory of Oncology and Experimental Surgery, Université Libre de Bruxelles, Belgium.
Sales
F
F
Deraemaecker
R
R
Morandini
R
R
Garcia-Borron
J C
JC
Ghanem
G
G
D006801:Humans; D007150:Immunohistochemistry; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D009336:Necrosis; D011863:Radioimmunoassay; D014407:Tumor Cells, Cultured
D009074:Melanocyte-Stimulating Hormones