Evidence for autocrine production of IGF-1 in human thyroid adenomas.
We have recently shown that epithelial cells from a high proportion of benign human thyroid tumours (follicular adenomas) have escaped from the requirement of the normal cell for an exogenous source of insulin-like growth factor 1 (IGF-1), suggesting either autocrine production or intracellular generation of an IGF-1-induced growth signal. We show here that conditioned medium from these adenoma cells can confer IGF-1 independence on normal thyroid epithelial cells and that this activity is abolished by immunoadsorption with an anti-IGF-1 antibody. In addition, tumour but not normal cells contain immunoreactive IGF-1. Our data provide the first evidence for autocrine production of IGF-1 (or a related factor) in a benign epithelial tumour and suggest that this may be a key early step in thyroid tumorigenesis.
Williams
D W
DW
Department of Pathology, University of Wales College of Medicine, Heath Park, Cardiff, U.K.
Williams
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ED
Wynford-Thomas
D
D
D000236:Adenoma / Q000378:metabolism*; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D003470:Culture Media; D006801:Humans; D007150:Immunohistochemistry; D007164:Immunosorbents; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000276:immunology; D008940:Mitotic Index; D013002:Somatomedins / Q000096:biosynthesis*; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D003470:Culture Media; D007164:Immunosorbents; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I