Pregnancy-dependent growth of mammary tumors is associated with overexpression of insulin-like growth factor II.
Year: 1996
Type: article
Abstract: We demonstrate that although IGF-II gene expression is approximately 3-fold higher in 9,10-dimethyl-1,2-benzanthracine (DMBA)-induced rat mammary tumors (MTs) than in nonneoplastic breast tissue, IGF-II mRNA abundance in DMBA-induced MTs is approximately 130-fold higher in pregnant as compared to nonpregnant hosts. This correlated with accelerated tumor growth in pregnant hosts. Immunohistochemical studies of DMBA-induced MTs with an anti-IGF-II antibody showed an intense staining of tumor cells for IGF-II, whereas a very low staining signal was observed for normal epithelial cells in the lobules. A similar immunostaining pattern was observed in three of three human ductal cancers and adjacent normal breast tissue obtained during pregnancy. DMBA-induced MTs expressed high levels of type I receptor for IGFs as determined by Northern blots. In vitro studies confirmed that IGF-II is a mitogen for neoplastic epithelial cells derived from DMBA-induced MTs. These results demonstrate that hormonal changes associated with pregnancy accelerate breast cancer cell proliferation in the DMBA-induced MT model and suggest that this acceleration is mediated by up-regulation of IGF-II expression within neoplasms.
Source: PubMed
Institution: Jewish General Hospital
Language: English
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1494778162