INSULIN-LIKE GROWTH FACTOR-II MESSENGER-RNA EXPRESSION IN HUMAN-BREAST CANCER

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  • 1 December 1988
    • journal article
    • research article
    • Vol. 48  (23) , 6691-6696
Abstract
Insulin-like growth factor II is a growth factor important in fetal development. Several cancer tissues and cell lines have been reported to express IGF-II and rat IGF-II is mitogenic for breast cancer cell lines. Using Northern analysis and ribonuclease protection assays, IGF-II mRNA was detected in normal fibroblasts and in the established breast cancer cell line, T47D. In this cell line, steady state levels of IGF-II message were increased by treatment with estradiol. 10 nM IGF-II, purified from human serum, was mitogenic for breast cancer cell lines. In vitro, IGF-II may act as an autocrine growth factor for some cell lines. RNA derived from breast cancer, pathologically normal breast tissue, and benign breast disease also contained IGF-II mRNA. When paired samples of normal and cancer tissue were obtained from the breast of the same patient, the level of IGF-II mRNA expression in the normal tissue was at least that found in the cancer. This is consistent with previous observations that show IGF-II is expressed in mesenchyme. These findings suggest that in breast cancer IGF-II is produced by stromal tissue elements and potentially by the malignant epithelial cells. Therefore, IGF-II may function as an autocrine or a paracrine growth factor in different breast tumors.