Hepatocyte growth factor/scatter factor expression in human mammary epithelium

This study reports expression of mRNA for the growth modulator hepatocyte growth factor/scatter factor (HGF/SF) in both benign and malignant human mammary epithelium by in situ hybridization. In benign breast tissue expression was prominent in areas of adenosis and in peripheral acinic cells in lactating breast; in malignant epithelium expression was seen in 15 of 21 cases of in situ and invasive breast cancer. In some cases of invasive ductal carcinoma stronger labeling appeared to be associated with areas of tubule formation compared with areas of infiltrating growth, although this was not a universal finding. In contrast, two examples each of in situ comedo carcinoma and invasive lobular carcinoma were completely negative. HGF/SF mRNA extracted from a breast tumor demonstrated the expected 6-kb transcript on Northern blot analysis. These findings suggest the possibility of an autocrine loop for action of HGF/SF in proliferating mammary epithelium.