Immunohistochemical study of overexpression of fibroblast growth factor-1 (FGF-1), FGF-2, and FGF receptor-1 in human malignant salivary gland tumours

Fibroblast growth factor-1 (FGF-1) and FGF-2 are broad spectrum mitogens. The expression of FGF-1, FGF-2, and their receptor, FGF receptor-1 (FGFR-1), was examined in malignant salivary gland tumours and normal salivary glands, using immunohistochemical methods. In seven cases of adenoid cystic carcinoma (ACC), both duct-like cells and modified myoepithelial cells were apparently immunopositive for FGF-1, FGF-2, and FGFR-1. In five cases of mucoepidermoid carcinoma (MC), all three types of tumour cells including epidermoid cells, mucous cells, and intermediate cells expressed immunoreactive FGF-1, FGF-2, and FGFR-1. In these malignant salivary gland tumours, increased expression of FGFR-1 correlated with the intensity of both FGF-1 and FGF-2 immunoreactivity. In contrast to malignant salivary gland tumours, eight cases of normal salivary gland showed negative immunostaining for FGF-1, FGF-2, and FGFR-1 while four cases were weakly immunoreactive for FGF and its receptor. These results demonstrate that malignant salivary gland tumours overexpress FGF-1, FGF-2, and FGFR-1 compared with normal salivary glands and suggest that these growth factors may play an important role in facilitating neoplastic progression in human salivary glands.