Basic fibroblast growth factor and angiogenesis in squamous carcinoma of the tongue

The relationship between basic fibroblast growth factor (bFGF), receptors for bFGF and neoangiogenesis was investigated in 51 patients with squamous cell carcinoma of the tongue, 26 of whom had metastatic disease in cervical lymph nodes. Vessels were demonstrated by immunocytochemical labelling for CD34 and expressed as raw counts and volume-weighted counts. bFGF protein and its receptors FGFR1(flg) and FGFR2(bek), were demonstrated using immunocytochemical labelling. In situ hybridisation for bFGF mRNA was performed using a 250-bp digoxigenin-labelled RNA probe. In normal epithelium, the expression of bFGF protein and mRNA was more intense in the basal layer, while receptors for bFGF were expressed more strongly in the superficial parts. In carcinomas, expression of bFGF was greater in the more poorly-differentiated cells, but showed no relation to the overall tumour differentiation. There was strong bFGF expression in tumour-infiltrating lymphocytes. The expression of bFGF receptors was variable, with FGFR2 being particularly high in areas of keratinisation. There were no consistent changes in bFGF or receptor expression between primary carcinomas and their lymph node metastases, and there was no correlation with measures of vascularity or tumour growth pattern. bFGF is synthesised by all squamous carcinomas and has the potential to modulate angiogenesis. However, these data suggest that changes in the expression of bFGF and its receptors are not related to the intensity of neoangiogenesis in lingual carcinomas or their nodal metastases.