Expression of vascular endothelial growth factor in normal and tumour oraltissues assessed with different antibodies

Expression of vascular endothelial growth factor (VEGF) in oral tissues was assessed using different antibodies. Quantitative and topographical differ ences were observed between paraffin and cryostat sections. Two polyclonal antibodies (PC36, PC37) differing in their cross-reactivity with VEGF(1)21 (not recognized by PC36), were used to stain serial cryostat sections of no rmal oral mucosa (n=8) and squamous cell carcinoma (n=7). The expression of VEGF in the epithelium was overall higher with PC37 than with PC36, the di fference being significant in normal oral mucosa (p=0.001) but not in squam ous cell carcinoma samples (p=0.094). With PC36, VEGF expression was signif icantly higher in squamous cell carcinoma than in normal oral mucosa specim ens, whereas the opposite was true with PC37. Our results suggest that the relative levels of isoform 121 to that of 165 (and possibly others) may be different in the tissues examined, with VEGF(121) preferentially expressed in normal oral mucosa. Previously published conflicting results may, theref ore, be due to the presence of variable ratios of VEGF isoforms in the tiss ues examined, combined with differences in the cross-reactivity of the anti bodies used. VEGF isoforms 121, 165 and (for the first time) 189 were detec ted in two frozen oral tissues by polymerase chain reaction amplification. Quantification of specific VEGF isoforms will be required in future studies concerned with the clinical value of VEGF expression.