Expression analysis of VEGFA, FGF2, TGFβ1, EGF and IGF1 in human nasal polyposis

A better understanding of the expression profile of a group of angiogenic markers in nasal polyps (NPs) would contribute considerably to the investigation of the formation of NPs. The aim of this study was to evaluate the combined mRNA expression of vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF2), transforming growth factor β1 (TGFβ1), epidermal growth factor (EGF) and insulin-like growth factor 1 (IGF1) in NPs obtained from 21 patients undergoing nasal polypectomy. Nasal mucosae were obtained from the adjacent inferior turbinates (AIT) and middle turbinates (AMT) of the patients, as well as from 11 control subjects undergoing nasal corrective surgery. Analysis was performed using real-time RT-PCR. VEGFA, TGFβ1 and IGF1 exhibited significant over-expression in the NPs compared to the control turbinates, EGF did not exhibit significant expression, and FGF2 presented constant over-expression in the NPs compared to both the adjacent and control turbinates. Since its mRNA levels were positively correlated with all the corresponding levels of the rest of the growth factors studied, TGFβ1 seems to be a key cytokine in interactions between NP cells and the leading molecule of the epithelial differentiation and tissue remodelling present in the disease. Many correlations between the transcript levels of the other growth factors arose in the NP group as well, supporting a co-regulation of these genes in nasal polyposis. Our conclusions were that that VEGFA and TGFβ1 participate significantly in the formation of NPs, whereas FGF2 and IGF1 are implicated in nasal polyposis to a lesser, but still significant, extent. EGF does not seem to be actively involved in the NP evolution process.