Down-regulation of FGF10 in hypospadias prepuce

Abstract Background: Fibroblast growth factors (FGF) expressed in the genital tubercle, especially FGF8 and FGF10, may be implicated in the morphogenesis of external genitalia. We investigated the expression of FGF8 and FGF10 in hypospadias prepuce to confirm any correlation.Methods: Hypospadias was classified according to the location of the external meatus as coronal/subcoronal (mild; n=7), midshaft (moderate; n=6), penoscrotal (severe; n=3). Prepuce tissue specimens obtained intraoperatively from hypospadias patients (H; n=16), phimosis patients (P; n=8) between 2010 and 2016 were examined immunohistochemically. Quantification of immunostaining was performed using imageJ®. The protein expression of FGF10 in each group was examined by Western blot analysis.Results: Mean ages at surgery were 3.9 and 4.5 years for H and P, respectively. Both FGF8 and FGF10 were expressed in the upper dermis, especially the papillary layer. FGF8 was similar, but FGF10 was down-regulated in H in proportion to severity (P: 13.08% versus mild H: 7.28%, moderate H: 5.01%, severe H: 1.38%). The FGF10 protein amount results showed FGF10 was down-regulated in H (phimosis 0.91, mild 0.99, moderate 0.65, severe 0.48).Conclusion: The significant down-regulation of FGF10 identified may contribute to further understanding the etiology of hypospadias and may have some possible applications for treating hypospadias.