FGF8, FGF10 and FGF receptor 2 in foreskin of children with hypospadias: an analysis of immunohistochemical expression patterns and gene transcription

Fibroblast growth factors (FGFs) play a crucial role in early embryogenesis of the genital tubercle and are involved in the development of hypospadias, affecting both endo- and ectodermally derived tissues. It was hypothesized that expression of FGFs could be qualitatively or quantitatively altered in skin of children with hypospadias. The objective of the study was to investigate expression patterns and transcription levels of FGF8, FGF10, and FGF Receptor 2 (FGFR2) in patients with hypospadias compared to normal controls. Skin samples from the ventro-lateral aspect of the foreskin of 32 patients with hypospadias (17 distal and 15 proximal, mean age 25 months) and 10 normal foreskin samples (mean age 77 months) were analyzed by immunohistochemistry. Staining, localization, and distribution of positive cells in epidermis and dermis were categorized independently by two researchers. Complementary DNA (cDNA) samples prepared from messenger RNA (mRNA) isolates of the same samples were analyzed by quantitative polymerase chain reaction (qPCR), comparing expressions of FGF8, FGF10, and FGFR2 with loading controls. Patients with hypospadias consistently showed aberrant immunohistochemical staining patterns for FGF8/FGF10/FGFR2 in epidermis and dermis compared to patients without penile malformation (p