Cytochrome P450 aromatase expression in human seminoma

The tumour-bearing testes were obtained from 20 patients with classic seminoma undergoing to therapeutic orchidectomy. Paraffin embedded tissues were processed for immunohistochemistry using a mouse monoclonal antibody generated against human placental cytochrome P450 arom, as primary antibody, and a biotinylated goat-anti-mouse IgG, as secondary antibody. Furthermore, Western blot analysis of seminoma extracts was carried out.Intense P450 arom immunoreactivity was observed in the seminoma cells and Western blot analysis confirmed the immunodetection. A strong immunostaining was also detected in cells of intratubular germ cell neoplasia (IGCN), adjacent to seminoma.The present study demonstrated, for the first time in human, aromatase expression in neoplastic cells of seminoma suggesting a relation between local estrogen biosynthesis and germ cell tumorigenesis. The P450 arom immunolocalization in the cells of IGCN, representing the common precursor of most germ cell tumors, seems to support these findings.Somatic and germ cell tumors are typical testicular neoplasms which can affect young, adult and elderly men. In the last years, testis tumor management has improved by new diagnostic and surgical tools, as well as by innovative therapy options to preserve fertility against cytotoxic treatments [1]. However, pathogenesis of male gonad malignancies is often still unknown.Somatic and germ cells of normal human testis have revealed the expression of estrogens receptor-β and /or aromatase, which is the microsomial enzyme catalysing the conversion of androgens into estrogens [2-8]. Therefore, testicular cells are considered targets and in situ biosynthesis sites of estrogens, suggesting a physiological role of these hormones in steroidogenesis control and sperm maturation.Estrogens are also known to regulate cell growth and apoptosis, therefore they can be involved in tumorigenesis process [9,10] but, up to now, their possible link with testicular neoplastic process is