Expression of activated HER2 in human testes

The her2 messenger RNA (mRNA) was the most abundant among the erb type-1 tyrosine kinase receptors mRNA in human testis and was statistically significantly decreased in impaired spermatogenesis. Testicular HER2 was tyrosine phosphorylated and strongly expressed in spermatogonia, early spermatocytes, elongating/elongated spermatids, Sertoli cells, Leydig cells, and peritubular cells, suggesting that activated HER2 participates in mitosis and meiotic entry of germ cells, spermiogenesis, and steroidogenesis via mediating the epidermal growth factor–growth factor signaling.