Furthermore, the expression intensity of NSE in the testes of young rats and hamsters was higher than that of adults, and NSE is positively expressed not only in Leydig cells,but also in sperm cells and Sertoli cells in adult guinea pig testes (Angelova et al., 1991).The demonstration that the nervous system and neuroendocrine origin tumors contain NSE promoted the NSE as a possible tumor marker. The gene discussed is ENO2; the disease is neoplasm.