Moreover, the results presented in this paper, and previously published findings [23], indicated that NEP had a tumor-promoting role in osteosarcoma and that thiorphan, i.e., an inhibitor of NEP enzymatic activity used as an active component of approved antidiarrheal drugs [23,36], exerted moderate antiproliferative activity towards HOS cells. The gene discussed is MME; the disease is osteosarcoma.