Testicular cancer is a relatively rare cancer that accountsfor approximately 1–1.5% of male cancers, and 90–95%of these cancers are testicular germ cell tumors (TGCTs)[1]. TGCTs can be classified into two major histologicalcategories, namely, seminomatous germ cell tumor (SGCT)and nonseminomatous germ cell tumor (NGCT). NGCTs,which include yolk sac tumors, embryonal cell carcinomas,teratomas, and choriocarcinomas, are different from SGCTswith regard to clinical characteristics and therapy required.Amyloid precursor protein (APP) is a type 1transmembrane protein that is considered to play a key rolein Alzheimer’s disease. It has multiple isoforms attributableto alternative splicing and is expressed in various types ofhuman cells. APP695 predominantly exists in the neuronswhereas other isoforms such as the APP751 and APP770are expressed in nonneuronal cells [2]. The biological roleof APP is not well understood. APP and its cleaved formshave been suggested to mediate various functions, includingcell adhesion [3], cell signaling [4], and cell growth [5–7].These functions are important in carcinogenesis, and APPexpression may be involved in the development of variouscancers [8–13].We have previously shown that APP is a primaryandrogen-responsive gene that promotes the growth of2 Advances in Urologyprostate cancer cells [14]. In the present study, we investigatedAPP immunoreactivity (IR) and APP mRNA expression inTGCTs and evaluated its clinical significance.
A human testicular germ cell tumor with borderline histology between seminoma and embryonal carcinoma secreted beta-human chorionic gonadotropin and alpha-fetoprotein only as a xenograft
