Molecular analysis for p53 and mdm2 in intracranial germ cell tumors

Intracranial germ cell tumors (ICGTs) are uncommon neoplasms. The histologi cal appearance of ICGTs is indistinguishable from that of the usual testicu lar germ cell tumors (TGTs). Recently, several reports have associated mole cular abnormalities of p53 and mdm2 in TCTs with their malignancies. Howeve r, whether ICGTs are associated with molecular abnormalities is still unkno wn. We analyzed a series of 16 ICGTs for mutations in the TP53 gene by sing le-strand conformation polymorphisms, and for amplification of the MDM2 gen e using differential PCR. In addition, the same 16 tumors were examined for p53 and mdm2 protein overexpression using antibodies directed against p53 [monoclonal antibodies (mAb) 1801 and DO7] and mdm2 (IF2), respectively. Tw elve (75%) and 2 (13%) of the 16 ICCTs reacted with DO7 and PAb1801, respec - tively, and 1 (6%) carried a TP53 gene mutation. Thirteen (81%) of the 16 ICGTs reacted with IF2, and 3 (19%) carried MDM2 gene amplification. The l ess frequent TP53 gene mutation compared with MDM2 gene amplification, and the frequently expressed p53 and mdm2 protein, are similar to the case for TGTs. It is tempting to speculate that ICGTs might have the same cellular o rigins as TGTs with abnormalities in p53 and mdm2, which could play an impo rtant role of tumorigenesis.