Molecular cytogenetic analysis of i(12p)-negative human male germ cell tumors

✍ Scribed by Eduardo Rodriguez; Jane Houldsworth; Victor E. Reuter; Paul Meltzer; Ji Zhang; Jeffrey M. Trent; George J. Bosl; R. S. K. Chaganti

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 490 KB
• Volume: 8
• Category: Article
• ISSN: 1045-2257
• DOI: 10.1002/gcc.2870080405

✦ Synopsis

The i( I2p) chromosome has been shown to characterize more than 80% of male germ cell tumors (GCTs) and is an important diagnostic marker. Although recent cytogenetic analyses of GCTs have defined nonrandom chromosome abnormalities in these tumors, no attempt has so far been made to compare i( I2p)-positive and -negative tumors in terms of their cytogenetic, histologic, and clinical features. During a 5-year period, we have ascertained 202 GCTs, of which I17 had clonally abnormal karyotypes. Among the latter, 9 I had one or more copies of i( I2p), whereas 26 lacked an i( I2p). We report here the karyotypic analysis of these 26 i( I2p)-negative GCTs. In this group, nonrandom sites of chromosomal rearrangements included I2p I 3 (9/26) and I p I I -q I I (5126). Comparison of the cytogenetic features of i( I2p)-negative tumors with i( I2p)-positive tumors revealed the only significant difference t o be rearrangements affecting I2pl3 in the former (35%) as compared t o their absence in the latter (3%). Hybridization of metaphase preparations of 9 i( I 2p)-negative tumors with a chromosome I 2 painting probe and with a microdissected I2p painting probe revealed extra copies of chromosome I 2 segments incorporated into marker chromosomes whose composition could not otherwise be resolved by banding analysis; all were shown t o be derived from I2p. These data demonstrate that both i( I 2p)-negative and -positive groups are characterized by an increased copy number of I 2p, which is consistent with a lack of significant clinical or biological difference between them. An increased I2p copy number thus is a specific aberration of significance t o the development of germ cell tumors.