| Abstract: |
We report the cytogenetic analysis of 124 adult male germ cell tumors ascertained consecutively at the Memorial Sloan-Kettering Cancer Center between 1988 and 1990. Biopsies from testicular and extragonadal pri mary and metastatic lesions studied included all histolã3gica!subtypes of germ cell tumors and cases of malignant transformation. Nonrandom numerical and structural chromosomal abnormalities including i(12p), the previously described characteristic marker of these tumors, were determined, and their frequency was compared between histolã3gica! subtypes, between gonadal and extragonadal lesions, and between pri mary and transformed lesions. The frequency and copy number of i(12p) were found to be higher in nonseminomas compared with seminomas. Nonrandom sites of chromosome rearrangements associated with specific histologies comprised lp32-36 and 7ql 1.2 in teratomas and Ip22 in yolk sac tumors. Some tumors that underwent malignant differentiation exhib ited chromosome changes previously described to be nonrandomly asso ciated with de novo tumors with the same histolã3gica!characteristics. Cytological evidence of gene amplification in the form of homogeneously staining regions and/or double minutes was detected in 24% of extrago nadal lesions, mainly metastatic tumors, suggesting amplification of a gene(s) associated with metastatic progression of these tumors. While a number of previous small cytogenetic series or individual case reports of germ cell tumors identified several of the features of these tumors reported here, this series comprises analysis of the largest group of tumors ascertained consecutively at a single institution, defines the inci dence of nonrandom abnormalities in tumor subsets, and addresses their biological significance. © 1992, American Association for Cancer Research. All rights reserved. |
