Cytogenetic analysis of germ cell tumors (GCTs) has identified i(12p) as a specific cytogenetic abnormality identified in more than 80% of GCTs, present in all histologies, in primary and metastatic lesions, in testicular and extragonadal presentations, and in ovarian and sex cord stromal tumors.
Clonal relationship between the teratoma and rhabdomyosarcoma of the germ cell tumor was established by the presence in both of i(12p), the characteristic marker of germ cell tumors.
In comparison with normal DNA, tumour DNA of a total of eight patients (seven with germ cell neoplasm and one with testicular lymphoma) showed increased dosages of KRAS2, PDGFA, EGFR, MET and PDGFB.
There were significant differences in oncogene expression between seminomas and nonseminomas with c-kit being expressed in 24 of 30 (80%) seminomas but in only 3 of 40 (7%) nonseminomatous tumors (P = 0.0001, chi 2 test) and hst-1 being expressed in 24 of 38 (63%) nonseminomas but only 1 of 24 (4%) of seminomas (P = 0.0001, chi 2 test), demonstrating an inverse relationship in the expression pattern of these 2 oncogenes in human testicular germ cell tumors.
In comparison with normal DNA, tumour DNA of a total of eight patients (seven with germ cell neoplasm and one with testicular lymphoma) showed increased dosages of KRAS2, PDGFA, EGFR, MET and PDGFB.
No gross alterations in the c-kit, hst-1, and int-2 loci were found at the DNA level and no int-2 mRNA expression was detected in any of the germ cell tumors examined.
No gross alterations in the c-kit, hst-1, and int-2 loci were found at the DNA level and no int-2 mRNA expression was detected in any of the germ cell tumors examined.
A diverse group of gonadal and extragonadal human germ cell tumors (GCT) and GCT-derived cell lines was examined for the presence of an i(12p) marker chromosome and/or other abnormalities involving chromosome 12, especially 12p, by bicolor double fluorescence in situ hybridization (FISH).
Since all three glutathione S-transferase isoenzyme classes contribute to the resistance to antineoplastic drugs, the altered glutathione S-transferase isoenzyme pattern and the decrease of glutathione S-transferase activity may play a role in the high inherent drug sensitivity of human testicular germ cell tumors.
Overrepresentation of chromosome 12p sequences and karyotypic evolution in i(12p)-negative testicular germ-cell tumors revealed by fluorescence in situ hybridization.
The P53 tumor suppressor gene protein is expressed to some degree in most testicular germ cell tumors and degree of staining/expression varies according to stage of disease.
Because testicular germ cell tumors of adults originate from an early germ cell and, to a certain extent, mimic normal embryonal development, we investigated the patterns of allelic expression of the H19 and IGF2 genes in these tumors to determine if genomic imprinting, or a disturbance of it, is involved in their pathogenesis.
Analysis of the products of RT-PCR showed biallelic expression of the H19 gene in 12 testicular germ cell tumors (patients numbered 6, 8-13, 15, 16, and 18-20) and of the IGF2 gene in 10 testicular germ cell tumors (patients numbered 1, 3, 6, 8-13, and 15-20).
We suggest that loss of genetic information from the short arm of chromosome 11, without affecting the WT1 gene in the regions studied, is relatively frequent but not crucial in the pathogenesis of testicular germ cell tumors of adults.
By allelotype analysis using the DCC-flanking polymorphic marker D18S5 we have previously shown that allelic deletions at 18q21 occur in 40% of male germ cell tumors (Murty et al., 1994).
Overexpression of p53 was not observed in all of the 22 ovarian germ cell tumors; only 3 were found to have nuclear staining in a small fraction of the malignant cells (< 5% in 1 immature teratoma, 5-10% in 2 yolk-sac tumors).