Chromosome changes in germ cell tumors of the testis

Analysis of ovarian teratomas for isochromosome 12p: evidence supporting a dual histogenetic pathway for teratomatous elements

“…Of cases of ovarian mixed GCT, 83% had i(12p) in their nonteratomatous components and 66% in their teratomatous components, whereas all cases of pure mature cystic teratoma and immature teratoma lacked i(12p) or other evidence of 12p amplification. These findings parallel the presence of i(12p) and other forms of 12p amplification in postpubertal testicular teratomas [19][20][21][22][23] and the absence of such genetic findings in prepubertal testicular teratomas. [29][30][31] Additionally, the finding of 12p amplification in both the teratomatous and nonteratomatous components of ovarian mixed GCTs supports the origin of the former from the latter.…”

“…2,17 In this model, virtually all adult testicular teratomas are initially a component of a mixed GCT, and the occasional pure teratoma of the adult testis mostly represents the persistence of teratoma with spontaneous regression of other GCT types. Evidence supporting the origin of postpubertal testicular teratomas and the teratomatous components of mixed GCTs of the testis from malignant germ cells includes their association with intratubular germ cell neoplasia, unclassified (IGCNU), 18 the presence of i(12p) and of chromosome 12p amplification in both teratomatous and nonteratomatous components of postpubertal GCTs, [19][20][21][22][23] the presence of aneuploidy in postpubertal teratomas, 22,24 the similarities in allelic losses between mature teratoma and other components of malignant mixed GCTs of the testis, 25 the malignant behavior of postpubertal testicular teratomas, [26][27][28] and the atypical cytologic appearance of some postpubertal testicular teratomas. 2,17 Conversely, evidence supporting the origin of prepubertal testicular teratomas from benign germ cells includes a lack of chromosome 12p amplification, 29 a generally diploid, 46 XY karyotype, 30 normal findings on comparative genomic hybridization studies, 31 and lack of IGCNU.…”

Germ cell tumors of the gonads: a selective review emphasizing problems in differential diagnosis, newly appreciated, and controversial issues

“…[7][8][9] DNA quantification shows that mature ovarian teratomas are diploid, and cytogenetic study demonstrates that they almost always have a normal 46,XX karyotype, 10,11 whereas mature teratomas of the postpubertal testis are hyperdiploid to hypotriploid with complex cytogenetic abnormalities including invariable 12p amplification, often in the form of an isochromosome [i (12p)]. [12][13][14][15][16] Molecular genetic analysis has also shown that mature ovarian teratomas are usually homozygous for polymorphic markers, 17 indicating that they derive most often from a germ cell that has completed meiosis I but not meiosis II, a conclusion supported by cytogenetic analysis. 11 When heterozygosity does occur, it predictably is in loci that tend to be located distant from the centromere-that is, in genes most susceptible to crossing over at the metaphase plate of meiosis I.…”

Imprints and DPPA3 are bypassed during pluripotency- and differentiation-coupled methylation reprogramming in testicular germ cell tumors

“…S1). Next we performed somatic copy number aberration (SCNA) analysis for presence of anticipated anomalies (see Methods), typified by tumor-specific gain of the short arm of Chromosome 12, which is independent of subtype histology (Atkin and Baker 1982;Gibas et al 1986;van Echten et al 1995). Based on these data, 108 of the 130 assayed tumors and 113 of 128 BNTs met inclusion criteria for further analysis (Methods) (Supplemental Fig.…”