Comparative genomic hybridization of microdissected samples from different stages in the development of a seminoma and a non-seminoma.

Human testicular germ cell tumours (TGCTs) of adolescents and adults, both seminomas and non-seminomas, originate from intratubular germ cell neoplasia (IGCN). Comparative genomic hybridization (CGH) was applied to microdissected samples from different stages of the development of a seminoma and a mixed non-seminoma, including IGCN of both. The different stages of the seminoma development, namely IGCN, intratubular and invasive seminoma, showed a very similar pattern of chromosomal imbalances, including gains of parts of 7, 8, 12,14, and X, and losses of parts of 3, 4, 5, 10, 11, 12q, 16, 18, 22, and Y. A more heterogeneous pattern was found for the non-seminoma. Some aberrations were present only in IGCN, or in IGCN and in all invasive components (gains of parts of 1q, 17, 19p, 20q, and 22, and losses of parts of 4, 5, 9p, 13, and 18q), while others were present in a less consistent pattern. These are the first reported CGH data from different stages in the development of TGCTs. Although only two cases were studied, the results suggest that particular numerical changes of (parts of) chromosomes are involved in the early development and progression of this cancer. Copyright 2000 John Wiley & Sons, Ltd.