Histological groups of human postpubertal testicular germ cell tumours harbour different genetic alterations

Background: Testicular germ cell tumours are the most common malignancies in young males. Molecular biology studies of these tumours are often contradictory. Two histological groups, seminoma and non-seminoma, differ both morphologically and in malignant behaviour. Although a common cytogenetic feature is seen, namely the amplification of the 12p chromosomal region, the development mechanisms of less aggressive seminomas and more aggressive non-seminomas are unknown.

Materials and methods: Occurrence of structural genetic alterations was analyzed in 18 seminomas and 22 non-seminomas for genes involved in the malignant tumour phenotype: cadherin 1, Type 1, E-cadherin (Epithelial), CDH1; adenomatous polyposis coli, APC; NME/NM23 nucleoside diphosphate kinase 1, NME1; tumour protein P53, TP53; cyclin-dependent kinase inhibitor 2A, CDKN2A; retinoblastoma 1, RB1; RAD51 recombinase, RAD51; mutS homolog 2, MSH2; MutL homolog 1, MLH1; breast cancer 1, early onset, BRCA1; BCL2-Associated X Protein, BAX; ATP-Binding Cassette, Sub-Family G (WHITE), Member 2, ABCG2. Genetic alterations, loss of heterozygosity and microsatellite instability, were analyzed using restriction fragment or microsatellite repeat length polymorphisms.

Results: A difference in genetic alteration occurrence between seminomas and non-seminomas was observed.

Conclusion: Occurrence of genetic alterations correlates with clinical behaviour of these tumours and may indicate that such alterations could occur early in the development of seminomas and non-seminomas.