Molecular cytogenetic analysis of human spermatocytic seminomas

We performed comparative genomic hybridization (CGH) on 8 formalin-fixed, paraffin wax-embedded primary spermatocytic seminomas (SS) from 7 patients, one of whom developed metastatic disease. In general, this tumour type is not associated with development of metastases. Since there are only few reported cases of metastatic SS in the literature, this study is the first report of chromosomal constitution in a patient with metastatic disease. Chromosomal imbalances were observed in all 8 tumours analysed by CGH. Frequent copy number alterations were enh(9), dim(16 or 16p), enh(20) and enh(X), each in 6 samples, followed by dim(7) in 4, and enh(1), enh(18) and dim(15), each in 3 samples. In addition to the CGH analysis, interphase fluorescence in situ hybridisation (I-FISH) was applied to evaluate the CGH results and to define the size of the aberrant cell population. Interphase cytogenetics showed gain of material on chromosomes 9 and X in all tumours analysed. Overall, the I-FISH results were in agreement with the CGH data. In conclusion, gain of chromosome 9 seems to be restricted to SS and point to an important role for this aberration in the development of this tumour type.