Altered dosage of the sex chromosomes in human testicular cancer: a molecular genetic study.
Thirty-one males with testicular germ-cell tumors were studied by Southern hybridization using X- and Y-chromosome-specific probes as well as a pseudoautosomal probe. Densitometric analysis showed changes in the relative dosage of Y-chromosomal fragments in tumor DNA from 12 out of 31 patients (39%) as compared to normal DNA from the same patients. In 11 tumors the relative intensity ratios of Y-chromosome-specific fragments had decreased from the normal value of 1 to values between 0 and 0.77. An increase in the Y-chromosomal dosage was observed in 1 case. The entire Y chromosome was apparently involved in most patients but 2 tumors revealed regional variation. Tumor DNA of 2 patients with Y-chromosomal deficiency showed a concomitant increase in the X chromosomal dosage. The pseudoautosomal region that is shared by both sex chromosomes was involved in a total of 8 tumors (26%), 2 of which did not show any obvious dosage changes with probes detecting strictly X- or Y-chromosome-specific fragments. Autosomal alterations in the present tumor series have been described. A dosage change involving the sex chromosomes accompanied loss of heterozygosity at loci in 3p or 11p in 10 tumors out of 15 (67%). Seminomas tended to be affected more often than non-seminomas by either type of alteration. Our results indicate that changes in the sex chromosomes occur in a substantial proportion of male germ-cell tumors and, together with other defects, may constitute an important step in tumor development and/or progression.
Peltomäki
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Department of Medical Genetics, University of Helsinki, Finland.
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D002869:Chromosome Aberrations; D004273:DNA, Neoplasm / Q000032:analysis; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization; D011003:Ploidies; D013736:Testicular Neoplasms / Q000209:etiology / Q000235:genetics*; D014960:X Chromosome; D014998:Y Chromosome
D004273:DNA, Neoplasm