Association of the polymorphism of the CAG repeat in the mitochondrial DNA polymerase gamma gene (POLG) with testicular germ-cell cancer

Ann Oncol. 2008 Nov;19(11):1910-4. doi: 10.1093/annonc/mdn407. Epub 2008 Jul 15.


Background: A possible association between the polymorphic CAG repeat in the DNA polymerase gamma (POLG) gene and the risk of testicular germ-cell tumours (TGCT) was investigated in this study. The hypothesis was prompted by an earlier preliminary study proposing an association of the absence of the common 10-CAG-long POLG allele with testicular cancer as well as previously reported in some European populations' association with male subfertility, which is a condition carrying an increased risk of TGCT.

Patients and methods: The number of CAG repeats in both POLG alleles was established in 243 patients with TGCT and in 869 controls by the analysis of the genomic DNA fragment.

Results: A significantly higher proportion of men homozygous allele of other than the common 10 CAG repeats was found among the patients with TGCT in comparison to the controls (4.9% versus 1.3%, respectively, P = 0.001). The vast majority of the homozygous patients had a seminoma (11 of 12; 97%), despite that only about half (55%) of the studied patients had this tumour type.

Conclusions: The findings indicate that the POLG polymorphism may be a contributing factor in the pathogenesis of TGCT particularly in seminoma, but the mechanisms remain to be elucidated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alleles
  • Case-Control Studies
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase / genetics*
  • Genotype
  • Humans
  • Male
  • Neoplasm Staging
  • Neoplasms, Germ Cell and Embryonal / enzymology
  • Neoplasms, Germ Cell and Embryonal / genetics*
  • Neoplasms, Germ Cell and Embryonal / pathology
  • Polymorphism, Genetic
  • Testicular Neoplasms / enzymology
  • Testicular Neoplasms / genetics*
  • Testicular Neoplasms / pathology
  • Trinucleotide Repeats*


  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase
  • POLG protein, human