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Influence of the MDM2 single nucleotide polymorphism SNP309 on tumour development in BRCA1 mutation carriers

Ellen R Copson1, Helen E White, Jeremy P Blaydes

  • 1Cancer Research UK Oncology Unit, Cancer Sciences Division, University of Southampton School of Medicine, Southampton General Hospital, Southampton, SO16 6YD, UK. erc1@soton.ac.uk

BMC Cancer
|March 28, 2006
PubMed
Abstract

Insights

The MDM2 SNP309 genetic variation does not accelerate tumor development in individuals with BRCA1 mutations. This study found no significant difference in cancer incidence or age of diagnosis among BRCA1 carriers with or without the MDM2 SNP309.

Area of Science:

  • Genetics
  • Oncology
  • Molecular Biology

Background:

  • The MDM2 gene regulates the p53 tumor suppressor protein.
  • A specific MDM2 promoter polymorphism (SNP309) may influence tumor formation.
  • Previous research suggested SNP309 accelerates tumors in individuals with inherited p53 mutations.

Purpose of the Study:

  • To investigate the impact of the MDM2 SNP309 on clinical outcomes in BRCA1 mutation carriers.
  • To determine if MDM2 SNP309 affects tumor development or age of diagnosis in this patient group.

Main Methods:

  • Genomic DNA was collected from 102 healthy controls and 116 patients with pathogenic BRCA1 mutations.
  • Pyrosequencing technology was used to genotype the MDM2 SNP309 locus.
  • Cancer incidence and age of diagnosis were analyzed in relation to MDM2 SNP309 genotypes.

Main Results:

  • The MDM2 SNP309 polymorphism was present in 58.6% of BRCA1 carriers.
  • No significant difference in malignancy incidence was observed between SNP309 carriers and wildtype BRCA1 individuals (72.7% vs. 75.6%).
  • Mean age of breast cancer diagnosis was similar across different MDM2 SNP309 genotypes (41.2 years for G/G, 38.6 years for G/T, 39.0 years for T/T).

Conclusions:

  • The MDM2 SNP309 does not appear to accelerate tumor development in carriers of pathogenic BRCA1 germline mutations.
  • This finding suggests that MDM2 SNP309 is not a significant modifier of cancer risk or progression in the context of BRCA1-related cancers.

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