Influence of the MDM2 single nucleotide polymorphism SNP309 on tumour development in BRCA1 mutation carriers.
BACKGROUND
The MDM2 gene encodes a negative regulator of the p53 tumour suppressor protein. A single nucleotide polymorphism (SNP) in the MDM2 promoter (a T to G exchange at nucleotide 309) has been reported to produce accelerated tumour formation in individuals with inherited p53 mutations. We have investigated the effect of the MDM2 SNP309 on clinical outcome in a cohort of patients with germline mutations of BRCA1.


METHODS
Genomic DNA was obtained for 102 healthy controls and 116 patients with established pathogenic mutations of BRCA1 and Pyrosequencing technologytrade mark was used to determine the genotype at the MDM2 SNP309 locus.


RESULTS
The polymorphism was present in 52.9% of the controls (G/T in 37.3% and G/G in 15.6%) and 58.6% of the BRCA1 mutation carriers (47.4% G/T and 11.2% G/G). Incidence of malignancy in female BRCA1 carriers was not significantly higher in SNP309 carriers than in wildtype (T/T) individuals (72.7% vs. 75.6%, p = 1.00). Mean age of diagnosis of first breast cancer was 41.2 years in the SNP309 G/G genotype carriers, 38.6 years in those with the SNP309 G/T genotype and 39.0 years in wildtype subjects (p = 0.80).


CONCLUSIONS
We found no evidence that the MDM2 SNP309 accelerates tumour development in carriers of known pathogenic germline mutations of BRCA1.
Cancer Research UK Oncology Unit, Cancer Sciences Division, University of Southampton School of Medicine, Southampton General Hospital, Southampton, SO16 6YD, UK. erc1@soton.ac.uk
Ellen R
ER
Copson
Helen E
HE
White
Jeremy P
JP
Blaydes
David O
DO
Robinson
Peter W
PW
Johnson
Diana M
DM
Eccles
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D019398:Genes, BRCA1; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation; D006801:Humans; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics*
C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2