No association between the MDM2 -309 T/G promoter polymorphism and breast cancer in African-Americans or Whites.

MDM2, a protein that binds and inactivates the tumor suppressor p53, is overexpressed in a variety of human cancers (1). Bond et al. (2) recently identified a single nucleotide polymorphism in the MDM2 gene, 309 T/G within the MDM2 promoter (database for single nucleotide polymorphism reference sequence number 2279744; http:// snp500cancer.nci.nih.gov). The G allele showed increased affinity for the transcriptional activator Sp1, resulting in elevated MDM2 transcription, higher MDM2 protein levels, and enhanced p53 inhibition. Among 88 members of LiFraumeni syndrome families who carried germ line mutations in p53 , persons with one or two copies of the MDM2 309 G allele showed earlier onset of cancer, including breast cancer, and G/G homozygous individuals showed increased frequency of multiple primary cancers. We examined the association of MDM2 genotype and breast cancer in the Carolina Breast Cancer Study, a population-based case-control study of African-Americans and Whites in North Carolina.