Superior survival of breast cancer BRCA1 /2 mutation carriers harboringG/G at the -309 position at the MDM2 promoter compared to those harboring T/T or G/T at this SNP
10600 Background: A germ line single polymorphism in the promoter of the gene encoding the important modulator of P53, MDM2 has been described. The findings of G/G nucleotides at this position in contrast to G/Tor T/T were demonstrated to increase MDM2 transcriptional levels and were correlated with younger onset of cancers in patients with the Li-Fraumeni syndrome. Furhtermore gastric cancer patients harboring T/T at this position and treated with chemotherapy were found to have decresed survival compared to the other SNP carriers. P53 mutations appear in high frequency in tumors associated with BRCA1/2 mutations. Indeed it has been suggested that mutations in the p53 gene are a necessary step in tumorigenesis in BRCA tumors. Methods: Here we investigate the effect of the MDM2 SNP309 on overall survival and age of onset in breast cancer patients. MDM2 SNP309 was evaluated in Breast cancer Ashkenazy patients analyzed for the three common mutations in BRCA1/2- 180 patients who are positive for either of these mutation and 272 negative ones. 194 negative, Disease onset age and survival were analyzed for the different subgroups Results: Around a quarter of the whole population analyzed were identified as carriers of G/G at the -309 MDM2. There was no correlation between age of disease onset in either BRCA1/2mutation carriers and the specific genotype. In the BRCA1/2 mutation carriers we found a survival advantage in patients harboring the SNP309 G/G genotype(p-0.001 log rank test). Such an effect was not demonstrated in patients tested negative for the known Ashkenazy mutations Conclusions: In specific subgroups of breast cancer patients SNP309 G/G is associated with improved patient survival. A possible explanation for this finding could be the presence of a P53 which can be reactivated in the MDM2 SNP309 G/G carriers. No significant financial relationships to disclose.