DNA Repair Gene Expression Levels (ATM/MSH2) as Indicators of Breast Cancer in the Breast Cancer Family Registry

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 In the current study, we demonstrated an association between reduced ATM and MSH2 expression levels and breast cancer status.

 While ATM is a known breast cancer susceptibility gene, a role for a deficiency in MSH2, or any other constituents of the mismatch repair pathway, has not been commonly reported in association with breast cancer risk. MSH2, acts in conjunction with either MSH6 to recognize small loops and insertions or MSH3 to recognize single base mismatches in the mismatch repair pathway.

 Analysis conducted using GEE indicated an inverse association between ATM expression level and breast cancer status with expression assessed as a continuous variable (odds ratio (OR)=1.10, 95% confidence interval (CI)=1.02, 1.18). Upon tertiling expression level, a significant association with breast cancer status was observed among women in the lowest tertile of expression for MSH2 (OR=1.90, 95%CI=1.21, 2.97). Adjusting for age at blood draw and smoking status did not appreciably alter the estimates from the crude model (Table II).