NAT1*10 and NAT1*11 polymorphisms and breast cancer risk

Several recent epidemiological studies examined the association of N-acetyl transferase (NAT) 1 and 2 genotypes and breast cancer risk. Taken together, these studies do not support a strong role for the most common NAT alleles in etiology of breast cancer. Only one study estimated odds ratios (ORs) f or the relatively rare NAT1*11 allele: a strong positive association for th e NAT1*11 allele and breast cancer was reported, as well as strong combined effects for NAT1*11-containing genotypes and two environmental factors, sm oking and red meat consumption. To further address the association of NAT1* 11 and breast cancer, an analysis was performed using previously collected data from the Carolina Breast Cancer Study, a population-based, case-contro l study conducted in North Carolina. The OR for NAT1*11-containing genotype s and breast cancer was 0.5 (95% confidence interval, 0.2-1.3) among white women; ORs were not calculated among African Americans because only one par ticipant exhibited the NAT1*11 allele, There was no evidence for combined e ffects of NAT1*11 and smoking. Unfortunately, the results of both studies o f NAT1*11 are imprecise and lack sufficient statistical power to address fu lly the potential contribution of NAT1*11 to breast cancer. These results i llustrate that the limitations imposed by sample size, as well as incomplet e knowledge of biological function, need to be considered when planning and interpreting studies of genetic polymorphisms and environmental exposures.