Despite the significant finding of SNPs in NCS-1 being associated with CA in the AA population (discovery and combined but not replication sample) there are a number of limitations to this study. One limitation is that population stratification has not been addressed in this study. This is particularly pertinent for the AA population and might explain the failure to confirm the rs1342043 association in the replication sample. Different AA populations may have different degrees of population admixture and unless ancestry informative markers are genotyped in this sample it is not possible to conclusively state that the associations we are observing are due to population stratification or association with CA. The initial evidence of the protective role of the C allele in rs1342043 and the T allele in rs7849345 against CA in the AA population requires genotyping in additional samples in order to confirm this finding. Another limitation is the limited power of our replication sample for both AA and EA due to relatively small sample size. In an attempt to address this limitation, we have carried out a combined analysis
