ADD3 and breast angiosarcoma: However, we did not have a large enough sample size to estimate whether the C allele of the rs10509906-containing haplotype, as a protective allele carried by individuals, might enhance the transcriptional activity of ADD3 and thus prevent the phenotype that usually results from a low level of ADD3. Therefore, the haplotype construction may suggest that the two SNPs together tag a third, untyped, SNP associated to BA, to some extent, probably revealed increased risk in the BA susceptibility.