Table 1.

Description of genes and variants studied

GeneSNP nucleotide designationRs no.SNP aliasesPrimary variant functionHypothesized estrogenicity of variantHypothesized mutagenicity of variantHypothesized breast cancer risk of variant
COMT1947G>Ars4680Val158Met, Val108MetMethionine allozyme has decreased activity (42)IncreasedIncreased
CYP1A16750A>Grs1048943Ile462Val, *2C, m2Valine allozyme has increased inducibility to produce 2-, 4-, and 16α-catecholestrogens and the main source of extrahepatic 16α catecholestrogen (43)WeakAntioxidant, DNA damage protectiveProtective
CYP1A2734C>A, 163C>Ars762551*1F*1F has increased inducibility and ultrarapid activity to produce 2-OH- and 4-OH-catecholestrogens (44)WeakAntioxidant, DNA damage protectiveProtective
CYP1B11358A>G or 3290A>Grs1800440Asn452Ser, *4Serine allozyme associated with higher catalytic efficiency toward 4-OH-estradiol (45)PotentGenotoxic, Free radical generatorIncreased
CYP3A4729A>Grs2740574*1B*1B allele may confer increased CYP3A4 expression (46)PotentGenotoxic, Free radical generatorIncreased
SULT1A1638G>Ars9282861Arg213His, *2*2 allozyme has lower thermostability, lower enzyme activity, and lower estrogen sulfation ability (36, 37, 47)IncreasedIncreasedIncreased
SULT1E1−64G>Ars3736599Promoter variantNot determinedUnknownUnknownUnknown