Polymorphisms in Phase I and Phase II genes and breast cancer risk and relations to persistent organic pollutant exposure: a case–control study in Inuit women

Table 1 Characteristics of the studied gene polymorphisms

Gene	Position	Reference SNP	Location/amino acid change	Genotyping method	Main function	Activity
Gene	Position	Reference SNP	Location/amino acid change	Genotyping method	Main function	Low	High
CYP1A1	15q24.1	rs1048943	A> C	C_25624888_50^#	Carcinogen activation	Ile (wt)	Val (var)
CYP1A1	15q24.1	rs1048943	Ile462Val	C_25624888_50^#	2-hydroxylation of E2	Ile (wt)	Val (var)
CYP1B1	2p22.2	rs1056836	C> G Leu432val	C_3099976_30^#	Carcinogen activation	Leu (wt)	Val^a (var)
CYP1B1	2p22.2	rs1056836	C> G Leu432val	C_3099976_30^#	4-hydroxylation of E2	Leu (wt)	Val^a (var)
COMT	22q11.21	rs4680	G> A	C_25746809_50^#	Estradiol catabolism	Met (mut)	Val (var)
COMT	22q11.21	rs4680	Val158Met	C_25746809_50^#	Estradiol catabolism	Met (mut)	Val (var)
CYP17A1	10q24.3	rs743572	5′UTR	C_2852784_30^#	Steroid 17α-hydroxylase		A2^b
CYP17A1	10q24.3	rs743572	−34 T> C (A1> A2)	C_2852784_30^#	Steroid 17α-hydroxylase		A2^b
CYP19A1	15q21.1	rs10046	3′UTR	C_8234731_30^#	Aromatase activity (androgen to estrogen)		T^c (var)
CYP19A1	15q21.1	rs10046	C> T	C_8234731_30^#	Aromatase activity (androgen to estrogen)		T^c (var)
CYP19A1	15q21.1	-	(TTTA)n repeats	PCR-based	Aromatase activity	-	-
BRCA1	17q21	rs80357164	Cys39Gly	PCR-based	DNA damage repair	-	-

wt: wild-type; var: variant.
^#TaqMan Drug Metabolism Genotyping Assay.
^a432Val variant has the higher 17β-estradiol hydroxylation activity, but lower carcinogenic activity [14].
^bA2 is postulated to correlate with higher serum levels of various sex steroids [22, 24, 25].
^cVariant alleles T has been associated with higher levels of postmenopausal circulating E2 [27].

ISSN: 1476-069X