title: Glutathione S-transferase M1 and P1 polymorphisms and risk of breast cancer and fibrocystic breast conditions in Chinese women.
abstract: Enzymes encoded by the glutathione S-tranferase mu 1 (GSTM1) and pi 1 (GSTP1) genes, which are expressed in breast tissue, catalyze the detoxification of endogenous and exogenous electrophiles. Reduced enzyme activity, due to carriage of the GSTM1 deletion or the GSTP1 Ile105Val Val allele, may therefore affect susceptibility to breast cancer and related conditions. In a case-control study of Chinese women, we examined whether these polymorphisms were associated with risk of breast cancer and fibrocystic breast conditions. Women diagnosed with breast cancer (n=615) or fibrocystic breast conditions (n=467) were compared to women without clinical breast disease (n=878). We also examined whether these associations differed by menopausal status or by presence of proliferation in the extra-tumoral epithelium among women with breast cancer and in lesions among women with fibrocystic conditions. No overall association of either GST polymorphism with risk of breast cancer or fibrocystic breast conditions was observed. There was some evidence of slightly elevated cancer risk associated with carriage of the GSTM1 null genotype and at least one GSTP1 105-Val allele (OR=1.33, 95% CI, 0.99-1.80), compared to carriage of the GSTM1 non-null and GSTP1 Ile/Ile genotypes. This relationship was stronger in women who had breast cancer with extra-tumoral tissue proliferation (OR=1.77, 95% CI, 1.03-3.04). Our results suggest that GSTM1 and GSTP1 genotypes do not individually influence susceptibility to breast cancer or fibrocystic breast conditions. The observed increased risk of breast cancer associated with joint carriage of the GSTM1 null genotype and GSTP1 105-Val allele needs confirmation in other studies.
authors.affiliation: Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Department of Epidemiology, University of Washington, Mailstop M4-C308, P.O. Box 19024, Seattle, WA 98109-1024, USA.
authors.forename: Lori C
authors.initials: LC
authors.lastname: Sakoda
authors.forename: Christie R
authors.initials: CR
authors.lastname: Blackston
authors.forename: Kan
authors.initials: K
authors.lastname: Xue
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Doherty
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Ray
authors.forename: Ming Gang
authors.initials: MG
authors.lastname: Lin
authors.forename: Helge
authors.initials: H
authors.lastname: Stalsberg
authors.forename: Dao Li
authors.initials: DL
authors.lastname: Gao
authors.forename: Ziding
authors.initials: Z
authors.lastname: Feng
authors.forename: David B
authors.initials: DB
authors.lastname: Thomas
authors.forename: Chu
authors.initials: C
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D016022:Case-Control Studies; D002681:China; D015331:Cohort Studies; D005260:Female; D005348:Fibrocystic Breast Disease / Q000175:diagnosis* / Q000235:genetics*; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D012306:Risk
chemical_list: D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase