Screening and association testing of common coding variation in steroid hormone receptor co-activator and co-repressor genes in relation to breast cancer risk: the Multiethnic Cohort.
BACKGROUND
Only a limited number of studies have performed comprehensive investigations of coding variation in relation to breast cancer risk. Given the established role of estrogens in breast cancer, we hypothesized that coding variation in steroid receptor coactivator and corepressor genes may alter inter-individual response to estrogen and serve as markers of breast cancer risk.


METHODS
We sequenced the coding exons of 17 genes (EP300, CCND1, NME1, NCOA1, NCOA2, NCOA3, SMARCA4, SMARCA2, CARM1, FOXA1, MPG, NCOR1, NCOR2, CALCOCO1, PRMT1, PPARBP and CREBBP) suggested to influence transcriptional activation by steroid hormone receptors in a multiethnic panel of women with advanced breast cancer (n = 95): African Americans, Latinos, Japanese, Native Hawaiians and European Americans. Association testing of validated coding variants was conducted in a breast cancer case-control study (1,612 invasive cases and 1,961 controls) nested in the Multiethnic Cohort. We used logistic regression to estimate odds ratios for allelic effects in ethnic-pooled analyses as well as in subgroups defined by disease stage and steroid hormone receptor status. We also investigated effect modification by established breast cancer risk factors that are associated with steroid hormone exposure.


RESULTS
We identified 45 coding variants with frequencies > or = 1% in any one ethnic group (43 non-synonymous variants). We observed nominally significant positive associations with two coding variants in ethnic-pooled analyses (NCOR2: His52Arg, OR = 1.79; 95% CI, 1.05-3.05; CALCOCO1: Arg12His, OR = 2.29; 95% CI, 1.00-5.26). A small number of variants were associated with risk in disease subgroup analyses and we observed no strong evidence of effect modification by breast cancer risk factors. Based on the large number of statistical tests conducted in this study, the nominally significant associations that we observed may be due to chance, and will need to be confirmed in other studies.


CONCLUSIONS
Our findings suggest that common coding variation in these candidate genes do not make a substantial contribution to breast cancer risk in the general population. Cataloging and testing of coding variants in coactivator and corepressor genes should continue and may serve as a valuable resource for investigations of other hormone-related phenotypes, such as inter-individual response to hormonal therapies used for cancer treatment and prevention.
Haiman
Christopher A
CA
Department of Preventive Medicine, Keck School of Medicine, University of Southern California/Norris Comprehensive Cancer Center, Los Angeles, California, USA. haiman@usc.edu
Garcia
Rachel R
RR
Hsu
Chris
C
Xia
Lucy
L
Ha
Helen
H
Sheng
Xin
X
Le Marchand
Loic
L
Kolonel
Laurence N
LN
Henderson
Brian E
BE
Stallcup
Michael R
MR
Greene
Geoffrey L
GL
Press
Michael F
MF
D001741:Black or African American / Q000235:genetics; D000368:Aged; D000483:Alleles; D001213:Asian / Q000235:genetics; D001943:Breast Neoplasms / Q000208:ethnology / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D014644:Genetic Variation / Q000235:genetics*; D006254:Hawaii; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011960:Receptors, Estrogen / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics*; D044465:White People / Q000235:genetics
D011960:Receptors, Estrogen; D014157:Transcription Factors