Estrogen receptor polymorphisms and the risk of endometrial cancer.
OBJECTIVE
There is evidence that estrogens and some of their metabolites are involved in endometrial cancer pathogenesis. As estrogens mediate their effects via the estrogen receptors, ESR1 and ESR2, the objective of this investigation was to determine whether six single nucleotide polymorphisms (SNPs) in these two genes were over-represented in a population of endometrial cancer patients compared with a healthy matched control population, thereby associating differences in these genes with endometrial cancer.


METHODS
The study is a case-control investigation large enough to detect a two-fold increased risk, assuming a dominant genetic model, with P = 0.05 and 80% power.


METHODS
The study and control populations were all from the Hunter-New England region of New South Wales, Australia collected between the years 1992 and 2005.


METHODS
The study consisted of 191 endometrial cancer patients and 291 healthy controls matched for gender and age.


METHODS
Two SNPs in ESR1 and four SNPs in ESR2 were genotyped using PCR-based restriction fragment length polymorphism analysis and real-time PCR. Odds ratios were calculated using unconditional logistic regression and SIMHAP was used for haplotype analysis, adjusting for potential endometrial cancer risk factors. Kaplan-Meier survival analysis, Cox regression and t tests were used to examine the patient's age of diagnosis of endometrial cancer and genotype.


METHODS
Over-representation of ESR1 and ESR2 polymorphisms in the endometrial cancer population compared with the control population indicates an involvement in the development and/or progression of disease.


RESULTS
Two ESR1 (rs2234693 and rs9340799) and two ESR2 (rs1255998 and rs944050) polymorphisms were associated with an increased risk of endometrial cancer. Following adjustment for risk factors, the association with the ESR1 and ESR2 polymorphisms (rs2234693, rs1255998 and rs944050) remained highly significant. Haplotype analysis revealed that carriers of the ESR1 haplotype (variant alleles; rs2234693 and rs9340799) and the ESR2 haplotype (variant allele; rs1255998 and wild-type alleles; rs944050, rs4986938 and rs1256049) were at an increased risk (OR 1.862, P = 0.013 and OR 1.918, P = 0.046 respectively). This risk was even greater in women carrying both risk haplotypes (OR 5.041, P = 0.007).


CONCLUSIONS
Our data suggest that the ESR1 (rs2234693 and rs9340799) and the ESR2 (rs1255998 and rs944050) polymorphisms may be associated with an increased risk of developing endometrial cancer.
Discipline of Medical Genetics, School of Biomedical Sciences, Faculty of Health, University of Newcastle; and the Hunter Medical Research Institute, Newcastle, NSW, Australia.
K A
KA
Ashton
A
A
Proietto
G
G
Otton
I
I
Symonds
M
M
McEvoy
J
J
Attia
M
M
Gilbert
U
U
Hamann
R J
RJ
Scott
D016022:Case-Control Studies; D016889:Endometrial Neoplasms / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011960:Receptors, Estrogen / Q000235:genetics*; D012307:Risk Factors
D011960:Receptors, Estrogen