Two variants, 6q25.1-rs9383938 and TXNRD2-rs8141691, were statistically significantly associated with percent MD (P = 0.019 and 0.03, respectively), with the 6q25.1-rs9383938 association being consistent with the SNP effect on breast cancer risk.
We also identified two variants (rs3734805 and rs9383938) mapping to 6q25.1 estrogen receptor 1 (ESR1), which were associated with breast cancer in subjects of northern European ancestry (rs3734805: OR = 1.19, 95% CI = 1.11 to 1.27, P = 1.35 × 10(-7); rs9383938: OR = 1.18, 95% CI = 1.11 to 1.26, P = 1.41 × 10(-7)).
However, the haplogenotypes CTAG and CCGG of rs2234693 and rs9340799 polymorphisms could contribute significantly to the susceptibility of risk in BC positive at miscarriage and tobacco consumption in this sample population.
ESR1 rs3798577 and ESR2 rs1256049 were associated with breast cancer in ER-positive cases, and ESR1 rs2234693, and rs3798577 were associated with breast cancer in Her-2-negative cases, while the association of ESR2 rs1256049 with breast cancer was seen in Her-2 positive cases.
To investigate the association between PvuII (rs2234693), XbaI (rs9340799) and P325P (rs1801132) polymorphisms of ESR1 gene with the risk of breast cancer under different population categorizations, we searched multiple databases for data collection, and performed the meta-analysis on a total of 25 case-control studies.
We examined the association of single nucleotide polymorphism (SNP) in estrogen receptors, ESR1 (rs2234693) and ESR2 (rs2987983); estrogen biosynthesis enzymes, CYP17A1 (rs743572); and aromatase, CYP19A1 (rs700519) with breast cancer risk.
The combination of the TC/CC genotypes of ESR1 rs2234693 and passive smoking significantly increased the risk of breast cancer [OR (95%CI): 2.06 (1.39-3.05)] in pre-menopausal women.
When all the eligible studies were pooled into the meta-analysis, the higher transcriptional activity variant allele T of ESR1 PvuII (C>T) (rs2234693) in pre-menopausal breast cancer women showed a significant relation to increased risk (OR = 1.13, 95%CI: 1.01-1.28, P = 0.040) in contrast to their post-menopausal counterparts which showed non-significant increased risk (OR = 1.01, 95%CI: 0.87-1.18, P = 0.858).
In a case-control study of women from Shanghai, China, we examined the risk of breast cancer and fibrocystic breast conditions associated with the ESR1 PvuII (rs2234693) and XbaI (rs9340799) and AR CAG repeat ((CAG)(n)) and GGC repeat ((GGC)(n)) polymorphisms among 614 women with breast cancer, 467 women with fibrocystic conditions, and 879 women without breast disease.
Our results showed that rs3798577 was significantly associated with the risk of breast cancer, the common allele C conferring susceptibility (p-trend=4 x 10(-5)); rs3798577 was also correlated with PR expression (p=0.01), but not with ER expression; rs2228480 (p=0.047) and rs1801132 (p=0.02) were associated with the age at diagnosis; rs1801132 was correlated with hypercholesterolemia (p=0.003) and increased BMI (body mass index) (p=0.01); rs2234693 showed a low significant association (p=0.042) with the tumor grade; rs3798577 was correlated with disease-free survival (p=0.05), allele C conferring increased risk for relapses, but it reached not statistical significance after adjustments.
This current analysis on 10,300 breast cancer cases and 16,620 controls on rs2234693 showed a borderline significant decreased breast cancer risk for CC and CC/CT carriers (CC vs. TT: OR, 0.92, 95% CI, 0.86-0.99; CC/CT vs. TT: OR, 0.95, 95% CI, 0.89-1.00).
In this study, we investigated breast cancer risk associated with genotypes and haplotypes resulting from four ESR1 single nucleotide polymorphisms (SNPs), rs746432, rs2234693, rs9340799, and rs1801132.
Collectively, these data demonstrate an important role for the K303R ERalpha mutation in hormonal regulation of tumor growth and estrogen-regulated promoter dynamics in human breast cancer.
Our data suggest that the K303R mutation and the S305 ERalpha residue may be a novel determinant of AI response in breast cancer, and blockade of S305 phosphorylation represents a new therapeutic strategy for treating tumors resistant to hormone therapy.
Expression of the K303R estrogen receptor-alpha breast cancer mutation induces resistance to an aromatase inhibitor via addiction to the PI3K/Akt kinase pathway.
ESR1 A908G mutation-positive breast cancer was significantly associated with a first-degree family history of breast cancer (odds ratio [OR] = 2.69, 95% confidence interval [CI] = 1.15 to 6.28), whereas mutation-negative breast cancer was not.
The A908G (Lys303-->Arg) change in the gene encoding oestrogen receptor-alpha (ER-alpha) creates a hypersensitivity to oestradiol and would have significant consequences if present in breast carcinoma, especially those treated with endocrine therapy.
This population-based study, the largest so far to screen for the ER-alpha A908G mutation in breast cancer, confirms the presence of the mutant in invasive breast tumors.
However, the haplogenotypes CTAG and CCGG of rs2234693 and rs9340799 polymorphisms could contribute significantly to the susceptibility of risk in BC positive at miscarriage and tobacco consumption in this sample population.