Polymorphism Thr160Thr in SRD5A1, involved in the progesterone metabolism, modifies postmenopausal breast cancer risk associated with menopausal hormone therapy

The role of 17βHSDs in breast tissue and breast cancers

The family of seventeen beta hydroxysteroid dehydrogenase enzymes has a long and diverse history in breast and breast cancer research. Given the known dependence of the breast on steroid signalling and intracrine steroid metabolism these enzymes are considered to be essential local fine tuners of overall steroid balance in the tissue. This review will cover the current state of knowledge regarding the expression, clinical effect and biological regulation of enzymes in both cancerous and normal states. In addition we will also cover the current state of knowledge regarding 17βHSD actions in the often neglected adipose and stromal components of tumours.

Conserved effect of aging on DNA methylation and association with EZH2 polycomb protein in mice and humans

In humans, DNA methylation at specific CpG sites can be used to estimate the 'epigenetic clock', a biomarker of aging and health. The mechanisms that regulate the aging epigenome and level of conservation are not entirely clear. We performed affinity-based enrichment with methyl-CpG binding domain protein followed by high-throughput sequencing (MBD-seq) to assay DNA methylation in mouse samples. Consistent with previous reports, aging is associated with increase in methylation at CpG islands that likely overlap regulatory regions of genes that have been implicated in cancers (e.g., C1ql3, Srd5a2 and Ptk7). The differentially methylated regions in mice have high sequence conservation in humans and the pattern of methylation is also largely conserved between the two species. Based on human ENCODE data, these sites are targeted by polycomb proteins, including EZH2. Chromatin immunoprecipitation confirmed that these regions interact with EZH2 in mice as well, and there may be reduction in EZH2 occupancy with age at C1ql3. This adds to the growing evidence that EZH2 is part of the protein machinery that shapes the aging epigenome. The conservation in both sequence and methylation patterns of the age-dependent CpGs indicate that the epigenetic clock is a fundamental feature of aging in mammals.

Genetic modifiers of menopausal hormone replacement therapy and breast cancer risk: a genome-wide interaction study

Women using menopausal hormone therapy (MHT) are at increased risk of developing breast cancer (BC). To detect genetic modifiers of the association between current use of MHT and BC risk, we conducted a meta-analysis of four genome-wide case-only studies followed by replication in 11 case-control studies. We used a case-only design to assess interactions between single-nucleotide polymorphisms (SNPs) and current MHT use on risk of overall and lobular BC. The discovery stage included 2920 cases (541 lobular) from four genome-wide association studies. The top 1391 SNPs showing P values for interaction (Pint) <3.0 × 10(-3) were selected for replication using pooled case-control data from 11 studies of the Breast Cancer Association Consortium, including 7689 cases (676 lobular) and 9266 controls. Fixed-effects meta-analysis was used to derive combined Pint. No SNP reached genome-wide significance in either the discovery or combined stage. We observed effect modification of current MHT use on overall BC risk by two SNPs on chr13 near POMP (combined Pint≤8.9 × 10(-6)), two SNPs in SLC25A21 (combined Pint≤4.8 × 10(-5)), and three SNPs in PLCG2 (combined Pint≤4.5 × 10(-5)). The association between lobular BC risk was potentially modified by one SNP in TMEFF2 (combined Pint≤2.7 × 10(-5)), one SNP in CD80 (combined Pint≤8.2 × 10(-6)), three SNPs on chr17 near TMEM132E (combined Pint≤2.2×10(-6)), and two SNPs on chr18 near SLC25A52 (combined Pint≤4.6 × 10(-5)). In conclusion, polymorphisms in genes related to solute transportation in mitochondria, transmembrane signaling, and immune cell activation are potentially modifying BC risk associated with current use of MHT. These findings warrant replication in independent studies.

A genome-wide association study to identify genetic susceptibility loci that modify ductal and lobular postmenopausal breast cancer risk associated with menopausal hormone therapy use: a two-stage design with replication

Menopausal hormone therapy (MHT) is associated with an elevated risk of breast cancer in postmenopausal women. To identify genetic loci that modify breast cancer risk related to MHT use in postmenopausal women, we conducted a two-stage genome-wide association study (GWAS) with replication. In stage I, we performed a case-only GWAS in 731 invasive breast cancer cases from the German case-control study Mammary Carcinoma Risk Factor Investigation (MARIE). The 1,200 single nucleotide polymorphisms (SNPs) showing the lowest P values for interaction with current MHT use (within 6 months prior to breast cancer diagnosis), were carried forward to stage II, involving pooled case-control analyses including additional MARIE subjects (1,375 cases, 1,974 controls) as well as 795 cases and 764 controls of a Swedish case-control study. A joint P value was calculated for a combined analysis of stages I and II. Replication of the most significant interaction of the combined stage I and II was performed using 5,795 cases and 5,390 controls from nine studies of the Breast Cancer Association Consortium (BCAC). The combined stage I and II yielded five SNPs on chromosomes 2, 7, and 18 with joint P values <6 × 10(-6) for effect modification of current MHT use. The most significant interaction was observed for rs6707272 (P = 3 × 10(-7)) on chromosome 2 but was not replicated in the BCAC studies (P = 0.21). The potentially modifying SNPs are in strong linkage disequilibrium with SNPs in TRIP12 and DNER on chromosome 2 and SETBP1 on chromosome 18, previously linked to carcinogenesis. However, none of the interaction effects reached genome-wide significance. The inability to replicate the top SNP × MHT interaction may be due to limited power of the replication phase. Our study, however, suggests that there are unlikely to be SNPs that interact strongly enough with MHT use to be clinically significant in European women.

Polymorphisms in AKR1C4 and HSD3B2 and differences in serum DHEAS and progesterone are associated with paranoid ideation during mania or hypomania in bipolar disorder

Paranoia is commonly a mood-incongruent psychotic symptom of mania which may be related to dopamine dysregulation. Progesterone and its metabolite allopregnanolone (ALLO) have been found in animals to antagonize the effects of dopamine. We therefore examined serum progesterone, its endogenous antagonist DHEAS and polymorphisms of the genes coding for certain steroidogenetic enzymes (AKR1C4, HSD3B2, and SRD5A1) in 64 males and 96 females with bipolar 1 or 2 disorder with or without paranoid ideation during mood elevation. Euthymic morning serum progesterone, DHEAS and cortisol concentrations were measured in males and in premenopausal women who were in follicular phase and not taking oral contraceptives. In women only, SNPs in AKR1C4 reduced the likelihood of having exhibited paranoid ideation by circa 60%. The haplotype of all 4 SNPs in the AKR1C4 gene reduced the risk of exhibiting paranoia by 80% (OR 0.19, 95% CI 0.06-0.61, p=0.05). A history of paranoid ideation was not, however, related to progesterone or DHEAS concentration. Serum DHEAS and progesterone concentrations were lower in men who had shown paranoid ideation during mania/hypomania compared with those who had not (F=7.30, p=0.006) however this was not coupled to polymorphisms in the selected genes. The ancestral G in rs4659174 in HSD3B2 was in men associated with a lower risk of paranoid ideation (likelihood ratio χ(2) 3.97, p=0.046, OR 0.31 (95% CI 0.10-0.96)) but did not correlate with hormone concentrations. Hence, gene variants in the steroidogenetic pathway and steroids concentration differences may be involved in the susceptibility to paranoia during mood elevation.