Variations in sex hormone metabolism genes, postmenopausal hormone therapy and risk of endometrial cancer

CYP17A1 (rs74357) polymorphism and polycystic ovary syndrome risk: a systemic review and meta-analysis

BACKGROUND AND AIM

To investigate the association between CYP17A1 (rs74357) polymorphism and the risk of Polycystic Ovary Syndrome (PCOS).

METHODS

Literature on the association of CYP17rs74357 gene polymorphism and susceptibility to PCOS was retrieved by searching databases such as PubMed, Science Direct, Google Scholar and Embase from. The association measure was analyzed using an Odds Ratio (OR) and 95% Confidence Interval (CI). All the statistical analyses were executed using CMA 3.0 Software.

RESULTS

In the present meta-analysis,24 studies including 3462 PCOS and 2898 controls were analyzed. The overall results validated that the 17 CYP17 T/C (rs74357) gene polymorphism was significantly associated with PCOS risk in 5 genetic models: recessive model (fixed and random effect), dominant model (random effect), CC vs. TT (fixed effect), CT vs. TT (fixed effect), and allele contrast (random effect). Stratified analyses by ethnicity/country also detected significant association between Asian and Caucasian under the recessive, dominant, CC vs. TT, CC vs. CT, and the allele contrast models.

CONCLUSIONS

In the present study, CYP17 T/C (rs74357) gene polymorphism increase the susceptibility of PCOS, and the recessive C allele, can be proposed as a predictive factor for the risk of PCOS or an important pathway in PCOS associated metabolic and hormonal dysregulation especially insulin resistance.However, larger sample size andmultiracial studies are needed in the future to confirm the findings.

The single-nucleotide polymorphism rs743572 of CYP17A1 shows significant association with polycystic ovary syndrome: a meta-analysis

Polycystic ovary syndrome (PCOS) is a multifactorial reproductive and endocrine disease, believed to be caused by aberrant steroid biosynthesis pathways involving cytochrome P450, 17α-hydroxylase (CYP17A1). This meta-analysis aimed to evaluate the association between CYP17A1 polymorphism rs743572 and PCOS risk. Studies on the CYP17A1 gene were retrieved by searching PubMed, Embase and Web of Science and statistical analyses were performed by STATA software. Fifteen eligible studies were included, dated from January 1994 to 19 November 2020, involving 2277 patients with PCOS and 1913 control individuals. Overall, the results showed that the rs743572 T>C mutation was most likely to be associated with PCOS risk under the recessive model, which was further confirmed by heterogeneity analysis and publication bias detection (CC versus CT + TT, odds ratio [OR] 1.24, 95% confidence interval [CI] 1.02-1.50, P = 0.028, I² = 35.9%). Moreover, subgroup analysis by ethnicity demonstrated that Caucasian but not Asian women carrying the CC genotype of rs743572 had an elevated risk of PCOS (CC versus CT + TT, OR 1.45, 95% CI 1.03-2.06, P = 0.035, I² = 15.10%, six studies). In conclusion, rs743572 is highly likely to be a risk factor for PCOS, and the mutant genotype CC may increase susceptibility to PCOS in Caucasians rather than Asians.

Menopausal Hormone Therapy and Risk of Endometrial Cancer: A Systematic Review

Background: Menopausal hormone therapy (MHT) is an appropriate treatment for women with the climacteric syndrome. The estrogen component of MHT effectively alleviates climacteric symptoms but also stimulates the endometrium and thus may increase the risk of endometrial cancer (EC). Materials and Methods: We performed a systematic literature search of the databases PubMed and Cochrane Central Register of Controlled Trials to identify controlled and uncontrolled clinical trials reporting on the prevalence and/or incidence of EC among women using MHT. Results: 31 publications reporting on 21,306 women with EC diagnosed during or after MHT were identified. A significantly reduced risk of EC among continuous-combined (cc)MHT users with synthetic progestins (SPs) was demonstrated in 10/19 studies with odds ratios (ORs)/hazard ratios (HRs) between 0.24 and 0.71. Only one study documented an increased risk of EC among long-term users (≥10 years), not confirmed in three other sub-group analyses of women with ≥6, ≥5, and >10 years of ccMHT use. A significantly increased risk of EC among users of sequential-combined (sc)MHT with SPs was demonstrated in 6/12 studies with ORs/HRs between 1.38 and 4.35. Number of days of progestin per month was a significant modulator of EC risk. A decreased risk of EC was seen in obese women. Two studies documented an increased risk of EC among users of cc/scMHT with micronized progesterone. A significantly increased risk of EC among estrogen-only MHT users was demonstrated in 9/12 studies with ORs/HRs between 1.45 and 4.46. The adverse effect of estrogen-only MHT was greatest among obese women. Conclusion: ccMHT with SPs reduces the risk of EC, whereas estrogen-only MHT increases the risk. scMHT with SPs and cc/scMHT with micronized progesterone increase the risk of EC depending on type of progestin, progestin dosage, and duration of MHT use.

A Possible Link of Genetic Variations in ER/IGF1R Pathway and Risk of Melanoma

The mechanism of gender disparity in cutaneous melanoma incidence remains unclear. Steroid hormones including estrogens have long been implicated in the course of melanoma, but the conclusion is controversial. Estrogen receptors (ERs) and insulin-like growth factor 1 receptor (IGF1R) show extensive crosstalk in cancer development, but how the ER/IGF1R network impacts melanoma is currently unclear. Here we studied the melanoma associations of selected SNPs from the ER/IGF1R network. Part of the International Genes, Environment, and Melanoma (GEM) cohort was used as a discovery set, and the Gene Environment Association Studies Initiative (GENEVA) dataset served as a validation set. Based on the associations with other malignant disease conditions, thirteen single nucleotide polymorphism (SNP) variants in ESR1, ESR2, IGF1, and IGF1R were selected for candidate gene association analyses. The rs1520220 in IGF1 and rs2229765 in IGF1R variants were significantly associated with melanoma risk in the GEM dataset after Benjamini-Hochberg multiple comparison correction, although they were not validated in the GENEVA set. The discrepancy may be caused by the multiple melanoma characteristics in the GEM patients. Further analysis of gender disparity was carried out for IGF1 and IGF1R SNPs in the GEM dataset. The GG phenotype in IGF1 rs1520220 (recessive model) presented an increased risk of melanoma (OR = 8.11, 95% CI: 2.20, 52.5, p = 0.006) in men but a significant opposite effect in women (OR = 0.15, 95% CI: 0.018, 0.86, p = 0.045). The AA genotype in IGF1R rs2229765 (recessive model) showed a significant protective effect in men (OR = 0.24, 95% CI: 0.07, 0.64, p = 0.008) and no effect in women. Results from the current study are warranted for further validation.

Body Mass Index Genetic Risk Score and Endometrial Cancer Risk

Genome-wide association studies (GWAS) have identified common variants that predispose individuals to a higher body mass index (BMI), an independent risk factor for endometrial cancer. Composite genotype risk scores (GRS) based on the joint effect of published BMI risk loci were used to explore whether endometrial cancer shares a genetic background with obesity. Genotype and risk factor data were available on 3,376 endometrial cancer case and 3,867 control participants of European ancestry from the Epidemiology of Endometrial Cancer Consortium GWAS. A BMI GRS was calculated by summing the number of BMI risk alleles at 97 independent loci. For exploratory analyses, additional GRSs were based on subsets of risk loci within putative etiologic BMI pathways. The BMI GRS was statistically significantly associated with endometrial cancer risk (P = 0.002). For every 10 BMI risk alleles a woman had a 13% increased endometrial cancer risk (95% CI: 4%, 22%). However, after adjusting for BMI, the BMI GRS was no longer associated with risk (per 10 BMI risk alleles OR = 0.99, 95% CI: 0.91, 1.07; P = 0.78). Heterogeneity by BMI did not reach statistical significance (P = 0.06), and no effect modification was noted by age, GWAS Stage, study design or between studies (P≥0.58). In exploratory analyses, the GRS defined by variants at loci containing monogenic obesity syndrome genes was associated with reduced endometrial cancer risk independent of BMI (per BMI risk allele OR = 0.92, 95% CI: 0.88, 0.96; P = 2.1 x 10⁻⁵). Possessing a large number of BMI risk alleles does not increase endometrial cancer risk above that conferred by excess body weight among women of European descent. Thus, the GRS based on all current established BMI loci does not provide added value independent of BMI. Future studies are required to validate the unexpected observed relation between monogenic obesity syndrome genetic variants and endometrial cancer risk.