Identification of a novel uterine leiomyoma GWAS locus in a Japanese population

Genetic Mechanisms Driving Uterine Leiomyoma Pathobiology, Epidemiology, and Treatment

Uterine leiomyomas (ULs) are the most common benign tumor of the uterus. They can be associated with symptoms including abnormal uterine bleeding, pelvic pain, urinary frequency, and pregnancy complications. Despite the high prevalence of UL, its underlying pathophysiology mechanisms have historically been poorly understood. Several mechanisms of pathogenesis have been suggested, implicating various genes, growth factors, cytokines, chemokines, and microRNA aberrations. The purpose of this study is to summarize the current research on the relationship of genetics with UL. Specifically, we performed a literature review of published studies to identify how genetic aberrations drive pathophysiology, epidemiology, and therapeutic approaches of UL. With regards to pathophysiology, research has identified MED12 mutations, HMGA2 overexpression, fumarate hydratase deficiency, and cytogenetic abnormalities as contributors to the development of UL. Additionally, epigenetic modifications, such as histone acetylation and DNA methylation, have been identified as contributing to UL tumorigenesis. Specifically, UL stem cells have been found to contain a unique DNA methylation pattern compared to more differentiated UL cells, suggesting that DNA methylation has a role in tumorigenesis. On a population level, genome-wide association studies (GWASs) and epidemiologic analyses have identified 23 genetic loci associated with younger age at menarche and UL growth. Additionally, various GWASs have investigated genetic loci as potential drivers of racial disparities in UL incidence. For example, decreased expression of Cytohesin 4 in African Americans has been associated with increased UL risk. Recent studies have investigated various therapeutic options, including ten-eleven translocation proteins mediating DNA methylation, adenovirus vectors for drug delivery, and "suicide gene therapy" to induce apoptosis. Overall, improved understanding of the genetic and epigenetic drivers of UL on an individual and population level can propel the discovery of novel therapeutic options.

Racial disparity in uterine leiomyoma: new insights of genetic and environmental burden in myometrial cells

Uterine leiomyoma (LM), also known as uterine fibroids, are common gynecological tumors and can reach a prevalence of 70% among women by the age of 50 years. Notably, the LM burden is much higher in Black women with earlier onset, a greater tumor number, size, and severity compared to White women. Published knowledge shows that there are genetic, environmental, and lifestyle-based risk factors associated with racial disparity for LM. Significant strides have been made on genomic, epigenomic, and transcriptomic data levels in Black and White women to elucidate the underlying pathomolecular reasons of racial disparity in LM development. However, racial disparity of LM remains a major area of concern in gynecological research. This review highlights risk factors of LM and their role in different races. Furthermore, we discuss the genetics and uterine myometrial microenvironment in LM development. Comparative findings revealed that a major racial difference in the disease is linked to myometrial oxidative burden and altered ROS pathways which is relevant to the oxidized guanine in genomic DNA and MED12 mutations that drive the LM genesis. Considering the burden and morbidity of LM, we anticipate that this review on genetic risk and myometrial microenvironment will strengthen understanding and propel the growth of research to address the racial disparity of LM burden.

A View on Uterine Leiomyoma Genesis through the Prism of Genetic, Epigenetic and Cellular Heterogeneity

Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology. In this review, we comprehensively analyse risk and protective factors for UL development, UL cellular composition, hormonal and paracrine signalling, epigenetic regulation and genetic abnormalities. We conclude the need to carefully update the concept of UL genesis in light of the current data. Staying within the framework of the existing hypotheses, we introduce a possible timeline for UL development and the associated key events—from potential prerequisites to the beginning of UL formation and the onset of driver and passenger changes.

Genome-wide causal mediation analysis identifies genetic loci associated with uterine fibroids mediated by age at menarche

STUDY QUESTION

Could the direct contribution of genetic variants to the pathophysiology of uterine fibroids and the contribution mediated by age at menarche be different?

SUMMARY ANSWER

Age at menarche plays a mediation role in the genetic influence on uterine fibroids, and four causal genetic mechanisms underlying the age at menarche-mediated effects of common genetic loci on uterine fibroid development were identified.

WHAT IS KNOWN ALREADY

Uterine fibroids are common benign tumors developing from uterine smooth muscle. Genome-wide association studies (GWASs) have identified over 30 genetic loci associated with uterine fibroids in different ethnic populations. Several genetic variations in or nearby these identified loci were also associated with early age at menarche, one of the major risk factors of uterine fibroids. Although the results of GWASs reveal how genetic variations affect uterine fibroids, the genetic mechanism of uterine fibroids mediated by age at menarche remains elusive.

STUDY DESIGN, SIZE, DURATION

In this study, we conducted a genome-wide causal mediation analysis in two cohorts covering a total of 69 552 females of Han Chinese descent from the Taiwan Biobank (TWB). TWB is an ongoing community- and hospital-based cohort aiming to enroll 200 000 individuals from the general Taiwanese population between 30 and 70 years old. It has been enrolling Taiwanese study participants since 2012 and has extensive phenotypic data collected from 148 291 individuals as of May 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We recruited individuals in two cohorts, with 13 899 females in TWB1 and 55 653 females in TWB2. The two sets of individuals are almost distinct, with only 730 individuals enrolled in both cohorts. Over 99% of the participants are Han Chinese. Approximately 21% of participants developed uterine fibroids. DNA samples from both cohorts were genotyped using two different customized chips (TWB1 and TWB2 arrays). After quality control and genotype imputation, 646 973 TWB1 single-nucleotide polymorphisms (SNPs) and 686 439 TWB2 SNPs were assessed in our analysis. There were 99 939 SNPs which overlapped between the TWB1 and TWB2 arrays, 547 034 TWB1 array-specific SNPs and 586 500 TWB2 array-specific SNPs. We performed GWASs for screening potential risk SNPs for age at menarche and for uterine fibroids. We subsequently identified causal mediation effects of risk SNPs on uterine fibroids mediated by age at menarche.

MAIN RESULTS AND THE ROLE OF CHANCE

In addition to known loci at LIN28B associated with age at menarche and loci at WNT4 associated with uterine fibroids, we identified 162 SNPs in 77 transcripts that were associated with menarche-mediated causal effects on uterine fibroids via four different causal genetic mechanisms: a both-harmful group with 52 SNPs, a both-protective group with 34 SNPs, a mediator-harmful group with 22 SNPs and a mediator-protective group with 54 SNPs. Among these SNPs, rs809302 in SLK significantly increased the risk of developing uterine fibroids by 3.92% through a mechanism other than age at menarche (P < 10-10), and rs371721345 in HLA-DOB was associated with a 2.70% decreased risk (P < 10-10) in the occurrence of uterine fibroids, mediated by age at menarche. These findings provide insights into the mechanism underlying the effect of genetic loci on uterine fibroids mediated by age at menarche.

LIMITATIONS, REASONS FOR CAUTION

A potential issue is that the present study relied upon self-reported age at menarche and uterine fibroid information. Due to the experimental design, the consistency between self-reports and medical records for uterine fibroids in Taiwan cannot be checked. Fortunately, the literature support that self-reporting even years later remains a practical means for collecting data on menarche and uterine fibroids. We found that the impact of under-reporting of uterine fibroids is less in our study. In addition, the rate of reporting a diagnosis of uterine fibroids was within the rates of medical diagnosis based on national health insurance data. Future work investigating the consistency between self-reports and medical records in Taiwan can remedy this issue.

WIDER IMPLICATIONS OF THE FINDINGS

This study is the first to investigate whether and to what extent age at menarche mediates the causal effects of genetic variants on uterine fibroids by using genome-wide causal mediation analysis. By treating age at menarche as a mediator, this report provides an insight into the genetic risk factors for developing uterine fibroids. Thus, this article represents a step forward in deciphering the role of intermediated risk factors in the genetic mechanism of disease.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the China Medical University, Taiwan (CMU110-ASIA-13 and CMU107-Z-04), the Ministry of Science and Technology, Taiwan (MOST 110-2314-B-039-058) and the International Joint Usage/Research Center, the Institute of Medical Science, the University of Tokyo, Japan (K2104). The authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Investigating the shared genetic architecture of uterine leiomyoma and breast cancer: A genome-wide cross-trait analysis

Little is known regarding the shared genetic architecture or causality underlying the phenotypic association observed for uterine leiomyoma (UL) and breast cancer (BC). Leveraging summary statistics from the hitherto largest genome-wide association study (GWAS) conducted in each trait, we investigated the genetic overlap and causal associations of UL with BC overall, as well as with its subtypes defined by the status of estrogen receptor (ER). We observed a positive genetic correlation between UL and BC overall (rg = 0.09, p = 6.00 × 10-3), which was consistent in ER+ subtype (rg = 0.06, p = 0.01) but not in ER- subtype (rg = 0.06, p = 0.08). Partitioning the whole genome into 1,703 independent regions, local genetic correlation was identified at 22q13.1 for UL with BC overall and with ER+ subtype. Significant genetic correlation was further discovered in 9 out of 14 functional categories, with the highest estimates observed in coding, H3K9ac, and repressed regions. Cross-trait meta-analysis identified 9 novel loci shared between UL and BC. Mendelian randomization demonstrated a significantly increased risk of BC overall (OR = 1.09, 95% CI = 1.01-1.18) and ER+ subtype (OR = 1.09, 95% CI = 1.01-1.17) for genetic liability to UL. No reverse causality was found. Our comprehensive genome-wide cross-trait analysis demonstrates a shared genetic basis, pleiotropic loci, as well as a putative causal relationship between UL and BC, highlighting an intrinsic link underlying these two complex female diseases.

Association between polymorphisms rs2228001 and rs2228000 in XPC and genetic susceptibility to preeclampsia: a case control study

BACKGROUND

Xeroderma pigmentosum complementation group C (XPC) is a DNA damage recognition protein that plays an important role in nucleotide excision repair and can reduce oxidative stress, which may be involved in the development of preeclampsia (PE). Therefore, the aim of this study was to explore whether XPC polymorphisms were relevant to the genetic susceptibility to PE in Chinese Han women.

METHOD

A total of 1276 healthy pregnant women were included as the control group and 958 pregnant women with PE as the case group. DNA was extracted from peripheral blood samples to perform genotyping of loci rs2228001 and rs2228000 in XPC through real-time quantitative polymerase chain reaction (PCR). The relationship between XPC and susceptibility to PE was evaluated by comparing the genotypic and allelic frequencies between the two groups of pregnant women.

RESULTS

Polymorphism of rs2228000 may be associated with PE risk and allele T may play a protective role (genotype, χ2 = 38.961, P < 0.001 and allele χ2 = 21.746 P < 0.001, odds ratio (OR) = 0.885, 95% confidence interval (CI) = 0.840-0.932). No significant difference was found between the two groups in rs2228001,(genotype χ2 = 3.148, P = 0.207 and allele χ2 = 0.59, P = 0.442, OR = 1.017, 95% CI = 0.974-1.062). When the frequencies of genotypes and alleles for early- and late-onset PE, mild PE and severe PE were compared with those of controls, the results were consistent with the large clinical sample.

CONCLUSION

Our data suggest that the genetic variant rs2228000 in XPC may be associated with PE risk in Chinese Han women, and that pregnant women with the TT genotype have a reduced risk of PE. Further investigations are needed to confirm these findings in other regions or larger prospective populations.

Long intergenic non-coding RNA LINC00485 exerts tumor-suppressive activity by regulating miR-581/EDEM1 axis in colorectal cancer

Long non-coding RNAs (lncRNA) play a vital role in colorectal cancer (CRC) progression. To investigate the role of long intergenic non-coding RNA LINC00485 in CRC, we performed in vitro functional experiments. LoVo tumor-bearing and liver metastasis mice were used as in vivo models. We found that LINC00485 expression was significantly lower in CRC tissues and cancer cells than in paired normal samples and human normal colonic epithelial cells. Lower expression of LINC00485 predicted poor prognosis in CRC patients. LINC00485 knockdown promoted the proliferation, migration, and invasion of FHC cells, while LINC00485 overexpression weakened these abilities of LoVo cells. MicroRNA miR-581 was the downstream target of LINC00485, which was downregulated in CRC samples and cancer cells compared to normal tissues and normal colonic epithelial cells. MiR-581 overexpression induced proliferation, migration, and invasion of FHC cells, while miR-581 antagomir treatment produced opposite results. MiR-581 directly targeted the 3'UTR of EDEM1 and inhibited its expression and induction of epithelial-mesenchymal transition of CRC. In mouse models, LINC00485 knockdown or down-regulation of miR-581 significantly repressed CRC cell growth and prevented CRC liver metastasis. Overall, LINC00485 suppressed CRC tumorigenesis and progression by targeting the miR-581/EDEM1 axis. LINC00485 may be a potential therapeutic target for CRC.

Long intergenic non-coding RNA Linc00485 promotes lung cancer progression by modulating miR-298/c-Myc axis

Long non‐coding RNAs (lncRNAs), which are non‐protein‐coding transcripts, are emerging as novel biomarkers for cancer diagnosis. Their dysregulation is increasingly recognized to contribute to the development and progression of human cancers, including lung cancer. Linc00485 is a newly discovered cancer‐related lncRNA; however, little is known about its role in lung cancer progression. In this study, we found that the expression of Linc00485 was significantly increased in human lung cancer tissue and associated with malignant phenotypes, including tumour‐node‐metastasis (TNM) stage, metastasis and relapse. Furthermore, the proliferative, migratory and invasive abilities of lung cancer cells in vitro were significantly enhanced by overexpression of Linc00485 but inhibited by its silencing. Mechanistically, Linc00485 regulated the expression of c‐Myc by directly binding to miR‐298; the effects of Linc00485 overexpression could be significantly reversed by a c‐Myc inhibitor or small interfering RNA. Xenotransplantation experiments showed that Linc00485 silencing significantly weakened the proliferation potential of A549 cells in vivo. Overall, these findings indicate that Linc00485 overexpression down‐regulates miR‐298, resulting in the up‐regulation of c‐Myc and thereby promoting the development of lung cancer.

Hereditary risk factors for uterine leiomyoma: a search for marker SNPs

Uterine leiomyomas are a worrying reproductive health issue that has serious social implications. The aim of this study was to conduct a search for marker single nucleotide polymorphisms (SNPs) associated with uterine leiomyoma. To test the hypothesis about the contribution of genetic predisposition to the pathogenesis of myomas, the initial group of 100 patients with a verified diagnosis of uterine leiomyoma was divided into 2 subgroups: subgroup Ia (women with a family history of the disease) and subgroup 1b (women with no family history of the disease). The control group consisted of 30 postmenopausal patients who did not have a medical history of uterine fibroids and denied uterine fibroids in their close female relatives. DNA sequences were read using Sanger sequencing. Statistically significant differences (p < 0.05) were discovered between the analyzed groups in terms of genotype frequencies for rs12637801 and rs12457644. Also, previously unknown protective SNPs were identified whose rare alleles could predict the reduced risk of uterine leiomyomas.