Involvement of fumarate hydratase in nonsyndromic uterine leiomyomas: genetic linkage analysis and FISH studies

Pathogenesis of uterine fibroids: current understanding and future directions

Fibroids are benign uterine tumors characterized by the proliferation of uterine smooth muscle cells, embedded in an abundant extracellular matrix. Their prevalence is estimated to be >50% in women aged >45 years. Fibroids represent a considerable health burden. It is time to acquire a deeper mechanistic understanding of uterine fibroid-related etiology and pathogenesis, which may help pinpoint new strategies and an individualized approach. There is a need to gather prospective data and conduct studies to compare alternative approaches and assess long-term outcomes with respect to quality of life, recurrence of symptoms (bleeding and bulk symptoms), fertility, and even complications The goal of this review was to evaluate the widely accepted pathogenesis and identify risks factors and future directions for clinical and basic research into fibroids.

Integrated histologic and molecular analysis of uterine leiomyosarcoma and 2 benign variants with nuclear atypia

Uterine leiomyosarcoma (LMS) is a rare but deadly disease. Due to poor understanding of the molecular and genetic causes of the disease, the diagnosis of LMS has been based primarily on histology. Nuclear atypia is one of hallmarks in LMS, however, it also occurs in 2 clinically benign variants, including smooth muscle tumors with fumarate hydratase alteration (SMT‐FH) and leiomyoma with bizarre nuclei (LM‐BN). In addition to nuclear atypia, many well recognized biomarkers used for LMS are also frequently overexpressed in LM‐BN, and the histogenesis and molecular natures for LM‐BN and LMS remain largely unknown. To characterize the molecular profiling of LMS, SMT‐FH, and LM‐BN, we performed integrated comprehensive genomic profiling including whole‐genome sequencing (WGS) and RNA sequencing and genomic microarray analyses to assess genome‐wide copy number alterations (CNAs) and immunohistochemistry (IHC) in all 3 tumor types. We found that both LM‐BN and LMS showed genomic instability and harbored extensive CNAs throughout the whole genome. By contrast, the SMT‐FH presented its characteristic 1q43‐44 deletions in all cases tested, with minimal CNAs in the rest of genomic regions. Further analyses revealed that LMS and LM‐BN groups showed similar patterns of CNAs that are tended to cluster together and separated from the SMT‐FH group. The integrated molecular profiling enabled the detection of novel and traditional biomarkers and showed excellent discrimination between LM‐BN and LMS. Our study suggests that LM‐BN, despite having similar nuclear atypia to SMT‐FH, showed similar genomic instability but distinct genomic alterations with its malignant counterpart of LMS. The integrated molecular profiling is of clinical importance in characterizing these rare uterine smooth muscle tumors.

The role of apoptosis in the complex pathogenesis of the most common obstetrics and gynaecology diseases

Purpose

We aimed to assess the etiological role of apoptotic genes Bcl-2 and Bax in the background of major obstetric and gynaecological diseases.

Methods

Placental tissue samples were collected from 101 pregnancies with intrauterine growth restriction and 104 pregnancies with premature birth with 140 controll samples from term, eutrophic newborns. In addition, gene expression assessment of the genes Bax and Bcl-2 was performed in 101 uterine leiomyoma tissue samples at our disposal with 110 control cases. Gene expression levels were assessed by PCR method.

Results

The expression of the Bcl-2 gene was decreased in placental samples with intrauterine growth restriction. Significant overexpression of the proapoptotic Bax gene was detected in samples from premature infants. Antiapoptotic Bcl-2 gene expression was found to be significantly increased in fibroid tissues.

Conclusion

Apoptosis plays a crucial role in the development of the most common OB/GYN conditions. Decrease in the placental expression of the antiapoptotic gene Bcl-2 may upset the balance of programmed cell death.

Molecular and clinicopathologic characterization of intravenous leiomyomatosis

Intravenous leiomyomatosis (IVL) is an unusual uterine smooth muscle proliferation that can be associated with aggressive clinical behavior despite a histologically benign appearance. It has some overlapping molecular characteristics with both uterine leiomyoma and leiomyosarcoma based on limited genetic data. In this study, we assessed the clinical and morphological characteristics of 28 IVL and their correlation with molecular features and protein expression, using array comparative genomic hybridization (aCGH) and Cyclin D1, p16, phosphorylated-Rb, SMARCB1, SOX10, CAIX, SDHB and FH immunohistochemistry. The most common morphologies were cellular (n = 15), usual (n = 11), and vascular (n = 5; including 3 cellular IVL showing both vascular and cellular features). Among the immunohistochemical findings, the most striking was that all IVL showed differential expression of either p16 or Cyclin D1 in comparison to surrounding nonneoplastic tissue. Cytoplasmic phosphorylated-Rb was present in all but one IVL with hyalinization. SMARCB1, FH, and SDHB were retained; S0X10 and CAIX were not expressed. The most common genetic alterations involved 1p (39%), 22q (36%), 2q (29%), 1q (25%), 13q (21%), and 14q (21%). Hierarchical clustering analysis of recurrent aberrations revealed three molecular groups: Groups 1 (29%) and 2 (18%) with associated del(22q), and Group 3 (18%) with del(10q). The remaining IVL had nonspecific or no alterations by aCGH. Genomic index scores were calculated for all cases and showed no significant difference between the 14 IVL associated with aggressive clinical behavior (extrauterine extension or recurrence) and those without (median scores 5.15 vs 3.5). Among the 5 IVL associated with recurrence, 4 had a vascular morphology and 3 had alterations of 8q. Recurrent chromosome alterations detected herein overlap with those observed in the spectrum of uterine smooth muscle tumors and involve genes implicated in mesenchymal tumors at different sites with distinct morphological features.

Role of Apoptosis in the Development of Uterine Leiomyoma: Analysis of Expression Patterns of Bcl-2 and Bax in Human Leiomyoma Tissue With Clinical Correlations

To describe gene expression patterns of the apoptotic regulatory genes Bcl and Bax in human uterine leiomyoma tissue. To investigate the relationship between alterations of gene expression patterns and several relevant clinical parameters. We obtained samples from 101 cases undergoing surgery for uterine leiomyoma for gene expression analysis of the Bcl-2 and Bax genes. Gene expression was quantified using RT-PCR technique. In the leiomyoma group, the Bcl-2 gene was significantly overexpressed compared with the control group although there was no such difference in the gene expression of Bax. Gene activity of Bcl-2 positively correlated with the tumor number in individual uterine leiomyoma cases. Although there was no significant correlation between the length of the cumulative lactation period before the development of uterine leiomyoma and Bcl-2 gene expression in the leiomyoma tissue, we observed a trend for a shorter cumulative lactation period to be associated with overexpression of the Bcl-2 gene. Overexpression of the antiapoptotic Bcl-2 gene appeared to be a factor in the development of uterine leiomyoma, whereas gene activity of the proapoptotic Bax gene did not seem to play a role in the process.

Epidemiology of Uterine Fibroids: From Menarche to Menopause

Uterine leiomyomata (UL) have a substantial impact on women's health, but relatively few studies have identified opportunities for primary prevention of these neoplasms. Most established risk factors are not modifiable, including premenopausal age, African ancestry, age at menarche, and childbearing history. The main challenge in studying UL is that a large proportion of tumors are asymptomatic. Herein, we review the epidemiology of UL from published studies to date. We highlight the advantages of ultrasound screening studies and the ways in which their innovative methods have helped clarify the etiology of disease. We conclude with a discussion of promising new hypotheses.

Fine Mapping of the Body Fat QTL on Human Chromosome 1q43

Introduction

Evidence for linkage and association of obesity-related quantitative traits to chromosome 1q43 has been reported in the Quebec Family Study (QFS) and in populations of Caribbean Hispanic ancestries yet no specific candidate locus has been replicated to date.

Methods

Using a set of 1,902 single nucleotide polymorphisms (SNPs) genotyped in 525 African American (AA) and 391 European American (EA) women enrolled in the NIEHS uterine fibroid study (NIEHS-UFS), we generated a fine association map for the body mass index (BMI) across a 2.3 megabase-long interval delimited by RGS7 (regulator of G-protein signaling 7) and PLD5 (Phospholipase D, member 5). Multivariable-adjusted linear regression models were fitted to the data to evaluate the association in race-stratified analyses and meta-analysis.

Results

The strongest associations were observed in a recessive genetic model and peaked in the 3’ end of RGS7 at intronic rs261802 variant in the AA group (p = 1.0 x 10⁻⁴) and in meta-analysis of AA and EA samples (p = 9.0 x 10⁻⁵). In the EA group, moderate associations peaked at rs6429264 (p = 2.0 x 10⁻³) in the 2 Kb upstream sequence of RGS7. In the reference populations for the European ancestry in the 1,000 genomes project, rs6429264 occurs in strong linkage disequilibrium (D’ = 0.94) with rs1341467, the strongest candidate SNP for total body fat in QFS that failed genotyping in the present study. Additionally we report moderate associations at the 3’ end of PLD5 in meta-analysis (3.2 x 10⁻⁴ ≤ p ≤ 5.8 x 10⁻⁴).

Conclusion

We report replication data suggesting that RGS7, a gene abundantly expressed in the brain, might be a putative body fat QTL on human chromosome 1q43. Future genetic and functional studies are required to substantiate our observations and to potentially link them to the neurobehavioral phenotypes associated with the RGS7 region.

Fine mapping of the uterine leiomyoma locus on 1q43 close to a lncRNA in the RGS7-FH interval

Mutations in fumarate hydratase (FH) on chromosome 1q43 cause a rare cancer syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC), but are rare in nonsyndromic and common uterine leiomyoma (UL) or fibroids. Studies suggested that variants in FH or in a linked gene may also predispose to UL. We re-sequenced 2.3 Mb of DNA spanning FH in 96 UL cases and controls from the multiethnic NIEHS-uterine fibroid study, and in 18 HLRCC-associated UL probands from European families then selected 221 informative SNPs for follow-up genotyping. We report promising susceptibility associations with UL peaking at rs78220092 (P=7.0×10(-5)) in the RGS7-FH interval in African Americans. In race-combined analyses and in meta-analyses (n=916), we identified promising associations with risk peaking upstream of a non-protein coding RNA (lncRNA) locus located in the RGS7-FH interval closer to RGS7, and associations with tumor size peaking in the distal phospholipase D family, member 5 (PLD5) gene at rs2654879 (P=1.7×10(-4)). We corroborated previously reported FH mutations in nine out of the 18 HLRCC-associated UL cases and identified two missense mutations in FH in only two nonsyndromic UL cases and one control. Our fine association mapping and integration of existing gene profiling data showing upregulated expression of the lncRNA and downregulation of PLD5 in fibroids, as compared to matched myometrium, suggest a potential role of this genomic region in UL pathogenesis. While the identified variations at 1q43 represent a potential risk locus for UL, future replication analyses are required to substantiate our observation.

Evaluation of GWAS candidate susceptibility loci for uterine leiomyoma in the multi-ethnic NIEHS uterine fibroid study

We evaluated the association of 56 candidate SNPs identified in two published genome-wide association studies (GWAS) of uterine leiomyoma (UL), or fibroids, with the risk and tumor size in the multi-ethnic uterine fibroid study (NIEHS-UFS). The selected SNPs were genotyped in 916 premenopausal women of African American (AA) and European American (EA) descents and their association with the outcomes was evaluated in race-stratified models and in meta-analysis of risk in NIEHS-UFS and discovery and replication GWAS in the Japanese population. We report moderate associations of variant rs4954368 in THSD7B (thrombospondin, type I, domain containing 7B) with tumor size in pooled analysis of AA and EA samples (P = 0.004), and at TNRC6B (trinucleotide repeat containing 6B) variants rs138039 and rs139909 in EA (P = 0.001 and 0.008, respectively). The most significant associations with risk in meta-analysis were observed at TNRC6B variants rs739182 (P = 3.7 × 10(-10)) and rs2072858 (P = 1.1 × 10(-9)) and were stronger than those reported in the discovery GWAS (P = 2.01 × 10(-8) and 2.58 × 10(-8), respectively). The present study failed to replicate the associations reported for CCDC57 and FASN in a discovery GWAS in populations of European descent. Consistent with previous replication studies in the Right From the Start Study (RFTS) and the BioVU DNA repository, we provide independent evidence for association of TNRC6B with both risk and size of UL. The present study is the first to report a replicated association of THSD7B with UL, albeit with tumor size and not with risk.

Admixture mapping of genetic variants for uterine fibroids

Uterine leiomyoma (UL) are benign neoplasms arising from the smooth muscle cells of the uterus. One of the established risk factors for UL is African American ethnicity. Studies have consistently shown that African Americans have 2-3 times higher risk compared with that of non-Hispanic Whites. However, there is still no adequate explanation for the higher risk among African Americans. To investigate the genetic contribution to the observed difference between the African American and European American populations, we conducted an admixture scan in 525 eligible African American women participants to the NIEHS uterine fibroid study (NIEHS-UFS). In models with no stratification, we found multiple genomic regions showing significant and suggestive evidence of association, with chromosomal band 2q32.2 at rs256552 showing the highest score (Z-score = 7.86, Bonferroni adjusted p-value = 5.5×10^-12) consistent with the suggestive evidence reported for this genomic region in the Black Women's Health Study. However, in models stratified by the body mass index (BMI) covariate, chromosomal 1q42.2 was the sole genomic region that consistently showed suggestive associations across the BMI categories tested (Z-scores ≤ -3.96, Bonferroni adjusted p-values ≤ 0.107). In age-stratified models, a significant association was observed in the older category (age > 40) reaching a Z-score of 6.44 (Bonferroni-adjusted p-value = 1.64 × 10^-7) at rs256552. The mean percentage of European ancestry among cases was lower than that among controls in the NIEHS-UFS study. However, our study did not show a significant association between mean percentage of European ancestry and UL.

Follow-up to genome-wide linkage and admixture mapping studies implicates components of the extracellular matrix in susceptibility to and size of uterine fibroids

OBJECTIVE

To conduct a follow-up association mapping to independent genome-wide linkage and admixture mapping studies of uterine leiomyoma.

DESIGN

Case-control, cross-sectional study.

SETTING

Not applicable.

PATIENT(S)

A total of 1,045 premenopausal North American participants in the National Institute of Environmental Health Sciences Uterine Fibroid Study.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

We genotyped 2,772 single-nucleotide polymorphisms from candidate genes located in peaks of linkage (2q37, 3p21, 5p13, 10p11, 11p15, 12q14, and 17q25) or admixture linkage disequilibrium (2q37, 4p16.1, and 10q26) mapping and reported to have regulated expression in uterine fibroids.

RESULT(S)

We report significant associations of variant members of the collagen gene family with risk and tumor size, including missense variants in COL6A3 and COL13A, with replications in African American and European American study groups. Furthermore, the cell-matrix Rho GTPase-encoding ARHGAP26 gene, and MAN1C1, a gene encoding a Golgi mannosidase involved in the maturation of procollagens, emerged as new candidate uterine leiomyoma genes affecting both risk and tumor size.

CONCLUSION(S)

Our data converge onto a possible model of uterine leiomyoma pathogenesis resulting from altered regulation, maintenance, and/or renewal of the extracellular matrix.

5-Hydroxymethylcytosine promotes proliferation of human uterine leiomyoma: a biological link to a new epigenetic modification in benign tumors

CONTEXT

Uterine leiomyoma, or fibroids, represent the most common benign tumors of the female reproductive tract. A newly discovered epigenetic modification, 5-hydroxymethylation (5-hmC), and its regulators, the TET (Ten Eleven Translocation) enzymes, were implicated in the pathology of malignant tumors; however, their roles in benign tumors, including uterine fibroids, remain unknown.

OBJECTIVE

To determine the role of 5-hmC and TET proteins in the pathogenesis of leiomyoma using human uterine leiomyoma and normal matched myometrial tissues and primary cells.

DESIGN

5-hmC levels were determined by ELISA and immunofluorescent staining in matched myometrial and leiomyoma tissues. TET expression was analyzed by quantitative RT-PCR and immunoblotting. TET1 or TET3 were silenced or inhibited by small interfering RNA or 2-hydroxyglutarate to study their effects on 5-hmC content and cell proliferation.

RESULTS

We demonstrated significantly higher 5-hmC levels in the genomic DNA of leiomyoma tissue compared to normal myometrial tissue. The increase in 5-hmC levels was associated with the up-regulation of TET1 or TET3 mRNA and protein expression in leiomyoma tissue. TET1 or TET3 knockdown significantly reduced 5-hmC levels in leiomyoma cells and decreased cell proliferation. Treatment with 2-hydroxyglutarate, a competitive TET enzyme inhibitor, significantly decreased both 5-hmC content and cell proliferation of leiomyoma cells.

CONCLUSION

An epigenetic imbalance in the 5-hmC content of leiomyoma tissue, caused by up-regulation of the TET1 and TET3 enzymes, might lead to discovery of new therapeutic targets in leiomyoma.

Uterine smooth muscle tumors with features suggesting fumarate hydratase aberration: detailed morphologic analysis and correlation with S-(2-succino)-cysteine immunohistochemistry

Rare, sporadic uterine leiomyomas arise in the setting of severe metabolic aberration due to a somatic fumarate hydratase mutation. Germline mutations account for the hereditary leiomyomatosis and renal cell carcinoma syndrome, which predisposes for cutaneous and uterine leiomyomas and aggressive renal cell carcinomas. Altered fumarate hydratase leads to fumarate accumulation in affected cells with formation of S-(2-succino)-cysteine, which can be detected with the polyclonal antibody. High levels of these modified cysteine residues are found characteristically in fumarate hydratase-deficient cells but not in normal tissues or tumors unassociated with hereditary leiomyomatosis and renal cell carcinoma syndrome. We hypothesized that S-(2-succino)-cysteine-positive leiomyomas, indicating fumarate hydratase aberration, have morphologic features that differ from those without S-(2-succino)-cysteine positivity. Hematoxylin and eosin-stained slides of uterine smooth-muscle tumors were prospectively analyzed for features suggesting hereditary leiomyomatosis and renal cell carcinoma syndrome, such as prominent eosinophilic macronucleoli with perinucleolar halos, yielding nine cases. Germline genetic testing for fumarate hydratase mutations was performed in three cases. A detailed morphological analysis was undertaken, and S-(2-succino)-cysteine immunohistochemical analysis was performed with controls from a tissue microarray (leiomyomas (19), leiomyosarcomas (29), and endometrial stromal tumors (15)). Of the nine study cases, four had multiple uterine smooth muscle tumors. All cases had increased cellularity, staghorn vasculature, and fibrillary cytoplasm with pink globules. All cases had inclusion-like nucleoli with perinuclear halos (7 diffuse, 1 focal). All showed diffuse granular cytoplasmic labeling with the S-(2-succino)-cysteine antibody. Two of three tested patients had germline fumarate hydratase mutations. Only one leiomyoma from the tissue microarray controls was immunohistochemically positive, and it showed features similar to other immunohistochemically positive cases. Smooth-muscle tumors with fumarate hydratase aberration demonstrate morphological reproducibility across cases and S-(2-succino)-cysteine immuno-positivity. Although the features described are not specific for the germline fumarate hydratase mutation or the hereditary leiomyomatosis and renal cell carcinoma syndrome, their presence should suggest fumarate hydratase aberration. Identifying these cases is an important step in the diagnostic workup of patients with possible hereditary leiomyomatosis and renal cell carcinoma.

[Epigenetic background of the most common non-oncologic gynecological diseases]

Epigenetic effects influence the function of genes regulating the main physiological mechanisms. Some of these environmental factors may reduce or inhibit the function of these genes. The environmental effects on gene function may result in a change of the DNA structure leading to non-heritable phenotype changes. Epigenetic factors play an important etiological role in the development of numerous diseases in obstetrics and gynecology. Uterine fibroids probably have a complex etiological background including epigenetic mechanisms. The multifactorial aetiology of endometriosis suggests key roles for immunological and hormonal factors in the development of the diseases. These mechanisms are influenced by epigenetic factors, which may serve as therapeutic targets in the future. The possible in utero origin of polycystic ovary syndrome determines the main directions of research concerning epigenetic factors in the etiological background, with the hope of eventual prevention and/or treatment in the preconceptional period as well as during pregnancy care.

The burden of uterine fibroids for African-American women: results of a national survey

BACKGROUND

Uterine fibroids have a disproportionate impact on African-American women. There are, however, no data to compare racial differences in symptoms, quality of life, effect on employment, and information-seeking behavior for this disease.

METHODS

An online survey was conducted by Harris Interactive between December 1, 2011 and January 16, 2012. Participants were U.S. women aged 29-59 with symptomatic uterine fibroids. African-American women were oversampled to allow statistical comparison of this high-risk group. Bivariate comparison of continuous and categorical measures was based on the t-test and the Chi-squared test, respectively. Multivariable adjustment of risk ratios was based on log binomial regression.

RESULTS

The survey was completed by 268 African-American and 573 white women. There were no differences between groups in education, employment status, or overall health status. African-American women were significantly more likely to have severe or very severe symptoms, including heavy or prolonged menses (RR=1.51, 95% CI 1.05-2.18) and anemia (RR=2.73, 95% CI 1.47-5.09). They also more often reported that fibroids interfered with physical activities (RR=1.67, 95% CI 1.20-2.32) and relationships (RR=2.27, 95% CI 1.23-4.22) and were more likely to miss days from work (RR=1.77, 95% CI 1.20-2.61). African-American women were more likely to consult friends and family (36 vs. 22%, P=0.004) and health brochures (32 vs. 18%, P<0.001) for health information. Concerns for future fertility (RR=2.65, 95% CI 1.93-3.63) and pregnancy (RR=2.89, 95% CI 2.11-3.97) following fibroid treatments were key concerns for black women.

CONCLUSIONS

African-American women have more severe symptoms, unique concerns, and different information-seeking behavior for fibroids.

Multiple hits for the association of uterine fibroids on human chromosome 1q43

Uterine leiomyomas (or fibroids) are the most common tumors in women of reproductive age. Early studies of two familial cancer syndromes, the multiple cutaneous and uterine leiomyomatosis (MCUL1), and the hereditary leiomyomatosis and renal cell cancer (HLRCC), implicated FH, a gene on chromosome 1q43 encoding the tricarboxylic acid cycle fumarate hydratase enzyme. The role of this metabolic housekeeping gene in tumorigenesis is still a matter of debate and pseudo-hypoxia has been suggested as a pathological mechanism. Inactivating FH mutations have rarely been observed in the nonsyndromic and common form of fibroids; however, loss of heterozygosity across FH appeared as a significant event in the pathogenesis of a subset of these tumors. To assess the role of FH and the linked genes in nonsyndromic uterine fibroids, we explored a two-megabase interval spanning FH in the NIEHS Uterine fibroid study, a cross-sectional study of fibroids in 1152 premenopausal women. Association mapping with a dense set of single nucleotide polymorphisms revealed several peaks of association (p = 10(-2)-8.10(-5)) with the risk and/or growth of fibroids. In particular, genes encoding factors suspected (cytosolic FH) or known (EXO1 - exonuclease 1) to be involved in DNA mismatch repair emerged as candidate susceptibility genes whereas those acting in the autophagy/apoptosis (MAP1LC3C - microtubule-associated protein) or signal transduction (RGS7 - Regulator of G-protein and PLD5- Phospoholipase D) appeared to affect tumor growth. Furthermore, body mass index, a suspected confounder altered significantly but unpredictably the association with the candidate genes in the African and European American populations, suggesting the presence of a major obesity gene in the studied region. With the high potential for occult tumors in common conditions such as fibroids, validation of our data in family-based studies is needed.

Gene expression patterns of insulin-like growth factor 2 in human uterine fibroid tissues: a genetic study with clinical correlations

BACKGROUND/AIMS

We investigated insulin-like growth factor 2 (IGF-2) gene activity in human uterine fibroid tissue. Results of the genetic testing were correlated with clinical data.

METHODS

We obtained samples from patients treated for uterine fibroid and from patients undergoing hysterectomy due to other indications (control group). The examined group (with fibroid) contained 101 cases, while the control group was similar with 110 patients. Gene expression values were determined using the standard PCR technique. Clinical data were available from the computer database of the department.

RESULTS

IGF-2 gene expression was significantly higher in the fibroid group. There was no correlation between increase in gene activity and the number of tumors. History of previous uterine fibroid did not seem to predict IGF-2 gene activity in the current fibroid tumor tissue. IGF-2 gene expression did not correlate with cumulative duration of lactation following prior pregnancies.

CONCLUSION

IGF-2 gene activity is significantly increased in leiomyoma tissue compared to normal myometrium. Familial aggregation of uterine fibroids is not significantly associated with increased IGF-2 gene activity; other genes may have a stronger etiological role. It appears that the genetic factors potentially important in the development of familiar uterine leiomyoma are not related to the IGF-2 gene.

Morphologic and molecular characteristics of uterine leiomyomas in hereditary leiomyomatosis and renal cancer (HLRCC) syndrome

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a hereditary cancer syndrome in which affected individuals are predisposed to the development of multiple leiomyomas of the skin and uterus and aggressive forms of kidney cancer. Affected individuals harbor a germline heterozygous loss-of-function mutation of the fumarate hydratase (FH) gene. Uterine leiomyomas are present in up to 77% of women with this syndrome. Previous studies have shown that inactivation of the FH gene is unusual for nonsyndromic leiomyomas. Therefore, it might be possible to distinguish 2 genetic groups of smooth muscle tumors: the most common group of sporadic uterine leiomyomas without FH gene inactivation and the more unusual group of HLRCC leiomyomas in patients who harbor a germline mutation of FH, although the exact prevalence of hereditary HLRCC is unknown. We reviewed the clinical, morphologic, and genotypic features of uterine leiomyomas in 19 HLRCC patients with FH germline mutations. Patients with HLRCC syndrome were younger in age compared with those with regular leiomyomata. DNA was extracted by microdissection, and analysis of loss of heterozygosity (LOH) at 1q43 was performed. Uterine leiomyomas in HLRCC have young age of onset and are multiple, with size ranging from 1 to 8 cm. Histopathologically, HLRCC leiomyomas frequently had increased cellularity, multinucleated cells, and atypia. All cases showed tumor nuclei with large orangeophilic nucleoli surrounded by a perinucleolar halo similar to the changes found in HLRCC. Occasional mitoses were found in 3 cases; however, the tumors did not fulfill the criteria for malignancy. Our study also showed that LOH at 1q43 was frequent in HLRCC leiomyomas (8/10 cases), similarly to what has been previously found in renal cell carcinomas from HLRCC patients. LOH is considered to be the second hit that inactivates the FH gene. We conclude that uterine leiomyomas associated with HLRCC syndrome have characteristic morphologic features. Both, uterine leiomyomas and renal cell carcinoma share some morphologic nuclear changes and genotypic features in HLRCC patients. The specific morphologic features of the uterine leiomyomas that we describe may help in the identification of patients who may be part of the hereditary syndrome.

Loss of the repressor REST in uterine fibroids promotes aberrant G protein-coupled receptor 10 expression and activates mammalian target of rapamycin pathway

Uterine fibroids (leiomyomas) are the most common tumors of the female reproductive tract, occurring in up to 77% of reproductive-aged women, yet molecular pathogenesis remains poorly understood. A role for atypically activated mammalian target of rapamycin (mTOR) pathway in the pathogenesis of uterine fibroids has been suggested in several studies. We identified that G protein-coupled receptor 10 [GPR10, a putative signaling protein upstream of the phosphoinositide 3-kinase-protein kinase B/AKT-mammalian target of rapamycin (PI3K/AKT-mTOR) pathway] is aberrantly expressed in uterine fibroids. The activation of GPR10 by its cognate ligand, prolactin releasing peptide, promotes PI3K-AKT-mTOR pathways and cell proliferation specifically in cultured primary leiomyoma cells. Additionally, we report that RE1 suppressing transcription factor/neuron-restrictive silencing factor (REST/NRSF), a known tumor suppressor, transcriptionally represses GPR10 in the normal myometrium, and that the loss of REST in fibroids permits GPR10 expression. Importantly, mice overexpressing human GPR10 in the myometrium develop myometrial hyperplasia with excessive extracellular matrix deposition, a hallmark of uterine fibroids. We demonstrate previously unrecognized roles for GPR10 and its upstream regulator REST in the pathogenesis of uterine fibroids. Importantly, we report a unique genetically modified mouse model for a gene that is misexpressed in uterine fibroids.

Comparing focused ultrasound and uterine artery embolization for uterine fibroids-rationale and design of the Fibroid Interventions: reducing symptoms today and tomorrow (FIRSTT) trial

OBJECTIVE

To present the rationale, design, and methodology of the Fibroid Interventions: Reducing Symptoms Today and Tomorrow (FIRSTT) study.

DESIGN

Randomized clinical trial.

SETTING

Two academic medical centers.

PATIENT(S)

Premenopausal women with symptomatic uterine fibroids.

INTERVENTION(S)

Participants are randomized to two U.S. Food and Drug Administration-approved minimally invasive treatments for uterine leiomyomas: uterine artery embolization and magnetic resonance-guided focused ultrasound.

MAIN OUTCOME MEASURE(S)

The primary endpoint is defined as the need for an additional intervention for fibroid symptoms following treatment. Secondary outcomes consist of group differences in symptom alleviation, recovery trajectory, health-related quality of life, impairment of ovarian reserve, treatment complications, and the economic impact of these issues.

RESULT(S)

The trial is currently in the phase of active recruitment.

CONCLUSION(S)

This randomized clinical trial will provide important evidence-based information for patients and health care providers regarding optimal minimally invasive treatment approach for women with symptomatic uterine leiomyomas.

CLINICAL TRIAL REGISTRATION

NCT00995878.

Disseminated peritoneal leiomyomatosis after laparoscopic supracervical hysterectomy with characteristic molecular cytogenetic findings of uterine leiomyoma

Disseminated peritoneal leiomyomatosis (DPL) is a rare condition characterized by scattered smooth muscle nodules over the peritoneal surfaces. The pathogenesis of DPL remains unclear. Herein, we report a case of DPL occurring 7 years after laparoscopic supracervical hysterectomy with morcellation for uterine leiomyomata (UL). We analyzed both the original UL and the subsequent DPL by molecular cytogenetics to assess the role of chromosomal abnormalities in DPL pathobiology. Interestingly, all of the chromosomal aberrations detected in this case of DPL, including r(1)(p34.3q41), del(3)(q23q26.33), and t(12;14)(q14.3;q24.1), are characteristic chromosomal abnormalities detected in UL. Fluorescence in situ hybridization analysis of the initial UL confirmed an interstitial deletion spanning at least 3q24 and 3q25.1, suggesting that functional alteration of a potential gene in this chromosomal region may play a role in DPL development from UL. With the increasing rate of hysterectomy through laparoscopic approach to UL, the unique complications of laparoscopy with morcellation, especially seeding and proliferation of tumor cells over abdominal organs and peritoneum, are becoming more significant and may necessitate review of current surgical protocols to prevent future seeding of the pelvic region with tumor particles.

[Uterine leiomyoma]

Uterine fibroids, benign tumors of the human uterus, are the most common indication for hysterectomy. They are clinically apparent in 20-25% of women and cause significant complaints, like prolonged and heavy menstruation, pelvic pressure or pain, sometimes reproductive dysfunction. Though surgery has been the mainstay of fibroid treatment, various minimally invasive procedures have been developed in addition to hysterectomy and abdominal myomectomy. Formation of new leiomyomas after these conservative therapies remains a substantial problem. Also drug-therapy methods are available, but the possible side-effects limit their long-term use. Authors attempt to give an overview of this common gynecological disease, yielding a new insight into the basic biology and genetics of fibroids, with the hope of new and effective methods of therapy in the future.

Racial diversity in uterine leiomyoma clinical studies

OBJECTIVE

To examine racial diversity in clinical studies on uterine leiomyomas included in a review of evidence-based practice because of the disproportionate burden of fibroids in Black women.

DESIGN

Review of 106 studies cited in the Agency for Healthcare Research and Quality (AHRQ) report on uterine leiomyomas.

SETTING

Academic medical centers.

PATIENT(S)

None.

INTERVENTION(S)

Estimation of the racial diversity of enrollment in studies on leiomyomas that did not report racial composition by two hypothetical models.

MAIN OUTCOME MEASURE(S)

Representation of Black women in studies from the AHRQ report.

RESULT(S)

Of the 106 analyzed studies, 81 studies did not report patients' race or ethnicity. Twenty-two of the 25 studies with reported race or ethnicity included Black participants. Analysis of studies reporting race and ethnicity, including studies specifically of African-American women, suggests that Black women comprise approximately half of all study participants. However, when estimating the proportion of Black women based on population demographics in each country, the representation of Black women in clinical leiomyoma studies appears to be closer to 15%.

CONCLUSION(S)

Most studies on uterine leiomyomas cited in the AHRQ evidence-based report did not report participation by race or ethnicity.

Cytogenetics of Mesenchymal Tumors of the Female Genital Tract

A great diversity of chromosome alterations have been reported in mesenchymal tumors of the female genital tract, particularly in the uterus. Some of these alterations specifically identify a certain tumor type. Cytogenetic studies on benign proliferations have not only demonstrated clonal chromosome changes, but have also pointed out clustering of aberrations to specific chromosome regions. For example, distinct cytogenetic subgroups have been described in uterine leiomyomas with overlapping histologic features. These findings may ultimately correlate with specific parameters, such as course of the disease, response to therapy, and recurrence. Moreover, such data may give a clue to an understanding of the biologic basis for distinctive behavior of benign versus malignant mesenchymal proliferations. No specific chromosomal abnormalities have been described in malignant mesenchymal tumors, with the exception of low-grade endometrial stromal sarcomas. This article reviews the information currently available on genetic changes in mesenchymal tumors of the female genital tract and, more specifically, those reported in the uterus, where they have been more frequently studied.

Association of germline mutations in the fumarate hydratase gene and uterine fibroids in women with hereditary leiomyomatosis and renal cell cancer

OBJECTIVE

To investigate the risk of uterine fibroids and other reproductive risk factors in women with hereditary leiomyomatosis and renal cell cancer (HLRCC).

DESIGN

Case-control study.

SETTING

National Institutes of Health, Rockville, Maryland. Patients A family-based case-control study was conducted between July 1, 2004, and June 30, 2006, including 105 women from families with HLRCC ascertained throughout North America. A telephone interview was conducted with all participants using a standardized questionnaire that elicited information about their menstrual, pregnancy, uterine fibroid, and hormonal contraceptive use history. Diagnosis of uterine fibroids was confirmed by pathologic diagnosis and by medical record review. DNA was extracted from blood samples and was screened for germline mutations in the fumarate hydratase (FH) gene.

MAIN OUTCOME MEASURES

FH germline mutation status, presence of uterine fibroids, age at diagnosis, and symptoms and treatment of uterine fibroids.

RESULTS

Of 105 women, 77 reported a history of uterine fibroids. Regardless of uterine fibroid status, 75 of 105 women had a germline mutation in FH (FH(mut) positive). The risk of uterine fibroids in FH(mut)-positive women was statistically significantly increased compared with that in FH(mut)-negative women (odds ratio [OR], 7.6; 95% confidence interval [CI], 2.9-20.0), as it was among women clinically affected with HLRCC compared with those clinically unaffected with HLRCC (8.6; 3.1-24.0). The median age at uterine fibroid diagnosis for FH(mut)-positive women (28 years) was significantly younger than that for FH(mut)-negative women (38 years) (P =.03). Women with a germline mutation in FH or clinically affected with HLRCC reported younger age at menarche (P < .004) compared with FH(mut)-negative women (P = .02) or women who were clinically unaffected with HLRCC. Women with HLRCC were more likely to have had treatment for uterine fibroids (OR, 4.6; 95% CI, 1.4-15.8), including hysterectomy (P =.02) at an earlier age compared with women who were clinically unaffected with HLRCC.

CONCLUSIONS

This study provides the first evidence (to our knowledge) that women with germline mutations in FH and with clinical HLRCC have an increased risk of developing uterine fibroids. These women also have a younger age at uterine fibroid diagnosis and are more likely to have treatment for uterine fibroids at a younger age than women without HLRCC in their families.

Activating transcription factor 3 gene expression suggests that tissue stress plays a role in leiomyoma development

OBJECTIVE

To determine whether expression of the stress response gene ATF3 and related members of activator protein complex-1, cJun and cFos, were altered in leiomyoma compared with myometrium, and whether this difference might correlate with leiomyoma size or race.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S)

Fifteen women undergoing hysterectomy for symptomatic leiomyoma.

INTERVENTION(S)

Tissue procurement, RNA isolation, reverse-transcriptase polymerase chain reaction, real-time reverse-transcriptase polymerase (RT-PCR) chain reaction, immunohistochemistry, Western blot.

MAIN OUTCOME MEASURE(S)

Expression of mRNA and protein in leiomyoma and patient-matched myometrium.

RESULT(S)

mRNA transcripts of ATF3 were decreased in leiomyoma compared with matched myometrium by both RT-PCR and real-time RT-PCR. The decrease was greater than fivefold in a majority of samples. The reduction seen in ATF3 mRNA expression did not show a correlation with race and leiomyoma size. Surprisingly, immunohistochemistry and Western blot analysis demonstrated an elevation of ATF3 protein expression by a mean of 2.9-fold. Transcripts of related AP-1 genes, cJun and cFos, were significantly decreased by a mean of -29.57 for cJun and -23.78 for cFos, but there was no significant change in protein expression of the two transcription factors.

CONCLUSIONS

Alterations in ATF3 gene expression resemble the response to mechanical and ischemic stress reported in other tissues. Results suggested that ATF3 protein expression was increased in leiomyoma, and may reflect increased tissue stress.

The impact of race as a risk factor for symptom severity and age at diagnosis of uterine leiomyomata among affected sisters

OBJECTIVE

The objective of the study was to identify risk factors for uterine leiomyomata (UL) in a racially diverse population of women with a family history of UL, and to evaluate their contribution to disease severity and age at diagnosis.

STUDY DESIGN

We collected and analyzed epidemiologic data from 285 sister pairs diagnosed with UL. Risk factors for UL-related outcomes were compared among black (n = 73) and white (n = 212) sister pairs using univariate and multivariate regression models.

RESULTS

Black women reported an average age at diagnosis of 5.3 years younger (SE, 1.1; P < .001) and were more likely to report severe disease (odds ratio, 5.22; 95% confidence interval, 1.99-13.7, P < .001) than white women of similar socioeconomic status.

CONCLUSION

Self-reported race is a significant factor in the severity of UL among women with a family history of UL. Differences in disease presentation between races likely reflect underlying genetic heterogeneity. The affected sister-pair study design can address both epidemiological and genetic hypotheses about UL.

Genetic heterogeneity among uterine leiomyomata: insights into malignant progression

Uterine leiomyomata (UL), also known as fibroids, are the most common pelvic tumors in women of reproductive age and are the primary indication for hysterectomy in the USA. Many lines of evidence indicate a strong genetic component to the development of these tumors. In fact, approximately 40% of UL have non-random, tumor-specific chromosome abnormalities which have allowed classification into well-defined subgroups (deletion of portions of 7q, trisomy 12 or rearrangements of 12q15, 6p21 or 10q22) as well as identification of candidate genes for UL predisposition. Although benign, UL have been linked to malignancy through two genomic regions on chromosome 1. Mutation of fumarate hydratase (FH) at 1q43 is known to cause the Mendelian syndromes of multiple cutaneous and uterine leiomyomata (MCL) and hereditary leiomyomatosis and renal cell cancer (HLRCC), and recently, FH mutations have been detected in some non-syndromic UL. In addition, transcriptional profiling suggests that loss of the short arm of chromosome 1 in cellular leiomyomata, an uncommon histological variant of UL, may account in part for the presumed yet rare malignant transformation of UL to uterine leiomyosarcoma.

The genetic heterogeneity of uterine leiomyomata

Research investigating the genetics of UL has already been successful in gathering epidemiologic evidence for heritability, establishing the clonal and mosaic nature of these tumors, correlating genotypic and phenotypic characteristics, defining cytogenetic subgroups, and identifying specific genes involved in tumorigenesis. Although UL are known to be benign tumors, the impact they have on the lives of so many women can only be described as "malignant". For this reason, continuing the quest to ascertain the genes, functions, and mechanisms integral to UL development is absolutely imperative. Genetic tests for personalized medical management of women with fibroids is at the threshold for providing the most appropriate treatments (Fig. 3), and combined with developing less invasive therapies portends a brighter future for a major health problem for women.

The genetics of uterine leiomyomata: what clinicians need to know

The genetics of many complex diseases, including hypertension, diabetes, and asthma, are receiving intense investigation and beginning to have therapeutic relevance. Family medical history can be a critical source of information for providing optimal patient care. For gynecologists, knowledge of cancer susceptibility genes such as BRCA1 and BRCA2 and the genetic syndrome hereditary nonpolyposis colorectal cancer (Lynch syndrome II) affects how patients are screened for ovarian and endometrial cancers. Similarly, identification of mutations in the fumarate hydratase (FH) gene that lead to a syndrome called hereditary leiomyomatosis and renal cell carcinoma (HLRCC) will impact screening and treatment of women with uterine leiomyomas. Hereditary leiomyomatosis and renal cell carcinoma syndrome is particularly relevant to clinicians and patients because of the resulting increased risk of malignant disease for both the affected woman and her family. The goals of this article are to summarize the evolving genetic information concerning uterine leiomyomas, including hereditary leiomyomatosis and renal cell carcinoma syndrome, and to discuss the clinical importance of these findings. The current role of family medical history and future implications of genes relevant to leiomyoma biology will be reviewed.

Gene therapy and uterine leiomyoma: a review

Leiomyomas (fibroids) are common estrogen-dependent uterine tumours that cause significant morbidity for women and a substantial economic impact on health delivery systems. Currently, there is no effective medical treatment option for this condition-hysterectomy is the mainstay of management. This is not an attractive choice for many women, especially patients desiring to preserve their fertility potential. Gene therapy is becoming a clinical reality, with more than 600 clinical trials worldwide. Researchers have recently attempted to develop a gene-therapy-based approach for the ablation of uterine fibroids. The localized nature of this condition and its accessibility using different imaging or endoscopic techniques make it an attractive target for direct delivery of gene-based vectors. Recent work from our laboratory suggests the potential use of a dominant-negative form of estrogen receptor (ER) to inactivate estrogen signalling in leiomyoma cells and induce apoptosis. Our in vivo data in a mouse model demonstrate the ability of an adenovirus-expressing dominant-negative ER to arrest leiomyoma growth. We and others also have described the utility of the herpes simplex virus-thymidine kinase (HSV-TK) plus ganciclovir (GCV) suicide gene-therapy system to effectively eradicate leiomyoma cells by utilizing the bystandard effect phenomena and the high expression of gap-junction protein in these tumours. Further work on rat models will pave the way for future leiomyoma gene-therapy clinical trials and allow the realization of gene therapy as a viable non-surgical option for this common problem in women's health.

Low serum concentrations of di-(2-ethylhexyl)phthalate in women with uterine fibromatosis

Di-(2-ethylhexyl)phthalate (DEHP) is the most commonly used plasticizer in flexible polyvinylchloride formulations, and is a widespread ubiquitous environmental contaminant. A potential role of exposure to DEHP and its primary metabolite, monoethylhexylphthalate (MEHP), on women's reproductive function is suggested in the current study. The aim of the study was to test serum concentrations of DEHP and/or MEHP in women with uterine fibromatosis. Two groups of women were enrolled in the study: (i) women with uterine fibromatosis undergoing surgical menopause (n = 15) and (ii) healthy women (n = 20). Serum DEHP and MEHP concentrations were measured by high-performance liquid chromatography. Serum MEHP distribution was found to be non-Gaussian (p = 0.001) while serum DEHP distribution was compatible with a normal curve (p = 0.141). Patients with uterine fibromatosis showed significantly lower serum MEHP concentrations (median [interquartile range]: 0 [0-0] microg/ml, range: 0-0.57 microg/ml) than controls (0.42 [0-0.51] microg/ml, range: 0-1.20 microg/ml, z = -2.93, p = 0.0034). Likewise, serum DEHP concentrations in women with fibromatosis were found to be significantly lower than in controls (patients: 0.27 +/- 0.096 microg/ml (mean +/- standard deviation (SD)), range: 0.14-0.59 microg/ml vs. controls: 0.30 +/- 0.14 microg/ml (mean +/- SD), range: 0-0.63 microg/ml; t = 3.212, df = 33, difference: -0.325 (95% confidence interval: -0.5309, -0.1191), p = 0.0029). In conclusion, the present findings indicate for the first time that serum DEHP and MEHP concentration are lower in women with uterine fibromatosis, suggesting a possible correlation between phthalate esters and fibromatosis pathology.

Fumarate hydratase mutations and predisposition to cutaneous leiomyomas, uterine leiomyomas and renal cancer

Germline heterozygous loss-of-function mutations of fumarate hydratase (FH) predispose to the autosomal dominant syndrome of multiple cutaneous and uterine leiomyomatosis (MCUL). Forty-five distinct FH mutations have been identified in 76 of 89 (85%) reported probands with skin leiomyomas. This suggests that MCUL is a genetically homogeneous condition and that most patients presenting with skin leiomyomas will have underlying FH mutations. FH mutations identified include 26/45 (58%) missense; 12/45 (27%) frameshift, 4/45 (9%) nonsense changes and 3/45 (7%) different whole gene deletions. In MCUL kindreds, the majority of females with FH mutations have both skin and uterine leiomyomas. A proportion of individuals with FH mutations have associated renal cancer, a variant known as hereditary leiomyomatosis and renal cell cancer (HLRCC). If selection bias is removed, the prevalence of renal cancer in MCUL lies between one of 46 (2%) families who were not radiologically screened, and two of 32 (6%) families who were radiologically screened. Truncating, particularly frameshift, mutations appear to be significantly associated with renal cancer (P = 0.003), suggesting a possible basis for selective screening. There may also be a significantly increased rate of renal cancer in females (P = 0.004), suggesting a possible role for hormonal factors. Review of the literature suggests that, unlike most individuals presenting with skin leiomyomas, the majority of patients presenting with uterine leiomyomas or renal cancer will not have underlying FH mutations.

Independent clonal origin of multiple uterine leiomyomas that was determined by X chromosome inactivation and microsatellite analysis

OBJECTIVE

In an attempt to clarify the clonality and genetic relationships that are involved in the tumorigenesis of uterine leiomyomas, we used a total of 43 multiple leiomyomas from 14 patients and analyzed the allelic status with 15 microsatellite markers and X chromosome inactivation analysis.

STUDY DESIGN

We have used a set of 15 microsatellite polymorphism markers mapped on 3q, 7p, 11, and 15q by automated analysis. The X chromosome inactivation was evaluated by the methylation status of the X-linked androgen receptor gene.

RESULTS

Loss of heterozygosity analysis showed a different pattern in 7 of the 8 cases with allelic loss for at least 1 of 15 microsatellite markers that were analyzed. A similar loss of heterozygosity findings at 7p22-15 was detected in 3 samples from the same patient. X chromosome inactivation analysis demonstrated the same inactivated allele in all tumors of the 9 of 12 informative patients; different inactivation patterns were observed in 3 cases.

CONCLUSION

Our data support the concept that uterine leiomyomas are derived from a single cell but are generated independently in the uterus. Loss of heterozygosity findings at 7p22-15 are consistent with previous data that suggested the relevance of chromosomal aberrations at 7p that were involved in individual uterine leiomyomas.

Uterine fibroids: the elephant in the room

Uterine fibroids (leiomyomas) have historically been viewed as important chiefly as the major indication for hysterectomy. As new therapies are developed, the heterogeneity of this disease becomes therapeutically relevant. An awareness of the role of genetics, the extracellular matrix, and hormones in tumor etiology is key to understanding this disease.

No evidence for epigenetic inactivation of fumarate hydratase in leiomyomas and leiomyosarcomas

Germline mutations in Fumarate Hydratase (FH) cause the development of leiomyomas and leiomyosarcomas in the syndromes Multiple Cutaneous and Uterine Leiomyomata (MCUL1) and Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). There is little evidence, however, that FH mutation plays a role in the development of sporadic leiomyomas or leiomyosarcomas. Such observations do not, however, exclude a role for FH in tumour development outside the context of MCUL1/HLRCC, as it is possible that FH expression could be silenced by epigenetic mechanisms. To explore this possibility we have developed a highly specific antibody to FH and analysed a series of forty-five fresh-frozen uterine leiomyomas and nine leiomyosarcomas for FH expression.