Switch in FOXA1 status associates with endometrial cancer progression

Histone Deacetylase Inhibitors: A Promising Therapeutic Alternative for Endometrial Carcinoma

Endometrial carcinoma is the most common malignant tumor of the female genital tract in the United States. Epigenetic alterations are implicated in endometrial cancer development and progression. Histone deacetylase inhibitors are a novel class of anticancer drugs that increase the level of histone acetylation in many cell types, thereby inducing cell cycle arrest, differentiation, and apoptotic cell death. This review is aimed at determining the role of histone acetylation and examining the therapeutic potential of histone deacetylase inhibitors in endometrial cancer. In order to identify relevant studies, a literature review was conducted using the MEDLINE and LIVIVO databases. The search terms histone deacetylase, histone deacetylase inhibitor, and endometrial cancer were employed, and we were able to identify fifty-two studies focused on endometrial carcinoma and published between 2001 and 2021. Deregulation of histone acetylation is involved in the tumorigenesis of both endometrial carcinoma histological types and accounts for high-grade, aggressive carcinomas with worse prognosis and decreased overall survival. Histone deacetylase inhibitors inhibit tumor growth, enhance the transcription of silenced physiologic genes, and induce cell cycle arrest and apoptosis in endometrial carcinoma cells both in vitro and in vivo. The combination of histone deacetylase inhibitors with traditional chemotherapeutic agents shows synergistic cytotoxic effects in endometrial carcinoma cells. Histone acetylation plays an important role in endometrial carcinoma development and progression. Histone deacetylase inhibitors show potent antitumor effects in various endometrial cancer cell lines as well as tumor xenograft models. Additional clinical trials are however needed to verify the clinical utility and safety of these promising therapeutic agents in the treatment of patients with endometrial cancer.

FOXA1 Expression by Immunohistochemistry in Carcinosarcomas of the Endometrium and Ovary/Fallopian Tube

FOXA1, a transcription factor essential for the binding of other transcription factors on chromatin, is associated with hormone receptor-associated cancers, such as breast and endometrial cancer. It is also considered an antagonist of epithelial-to-mesenchymal transition (EMT). In endometrial cancer, FOXA1 is considered a tumor suppressor; in carcinosarcoma, one of the most aggressive and rare subtypes of endometrial cancer, thought to be derived through an EMT mechanism, FOXA1 has not been studied. Thus, the aim of this study was to investigate the possible expression of FOXA1 in carcinosarcomas, and its correlation with clinicopathologic factors. This was a retrospective study of 31 patients diagnosed with carcinosarcomas of the uterus or the adnexa. Histologic and clinical factors were correlated with the immunohistochemical expression of FOXA1. FOXA1 was expressed by 38.7% of the carcinomatous components and 16.1% of the sarcomatous components. FOXA1-positive sarcomatous components were seen only with positive carcinomatous components (P=0.004). FOXA1 expression was not associated with age, primary tumor site, stage, metastases, overall survival, or tumor relapse. FOXA1 expression in the carcinomatous component was associated with an absence of lymphovascular invasion or the presence of heterologous components. FOXA1 expression in the sarcomatous component was associated with rhabdomyosarcoma, rather than the chondrosarcoma heterologous component. Carcinosarcomas harbor FOXA1 expression, although it is in their carcinomatous rather than sarcomatous components, suggesting a possible role of FOXA1 in the EMT of carcinosarcomas. FOXA1 shows no prognostic significance in this tumor group.

Knockdown of Forkhead box A1 suppresses the tumorigenesis and progression of human colon cancer cells through regulating the phosphatase and tensin homolog/Akt pathway

Background

This study aimed to evaluate the role and the underlying mechanisms of Forkhead box A1 (encoded by FOXA1) in colon cancer.

Methods

We analyzed FOXA1 mRNA and protein expression in colon cancer tissues and cell lines. We also silenced FOXA1 expression in HCT116 and SW480 cells to evaluate the effects on cell proliferation, cell cycle, migration, and invasion by using MTT, colony formation, flow cytometry, and the Transwell assay, respectively.

Results

FOXA1 immunostaining was higher in colon cancer tissues than adjacent healthy tissues. FOXA1 mRNA and protein expression was significantly increased in human colon cancer cells compared with a normal colonic cell line. FOXA1 expression was also significantly higher in colorectal cancer tissues from TCGA data sets and was associated with worse prognosis in the R2 database. FOXA1 expression was negatively correlated with the extent of its methylation, and its knockdown reduced proliferation, migration, and invasion, and induced G2/M phase arrest in HCT116 and SW480 cells by suppressing the phosphatase and tensin homolog/Akt signaling pathway and inhibiting epithelial–mesenchymal transition.

Conclusion

FOXA1 may act as an oncogene in colon cancer tumorigenesis and development.

High FOXA1 immunohistochemical expression level associates with mucinous histology, favorable clinico-pathological prognostic parameters and survival advantage in epithelial ovarian cancer

Background

Forkhead box (FOX) A1 is a potential therapeutic biomarker that has been investigated in various human cancers. Limited data exist about FOXA1 biologic role in epithelial ovarian cancer (EOC).

Aim

This study assessed FOXA1 immunohistochemical (IHC) expression and evaluated its association with clinico-pathological parameters in EOC including overall and disease-free survivals (OS, DFS) and patient’s outcome.

Methods

Patient’s socio-epidemiologic, clinical, radiological, laboratory, surgical, and follow-up data were collected. After histopathologic typing, grading and staging, FOXA1 IHC expression was scored in 98 EOC specimens. Clinico-pathological associations were investigated in high-and low-FOXA1 expression groups using appropriate statistical methods. Kaplan-Meier method was used for survival analysis.

Results

FOXA1 tumor cell nuclear staining was detected in 63.3% of EOC with weak, moderate and strong scores (28.6%, 12.2% and 22.5% respectively). Comparing high- and low-expression groups (34.7% and 65.3% respectively), high FOXA1 was associated with larger tumors, low mean serum CA-125, tumor histopathology (mucinous and low-grade serous), type I EOC, limited tumor’s anatomical extent, absence of nodal or distant metastases and omental nodules, earlier FIGO stages, non-recurrent tumors and survival advantage with longer and OS and DFS (all p ≤ 0.05). Independent predictors of high FOXA1 expression included: omental nodules, tumor’s anatomical extent and tumor’s size (p ≤ 0.001, = 0.046 and = 0.023 respectively).

Conclusion

FOXA1 is frequently expressed in EOC notably mucinous and low-grade serous carcinomas in association with favorable prognostic clinico-pathological parameters and longer OS and DFS. It likely has a suppressor function in EOC and could be recommended as a prognostic and therapeutic biomarker.

Longitudinal analysis of epigenome-wide DNA methylation reveals novel smoking-related loci in African Americans

Changes in DNA methylation may be a potential mechanism that mediates the effects of smoking on physiological function and subsequent disease risk. Given the dynamic nature of the epigenome, longitudinal studies are indispensable for investigating smoking-induced methylation changes over time. Using blood samples collected approximately five years apart in 380 African Americans (mean age 60.7 years) from the Genetic Epidemiology Network of Arteriopathy (GENOA) study, we measured DNA methylation levels using Illumina HumanMethylation BeadChips. We evaluated the association between Phase 1 smoking status and rate of methylation change, using generalized estimating equation models. Among the 6958 CpG sites examined, smoking status was associated with methylation change for 22 CpGs (false discovery rate q < 0.1), with the majority (91%) becoming less methylated over time. Methylation change was greater in ever smokers than never smokers, and the absolute differences in rates of change ranged from 0.18 to 0.77 per decade in M value, equivalent to a β value change of 0.013 to 0.047 per decade. Significant enrichment was observed for CpG islands, enhancers, and DNAse hypersensitivity sites (p < 0.05). Although biological pathway analyses were not significant, most of the 22 CpGs were within genes known to be associated with cardiovascular disease, cancers, and aging. In conclusion, we identified epigenetic signatures for cigarette smoking that may have been missed in cross-sectional analyses, providing insight into the epigenetic effect of smoking and highlighting the importance of longitudinal analysis in understanding the dynamic human epigenome.

FOXA1 levels are decreased in pleural breast cancer metastases after adjuvant endocrine therapy, and this is associated with poor outcome

Estrogen receptor-alpha (ERα)-positive breast cancer is often treated with antihormonal regimens. However, resistance to treatment is common, leading to metastatic disease. ERα activity requires the functional involvement of pioneer factors FOXA1 and GATA3, which enable ERα-chromatin binding and are crucial for ERα-driven cell proliferation. FOXA1 was found increased in metastatic breast cancers in relation to the primary tumor, but a comprehensive clinical assessment thereof, in relation to different metastatic sites and endocrine therapy usage, is currently lacking. Prior cell line-based reports, however, have revealed that FOXA1 is required for tamoxifen-resistant tumor cell proliferation. We studied expression levels of ERα, GATA3, and FOXA1 by immunohistochemistry in samples from both primary tumors and various metastatic sites. For all factors, expression levels varied between the metastatic sites. For pleural metastases, strong variation was found in FOXA1 and GATA3 levels. Although GATA3 levels remained unaltered between primary breast cancer and pleural metastases, FOXA1 levels were reduced exclusively in metastases of patients who received endocrine therapies in the adjuvant setting, even though ERα was still expressed. Importantly, decreased FOXA1 levels in pleural metastases correlated with hormone irresponsiveness in the palliative setting, while no such correlation was found for GATA3. With this, we show divergent clinical correlations of the two ERα pioneer factors FOXA1 and GATA3 in metastatic breast cancer, where endocrine therapy resistance was associated with decreased FOXA1 levels in pleural metastases.

The high expression of FOXA1 is correlated with a favourable prognosis in salivary duct carcinomas: a study of 142 cases

AIMS

Salivary duct carcinoma (SDC) is an uncommon, aggressive tumour that, histologically, resembles high-grade mammary ductal carcinoma, and is characterised by the expression of androgen receptor (AR). The androgen signalling pathway, a potential therapeutic target, can be regulated by FOXA1. This study aimed to evaluate the clinicopathological implications of FOXA1 in SDC.

METHODS AND RESULTS

We examined the relationship between the immunoexpression of FOXA1 and FOXA1 mutations and clinicopathological factors, including the biomarker status and clinical outcome, in 142 SDCs. FOXA1 was expressed in 128 SDCs (90.1%); the immunoexpression was heterogeneous. SDCs with a higher FOXA1 labelling index (LI) (≥20%) more frequently showed less advanced tumors on T classification (P = 0.002). FOXA1 LI was correlated positively with the AR expression value (r = 0.430, P < 0.001). PI3K and p-mTOR positivity, and intact-PTEN, were associated with a higher FOXA1 LI. Twenty-two of 121 SDCs (18.2%) harboured FOXA1 gene mutations at the flanking regions in and around the forkhead DNA binding domain; however, the given gene mutation and the expression of FOXA1 were not significantly correlated. A multivariate analysis revealed that SDCs with a higher FOXA1 LI were associated with longer overall survival and progression-free survival (P = 0.029 and 0.016, respectively).

CONCLUSIONS

In SDC, FOXA1, which may biologically interact with the AR and PI3K signalling pathways, is a putative biomarker that may be associated with a favourable prognosis. Further studies are needed to apply the findings to the development of targeted personalised therapy for patients with SDC.

Estrogen-regulated transcription: Mammary gland and uterus

Estrogen (E2) plays a central role in the developmental, metabolic and reproductive functions of both males and females. E2 acts via the estrogen receptor alpha (ERα) to regulate the transcription of genes involved in numerous cellular functions. The E2-dependent engagement of ERα across regulatory regions of the genome, termed "enhancers", exhibits a high degree of complexity and plasticity. The E2-transcriptional response is defined by pioneer factors, transcription co-factors, posttranslational modifications of ERα, the chromatin environment, and cross talk with other signaling pathways. These inputs collectively define the normal functions of tissues like the mammary gland and the uterus. This mechanism can also provide a selective and aberrant growth advantage in pathological conditions, such as cancer. E2-regulated transcription continues to be an area of great interest in the fields of reproduction and cancer. The goal of these field is to decipher the molecular mechanisms governing ERα transcription to design effective therapeutic strategies for the improvement of clinical care and control of fertility.

FOXA1 expression is a strong independent predictor of early PSA recurrence in ERG negative prostate cancers treated by radical prostatectomy

FOXA1 (Fork-head box protein A1, HNF-3a) is a transcription factor involved in androgen signaling with relevance for lineage-specific gene expression of the prostate. The expression was analyzed by immunohistochemistry on a tissue microarray containing 11152 prostate cancer specimens. Results were compared with tumor phenotype, biochemical recurrence, androgen receptor expression, ETS-related gene (ERG) status and other recurrent genomic alterations. FOXA1 expression was detectable in 97.6% of 8227 interpretable cancers and considered strong in 28.5%, moderate in 46.2% and weak in 22.9% of cases. High FOXA1 expression was associated with TMPRSS2:ERG rearrangement and ERG expression (P < 0.0001). High FOXA1 expression was linked to high Gleason grade, advanced pathological tumor (pT) stage and early PSA recurrence in ERG negative cancers (P < 0.0001), while these associations were either weak or absent in ERG positive cancers. In ERG negative cancers, the prognostic role of FOXA1 expression was independent of Gleason grade, pathological tumor stage, lymph node stage, surgical margin status and preoperative PSA. Independent prognostic value became even more evident if the analysis was limited to preoperatively available features such as biopsy Gleason grade, preoperative PSA, cT stage and FOXA1 expression (P < 0.0001). Within ERG negative cancers, FOXA1 expression was also strongly associated with PTEN and 5q21 deletions (P < 0.0001). High expression of FOXA1 is an independent prognostic parameter in ERG negative prostate cancer. Thus, FOXA1 measurement might provide clinically useful information in prostate cancer.

Asparaginase-like protein 1 is an independent prognostic marker in primary endometrial cancer, and is frequently lost in metastatic lesions

OBJECTIVE

Loss of Asparaginase-like protein 1 (ASRGL1) has been suggested as a prognostic biomarker in endometrial carcinoma. Our objective was to validate this in a prospectively collected, independent patient cohort, and evaluate ASRGL1 expression in endometrial carcinoma precursor lesion and metastases.

METHODS

782 primary endometrial carcinomas, 90 precursor lesions (complex atypical hyperplasia), and 179 metastases (from 87 patients) were evaluated for ASRGL1 expression by immunohistochemistry in relation to clinical and histopathological data. ASRGL1 mRNA level was investigated in 237 primary tumors and related to survival and ASRGL1 protein expression.

RESULTS

Low expression of ASRGL1 protein and ASRGL1 mRNA predicted poor disease specific survival (P<0.001). In multivariate survival analyses ASRGL1 had independent prognostic value both in the whole patient cohort (Hazard ratio (HR): 1.53, 95% confidence interval (CI): 1.04-2.26, P=0.031) and within the endometrioid subgroup (HR: 2.64, CI: 1.47-4.74, P=0.001). Low ASRGL1 expression was less frequent in patients with low grade endometrioid primary tumors compared to high grade endometrioid and non-endometrioid primary tumors, and ASRGL1 was lost in the majority of metastatic lesions.

CONCLUSIONS

In a prospective setting ASRGL1 validates as a strong prognostic biomarker in endometrial carcinoma. Loss of ASRGL1 is associated with aggressive disease and poor survival, and is demonstrated for the first time to have independent prognostic value in the entire endometrial carcinoma patient population.

FOXA1 is expressed in ovarian mucinous neoplasms

FOXA1 is a transcription factor essential for the binding and action of other transcription factors on the chromatin. It is the major regulator of endoderm differentiation. It has important roles in breast, prostate and endometrial cancer. It has never been studied in ovarian tumours. The aim of this study was to investigate its expression in ovarian epithelial neoplasms. A total of 195 primary ovarian epithelial borderline or malignant tumours were immunohistochemically studied for the expression of FOXA1. Nineteen percent of the tumours strongly and diffusely expressed FOXA1. Of these, 75.7% belong to the mucinous category (p < 0.0001). Seventy-five per cent of mucinous borderline tumours and 46.7% of mucinous carcinomas overexpressed FOXA1. Brenner tumours also expressed FOXA1. FOXA1 was rarely expressed in serous (6/115) and endometrioid tumours (1/11). Clear cell tumours were completely negative (0/16). Of normal structures, ciliated tubal cells, Walthard nests and transitional metaplasias of the tubal-mesothelial junction, all strongly expressed FOXA1. In conclusion, FOXA1 is found in ovarian mucinous and Brenner tumours.

Epidemiology of Endometrial Carcinoma: Etiologic Importance of Hormonal and Metabolic Influences

Endometrial carcinoma is the most common gynecologic cancer in developed nations, and the annual incidence is projected to increase, secondary to the high prevalence of obesity, a strong endometrial carcinoma risk factor. Although endometrial carcinomas are etiologically, biologically, and clinically diverse, hormonal and metabolic mechanisms are particularly strongly implicated in the pathogenesis of endometrioid carcinoma, the numerically predominant subtype. The centrality of hormonal and metabolic disturbances in the pathogenesis of endometrial carcinoma, combined with its slow development from well-characterized precursors in most cases, offers a substantial opportunity to reduce endometrial carcinoma mortality through early detection, lifestyle modification, and chemoprevention. In this chapter, we review the epidemiology of endometrial carcinoma, emphasizing theories that link risk factors for these tumors to hormonal and metabolic mechanisms. Future translational research opportunities related to prevention are discussed.

FOXA1 overexpression mediates endocrine resistance by altering the ER transcriptome and IL-8 expression in ER-positive breast cancer

Forkhead box protein A1 (FOXA1) is a pioneer factor of estrogen receptor α (ER)-chromatin binding and function, yet its aberration in endocrine-resistant (Endo-R) breast cancer is unknown. Here, we report preclinical evidence for a role of FOXA1 in Endo-R breast cancer as well as evidence for its clinical significance. FOXA1 is gene-amplified and/or overexpressed in Endo-R derivatives of several breast cancer cell line models. Induced FOXA1 triggers oncogenic gene signatures and proteomic profiles highly associated with endocrine resistance. Integrated omics data reveal IL8 as one of the most perturbed genes regulated by FOXA1 and ER transcriptional reprogramming in Endo-R cells. IL-8 knockdown inhibits tamoxifen-resistant cell growth and invasion and partially attenuates the effect of overexpressed FOXA1. Our study highlights a role of FOXA1 via IL-8 signaling as a potential therapeutic target in FOXA1-overexpressing ER-positive tumors.

The mutational spectrum of FOXA2 in endometrioid endometrial cancer points to a tumor suppressor role

BACKGROUND

Forkhead box protein A2 (FOXA2) plays an important in development, cellular metabolism and tumorigenesis. The Cancer Genome Atlas (TCGA) identified a modest frequency of FOXA2 mutations in endometrioid endometrial cancers (EEC). The current study sought to determine the relationship between FOXA2 mutation and clinicopathologic features in EEC and FOXA2 expression.

METHODS

Polymerase chain reaction (PCR) amplification and sequencing were used to identify mutations in 542 EEC. Western blot, quantitative reverse transcriptase PCR (qRT-PCR) and immunohistochemistry (IHC) were used to assess expression. Methylation analysis was performed using combined bisulfite restriction analysis (COBRA) and sequencing. Chi-squared, Fisher's exact, Student's t- and log-rank tests were performed.

RESULTS

Fifty-one mutations were identified in 49 tumors (9.4% mutation rate). The majority of mutations were novel, loss of function (LOF) (78.4%) mutations, and most disrupted the DNA-binding domain (58.8%). Six recurrent mutations were identified. Only two tumors had two mutations and there was no evidence for FOXA2 allelic loss. Mutation status was associated with tumor grade and not associated with survival outcomes. Methylation of the FOXA2 promoter region was highly variable. Most tumors expressed FOXA2 at both the mRNA and protein level. In those tumors with mutations, the majority of cases expressed both alleles.

CONCLUSION

FOXA2 is frequently mutated in EEC. The pattern of FOXA2 mutations and expression in tumors suggests complex regulation and a haploinsufficient or dominant-negative tumor suppressor function. In vitro studies may shed light on how mutations in FOXA2 affect FOXA2 pioneer and/or transcription factor functions in EEC.

The Estrogen Receptor α-Cistrome Beyond Breast Cancer

Although many tissues express estrogen receptor (ER)α, most studies focus on breast cancer where ERα occupies just a small fraction of its total repertoire of potential DNA-binding sites, based on sequence. This raises the question: Can ERα occupy these other potential binding sites in a different context? Ligands, splice variants, posttranslational modifications, and acquired mutations of ERα affect its conformation, which may alter chromatin interactions. To date, literature describes the DNA-binding sites of ERα (the ERα cistrome) in breast, endometrium, liver, and bone, in which the receptor mainly binds to enhancers. Chromosomal boundaries provide distinct areas for dynamic gene regulation between tissues, where the usage of enhancers deviates. Interactions of ERα with enhancers and its transcriptional complex depend on the proteome, which differs per cell type. This review discusses the biological variables that influence ERα cistromics, using reports from human specimens, cell lines, and mouse tissues, to assess whether ERα genomics in breast cancer can be translated to other tissue types.

Forkhead-box A1 induces cell senescence in endometrial cancer by regulating p16INK4a

We previously identified FOXA1 as a tumor-suppressor in EC cells. In the present study, we sought to delineate the different roles of FOXA1 associated with cell senescence and further investigated the correlation between FOXA1 and p16INK4a in the progression of EC. Using reverse transcription-quantitative PCR (RT-qPCR), we found that FOXA1 expression was significantly downregulated in EC cells compared to that in normal endometrial cells. Functionally, senescence‑associated β-galactosidase staining, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic and Transwell assays showed that in addition to acting as a pioneer factor, FOXA1 was significantly upregulated in senescent EC cells. Furthermore, restoration of FOXA1 expression triggered multiple steps of cellular senescence in EC cells and activated p16INK4a expression. All of these findings indicate that FOXA1 promotes cell senescence in EC by interaction with p16INK4a, possibly via the AKT pathway. Notably, a selective PI3K inhibitor raised the possibility that FOXA1‑induced senescence is associated with the AKT pathway in EC cells. Collectively, the present study provides a conceivable molecular mechanism by which cell senescence acts as the barrier to EC, and is regulated by FOXA1-induced p16INK4a expression. This may be a newly identified regulatory mechanism of cell senescence in EC.

Comparative Cistromics Reveals Genomic Cross-talk between FOXA1 and ERα in Tamoxifen-Associated Endometrial Carcinomas

Tamoxifen, a small-molecule antagonist of the transcription factor estrogen receptor alpha (ERα) used to treat breast cancer, increases risks of endometrial cancer. However, no parallels of ERα transcriptional action in breast and endometrial tumors have been found that might explain this effect. In this study, we addressed this issue with a genome-wide assessment of ERα-chromatin interactions in surgical specimens obtained from patients with tamoxifen-associated endometrial cancer. ERα was found at active enhancers in endometrial cancer cells as marked by the presence of RNA polymerase II and the histone marker H3K27Ac. These ERα binding sites were highly conserved between breast and endometrial cancer and enriched in binding motifs for the transcription factor FOXA1, which displayed substantial overlap with ERα binding sites proximal to genes involved in classical ERα target genes. Multifactorial ChIP-seq data integration from the endometrial cancer cell line Ishikawa illustrated a functional genomic network involving ERα and FOXA1 together with the enhancer-enriched transcriptional regulators p300, FOXM1, TEAD4, FNFIC, CEBP8, and TCF12. Immunohistochemical analysis of 230 primary endometrial tumor specimens showed that lack of FOXA1 and ERα expression was associated with a longer interval between breast cancer and the emergence of endometrial cancer, exclusively in tamoxifen-treated patients. Our results define conserved sites for a genomic interplay between FOXA1 and ERα in breast cancer and tamoxifen-associated endometrial cancer. In addition, FOXA1 and ERα are associated with the interval time between breast cancer and endometrial cancer only in tamoxifen-treated breast cancer patients. Cancer Res; 76(13); 3773-84. ©2016 AACR.

Tumor progression, metastasis, and modulators of epithelial-mesenchymal transition in endometrioid endometrial carcinoma: an update

Endometrioid endometrial carcinoma (EEC), also known as type 1 endometrial cancer (EC), accounts for over 70-80% of all cases that are usually associated with estrogen stimulation and often develops in a background of atypical endometrial hyperplasia. The increased incidence of EC is mainly confined to this type of cancer. Most EEC patients present at an early stage and generally have a favorable prognosis; however, up to 30% of EEC present as high risk tumors, which have invaded deep into the myometrium at diagnosis and progressively lead to local or extra pelvic metastasis. The poor survival of advanced EC is related to the lack of effective therapies, which can be attributed to poor understanding of the molecular mechanisms underlying the progression of disease toward invasion and metastasis. Multiple lines of evidence illustrate that epithelial-mesenchymal transition (EMT)-like events are central to tumor progression and malignant transformation, endowing the incipient cancer cell with invasive and metastatic properties. The aim of this review is to summarize the current knowledge on molecular events associated with EMT in progression, invasion, and metastasis of EEC. Further, the role of epigenetic modifications and microRNA regulation, tumor microenvironment, and microcystic elongated and fragmented glands like invasion pattern have been discussed. We believe this article may perhaps stimulate further research in this field that may aid in identifying high risk patients within this clinically challenging patient group and also lead to the recognition of novel targets for the prevention of metastasis - the most fatal consequence of endometrial carcinogenesis.

Loss of progesterone receptor links to high proliferation and increases from primary to metastatic endometrial cancer lesions

OBJECTIVE

In endometrial cancer loss of progesterone receptor (PR, gene name PGR) is associated with aggressive disease and altered response to hormonal treatment. The aim of this study was to investigate changes in PR expression level with disease progression, and explore whether differences in gene expression according to PR status can be linked to processes involved in cancer development elucidating new therapeutic opportunities.

METHODS

686 primary endometrial cancers and 171 metastatic lesions were investigated for PR expression in relation to clinical and histopathological data. Protein levels were investigated by immunohistochemistry and reverse phase protein array, and mRNA levels by DNA oligonucleotide microarray.

RESULTS

PR protein level was significantly associated with PGR mRNA expression (P<0.001) and patient survival (P<0.001). Loss of PR increased with disease progression, with 23% of the primary tumours and 76% of metastases demonstrating PR loss. Using a cell cycle progression signature score, PR loss was associated with increased proliferation for both oestrogen receptor (ER) positive and negative tumours. Through a Connectivity Map search, CDK inhibitors and other drugs with anti-proliferative effects were suggested in particular for treatment of patients with loss of PR.

CONCLUSION

Loss of PR in endometrial cancer is associated with increased proliferation, poor survival, and increases from primary to metastatic lesions. Based on expression profiles, CDK inhibitors may have activity in PR negative tumours, supporting further testing in clinical trials for patients with systemic endometrial cancer dependent on PR status.