Disappearance of steroid hormone dependency during malignant transformation of ovarian clear cell cancer

Endometriosis-Related Ovarian Cancer: Where Are We Now? A Narrative Review towards a Pragmatic Approach

BACKGROUND

Endometriosis affects more than 10% of reproductive-aged women, causing pelvic pain and infertility. Despite the benign nature of endometriosis, ovarian endometriomas carry a higher risk of developing endometrioid carcinomas (EnOCs) and clear cell ovarian carcinomas (CCCs). Atypical endometriosis, defined as cytological atypia resembling intraepithelial cancer, is considered the precursor of endometriosis-associated ovarian cancer (EAOC). This narrative review aims to provide an overview of EAOC, proposing a practical approach to clinical and therapeutic decision making.

METHODS

An electronic literature search was conducted from inception up to January 2023, using the MEDLINE database via PubMed to evaluate the existing literature on EAOC, including its pathogenesis, the diagnostic process, and the therapeutic possibilities, with articles not relevant to the topic or lacking scientific merit being excluded.

RESULTS

Eighty-one articles were included in the review to present the current state of the art regarding EAOC. A pragmatic clinical flowchart is proposed to guide therapeutic decisions and improve patient outcomes.

CONCLUSIONS

Endometriosis patients may have an increased risk of developing EAOC (either EnOC or CCC). Despite not being fully accepted, the concept of AE may reshape the endometriosis-ovarian cancer relationship. Further research is needed to understand the unaddressed issues.

Endometriosis Stem Cells as a Possible Main Target for Carcinogenesis of Endometriosis-Associated Ovarian Cancer (EAOC)

Endometriosis is a serious recurrent disease impairing the quality of life and fertility, and being a risk for some histologic types of ovarian cancer defined as endometriosis-associated ovarian cancers (EAOC). The presence of stem cells in the endometriotic foci could account for the proliferative, migrative and angiogenic activity of the lesions. Their phenotype and sources have been described. The similarly disturbed expression of several genes, miRNAs, galectins and chaperones has been observed both in endometriotic lesions and in ovarian or endometrial cancer. The importance of stem cells for nascence and sustain of malignant tumors is commonly appreciated. Although the proposed mechanisms promoting carcinogenesis leading from endometriosis into the EAOC are not completely known, they have been discussed in several articles. However, the role of endometriosis stem cells (ESCs) has not been discussed in this context. Here, we postulate that ESCs may be a main target for the carcinogenesis of EAOC and present the possible sequence of events resulting finally in the development of EAOC.

A Systematic Review of Atypical Endometriosis-Associated Biomarkers

Ovarian endometriosis may increase the risk of malignancy. Several studies have suggested atypical endometriosis as the direct precursor of endometriosis-associated ovarian cancer. We performed an advanced, systematic search of the online medical databases PubMed and Medline. The search revealed n = 40 studies eligible for inclusion in this systematic review. Of these, n = 39 were finally included. The results from included studies are characterized by high heterogeneity, but some consistency has been found for altered expression in phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway, ARID1a, estrogen and progesterone receptors, transcriptional, nuclear, and growth factors in atypical endometriosis. Although many targets have been proposed as biomarkers for the presence of atypical endometriosis, none of them has such strong evidence to justify their systematic use in clinical practice, and they all need expensive molecular analyses. Further well-designed studies are needed to validate the evidence on available biomarkers and to investigate novel serum markers for atypical endometriosis.

Differential expression of estrogen receptor subtypes in ovarian high-grade serous carcinoma and clear cell carcinoma

PURPOSE

To investigate the role of estrogen receptors (ERs) in high-grade serous carcinoma (HGSC) and clear cell carcinoma (CCC) of the ovary and evaluate ERs as prognostic biomarkers for ovarian cancer.

METHODS

This study included 79 patients with HGSC (n = 38) or CCC (n = 41) treated at our institution between 2005 and 2014. Immunohistochemistry examined protein expression of ERα, ERβ, and G protein-coupled estrogen receptor-1 (GPER-1); relationships between ERα, ERβ, and GPER-1 with patient survival were evaluated. Additionally, cell proliferation assay and phosphokinase proteome profiling were performed.

RESULTS

In HGSC patients, expression of ERα, cytoplasmic GPER-1, or nuclear GPER-1 was associated with poor progression-free survival (PFS) (P = .041, P = .010, or P = .013, respectively). Cytoplasmic GPER-1 was an independent prognostic factor for PFS in HGSC patients (HR = 2.83, 95% CI = 1.03-9.16, P = .007). ER expressions were not associated with prognosis in CCC patients. GPER-1 knockdown by siRNA reduced the cells number to 60% of siRNA-control-treated cells (P < .05), and GPER-1 antagonist, G-15 inhibited two HGSC cell lines proliferation (KF and UWB1.289) in a dose-dependent manner. Phosphoprotein array revealed that GPER-1 silencing decreased relative phosphorylation of glycogen synthase kinase-3.

CONCLUSIONS

High GPER-1 expression is an independent prognostic factor for PFS in HGSC patients, and GPER-1 may play a role in HGSC cell proliferation.

Endometriosis Malignant Transformation: Epigenetics as a Probable Mechanism in Ovarian Tumorigenesis

Endometriosis, defined as the presence of ectopic endometrial glands and stroma outside the uterine cavity, is a chronic, hormone-dependent gynecologic disease affecting millions of women across the world, with symptoms including chronic pelvic pain, dysmenorrhea, dyspareunia, dysuria, and subfertility. In addition, there is well-established evidence that, although endometriosis is considered benign, it is associated with an increased risk of malignant transformation, with the involvement of various mechanisms of development. More and more evidence reveals an important contribution of epigenetic modification not only in endometriosis but also in mechanisms of endometriosis malignant transformation, including DNA methylation and demethylation, histone modifications, and miRNA aberrant expressions. In this present review, we mainly summarize the research progress about the current knowledge regarding the epigenetic modifications of the relations between endometriosis malignant transformation and ovarian cancer in an effort to identify some risk factors probably associated with ectopic endometrium transformation.

The association between reproductive and hormonal factors and ovarian cancer by estrogen-α and progesterone receptor status

OBJECTIVE

We assessed the association between reproductive and hormonal factors and ovarian cancer incidence characterized by estrogen receptor-α (ERα) and progesterone receptor (PR) status.

METHODS

Tissue microarrays were used to assess ERα and PR expression among 197 Nurses' Health Study (NHS), 42 NHSII and 76 New England Case-Control Study (NECC) ovarian cancer cases. NHS/NHSII cases were matched to up to 4 controls (n=954) on diagnosis date and birth year. NECC controls (n=725) were frequency matched on age. Cases were considered receptor positive if ≥1% of tumor cells stained positive. Associations by ERα and PR status were assessed using polytomous logistic regression. p-Value for heterogeneity was calculated using a likelihood ratio test.

RESULTS

45% of ovarian tumors were PR(+), 78% were ERα(+) and 45% were ERα(+)/PR(+), while 22% were ERα(-)/PR(-). Postmenopausal status was associated with an increased risk of PR(-) tumors (OR: 2.07; 95%CI: 1.15-3.75; p-heterogeneity=0.01) and age at natural menopause was inversely associated with PR(-) tumors (OR, per 5years: 0.77; 95%CI: 0.61-0.96; p-het=0.01). Increasing duration of postmenopause was differentially associated by PR status (p-het=0.0009). Number of children and tubal ligation were more strongly associated with ERα(-) versus ERα(+) tumors (p-het=0.002 and 0.05, respectively). No differential associations were observed for oral contraceptive or hormone therapy use.

CONCLUSIONS

Postmenopausal women have an increased risk of developing PR(-) ovarian tumors compared to premenopausal women. The associations observed for ovarian cancer differ from those seen for breast cancer suggesting that the biology for tumor development through ERα and PR pathways may differ.

Novel biomarker candidates for the diagnosis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma can arise from endometriosis; however, it is distinct from other types of epithelial ovarian carcinoma in terms of its clinicopathological and molecular features. Cancer antigen 125 lacks the sensitivity and specificity required for accurate clinical diagnosis of clear cell carcinoma. Therefore, the aim of the current review was to identify novel biomarker candidates for the immunohistochemical and serological diagnosis of clear cell carcinoma. A search of the relevant English language literature published between 1966 and 2014 was conducted using the PubMed MEDLINE online database. High-throughput tissue microarray technology and proteomic screening combined with mass spectrometry may provide additional information regarding diagnostic biomarker candidates for ovarian clear cell carcinoma. The present review summarizes the characteristics of potential genomic alterations that activate cancer signaling pathways and, thus, contribute to carcinogenesis. The major signaling pathways activated in clear cell carcinoma are associated with cell cycle regulation (hepatitis A virus cellular receptor 1 and tumor protein D52), growth factor signaling (insulin-like growth factor binding protein 1; KiSS-1 metastasis-suppressor; erb-b2 receptor tyrosine kinase 2; and fibroblast growth factor receptor 2), anti-apoptosis and survival pathways [sialidase 3 (membrane sialidase)], metabolism (γ-glutamyltransferase 1), chemoresistance (napsin A aspartic peptidase, glutathione peroxidase 3; and aldehyde dehydrogenase 1 family, member A1), coagulation [coagulation factor III (thromboplastin, tissue factor); and tissue factor pathway inhibitor 2], signaling (lectin, galactoside-binding and soluble, 3), and adhesion and the extracellular matrix [cadherin 1, type 1, E-cadherin (epithelial); versican; and laminin, α 5]. The present review of the relevant literature may provide a basis for additional clinical investigation of the ovarian clear cell carcinoma serum biomarker candidate proteins identified herein.

Epigenetic determinants of ovarian clear cell carcinoma biology

Targeted approaches have revealed frequent epigenetic alterations in ovarian cancer, but the scope and relation of these changes to histologic subtype of disease is unclear. Genome-wide methylation and expression data for 14 clear cell carcinoma (CCC), 32 non-CCC and four corresponding normal cell lines were generated to determine how methylation profiles differ between cells of different histological derivations of ovarian cancer. Consensus clustering showed that CCC is epigenetically distinct. Inverse relationships between expression and methylation in CCC were identified, suggesting functional regulation by methylation, and included 22 hypomethylated (UM) genes and 276 hypermethylated (HM) genes. Categorical and pathway analyses indicated that the CCC-specific UM genes were involved in response to stress and many contain hepatocyte nuclear factor (HNF) 1-binding sites, while the CCC-specific HM genes included members of the estrogen receptor alpha (ERalpha) network and genes involved in tumor development. We independently validated the methylation status of 17 of these pathway-specific genes, and confirmed increased expression of HNF1 network genes and repression of ERalpha pathway genes in CCC cell lines and primary cancer tissues relative to non-CCC specimens. Treatment of three CCC cell lines with the demethylating agent Decitabine significantly induced expression for all five genes analyzed. Coordinate changes in pathway expression were confirmed using two primary ovarian cancer datasets (p < 0.0001 for both). Our results suggest that methylation regulates specific pathways and biological functions in CCC, with hypomethylation influencing the characteristic biology of the disease while hypermethylation contributes to the carcinogenic process.

Toward an understanding of the pathophysiology of clear cell carcinoma of the ovary (Review)

Endometriosis-associated ovarian cancers demonstrate substantial morphological and genetic diversity. The transcription factor, hepatocyte nuclear factor (HNF)-1β, may be one of several key genes involved in the identity of ovarian clear cell carcinoma (CCC). The present study reviews a considerably expanded set of HNF-1β-associated genes and proteins that determine the pathophysiology of CCC. The current literature was reviewed by searching MEDLINE/PubMed. Functional interpretations of gene expression profiling in CCC are provided. Several important CCC-related genes overlap with those known to be regulated by the upregulation of HNF-1β expression, along with a lack of estrogen receptor (ER) expression. Furthermore, the genetic expression pattern in CCC resembles that of the Arias-Stella reaction, decidualization and placentation. HNF-1β regulates a subset of progesterone target genes. HNF-1β may also act as a modulator of female reproduction, playing a role in endometrial regeneration, differentiation, decidualization, glycogen synthesis, detoxification, cell cycle regulation, implantation, uterine receptivity and a successful pregnancy. In conclusion, the present study focused on reviewing the aberrant expression of CCC-specific genes and provided an update on the pathological implications and molecular functions of well-characterized CCC-specific genes.

Molecular mechanisms linking endometriosis under oxidative stress with ovarian tumorigenesis and therapeutic modalities

Inflammation plays a role in the pathogenesis of endometriosis. Endometriosis-associated ovarian carcinogenesis might be promoted through oxidative stress-induced increased genomic instability, aberrant methylation, and aberrant chromatin remodeling, as well as mutations of tumor suppressor genes. Aberrant expression of ARID1A, PIK3CA, and NF-kB genes has been recognized as the major target genes involved in oxidative stress-induced carcinogenesis. HNF-1beta appears to play a key role in anti-oxidative defense mechanisms. We discuss the pathophysiologic roles of oxidative stress as somatic mutations as well as highly specific agents that effectively modulate these targets.

"Piling up" clear cells in müllerian-type mucinous and mixed cell-type borderline tumor do not represent concomitant clear cell neoplasms

The nature of "piling up" proliferation of clear cells in müllerian mucinous/mixed borderline tumor has not been well characterized. The purpose of this study was to clarify whether or not such clear cells represent concomitant clear cell neoplasms. First, we carefully reviewed hematoxylin and eosin slides taken from 139 ovarian tumors diagnosed as clear cell carcinoma (112 cases) and müllerian mucinous/mixed borderline tumor (27 cases) to clarify (1) the frequency of piling-up clear cells in müllerian mucinous/mixed borderline tumor and (2) the frequency of the coexistence of typical clear cell carcinoma and müllerian mucinous/mixed borderline tumor. Second, we investigated the immunohistochemical expression of estrogen receptor, hepatocyte nuclear factor-1β, and glypican-3 in proliferating clear cells in both tumors. We identified piling-up clear cells in 56% of müllerian mucinous/mixed borderline tumors. Such clear cells lacked the severe nuclear atypia, complex branching, and dense hyalinized cores of typical clear cell carcinoma. We did not find coexistence of typical clear cell carcinoma and müllerian mucinous/mixed borderline tumor in any tumors. Piling-up clear cells and endocervical-like mucinous cells were positive for estrogen receptor but negative for hepatocyte nuclear factor-1β and glypican-3. Most clear cell carcinomas showed a hepatocyte nuclear factor-1β-positive/estrogen receptor-negative immunophenotype, and about half of them were glypican-3 positive. In conclusion, piling-up clear cells in müllerian mucinous/mixed borderline tumor do not represent concomitant clear cell neoplasms because clear cell carcinoma and müllerian mucinous/mixed borderline tumor hardly ever coexist and because such clear cells in both tumors are immunophenotypically distinct.

The role of hepatocyte nuclear factor-1beta in the pathogenesis of clear cell carcinoma of the ovary

PROBLEM

Clear cell carcinoma (CCC) of the ovary has a number of features distinguishing it from other epithelial ovarian carcinomas (EOC) because of its characteristic histology and biology, frequent concurrence with endometriotic lesion, and highly chemoresistant nature resulting in an extremely poor prognosis. The incidence of CCC has been steadily increasing in Japan. They comprise approximately 20% of all EOC. Understanding the mechanisms of CCC development and elucidating pathogenesis and pathophysiology are intrinsic to prevention and effective therapies for CCC.

METHOD OF STUDY

This article reviews the English language literature for biology, pathogenesis, and pathophysiological studies on endometriosis-associated EOC. Several data are discussed in the context of endometriosis and CCC biology.

RESULTS

Recent studies based on genome-wide expression analysis technology have noted specific expression of hepatocyte nuclear factor-1beta (HNF-1beta) in endometriosis and CCC, suggesting that early differentiation into the clear cell lineage takes place in the endometriosis. The HNF-1beta-dependent pathway of CCC will be discussed, which are providing new insights into regulation of apoptosis and glycogen synthesis and resistance of CCC to anticancer agents.

CONCLUSIONS

This review summarizes recent advances in the HNF-1beta and its target genes; the potential challenges to the understanding of carcinogenesis, pathogenesis, and pathophysiology of CCC; and a possible novel model is proposed.

Hobnail-like cells in serous borderline tumor do not represent concomitant incipient clear cell neoplasms

Hobnail-like cells, which suggest a diagnosis of clear cell carcinoma, are also focally observed in serous borderline tumor of the ovary, causing diagnostic confusion. However, the precise nature of hobnail-like cells in serous borderline tumor has not been well characterized. The purpose of this study was to clarify whether or not hobnail-like cells in serous borderline tumor represent concomitant incipient clear cell neoplasms. First, we carefully reviewed hematoxylin and eosin slides taken from 115 ovarian tumors diagnosed as clear cell carcinoma (73 cases), mixed adenocarcinoma containing clear cell carcinoma (5 cases), and serous borderline tumor (37 cases) to clarify the frequency of coexistence of typical clear cell carcinoma and serous borderline tumor. Through the hematoxylin and eosin review, we paid special attention to the cytologic features of hobnail-like cells in serous borderline tumor and serous borderline tumor-like papillary areas in clear cell carcinoma. Second, we selected 19 serous borderline tumors and 16 clear cell carcinomas, in which hobnail-like cells were easily recognizable, and investigated the immunohistochemical expression of estrogen receptor and Wilms tumor gene protein. No coexistence of clear cell carcinoma and serous borderline tumor was evident in any of the above 115 ovarian tumors. Hobnail-like cells were focally positive for estrogen receptor and Wilms tumor gene protein in nearly all serous borderline tumors. Hobnail-like cells in all clear cell carcinomas were completely negative for estrogen receptor and Wilms tumor gene protein, although estrogen receptor expression was very focally observed (less than 5% area) in non-hobnail cells of only one clear cell carcinoma. In conclusion, hobnail-like cells in serous borderline tumor do not represent concomitant incipient clear cell neoplasms because (1) clear cell carcinoma and serous borderline tumor do not coexist and (2) hobnail-like cells in clear cell carcinoma and serous borderline tumor are immunophenotypically distinct. Recognition of our conclusion may protect a patient with "conspicuous hobnail-like cells in serous borderline tumor" from an erroneous overdiagnosis of "concomitant clear cell carcinoma admixed with serous borderline tumor."