Nucleolar organizer regions in endometriosis, atypical endometriosis, and clear cell and endometrioid carcinomas

Immune pathway through endometriosis to ovarian cancer

Endometriosis is an estrogen-dependent inflammatory disease, defined by the presence of functional endometrial tissue outside of the uterine cavity. This disease is one of the main gynecological diseases, affecting around 10%-15% women and girls of reproductive age, being a common gynecologic disorder. Although endometriosis is a benign disease, it shares several characteristics with invasive cancer. Studies support that it has been linked with an increased chance of developing endometrial ovarian cancer, representing an earlier stage of neoplastic processes. This is particularly true for women with clear cell carcinoma, low-grade serous carcinoma and endometrioid. However, the carcinogenic pathways between both pathologies remain poorly understood. Current studies suggest a connection between endometriosis and endometriosis-associated ovarian cancers (EAOCs) via pathways associated with oxidative stress, inflammation, and hyperestrogenism. This article aims to review current data on the molecular events linked to the development of EAOCs from endometriosis, specifically focusing on the complex relationship between the immune response to endometriosis and cancer, including the molecular mechanisms and their ramifications. Examining recent developments in immunotherapy and their potential to boost the effectiveness of future treatments.

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.

Precursors and pathogenesis of ovarian carcinoma

The ultimate goal of defining cancer specific precursors is to facilitate early detection and intervention before the development of invasive malignancy. Unlike other malignancies involving the female genital tract such as cervical or endometrial carcinomas, precursor lesions of ovarian carcinomas have not been well characterised, resulting in a failure to develop effective screening programs. Recent clinicopathological and molecular studies have provided new insight into the origin and pathogenesis of ovarian carcinomas. It has been shown that ovarian cancer is comprised of different tumour types differing not only in morphology, but also in pathogenesis, molecular alterations and clinical progression. A dualistic model of ovarian carcinogenesis has been proposed. Type I tumours which include low grade serous, low grade endometrioid, clear cell, mucinous carcinomas and Brenner tumours, are generally indolent and tend to be genetically stable, although clear cell carcinoma would probably belong to an intermediate category. They demonstrate a step-wise progression from a benign precursor such as a benign to borderline tumour or endometriosis and are characterised by genetic aberrations targeting specific cell signalling pathways. Type II tumours comprise high grade serous, high grade endometrioid, and undifferentiated carcinomas as well as malignant mixed mesodermal tumours. They are clinically aggressive and exhibit high genetic instability with frequent p53 mutations. Mounting evidence suggests that many high grade serous carcinomas originate from the epithelium of the distal fallopian tube, and that serous tubal intraepithelial carcinoma (STIC) represents the putative precursor of these neoplasms. Low grade serous carcinomas arise via transformation of benign and borderline serous tumours, thought to be derived from inclusion cysts originating from the ovarian surface or tubal epithelium. Recently it has been suggested that papillary tubal hyperplasia may be a putative precursor lesion for serous borderline tumours. Both endometrioid and clear cell carcinomas develop from endometriosis, via alterations affecting different genetic pathways. The origin of mucinous and transitional cell neoplasms is not well characterised, although new data suggest a possible origin from transitional cell nests present at the tubal-mesothelial junction. Likewise, the pathogenesis of carcinosarcomas is also not well established because of their rarity but there is accumulating evidence that the carcinomatous component determines the course of the disease and gives rise to the malignant mesenchymal component. This review discusses recent developments in the pathogenesis of ovarian carcinoma, with particular emphasis on the putative precursor lesions that give rise to the major histological subtypes. Recognition of these lesions is not only important in improving the understanding of ovarian carcinogenesis, but it will also influence our approach to prevent, detect and treat these tumours.

Prognostic analysis of ovarian cancer associated with endometriosis

OBJECTIVE

The objective of the study was to evaluate the prognosis of ovarian cancer arising in endometriosis.

STUDY DESIGN

We retrospectively compared 42 cases of endometriosis-associated ovarian cancer (EAOC) with 184 cases of ovarian carcinoma without endometriosis (OC).

RESULTS

The median age in the EAOC group was 52 vs 59 years in OC (P < .05). In comparison with OC, the EAOC patients were more likely to have low-grade (21% vs 8%; P = .04) and early-stage tumors (International Federation of Gynecology and Obstetrics I and II combined) (49% vs 24%; P = .002). Clear cell (21% vs 2%) and endometrioid (14% vs 3%) tumors were more frequent in EAOC, whereas mucinous tumors were more prevalent in OC (P = .001). The median survival (199 vs 62 months) and the 5 year survival (62% vs 51%) were better for EAOC when compared with OC (P = .038). After controlling for age, stage, grade, and treatment, association with endometriosis was not an independent predictor of better survival in ovarian cancer.

CONCLUSION

As such, EAOC has a much better survival rate than OC. This could be explained by the higher prevalence of early-stage and low-grade tumors in EAOC when compared with OC.

The pathology of endometriosis: a survey of the many faces of a common disease emphasizing diagnostic pitfalls and unusual and newly appreciated aspects

Although the histologic diagnosis of endometriosis is usually straightforward, many diagnostic problems can arise as a result of alterations or absence of its glandular or stromal components. The diagnostic difficulty in such cases can be compounded by tissue that is limited to a small biopsy specimen. The appearance of the glandular component can be altered by hormonal and metaplastic changes, as well as cytologic atypia and hyperplasia. Although the last 2 findings are often referred to collectively as "atypical endometriosis," they should be separately recognized as their premalignant potential likely differs. In some cases, the endometriotic glands are sparse or even absent (stromal endometriosis). The stromal component can be obscured or effaced by infiltrates of foamy and pigmented histiocytes, fibrosis, elastosis, smooth muscle metaplasia, myxoid change, and decidual change. Occasional findings in endometriosis that may raise concern for a neoplasm include necrotic pseudoxanthomatous nodules, polypoid growth (polypoid endometriosis), bulky disease, and venous, lymphatic, or perineural invasion. Inflammatory and reactive changes within, adjacent to, or at a distance from foci of endometriosis can complicate the histologic findings and include infection within endometriotic cysts, pseudoxanthomatous salpingitis, florid mesothelial hyperplasia, peritoneal inclusion cysts, and Liesegang rings. The histologic diagnosis of endometriosis can also be challenging when it involves an unusual or unexpected site. Five such site-specific problematic areas considered are endometriosis on or near the ovarian surface, superficial cervical endometriosis, vaginal endometriosis, tubal endometriosis, and intestinal endometriosis, including the important distinction of an endometrioid carcinoma arising from colonic endometriosis from a primary colonic adenocarcinoma. Finally, endometriotic foci can occasionally be intimately admixed with another process, such as peritoneal leiomyomatosis or gliomatosis, resulting in a potentially confusing histologic appearance.

Endometriosis and the development of malignant tumours of the pelvis. A review of literature

For several decades, endometriosis has been suspected of playing a role in the aetiology of ovarian cancer. The literature concerning a possible histogenesis of ovarian cancer from benign endometriosis is reviewed in this chapter. Epidemiological evidence from large-cohort studies confirms endometriosis as an independent risk factor for ovarian cancer. Further circumstantial evidence for this link was found in the common risk factors for ovarian cancer and endometriosis. These risk factors influence retrograde menstruation and endometriosis in the same positive or negative way. Based on data in the literature, the prevalence of endometriosis in epithelial ovarian cancer has been calculated to be 4.5, 1.4, 35.9, and 19.0% for serous, mucinous, clear-cell and endometrioid ovarian carcinoma, respectively. The risk of malignant transformation in ovarian endometriosis was calculated at 2.5% but this might be an underestimate. In addition, some authors described atypical endometriosis in a spatial and chronological association with ovarian cancer. Finally, molecular studies have detected common alterations in endometriosis and ovarian cancer. These data suggest that some tumours, especially endometrioid and clear-cell carcinomas, can arise from endometriosis. Moreover, endometriosis-associated ovarian cancer represents a distinct clinical entity, with a more favourable biological behaviour, given a lower stage distribution and better survival than non-endometriosis-associated ovarian cancer.

Nucleolar organizer regions (NORs) in adenomyosis

Nucleolar organizer regions (NORs) were evaluated in 11 women with adenomyosis. The material, sampled during operations, was silver-stained using the technique of Ploton et al. and verified histopathologically. A hundred cell nuclei per slide were assessed. The examined variables comprised the number of argyrophylic nucleolar organizer regions (AgNORs) in the nucleus, the surface area of a single AgNOR and the position of the AgNORs in the cell nucleus, as well as the AgNORs' coefficient, which were all estimated under a microscope. The parameters were quantitatively assessed using computer image analysis software Multi-Scan Base V.8. Adenomyosis was found to be associated with a significant decrease (up to 60%) in the nuclear area, as well as with a marked reduction (up to 50% as compared with normal endometrium) in the number of AgNOR granules. The total area of AgNORs in the cell nucleus also decreased from 3.55 to 1.57 microm2. There were no significant differences in the number of granules per nucleus either in the control group or in the adenomyosis group. The AgNOR coefficient was found to be lower in adenomyosis compared to normal endometrium.

Relationship of benign gynecologic diseases to subsequent risk of ovarian and uterine tumors

OBJECTIVE

Although endometriosis and uterine leiomyomas are common conditions, the extent to which either is associated with certain types of malignancies remains uncertain.

METHODS

Using record linkage techniques, we assessed the relationships between hospital and outpatient admissions for endometriosis or leiomyomas and the development of ovarian and uterine cancers in Denmark between 1978 and 1998. Based on a population-based cohort exceeding 99,000 women, including 2,491 ovarian cancers, 860 borderline ovarian tumors, and 1,398 uterine cancers, we derived relative risks (RR) and 95% confidence intervals (95% CI) associated with overall and histology-specific tumor risks after adjustment for calendar time and reproductive characteristics.

RESULTS

Endometriosis seemed to predispose to the development of ovarian cancer, with the association restricted to endometrioid or clear cell malignancies. Five or more years after the diagnosis of endometriosis, the RRs (95% CIs) were 2.53 (1.19-5.38) for endometrioid (7 exposed cases) and 3.37 (1.24-9.14) for clear cell (4 exposed cases) malignancies. Uterine leiomyomas were associated with increases in the risk of uterine malignancies, particularly sarcomas, where the RRs (95% CIs) were 20.80 (11.32-38.22) for women with 1 to 4 years of follow-up (11 exposed cases) and 5.70 (2.27-14.32) for those with more extended follow-up (5 exposed cases).

CONCLUSION

In combination with clinical, pathologic, and molecular data, our results support that some endometriotic lesions may predispose to clear cell and endometrioid ovarian cancers. Uterine leiomyomas also showed a strong connection with subsequent uterine sarcomas, although it was difficult to decipher whether this reflected detection bias, shared risk factors, or an etiologic relationship.

Origins and molecular pathology of ovarian cancer

Epithelial ovarian cancer comprises the majority of malignant ovarian tumors in adult women. These neoplasms are classified into distinct morphologic categories based on the appearance of the epithelium into tumors of serous, mucinous, endometrioid, clear cell, transitional, squamous, mixed and undifferentiated type. Current data indicate that each of these histologic subtypes is associated with distinct morphologic and molecular genetic alterations: high-grade serous and possibly endometrioid carcinomas most probably arise from surface epithelial inclusion glands with TP53 mutations and dysfunction of BRCA1 and/or BRCA2; low-grade serous carcinomas probably arise in a stepwise fashion in an adenoma-borderline tumor-carcinoma sequence from typical to micropapillary borderline tumors to low-grade invasive serous carcinoma via activation of the RAS-RAF signaling pathway secondary to mutations in KRAS and BRAF; mucinous carcinomas arise via an adenoma-borderline tumor-carcinoma sequence with mutations in KRAS; low-grade endometrioid carcinomas arise from endometriosis via mutations in CTNNB1 (the gene encoding beta-catenin) and PTEN. Although the morphologic data strongly support an origin of clear cell carcinoma from endometriosis, there is limited data on the genetic alterations in these uncommon tumors. Thus it is likely that most low-grade, relatively indolent ovarian carcinomas of serous, mucinous and endometrioid type arise from pre-existing cystadenomas or endometriosis whereas most high-grade serous carcinomas arise without an easily identifiable precursor lesion.

Endometriosis-associated ovarian carcinoma: differential expression of vascular endothelial growth factor and estrogen/progesterone receptors

BACKGROUND

Multiple epidemiologic and histologic studies have suggested that ovarian endometriosis can give rise to malignant ovarian tumors, primarily those of epithelial origin. The progression of endometriosis to endometriosis-associated ovarian carcinoma (EAOC) has not been investigated thoroughly and is poorly understood at best. Using immunohistochemical methods, we compared the differential expression patterns of various cytokines and growth factors in atypical endometriosis (AE) and EAOC.

METHODS

Using the Johns Hopkins Pathology Data Bank, tissue blocks from patients diagnosed with EAOC or AE were identified. Tissue blocks were stained for 4 markers: vascular endothelial growth factor (VEGF), Ki-67, estrogen receptor (ER), and progesterone receptor (PR).

RESULTS

Seventeen cases of EAOC and 8 cases of AE were identified. Staining for VEGF was documented in 16 of 17 (94%) EAOC tissue blocks and in only 1 of 8 (12.5%) AE tissue blocks (P < 0.0001). Only 4 of the 17 (23%) EAOC tissue blocks exhibited positive staining for ER, compared with 8 of 8 (100%) AE tissue blocks (P = 0.0005). Positive staining for PR was noted in only 6 of 17 (35%) EAOC samples but was present in 8 of 8 (100%) AE samples (P = 0.003). Seventy percent of EAOC samples exhibited positive staining for Ki-67, compared with 37.5% of AE samples (P = 0.19).

CONCLUSIONS

EAOC appears to be associated with overexpression of VEGF and reduced expression of both ER and PR. Variations in VEGF expression may be associated with the malignant transformation of endometriosis and may present both diagnostic and therapeutic options for the treatment of ovarian malignancies.

Ovarian endometriosis associated with ovarian carcinoma: a clinicopathological and immunohistochemical study

OBJECTIVE

The purpose of this study was to demonstrate the incidence, the histopathological characteristics, and the proliferation activity of endometriosis and atypical endometriosis associated with ovarian carcinoma.

METHODS

Microscopic slides of primary lesions from 127 patients with primary ovarian carcinoma were reviewed. The presence or absence of endometriosis and the transitions from typical endometriosis to atypical endometriosis and from atypical endometriosis to carcinoma were also histologically evaluated. Ki-67 immunoreactivity of typical and atypical endometriosis and carcinoma was examined. In addition, endometrial metaplasias were also evaluated.

RESULTS

Of the 127 patients, 37 had endometriosis: 70% (30/43) had clear cell adenocarcinoma, 43% (3/7) had endometrioid adenocarcinoma, 7% (4/60) had serous adenocarcinoma, and none (0/17) had mucinous adenocarcinoma. Thirty-three cases showed typical endometriosis and 29 cases had atypical endometriosis (25 cases had both). Tufting and the stratification of the lining epithelium were observed in 25 and 23 cases, respectively. The transition from typical endometriosis to atypical endometriosis was observed in 22 cases, and the transition from atypical endometriosis to carcinoma, in 23 cases. Only one case showed a direct transition from typical endometriosis to carcinoma. The mean Ki-67 indices were as follows: ovarian carcinoma, 23.1; atypical endometriosis, 9.9; typical endometriosis, 2.7. In 18 cases with metaplasia in endometriosis, eosinophilic metaplasia and ciliated metaplasia were the most common types. Five cases had two types of metaplasia.

CONCLUSIONS

Ovarian carcinomas, especially clear cell and endometrioid adenocarcinomas, are highly associated with endometriosis. Atypical endometriosis shows proliferation activity intermediate to those of typical endometriosis and ovarian carcinoma, suggesting it is a precancerous status.