Molecular pathogenesis of endometrial and ovarian cancer

Pathway crosstalk analysis based on protein-protein network analysis in ovarian cancer

Ovarian cancer is the fifth leading cause of cancer death in women aged 35 to 74 years. Although there are several popular hypothesis of ovarian cancer pathogenesis, the genetic mechanisms are far from being clear. Recently, systems biology approaches such as network-based methods have been successfully applied to elucidate the mechanisms of diseases. In this study, we constructed a crosstalk network among ovarian cancer related pathways by integrating protein-protein interactions and KEGG pathway information. Several significant pathways were identified to crosstalk with each other in ovarian cancer, such as the chemokine, Notch, Wnt and NOD-like receptor signaling pathways. Results from these studies will provide the groundwork for a combination therapy approach targeting multiple pathways which will likely be more effective than targeting one pathway alone.

TC-1 (C8orf4) expression is correlated with differentiation in ovarian carcinomas and might distinguish metastatic ovarian from metastatic colorectal carcinomas

Thyroid cancer 1 (TC-1, C8orf4) is involved in the development of many cancers. In this study, we investigated the correlation between the expression of TC-1 and the clinicopathological characteristics of ovarian and colorectal adenocarcinomas. We also explored the possible use of TC-1 as a marker to distinguish between metastatic tumors of the ovary and colorectum. We used immunohistochemistry to examine the expression level of TC-1 in 100 ovarian and 100 colorectal adenocarcinomas and 25 metastatic carcinomas with the ovary or colorectum as primary site. TC-1 was expressed in all ovarian carcinoma samples. The high expression rate of TC-1 was 84 % in ovarian carcinomas, which was much higher than that observed in colorectal adenocarcinomas (35 %, P < 0.001). High expression of TC-1 significantly correlated with poor differentiation of ovarian carcinomas (P = 0.013). To explore the value of TC-1 in distinguishing metastatic ovarian cancers from colorectal cancers, we found the area under the receiver operator characteristic curve of TC-1 to be 0.819 (95 % confidence interval, 0.760-0.878; P < 0.001). Furthermore, TC-1 was highly expressed in 100 % of nine metastatic ovarian cancers, but only in 31 % of 16 metastatic colorectal cancers. The higher expression of TC-1 in ovarian compared to colorectal adenocarcinomas suggests its potential use as a marker, to distinguish between metastatic ovarian and colorectal adenocarcinomas.

Reproductive characteristics in relation to ovarian cancer risk by histologic pathways

STUDY QUESTION

Do reproductive risk factor associations differ across subgroups of invasive epithelial ovarian cancer (EOC) defined by the dualistic model (type I/II) or a histologic pathway-based classification?

SUMMARY ANSWER

Associations with parity, history of endometriosis, tubal ligation and hysterectomy were found to differ in the context of the type I/II and the histologic pathways classification of ovarian cancer.

WHAT IS KNOWN ALREADY

Shared molecular alterations and candidate precursor lesions suggest that tumor histology and grade may be used to classify ovarian tumors into likely etiologic pathways.

DESIGN

This case-control study included 1571 women diagnosed with invasive EOC and 2100 population-based controls that were enrolled from 1992 to 2008. Reproductive risk factors as well as other putative risk factors for ovarian cancer were assessed through in-person interviews.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible cases were diagnosed with incident ovarian cancer, were aged 18 and above and resided in eastern Massachusetts or New Hampshire, USA. Controls were identified through random digit dialing, drivers' license and town resident lists and were frequency matched with the cases based on age and study center.

MAIN RESULTS AND THE ROLE OF CHANCE

We used polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for type I/II EOC or using a pathway-based grouping of histologic subtypes. In multivariate analyses, we observed that having a history of endometriosis (OR = 1.92, 95% CI: 1.36-2.71) increased the risk for a type I tumor. Factors that were strongly inversely associated with risk for a type I tumor included parity (≥ 3 versus 0 children, OR = 0.15, 95% CI: 0.11-0.21), having a previous tubal ligation (OR = 0.40, 95% CI: 0.26-0.60) and more weakly hysterectomy (OR = 0.71, 95% CI: 0.45-1.13). In analyses of histologic pathways, parity (≥ 3 versus 0 children, OR = 0.13, 95% CI: 0.10-0.18) and having a previous tubal ligation (OR = 0.41, 95% CI: 0.28-0.60) or hysterectomy (OR = 0.54, 95% CI: 0.34-0.86) were inversely associated with risk of endometrioid/clear cell tumors. Having a history of endometriosis strongly increased the risk for endometrioid/clear cell tumors (OR = 2.41, 95% CI: 1.78-3.26). We did not observe significant differences in the risk associations across these tumor classifications for age at menarche, menstrual cycle length or infertility.

LIMITATIONS, REASONS FOR CAUTION

A potential limitation of this study is that dividing the cases into subgroups may limit the power of these analyses, particularly for the less common tumor types. Since cases were enrolled after their diagnosis, it is possible that the most aggressive cases were not included in the study.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides insights about the role of reproductive factors in relation to risk of pathway-based subgroups of ovarian cancer that with further confirmation may assist with the development of improved strategies for the prevention of these different tumor types.

STUDY FUNDING/COMPETING INTEREST(S)

This research is funded by grants from the National Cancer Institute, the Department of Defense Ovarian Cancer Research Program and the Ovarian Cancer Research Fund. The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Ovarian cancer: in search of better marker systems based on DNA repair defects

Ovarian cancer is the fifth most common female cancer in the Western world, and the deadliest gynecological malignancy. The overall poor prognosis for ovarian cancer patients is a consequence of aggressive biological behavior and a lack of adequate diagnostic tools for early detection. In fact, approximately 70% of all patients with epithelial ovarian cancer are diagnosed at advanced tumor stages. These facts highlight a significant clinical need for reliable and accurate detection methods for ovarian cancer, especially for patients at high risk. Because CA125 has not achieved satisfactory sensitivity and specificity in detecting ovarian cancer, numerous efforts, including those based on single and combined molecule detection and “omics” approaches, have been made to identify new biomarkers. Intriguingly, more than 10% of all ovarian cancer cases are of familial origin. BRCA1 and BRCA2 germline mutations are the most common genetic defects underlying hereditary ovarian cancer, which is why ovarian cancer risk assessment in developed countries, aside from pedigree analysis, relies on genetic testing of BRCA1 and BRCA2. Because not only BRCA1 and BRCA2 but also other susceptibility genes are tightly linked with ovarian cancer-specific DNA repair defects, another possible approach for defining susceptibility might be patient cell-based functional testing, a concept for which support came from a recent case-control study. This principle would be applicable to risk assessment and the prediction of responsiveness to conventional regimens involving platinum-based drugs and targeted therapies involving poly (ADP-ribose) polymerase (PARP) inhibitors.

Malignant tumors of the female reproductive system

This review summarizes the epidemiology of cancer of the female reproductive system and associated lifestyle factors. It also assesses the available evidence for occupational factors associated with these cancers. Cervical, endometrial, and ovarian cancers are relatively common, and cause significant cancer morbidity and mortality worldwide, whereas vulvar, vaginal, fallopian tube cancers, and choriocarcinomas are very rare. As several lifestyle factors are known to play a major role in the etiology of these cancers, very few published studies have investigated possible relationships with occupational factors. Some occupational exposures have been associated with increased risks of these cancers, but apart from the available evidence on the relationships between asbestos fibers and ovarian cancer, and tetrachloroethylene and cervical cancer, the data is rather scarce. Given the multifactorial nature of cancers of the female reproductive system, it is of the utmost importance to conduct occupational studies that will gather detailed data on potential individual confounding factors, in particular reproductive history and other factors that influence the body's hormonal environment, together with information on socio-economic status and lifestyle factors, including physical activity from multiple sources. Studies on the mechanisms of carcinogenesis in the female reproductive organs are also needed in order to elucidate the possible role of chemical exposures in the development of these cancers.

Endometrial Cancer: Comparison of Patients with Synchronous Primary Carcinoma of the Endometrium and Ovary vs. Endometrial Carcinoma with Ovarian Metastases

Purpose: The aim of our study was to investigate the rate of secondary carcinomas in patients with endometrial carcinoma (EC). In particular, we wanted to describe the subset of patients with endometrial and simultaneous ovarian carcinoma (OC), including outcomes. The study also compared patients with EC and ovarian metastasis with patients with EC and simultaneous OC. Patients and Methods: Data from 251 patients with primary endometrial carcinoma who underwent surgery in the years 2005-2009 at the Department of Obstetrics and Gynaecology, University of Tübingen, were analysed retrospectively. Results: A total of 28 patients (11.1 %) had a secondary carcinoma: 18 patients (7.1 %) had OC; 9 (3.5 %) patients had a history of breast cancer, and one patient (0.4 %) respectively had simultaneous carcinoma of the vulva or bladder. 14 patients (5.5 %) had advanced stage EC with ovarian metastasis or, in one case, metastasis to the ovarian tube. Patients with ovarian metastasis had a mean age of 71.2 ± 9.2 years at primary diagnosis, making them significantly older compared to patients with EC and simultaneous OC (55.3 ± 11.8 years, p < 0.001). Moreover, patients with ovarian metastasis significantly more often had EC with a higher tumour grade (grade 1: 0, grade 2: 21.4 %, grade 3: 78.6 %) compared to patients with simultaneous EC and OC (grade 1: 11.1 %, grade 2: 77.8 %, grade 3: 11.1 %; p < 0.001). Conclusion: Almost one in 10 patients with EC had a secondary carcinoma. The most common secondary carcinoma was OC followed by breast cancer. This should be taken into account in the diagnosis and therapy of patients with EC. Patients with simultaneous EC and OC were significantly younger than patients with EC and ovarian metastasis. In addition, their tumour had better prognostic features: thus, the tumour grade of the EC was significantly lower. Overall, the prognosis for patients with synchronous EC and OC is better than that for patients with EC and ovarian metastasis.

Overexpression of enhancer of zeste homolog 2 (EZH2) and focal adhesion kinase (FAK) in high grade endometrial carcinoma

OBJECTIVE

The deregulation of E-cadherin is associated with Src/FAK signaling axis and histone deacetylase (HDAC)/EZH2 activity. However, the association between EZH2 and FAK and its clinical significance in endometrial carcinoma has not been reported.

METHODS

202 archived cases of endometrial carcinoma (1996-2000) were reviewed and divided into two subtypes. TMAs were developed as per established procedures. EZH2, FAK, and pFAK immunohistochemical stains were performed and the expression was scored as negative (0), low (1) and high (2). Proper statistical analysis was used to assess the correlation between the expression profiles and the clinicopathological parameters and clinical outcome.

RESULTS

A total of 141 (69.8%) type-1 tumors and 61 (30.2%) type-2 tumors were identified. EZH2 overexpression was identified in 7.6% of type-1 tumors vs. 63% of type-2 tumors (p<0.001). FAK and pFAK overexpression was only seen in 24.8% and 1.7% of Type-1 tumors as compared to 72% and 58.8% of type-2 tumors, respectively (p<0.001). A positive correlation between the expression of EZH2, FAK, pFAK and PTEN (p<0.0001) was found. The overexpression of EZH2, FAK, and pFAK were significantly associated with high histologic grade, angiolymphatic invasion, lymph node metastasis, myometrial invasion and cervical involvement (p<0.01). Kaplan-Meier analysis demonstrates that the overexpression of EZH2 (p=0.0024), FAK and pFAK (p=0.0001) was significantly associated with decreased overall survival.

CONCLUSION

The overexpression of EZH2, FAK and pFAK correlates with well established pathologic risk factors and may predict a more aggressive biologic behavior in endometrial carcinoma, transforming these proteins into potential therapeutic targets for treatment of endometrial cancer.

The emerging role of CXC chemokines in epithelial ovarian cancer

In recent years, chemokines have generated intense investigations due to their involvement in both physiological and pathological processes of inflammation, particularly in ovarian biology. The physiological process of ovulation in the normal ovary involves various chemokines that mediate the healing of the ruptured endometrium. It is now being reported that many of these chemokines are also associated with the cancer of the ovary. Chronic inflammation underlies the progression of ovarian cancer; therefore, it raises the possibility that chemokines are involved in the inflammatory process and mediate immune responses that may favour or inhibit tumour progression. Ovarian cancer is a gynaecological cancer responsible for highest rate of mortality in women. Although there have been several investigations and advances in surgery and chemotherapy, the survival rate for this disease remains low. This is mainly because of a lack of specific symptoms and biomarkers for detection. In this review, we have discussed the emerging role of the CXC chemokines in epithelial ovarian cancer (EOC). The CXC group of chemokines is gaining importance in the field of ovarian cancer for being angiostatic and angiogenic in function. While there have been several studies on the angiogenesis function, emerging research shows that ELR(-) CXC chemokines, CXCL9 and CXCL10, are angiostatic. Importantly, the angiostatic chemokines can inhibit the progression of EOC. Given that there are currently no biomarkers or specific therapeutic targets for the disease, these chemokines are emerging as promising targets for therapy.