A multivariate approach to the integration of multi-omics datasets

BACKGROUND

To leverage the potential of multi-omics studies, exploratory data analysis methods that provide systematic integration and comparison of multiple layers of omics information are required. We describe multiple co-inertia analysis (MCIA), an exploratory data analysis method that identifies co-relationships between multiple high dimensional datasets. Based on a covariance optimization criterion, MCIA simultaneously projects several datasets into the same dimensional space, transforming diverse sets of features onto the same scale, to extract the most variant from each dataset and facilitate biological interpretation and pathway analysis.

RESULTS

We demonstrate integration of multiple layers of information using MCIA, applied to two typical "omics" research scenarios. The integration of transcriptome and proteome profiles of cells in the NCI-60 cancer cell line panel revealed distinct, complementary features, which together increased the coverage and power of pathway analysis. Our analysis highlighted the importance of the leukemia extravasation signaling pathway in leukemia that was not highly ranked in the analysis of any individual dataset. Secondly, we compared transcriptome profiles of high grade serous ovarian tumors that were obtained, on two different microarray platforms and next generation RNA-sequencing, to identify the most informative platform and extract robust biomarkers of molecular subtypes. We discovered that the variance of RNA-sequencing data processed using RPKM had greater variance than that with MapSplice and RSEM. We provided novel markers highly associated to tumor molecular subtype combined from four data platforms. MCIA is implemented and available in the R/Bioconductor "omicade4" package.

CONCLUSION

We believe MCIA is an attractive method for data integration and visualization of several datasets of multi-omics features observed on the same set of individuals. The method is not dependent on feature annotation, and thus it can extract important features even when there are not present across all datasets. MCIA provides simple graphical representations for the identification of relationships between large datasets.

Inhibitory role of prohibitin in human ovarian epithelial cancer

OBJECTIVES

To characterize the exact individual roles of gonadotropins on ovarian epithelial carcinogenesis, an earlier study showed that prohibitin was significantly up-regulated by luteinizing hormone (LH). To further clarify the role of prohibitin in ovarian carcinogenesis and its association with LH, herein we studied the expression of prohibitin in various ovarian tissues including different developmental stages of ovarian epithelial tumors.

METHODS

A total of 135 samples were studied by immunohistochemistry. These included benign ovarian cases with follicles, ovarian surface epithelia and ovarian epithelial inclusions (OEI) (n=30), serous cystadenoma (n=14), serous borderline tumor (n=12), serous carcinoma (n=20), mucinous cystadenoma (n=10), mucinous borderline tumor (n=10), mucinous carcinomas (n=10), endometrioid carcinomas (n=12), poorly/undifferentiated carcinomas (n=5), and fallopian tube (n=12).

RESULTS

Strong and diffuse staining of prohibitin was detected in luteinized ovarian stromal cells, follicular cells, fallopian tube, and OEI with serous differentiation. A significantly higher prohibitin expression in luteinized stromal cells than in non-luteinized stromal cells was observed (P<.01). Within the ovarian epithelium, the level of prohibitin expression was basically negative in ovarian surface epithelia, but highly expressed in OEI. However, compared to the level of prohibitin expression in OEI, it showed a trend of gradual loss from benign ovarian tumors, to borderline tumors and to carcinomas (P<.0001). Compared to the serous tumors, epithelial tumors with mucinous differentiation showed a significant lower level of prohibitin (P<.0001). An inverse correlation was noted between prohibitin expression and cancer grade. It is interesting to note that a high prohibitin expression level was seen in the fallopian tube, which is similar to OEI.

CONCLUSIONS

These data further suggest that prohibitin plays a tumor suppressing role, which is probably associated with LH mediated protection role against ovarian epithelial carcinoma. In addition to the tumor suppressive role of prohibitin, it also plays a role in cellular differentiation, which may be helpful to differentiate ovarian mucinous tumors from the tumors with serous differentiation in clinical settings. More importantly, our findings are supportive that the ovarian epithelial cancers, particularly the serous cancers including those precursors with serous differentiation are likely to be derived from fallopian tube instead of ovarian surface epithelia.

Proteomic analysis of cancer and mesothelial cells reveals an increase in Mucin 5AC during ovarian cancer and peritoneal interaction

Ovarian cancer is a highly metastatic disease that is often characterized by widespread abdominal dissemination. A hallmark of ovarian cancer progression is the attachment of malignant cells to the mesothelium and the formation of invasive peritoneal implants. Therefore, delineating factors involved in cancer-peritoneal cell interaction is critical to improving patient survival, as it may lead to the discovery of novel therapeutic targets. As such, we aimed to identify proteins that participate in this interaction by comparing the secreted proteome of a co-culture model containing ovarian cancer (OVCAR-5) and mesothelial cells (LP-9), to their respective monoculture secretomes. In total, 49 proteins were differentially secreted during cancer and mesothelial cell contact. Relative mRNA expression of candidates was performed, which revealed a significant increase in MUC5AC gene expression in cancer cells cultured in three different co-culture models (OVCAR-5 and LP-9; BG-1 and LP-9; OV-90 and LP-9). An increased expression was also observed in LP-9 cells that were co-cultured with OVCAR-5 and OV-90 cancer cells. Further immunocytochemistry analysis also confirmed increased expression of MUC5AC in ovarian cancer and peritoneal co-cultures. Overall, our analysis uncovers novel molecular markers of peritoneal metastasis, which may have potential roles in regulating the progression of the disease.

BIOLOGICAL SIGNIFICANCE

In this study, our objective was to focus on identifying novel mediators of ovarian cancer and peritoneal interaction using a mass spectrometry-based approach. Our analysis resulted in the discovery of both previously known and novel factors involved this interaction, and as such, these newly discovered proteins might have potential roles in cancer progression, such as invasion and adhesion. We believe that these findings add to our current knowledge and understanding of ovarian cancer progression, and will aid researchers in their future attempts in finding new targets of the disease.

Metastatic ovarian papillary cystadenocarcinoma to the small intestine serous surface: report of a case of high-grade histopathologic malignancy

Ovarian cystadenocarcinoma is characterized by marked heterogeneity and may be composed of an admixture of histologic growth patterns, including acinar, papillary and solid. In the present study, a case of isolated small intestine metastasis of ovarian papillary cystadenocarcinoma was reported. A 7-year-old female mixed-breed dog presented with a mass in the left upper quadrant with progressive enlargement of the abdomen, periodic bloody discharge from the vulva and incontinence. The tumor was histologically characterized by the presence of cysts and proliferation of papillae, both lined by single- or multi-layered pleomorphic epithelial cells. Furthermore, the mass was composed by intense cellular and nuclear pleomorphism and numerous mitotic figures. These findings indicate a tumor of high-grade malignancy with infiterative tumor cells resembling the papillary ovarian tumor in the serosal surface of the small intestine along with an intact serosa. Immunohistochemically, tumor was positive for CK7 and negative immunoreactivity for CK20. The histopathologic features coupled with the CK7 immunoreactivity led to a diagnosis of high grade ovarian papillary cystadenocarcinoma. To the best of our knowledge, this is the first case of small intestine serousal surface metastasis from ovarian papillary cystadenocarcinoma.

A high M1/M2 ratio of tumor-associated macrophages is associated with extended survival in ovarian cancer patients

BACKGROUND

Tumor-associated macrophages (TAMs) are classified into two major phenotypes, M1 and M2. M1 TAMs suppress cancer progression, while M2 TAMs promote it. However, little is known regarding the role of TAMs in the development of ovarian cancer. Here, we investigated the relationship between TAM distribution patterns (density, microlocalization, and differentiation) and ovarian cancer histotypes, and we explored whether altered TAM distribution patterns influence long-term outcomes in ovarian cancer patients.

METHODS

A total of 112 ovarian cancer patients were enrolled in this study, and the subjects were divided into two groups according to their survival (< 5 years vs. ≥ 5 years). Immunohistochemistry and immunofluorescence were used to determine the density, microlocalization, and differentiation status of TAMs in ovarian cancer tissues for each histotype. Kaplan-Meier survival and multivariate Cox regression analyses were used to evaluate the prognostic significance of TAM-related parameters in ovarian cancer.

RESULTS

TAMs most frequently infiltrated into the cancer tissue of the serous histotype, followed by mucinous, undifferentiated, endometrioid, and clear cell histotypes (p = 0.049). The islet/stroma ratio of total TAMs varied among the cancer histotypes, with mucinous and undifferentiated cancers displaying the lowest and highest ratios, respectively (p = 0.005). The intratumoral TAM density significantly increased with increasing cancer stage and grade (p = 0.023 and 0.006, respectively). However, the overall M1/M2 TAM ratio decreased as the cancer stage increased (p = 0.012). In addition, the intra-islet M1/M2 ratio inversely correlated with the residual site size (p = 0.004). Among the TAM-related parameters, only the increased overall and intra-islet M1/M2 TAM ratios displayed prognostic significance in both the Kaplan-Meier survival and multivariate Cox regression analyses; however, the values of these two parameters did not differ significantly among the cancer histotypes.

CONCLUSIONS

The patients with increased overall or intra-islet M1/M2 TAM ratios presented with an improved 5-year prognosis. Nevertheless, the TAM distribution patterns did not influence the overall outcomes of different ovarian cancer histotypes.

Biomarkers for predicting complete debulking in ovarian cancer: lessons to be learned

AIM

We aimed to construct and validate a model based on biomarkers to predict complete primary debulking surgery for ovarian cancer patients.

PATIENTS AND METHODS

The study consisted of three parts: Part I: Biomarker data obtained from mass spectrometry, baseline data and, surgical outcome were used to construct predictive indices for complete tumour resection; Part II: sera from randomly selected patients from part I were analyzed using enzyme-linked immunosorbent assay (ELISA) to investigate the correlation to mass spectrometry; Part III: the indices from part I were validated in a new cohort of patients.

RESULTS

Part I: The area under the receiver operating characteristic curve (AUC) was 0.82 for both indices. Part II: Linear regression analysis gave an R(2) value of 0.52 and 0.63 for transferrin and β2-microglobulin, respectively. Part III: The AUC of the two indices decreased to 0.64.

CONCLUSION

Our validated model based on biomarkers was unable to predict surgical outcome for patients with ovarian cancer.

Platelet-derived growth factor receptor alpha (PDGFRα) targeting and relevant biomarkers in ovarian carcinoma

OBJECTIVE

Platelet-derived growth factor receptor alpha (PDGFRα) is believed to be associated with cell survival. We examined (i) whether PDGFRα blockade enhances the antitumor activity of taxanes in ovarian carcinoma and (ii) potential biomarkers of response to anti-PDGFRα therapy.

METHODS

PDGFRα expression in 176 ovarian carcinomas was evaluated with tissue microarray and correlated to survival outcome. Human-specific monoclonal antibody to PDGFRα (IMC-3G3) was used for in vitro and in vivo experiments with or without docetaxel. Gene microarrays and reverse-phase protein arrays with pathway analyses were performed to identify potential predictive biomarkers.

RESULTS

When compared to low or no PDGFRα expression, increased PDGFRα expression was associated with significantly poorer overall survival of patients with ovarian cancer (P=0.014). Although treatment with IMC-3G3 alone did not affect cell viability or increase apoptosis, concurrent use of IMC-3G3 with docetaxel significantly enhanced sensitization to docetaxel and apoptosis. In an orthotopic mouse model, IMC-3G3 monotherapy had no significant antitumor effects in SKOV3-ip1 (low PDGFRα expression), but showed significant antitumor effects in HeyA8-MDR (high PDGFRα expression). Concurrent use of IMC-3G3 with docetaxel, compared with use of docetaxel alone, significantly reduced tumor weight in all tested cell lines. In protein ontology, the EGFR and AKT pathways were downregulated by IMC-3G3 therapy. MAPK and CCNB1 were downregulated only in the HeyA8-MDR model.

CONCLUSION

These data identify IMC-3G3 as an attractive therapeutic strategy and identify potential predictive markers for further development.

Importance of spondin 1 and cellular retinoic acid binding protein 1 in the clinical diagnosis of ovarian cancer

BACKGROUND

Diagnosis of ovarian cancer is often delayed because of subtle symptoms and a lack of a specific, sensitive test useful for the general population. The majority of cases are diagnosed at late stages, after the tumor has metastasized and implanted on many other abdominal organs and cavity surfaces. A paucity of prognostic markers makes it difficult to define which tumors will act aggressively and shorten survival. Hence, it is imperative to have new screening tests for diagnosis of ovarian cancer at earlier stages, prior to metastatic progression. Diagnosis at these early stages will dramatically increase the overall survival of women with ovarian cancer.

MATERIAL AND METHODS

Based on previously published literature on proposed molecular cell markers in ovarian carcinoma, we sought to validate the overexpression of two genes (cellular retinoic acid Binding Protein, CRABP-1, and spondin 1) through immunohistochemistry.

RESULTS

We verified the overexpression of spondin 1 in ovarian cancer. Expression of cellular retinoic acid Binding Protein, CRABP-1 in whole ovarian cancer tissue sections was higher than in the TMA tissue cores.

CONCLUSION

Our results thus demonstrate that spondin 1 is a useful marker for ovarian cancer; additionally, the high percentages of tumors that are positive for spondin 1 make it an ideal target for therapy. CRABP-1 was not expressed at high levels in any subtype of ovarian cancer, making it a poor marker.

Leiomyomatosis peritonealis disseminata coexisting with endometriosis within the same lesions: a case report with review of the literature

Leiomyomatosis peritonealis disseminata (LPD) is an extremely rare condition, which is characterized by the presence of multiple peritoneal and subperitoneal nodules composed of bland smooth muscle cells. Albeit extremely rare, coexistence of endometriosis within LPD lesions has also reported. Herein, we report the seventh documented case of LPD coexisting with endometriosis within the same lesions and review the pathogenesis of this lesion. A 42-year-old Japanese female presented with an abdominal tumor. Computed tomography revealed a tumorous lesion in the right ovary and multiple small nodules in the abdominal cavity. Under a clinical diagnosis of ovarian cancer with peritoneal dissemination, resection of these lesions was performed. Histopathological study of the disseminated peritoneal nodules revealed proliferation of interlacing bundles of spindle cells with eosinophilic cytoplasm and bland cigar-shaped nuclei. Mitotic figures were hardly seen. The peritoneal nodules of the rectum had cystic cavities within the spindle cell bundles, and endometrial glands and stroma were present around the cystic cavities and spindle cells. The resected tissues of the ovary and cecum showed the same histopathological features. Accordingly, a diagnosis of LPD with endometriosis within the same lesions was made. A possible origin of LPD is thought to be the submesothelial multipotential stem cells, also referred to as the secondary müllerian system. The presence of endometrial tissues within LPD lesions, as seen in the present case, also support this hypothesis because endometrial tissues are also derived from the müllerian system.

Ovarian cancers arising from endometriosis: a microenvironmental biomarker study including ER, HNF1ß, p53, PTEN, BAF250a, and COX-2

BACKGROUND

The microenvironmental biomarkers of different subtypes of ovarian cancers arising from endometriosis have not been studied in Taiwan. Their expression can help in understanding the carcinogenic mechanism.

METHODS

Our study used immunohistochemistry to compare the expression of estrogen receptor (ER), hepatocyte nuclear factor-1 beta (HNF1ß), p53, phosphatase and tensin homolog (PTEN), BAF250a, and cyclooxygenase-2 (COX-2) among 79 cases of endometriosis-associated ovarian cancers, including 40 (50%) clear cell carcinomas (CCCs), 33 (41%) endometrioid (EM) adenocarcinomas, four (5%) serous carcinomas, one adenosquamous carcinoma, and one adenosarcoma.

RESULTS

Positive stainings for ER, HNF1ß, p53, and COX-2 were identified in 34 (43%), 30 (38%), 10 (13%), and 44 (56%) cases. Loss of PTEN and BAF250a were noted in 29 (37%) and 37 (47%) cases. The expression of ER was reversely correlated with that of HNF1ß (rho = -0.417, p < 0.001) and correlated with p53 (rho = 0.284, p = 0.011). ER positivity was commonly identified in EM adenocarcinomas (91%), and rarely in CCCs (8%) and serous carcinoma (0%; p < 0.001). By contrast, HNF1ß expression was frequently noted in CCCs (65%) and serous carcinomas (50%), but less in EM adenocarcinoma (6%; p < 0.001). All staining results were similar between atypical endometriosis glandular epithelium and contiguous malignant parts. Only nine cases showed 10 minor differences (10/474, 2%) in ER, HNF1ß, and BAF250a. For the staining patterns of p53, COX-2, and PTEN, there was no difference between the invasive and precursor parts.

CONCLUSION

Our results supported the suggestion that estrogen-dependent ovarian cancer arising from endometriosis is substantially more associated with EM adenocarcinoma than CCCs. The positive HNF1ß staining was a frequent finding in CCCs, but not in EM adenocarcinoma. The similar staining patterns of atypical endometriosis glandular cells with the invasive parts confirmed their precursor status.

A dendritic cell vaccine pulsed with autologous hypochlorous acid-oxidized ovarian cancer lysate primes effective broad antitumor immunity: from bench to bedside

PURPOSE

Whole tumor lysates are promising antigen sources for dendritic cell (DC) therapy as they contain many relevant immunogenic epitopes to help prevent tumor escape. Two common methods of tumor lysate preparations are freeze-thaw processing and UVB irradiation to induce necrosis and apoptosis, respectively. Hypochlorous acid (HOCl) oxidation is a new method for inducing primary necrosis and enhancing the immunogenicity of tumor cells.

EXPERIMENTAL DESIGN

We compared the ability of DCs to engulf three different tumor lysate preparations, produce T-helper 1 (TH1)-priming cytokines and chemokines, stimulate mixed leukocyte reactions (MLR), and finally elicit T-cell responses capable of controlling tumor growth in vivo.

RESULTS

We showed that DCs engulfed HOCl-oxidized lysate most efficiently stimulated robust MLRs, and elicited strong tumor-specific IFN-γ secretions in autologous T cells. These DCs produced the highest levels of TH1-priming cytokines and chemokines, including interleukin (IL)-12. Mice vaccinated with HOCl-oxidized ID8-ova lysate-pulsed DCs developed T-cell responses that effectively controlled tumor growth. Safety, immunogenicity of autologous DCs pulsed with HOCl-oxidized autologous tumor lysate (OCDC vaccine), clinical efficacy, and progression-free survival (PFS) were evaluated in a pilot study of five subjects with recurrent ovarian cancer. OCDC vaccination produced few grade 1 toxicities and elicited potent T-cell responses against known ovarian tumor antigens. Circulating regulatory T cells and serum IL-10 were also reduced. Two subjects experienced durable PFS of 24 months or more after OCDC.

CONCLUSIONS

This is the first study showing the potential efficacy of a DC vaccine pulsed with HOCl-oxidized tumor lysate, a novel approach in preparing DC vaccine that is potentially applicable to many cancers.

Synchronous ovarian dysgerminoma and breast carcinoma in a patient with positive immunostain of BRCA1

Breast cancer is the most common malignant neoplastic process and the second cause of death for women. Ovarian cancer, despite having a lower incidence, represents an important cause of morbidity and mortality because it is usually discovered in advanced stages. The presence of both forms of cancer in a patient is associated with a high risk of BRCA1 gene mutations, which are responsible, together with BRCA2 gene mutations, for most of the breast and ovarian cancer family. Our case is special because it presents a synchronous and a rare association of a primary ovarian dysgerminoma (with an incidence of less than 1% of ovarian cancers) and a primary breast carcinoma in a patient of 46 years old. Immunohistochemical examination was performed using a panel of five biomarkers: oestrogen receptor, progesterone receptor, Herceptest, p53 and BRCA1. In our case, we identified a negative hormonal status and the absence of HER2/neu expression but a positive immuno-expression for p53 protein and BRCA1 protein. Postoperative course was favourable for the patient after each surgery, and she was discharged with the recommendation to perform a genetic counselling.

[Biomarkers in solid tumors]

In the past decade the revolutionary development of molecular technology contributed a lot to the increase of our knowledge on cancer. These informations led to the discovery and understanding of those key regulatory changes in the genesis and progression of malignancies that can serve as targets in tumor diagnostics and therapy. One of the main challenges in the research field is to identify the most important molecular networks, the molecular targets, the markers (biomarkers) which can predict therapeutic responsiveness in order to select the appropriate patients, as well as markers to judge the prognosis of the disease. The aims of our study approached some details of the biomarker area and reached certain conclusions: (1) The anti-EGFR therapy, used in the second line or even further, proved to be effective, providing clinical advantage (operability, regression) in 36% of patients carrying wild-type KRAS. G13D mutations were the most frequent among the KRAS-mutants, which, according to current data, could react to anti-EGFR therapy. (2) Extended immunohistochemical (IHC) analysis on colorectal cancer samples (using tissue microarray) found rather few correlations between the IHC estimation and the clinical characteristics related mainly to survival. According to the results with anti-EGFR antibodies in the diagnostic histological samples, the regulatory pathway which rules the proliferation of normal colonic mucosa is also present in colonic cancer cells. This finding is supported by the increased ativity of the downstream members (as RAS, RAF, ERK) of the EGFR signalling. (3) The level of D-dimer increased at least as much as the level of classical tumor markers in the early stages of tumor growth. D-dimer can be considered as a prognostic factor in tumor types studied (breast-, colorectal-, ovarian cancers) and its measurement is advised besides the classical markers. We hope that these results may contribute to the design of a more individual-based and more effective antitumor strategy.

Isomer-specific chromatographic profiling yields highly sensitive and specific potential N-glycan biomarkers for epithelial ovarian cancer

Aberrant glycosylation has been observed for decades in essentially all types of cancer, and is now well established as an indicator of carcinogenesis. Mining the glycome for biomarkers, however, requires analytical methods that can rapidly separate, identify, and quantify isomeric glycans. We have developed a rapid-throughput method for chromatographic glycan profiling using microfluidic chip-based nanoflow liquid chromatography (nano-LC)/mass spectrometry. To demonstrate the utility of this method, we analyzed and compared serum samples from epithelial ovarian cancer cases (n=46) and healthy control individuals (n=48). Over 250 N-linked glycan compound peaks with over 100 distinct N-linked glycan compositions were identified. Statistical testing identified 26 potential glycan biomarkers based on both compositional and structure-specific analyses. Using these results, an optimized model was created incorporating the combined abundances of seven potential glycan biomarkers. The receiver operating characteristic (ROC) curve of this optimized model had an area under the curve (AUC) of 0.96, indicating robust discrimination between cancer cases and healthy controls. Rapid-throughput chromatographic glycan profiling was found to be an effective platform for structure-specific biomarker discovery.

The role of estrogen in the survival of ovarian tumors--a study of the human ovarian adenocarcinoma cell lines OC-117-VGH and OVCAR3

BACKGROUND

The role of estrogen in the growth and survival of ovarian cancer cells is controversial. In this study, we investigated the changes in cell-cycle regulatory proteins in ovarian cancer cell lines after estrogen treatment to explore the role of estrogen in ovarian cancers.

METHODS

Two ovarian adenocarcinoma cell lines were used for the study: the first, OC-117-VGH, was deficient in estrogen receptors (ER)α and ERβ, and the second, OVCAR3, was positive for ERα and ERβ. Serial concentrations of estrogen were used to evaluate the effects of estrogen on the survival of ovarian cancer cells. The cell-cycle regulatory proteins, including cyclin D1, cyclin E, p16/INK4a, and p27/KIP1, were used to check the possible mechanism of an estrogen effect on survival of the cancer cell line.

RESULTS

Estrogen 0.01-1.0 μM inhibited the growth of both cell lines. There were no differences in cyclin D1 and E expression between the two cell lines after estrogen treatment, but the expression of p16/INK4a and p27/KIP1 was significantly higher in the OC-1170-VGH cell line than in the OVCAR3 cell line.

CONCLUSION

Although the ER-positive and ER-negative ovarian cancer cell lines were inhibited by estrogen, the influence of cell-cycle regulatory proteins was different between the two, suggesting that the inhibitory effect of estrogen on ovarian cancer cell lines might be mediated through different pathways.

Rare epithelial tumors arising in or near the ovary: a review of the risk factors, presentation, and future treatment direction for ovarian clear cell and mucinous carcinoma

Currently all advanced-stage epithelial ovarian cancers are treated with a total abdominal hysterectomy, bilateral oophorectomy, and complete tumor debulking surgery, followed by carboplatin and paclitaxel. This treatment recommendation is based on clinical trials that are mostly populated with women with high-grade serous carcinomas. Patients with mucinous or clear cell carcinomas of the ovary tend to present with earlier-stage disease, and may not require adjuvant chemotherapy; those with advanced-stage disease tend to have carboplatin-resistant disease. Patients with mucinous ovarian carcinoma have presentations and tumor biology that are similar to colorectal carcinomas and may benefit from colorectal regimens containing fluorouracil (FU) and oxaliplatin. Their tumors may also be KRAS wild-type or have HER2 amplification, and could benefit from drugs like cetuximab or trastuzumab. Patients with clear cell carcinoma of the ovary often harbor AIRD1a mutations, an early event in oncogenesis that is not a currently drugable target. Anecdotal cases and our biologic understanding of these malignancies suggest they might be preferentially sensitive to antiangiogenesis inhibitors. Focused international trials will be needed in both of these rare epithelial ovarian cancers to better define optimal treatment regimens.

The life and times of low-grade serous carcinoma of the ovary

For the past several years, all women with epithelial ovarian cancer have been treated identically, whether in a clinical trial or off protocol. Over the past decade, we have come to appreciate the magnitude of the heterogeneity of ovarian cancer. The development of the binary grading system for serous carcinoma was a major advance, leading to separate clinical trials for patients with this subtype, originating from the Gynecologic Oncology Group's Rare Tumor Committee. The mitogen-activated protein kinase (MAPK) pathway appears to play a prominent role in the pathogenesis of this subtype. Approximately 20% to 40% of low-grade serous carcinomas have a KRAS mutation, while BRAF mutations are rare-approximately 5%. In genomic profiling studies, these tumors appear to cluster with serous tumors of low malignant potential. Compared with high-grade serous carcinomas, low-grade serous carcinomas are also characterized by a low frequency of p53 mutations, greater expression of ER and PR, and greater expression of PAX2 and IGF-1. Primary treatment of low-grade serous carcinoma includes surgery plus platinum-based chemotherapy (either adjuvant or neoadjuvant). Clinical behavior is characterized by young age at diagnosis, relative chemoresistance, and prolonged overall survival. Current options for treatment of relapsed disease include secondary cytoreduction in selected patients, salvage chemotherapy, or hormone therapy. A recently completed trial of a MEK inhibitor for women with recurrent disease demonstrated promising activity. Future directions will include further investigations of the molecular biology and biomarker-driven clinical trials with targeted agent monotherapy and combinations.

[Preparation, identification and application of monoclonal antibody against matrix metalloproteinases-2]

AIM

To prepare and characterize monoclonal antibodies against matrix metalloproteinase-2 (MMP-2), check its expression in the tissues of human ovarian cancer and transplanted tumors in nude mice.

METHODS

MMP-2 were linked to the carrier protein bovine serumalbumin (BSA) and keyhole limpet hemocyanin (KLH) using glutaraldehyde method to obtain MMP-2-BSA and MMP-2-KLH, respectively. The anti-MMP-2 monoclonal antibody was obtained through hybridoma technique. We established the cell strains secreting mAb by hybridoma technique and prepared the mAb by induction of ascites in vivo. The prepared mAb was purified by salting out with ammonium sulfate and identified by ELISA and Western blotting. We compared the mAb and commercial polyclonal antibody by immunohistochemistry and detected the expressions of MMP-2 and CA125 in ovarian cancer issues and transplanted tumor.

RESULTS

The artificial antigen and 3 hybridoma cell lines secreting monoclonal antibodies (mAb) against MMP-2 were obtained. The subclasses of mAb were all IgG1. The titer of peritoneal exudates was 1:1×10(6);. The expressions of MMP-2 and CA125 in transplanted tumor and ovarian cancer tissues were all high. The positive expression rate of MMP-2 checked using generated antibody was 71.2%(57/80) in ovarian cancer tissues and 16.67% (5/30) in normal tissues, with significant difference between them (P<0.01). In early stage, the positive rate of MMP-2 and CA125 combined detection was higher than that of CA125 detection alone (P<0.01). The mAb was suitable for detecting the expression of MMP-2 in human tissues and gave results consistent with commercial polyclonal antibody. The mAb was more specific than commercial mAb (P<0.01).

CONCLUSION

The anti-human MMP-2 mAb is successfully prepared, which may serve as a valuable tool in the functionaI studies of ovarian cancer.

Current approach to epithelial ovarian cancer based on the concept of cancer stem cells

Epithelial ovarian cancer (EOC) is the most common ovarian malignancy. EOCs comprise a diverse group of neoplasms, exhibiting a wide range of morphological characteristics, genetic alterations, and biological behaviors. Currently, there is no effective screening for early detection of EOCs and more than two-thirds of EOC patients are diagnosed with advanced stage disease. The major limiting factors in the treatment of EOC patients are recurrence and chemoresistance. Recent studies suggest that EOCs, like other solid tumors, contain distinct populations of cells that are responsible for tumor initiation, maintenance and growth. These cells, termed cancer stem cells (CSCs), display some of the features of normal stem cells and are thought to evade current chemotherapeutic strategies for the treatment of EOCs. Distinguishing CSC-associated antigen profiles may elucidate novel, more sensitive biomarkers for early detection of EOCs and provide molecular targets for the development of new treatment modalities. This review summarizes the current approaches to EOCs based on the concept of CSCs and evaluates their clinical relevance.

A DNA repair pathway-focused score for prediction of outcomes in ovarian cancer treated with platinum-based chemotherapy

Background

New tools are needed to predict outcomes of ovarian cancer patients treated with platinum-based chemotherapy. We hypothesized that a molecular score based on expression of genes that are involved in platinum-induced DNA damage repair could provide such prognostic information.

Methods

Gene expression data was extracted from The Cancer Genome Atlas (TCGA) database for 151 DNA repair genes from tumors of serous ovarian cystadenocarcinoma patients (n = 511). A molecular score was generated based on the expression of 23 genes involved in platinum-induced DNA damage repair pathways. Patients were divided into low (scores 0–10) and high (scores 11–20) score groups, and overall survival (OS) was analyzed by Kaplan–Meier method. Results were validated in two gene expression microarray datasets. Association of the score with OS was compared with known clinical factors (age, stage, grade, and extent of surgical debulking) using univariate and multivariable Cox proportional hazards models. Score performance was evaluated by receiver operating characteristic (ROC) curve analysis. Correlations between the score and likelihood of complete response, recurrence-free survival, and progression-free survival were assessed. Statistical tests were two-sided.

Results

Improved survival was associated with being in the high-scoring group (high vs low scores: 5-year OS, 40% vs 17%, P < .001), and results were reproduced in the validation datasets (P < .05). The score was the only pretreatment factor that showed a statistically significant association with OS (high vs low scores, hazard ratio of death = 0.40, 95% confidence interval = 0.32 to 0.66, P < .001). ROC curves indicated that the score outperformed the known clinical factors (score in a validation dataset vs clinical factors, area under the curve = 0.65 vs 0.52). The score positively correlated with complete response rate, recurrence-free survival, and progression-free survival (Pearson correlation coefficient [r²] = 0.60, 0.84, and 0.80, respectively; P < .001 for all).

Conclusion

The DNA repair pathway–focused score can be used to predict outcomes and response to platinum therapy in ovarian cancer patients.