Progression Of High-grade Serous Carcinoma Research Articles

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis

Abstract B069: Bone marrow-derived adipocytes promote ovarian cancer progression and metastasis

Norepinephrine induces anoikis resistance in high-grade serous ovarian cancer precursor cells.

High-grade serous carcinoma (HGSC) is the most lethal gynecological malignancy in the United States. Late diagnosis and the emergence of chemoresistance have prompted studies into how the tumor microenvironment, and more recently tumor innervation, may be leveraged for HGSC prevention and interception. In addition to stess-induced sources, concentrations of the sympathetic neurotransmitter norepinephrine (NE) in the ovary increase during ovulation and after menopause. Importantly, NE exacerbates advanced HGSC progression. However, little is known about the role of NE in early disease pathogenesis. Here, we investigated the role of NE in instigating anchorage independence and micrometastasis of preneoplastic lesions from the fallopian tube epithelium (FTE) to the ovary, an essential step in HGSC onset. We found that in the presence of NE, FTE cell lines were able to survive in ultra-low-attachment (ULA) culture in a β-adrenergic receptor-dependent (β-AR-dependent) manner. Importantly, spheroid formation and cell viability conferred by treatment with physiological sources of NE were abrogated using the β-AR blocker propranolol. We have also identified that NE-mediated anoikis resistance may be attributable to downregulation of colony-stimulating factor 2. These findings provide mechanistic insight and identify targets that may be regulated by ovary-derived NE in early HGSC.

Mutant p53 murine oviductal epithelial cells induce progression of high-grade serous carcinoma and are most sensitive to simvastatin therapy in vitro and in vivo

High-grade serous carcinoma (HGSC) is the most common and aggressive subtype of epithelial ovarian cancer, characterized by gain-of-function TP53 mutations originating in the fallopian tube epithelium. Therapeutic intervention occurs at advanced metastatic disease, due to challenges in early-stage diagnosis, with common disease recurrence and therapy resistance despite initial therapy success. The mevalonate pathway is exploited by many cancers and is potently inhibited by statin drugs. Statins have shown anti-cancer activity in many, but not all cancers. Here, we investigated the role of p53 status in relation to mevalonate pathway signaling in murine oviductal epithelial (OVE) cells and identified OVE cell sensitivity to statin inhibition. We found that p53R175H mutant and Trp53 knockout OVE cells have increased mevalonate pathway signaling compared to p53 wild-type OVE cells. Through orthotopic implantation to replicate the fallopian tube origin of HGSC, p53R175H mutant cells upregulated the mevalonate pathway to drive progression to advanced-stage ovarian cancer, and simvastatin treatment abrogated this effect. Additionally, simvastatin was more efficacious at inhibiting cell metabolic activity in OVE cells than atorvastatin, rosuvastatin and pravastatin. In vitro, simvastatin demonstrated potent effects on cell proliferation, apoptosis, invasion and migration in OVE cells regardless of p53 status. In vivo, simvastatin induced ovarian cancer disease regression through decreased primary ovarian tumor weight and increased apoptosis. Simvastatin also significantly increased cytoplasmic localization of HMG-CoA reductase in ovarian tumors. Downstream of the mevalonate pathway, simvastatin had no effect on YAP or small GTPase activity. This study suggests that simvastatin can induce anti-tumor effects and could be an important inhibitor of ovarian cancer progression.

Insulin-like growth factor (IGF) and hepatocyte growth factor (HGF) in follicular fluid cooperatively promote the oncogenesis of high-grade serous carcinoma from fallopian tube epithelial cells: Dissection of the molecular effects.

Incessant ovulation is believed to be a potential cause of epithelial ovarian cancer (EOC). Our previous investigations have shown that insulin-like growth factor(IGF2) and hepatocyte growth factor(HGF) in the ovulatory follicular fluid (FF) contributed to the malignant transformation initiated by p53 mutations. Here we examined the individual and synergistic impacts of IGF2 and HGF on enhancing the malignant properties of high-grade serous carcinoma (HGSC), the most aggressive type of EOC, and its precursor lesion, serous tubal intraepithelial carcinoma (STIC). In a mouse xenograft co-injection model, we observed that FF co-injection induced tumorigenesis of STIC-mimicking cells, FE25. Co-injection with IGF2 or HGF partially recapitulated the tumorigenic effects of FF, but co-injection with both resulted in a higher tumorigenic rate than FF. We analyzed the different transformation phenotypes influenced by these FF growth signals through receptor inhibition. The IGF signal was necessary for clonogenicity, while the HGF signal played a crucial role in the migration and invasion of STIC and HGSC cells. Both signals were necessary for the malignant phenotype of anchoring-independent growth but had little impact on cell proliferation. The downstream signals responsible for these HGF activities were identified as the tyrosine-protein kinase Met (cMET)/mitogen-activated protein kinase and cMET/AKT pathways. Together with the previous finding that the FF-IGF2 could mediate clonogenicity and stemness activities via the IGF-1R/AKT/mammalian target of rapamycin and IGF-1R/AKT/NANOG pathways, respectively, this study demonstrated the cooperation of the FF-sourced IGF and HGF growth signals in the malignant transformation and progression of HGSC through both common and distinct signaling pathways. These findings help develop targeted prevention of HGSC.

Differential epithelial and stromal LGR5 expression in ovarian carcinogenesis

Lgr5 has been identified as a marker of the stem/progenitor cells in the murine ovary and oviduct by lineage tracing. However, little is known regarding LGR5 expression or its functional significance in human ovary tissues. Here, using RNA in situ hybridization and/or immunohistochemistry, we thoroughly investigated LGR5 expression in normal human ovaries, fallopian tubes and various ovarian tumors. We discovered that LGR5 expression is negligible in the human ovary surface epithelium, whereas ovarian stromal cells normally express low levels of LGR5. Remarkably, fallopian tube epithelium, inclusion cysts and serous cystadenomas with a Müllerian phenotype expressed high levels of LGR5, and LGR5 expression was restricted to PAX8+/FOXJ1− secretory cells of the tubal epithelium. Strong stromal LGR5 expression without epithelial LGR5 expression was consistently observed in the path from serous cystadenoma to serous borderline tumor to low grade serous carcinoma (LGSC). Unlike LGSC, high grade serous carcinoma (HGSC), clear cell carcinoma, endometrioid carcinomas displayed various epithelial-stromal LGR5 expression. Notably, high levels of LGR5 expression were observed in serous tubal intraepithelial carcinoma, which slightly declined in invasive HGSC. LGR5 expression was significantly associated with improved progression-free survival in HGSC patients. Moreover, in vitro assays demonstrated that LGR5 expression suppressed tumor proliferation and migratory capabilities. Taken together, these findings indicate a tumor-suppressive role for LGR5 in the progression of HGSC.

Targeted Microchip Capillary Electrophoresis-Orbitrap Mass Spectrometry Metabolomics to Monitor Ovarian Cancer Progression.

The lack of effective screening strategies for high-grade serous carcinoma (HGSC), a subtype of ovarian cancer (OC) responsible for 70–80% of OC related deaths, emphasizes the need for new diagnostic markers and a better understanding of disease pathogenesis. Capillary electrophoresis (CE) coupled with high-resolution mass spectrometry (HRMS) offers high selectivity and sensitivity for ionic compounds, thereby enhancing biomarker discovery. Recent advances in CE-MS include small, chip-based CE systems coupled with nanoelectrospray ionization (nanoESI) to provide rapid, high-resolution analysis of biological specimens. Here, we describe the development of a targeted microchip (µ) CE-HRMS method, with an acquisition time of only 3 min and sample injection volume of 4nL, to analyze 40 target metabolites in serum samples from a triple-mutant (TKO) mouse model of HGSC. Extracted ion electropherograms showed sharp, baseline resolved peak shapes, even for structural isomers such as leucine and isoleucine. All calibration curves of the analytes maintained good linearity with an average R2 of 0.994, while detection limits were in the nM range. Thirty metabolites were detected in mouse serum with recoveries ranging from 78 to 120%, indicating minimal ionization suppression and good accuracy. We applied the µCE-HRMS method to biweekly-collected serum samples from TKO and TKO control mice. A time-resolved analysis revealed characteristic temporal trends for amino acids, nucleosides, and amino acid derivatives. These metabolic alterations are indicative of altered nucleotide biosynthesis and amino acid metabolism in HGSC development and progression. A comparison of the µCE-HRMS dataset with non-targeted ultra-high performance liquid chromatography (UHPLC)–MS results showed identical temporal trends for the five metabolites detected with both platforms, indicating the µCE-HRMS method performed satisfactorily in terms of capturing metabolic reprogramming due to HGSC progression while reducing the total data collection time three-fold.

Changes in focal adhesion protein Talin-1 expression during malignant transformation leading to ovarian high-grade serous carcinoma.

e17586 Background: Ovarian high-grade serous carcinoma (HGSC), the most lethal form of ovarian cancer, is often detected at late stages due to the lack of an early detection test resulting in low 5-year survival rates. Information on factors associated with malignant transformation and early metastasis is critical in developing interventional strategies to reduce the incidence and death due to HGSC. Talin-1, a focal adhesion protein, regulates cell–cell adhesion, and induces cytoskeletal remodeling leading to tumor cell migration and adhesion. Destabilization of the cell membrane during malignant development may shed Talin-1 in circulation which may be a potential early marker of progression of HGSC. Objective: The goal of this study was to examine the changes in Talin-1 expression during malignant transformation in ovaries and fimbria of the fallopian tube and its prevalence in serum. Difficulty in accessing patients with early-stage HGSC is a significant barrier to study malignant transformation and progression. Laying hen model of spontaneous ovarian HGSC was used together with clinical specimens. Methods: Two experiments were conducted. Exploratory study:Archived normal ovaries (n = 10), ovaries with HGSC at early (n = 10) and late (n = 10) stages from patients and their serum samples were used. Prospective study: Laying hens with no detectable abnormalities were selected and monitored using transvaginal ultrasound (TVUS) imaging at 10 week intervals for 10 months and sera were collected at each scan. Hens were euthanized at diagnosis of solid mass during scanning or at the end of the study; ovaries, fimbria and serum samples were collected. Normal hens (n = 10), hens with early (n = 7) and late-stage (n = 8) tumors were selected. Talin-1 expression in tissues and serum was determined by immunohistochemistry (IHC), Western blotting (WB), gene expression (qPCR), and immunoassay (ELISA). Significant differences in Talin-1 expression among all groups were determined by ANOVA and/or paired/unpaired t-tests, significance was taken when P< 0.05. Results: Expression of Talin-1was detected in all tissues with various intensities. Compared with normal, ovarian HGSC tissues showed intense expression of Talin-1 in IHC, WB and qPCRs ( P< 0.05). Similar patterns were observed in serum levels in ELISA ( P< 0.01) in the exploratory study. Prospective study in hens showed significant increase in serum Talin-1 levels even before the formation of a solid tumor mass in the ovary or fimbria detectable by TVUS. Conclusions: Elevated Talin-1 expression in early-stage ovarian HGSC tumors suggests its association with malignant development. Serum prevalence of Talin-1 during malignant transformation makes it a potential marker for early detection of HGSC and its progression. These results will serve as foundation for a clinical study with larger cohorts. Support: NIH R01 CA210370 (AB)

Space- and Time-Resolved Metabolomics of a High-Grade Serous Ovarian Cancer Mouse Model.

Simple SummaryThe underlying mechanisms associated with ovarian cancer progression remain largely unknown, making it one of the most lethal cancers. To understand the disease pathogenesis, our study involved longitudinal serum metabolomics profiling of a triple-mutant mouse model of ovarian cancer that captured the dynamic metabolic response from disease onset until mouse death. These experiments were complemented with spatial lipidomic profiling of the entire reproductive system of the triple-mutant mice, enabling us to visualize the tissue heterogeneity and lipid alterations within tumors. A combined longitudinal and spatial map of metabolomic alterations associated with ovarian cancer progression is presented, serving as a comprehensive guide towards understanding the disease origin and progression.The dismally low survival rate of ovarian cancer patients diagnosed with high-grade serous carcinoma (HGSC) emphasizes the lack of effective screening strategies. One major obstacle is the limited knowledge of the underlying mechanisms of HGSC pathogenesis at very early stages. Here, we present the first 10-month time-resolved serum metabolic profile of a triple mutant (TKO) HGSC mouse model, along with the spatial lipidome profile of its entire reproductive system. A high-coverage liquid chromatography mass spectrometry-based metabolomics approach was applied to longitudinally collected serum samples from both TKO (n = 15) and TKO control mice (n = 15), tracking metabolome and lipidome changes from premalignant stages to tumor initiation, early stages, and advanced stages until mouse death. Time-resolved analysis showed specific temporal trends for 17 lipid classes, amino acids, and TCA cycle metabolites, associated with HGSC progression. Spatial lipid distributions within the reproductive system were also mapped via ultrahigh-resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and compared with serum lipid profiles for various lipid classes. Altogether, our results show that the remodeling of lipid and fatty acid metabolism, amino acid biosynthesis, TCA cycle and ovarian steroidogenesis are critical components of HGSC onset and development. These metabolic alterations are accompanied by changes in energy metabolism, mitochondrial and peroxisomal function, redox homeostasis, and inflammatory response, collectively supporting tumorigenesis.

Aging accelerates while multiparity delays tumorigenesis in mouse models of high-grade serous carcinoma

ObjectivesThe “incessant ovulation” hypothesis links increased risk for tubo-ovarian high-grade serous carcinoma (HGSC) due to more ovulations and reduced risk conferred by pre-menopausal exposures like oral contraceptive use, multiparity, and breastfeeding. However, most women diagnosed with HGSC are postmenopausal, implying age is a major risk factor for HGSC. Our mouse model for HGSC, based on tamoxifen (TAM)-induced somatic inactivation of the Brca1, Trp53, Rb1, and Nf1 (BPRN) tumor suppressor genes in oviductal epithelium, recapitulates key genetic, histopathologic, and biological features of human HGSCs. We aimed to credential the model for future efforts to define biological and risk modification factors in HGSC pathogenesis. MethodsBPRN mice were treated with TAM to induce tumors at defined ages and parity status. ResultsBPRN mice aged 9-months prior to tumor induction had markedly shorter survival than 6–8 week old mice induced to form tumors (median 46.5 weeks versus 61.5 weeks, log-rank test P = 0.0006). No significant differences in cancer phenotypes were observed between multiparous versus nulliparous BPRN mice. However, using a modified tumor model with one wild-type Nf1 allele (BPRNfl/+), nulliparous mice had more advanced tumors than multiparous mice (Mantel-Haenszel Chi-square test of association, P = 0.01). ConclusionsOur findings show aging is associated with significantly shortened survival post tumor induction in the BRPN model and multiparity delays development and/or progression of HGSC in certain genetic contexts. The findings support relevance of our mouse model to gain mechanistic insights into how known factors exert their protective effects and to test novel approaches for HGSC prevention.

The multicellular signalling network of ovarian cancer metastases.

BackgroundTranscoelomic spread is the major route of metastasis of ovarian high‐grade serous carcinoma (HGSC) with the omentum as the major metastatic site. Its unique tumour microenvironment with its large populations of adipocytes, mesothelial cells and immune cells establishes an intercellular signaling network that is instrumental for metastatic growth yet poorly understood.MethodsBased on transcriptomic analysis of tumour cells, tumour‐associated immune and stroma cells we defined intercellular signaling pathways for 284 cytokines and growth factors and their cognate receptors after bioinformatic adjustment for contaminating cell types. The significance of individual components of this network was validated by analysing clinical correlations and potentially pro‐metastatic functions, including tumour cell migration, pro‐inflammatory signal transduction and TAM expansion.ResultsThe data show an unexpected prominent role of host cells, and in particular of omental adipocytes, mesothelial cells and fibroblasts (CAF), in sustaining this signaling network. These cells, rather than tumour cells, are the major source of most cytokines and growth factors in the omental microenvironment (n = 176 vs. n = 13). Many of these factors target tumour cells, are linked to metastasis and are associated with a short survival. Likewise, tumour stroma cells play a major role in extracellular‐matrix‐triggered signaling. We have verified the functional significance of our observations for three exemplary instances. We show that the omental microenvironment (i) stimulates tumour cell migration and adhesion via WNT4 which is highly expressed by CAF; (ii) induces pro‐tumourigenic TAM proliferation in conjunction with high CSF1 expression by omental stroma cells and (iii) triggers pro‐inflammatory signaling, at least in part via a HSP70–NF‐κB pathway.ConclusionsThe intercellular signaling network of omental metastases is majorly dependent on factors secreted by immune and stroma cells to provide an environment that supports ovarian HGSC progression. Clinically relevant pathways within this network represent novel options for therapeutic intervention.

Upregulation of mesothelial genes in ovarian carcinoma cells is associated with an unfavorable clinical outcome and the promotion of cancer cell adhesion.

A hallmark of ovarian high‐grade serous carcinoma (HGSC) is its early and massive peritoneal dissemination via the peritoneal fluid. It is generally believed that tumor cells must breach the mesothelium of peritoneal organs to adhere to the underlying extracellular matrix (ECM) and initiate metastatic growth. However, the molecular mechanisms underlying these processes are only partially understood. Here, we have analyzed 52 matched samples of spheroids and solid tumor masses (suspected primary lesions and metastases) from 10 patients by targeted sequencing of 21 loci previously proposed as targets of HGSC driver mutations. This analysis revealed very similar patterns of genetic alterations in all samples. One exception was FAT3 with a strong enrichment of mutations in metastases compared with presumed primary lesions in two cases. FAT3 is a putative tumor suppressor gene that codes for an atypical cadherin, pointing a potential role in peritoneal dissemination in a subgroup of HGSC patients. By contrast, transcriptome data revealed clear and consistent differences between tumor cell spheroids from ascites and metastatic lesions, which were mirrored by the in vitro adherence of ascites‐derived spheroids. The adhesion‐induced transcriptional alterations in metastases and adherent cells resembled epithelial–mesenchymal transition, but surprisingly also included the upregulation of a specific subset of mesothelial genes, such as calretinin (CALB2) and podoplanin (PDPN). Consistent with this finding, calretinin staining was also observed in subsets of tumor cells in HGSC metastases, particularly at the invasive tumor edges. Intriguingly, a high expression of either CALB2 or PDPN was strongly associated with a poor clinical outcome. siRNA‐mediated CALB2 silencing triggered the detachment of adherent HGSC cells in vitro and inhibited the adhesion of detached HGSC cells to collagen type I. Our data suggest that the acquisition of a mesenchymal–mesothelial phenotype contributes to cancer cell adhesion to the ECM of peritoneal organs and HGSC progression.

Nicotinamide N-methyltransferase epigenetic and metabolic rewiring promotes metastatic progression

High-grade serous carcinoma (HGSC) is amongst the most deadly forms of cancer. Approximately 80% of patients with HGSC suffer recurrence following surgical resection and cytoreduction; a consequence of the widespread and inaccessible metastatic lesions throughout the abdominal cavity. HGSC progression and metastases co-evolves with the tumor microenvironment (TME), composing fibroblasts, mesenchymal stem cells, osteoblasts, and chondrocytes.

Dual-platform affinity proteomics identifies links between the recurrence of ovarian carcinoma and proteins released into the tumor microenvironment.

The peritoneal fluid (ascites), replete with abundant tumor-promoting factors and extracellular vesicles (EVs) reflecting the tumor secretome, plays an essential role in ovarian high-grade serous carcinoma (HGSC) metastasis and immune suppression. A comprehensive picture of mediators impacting HGSC progression is, however, not available.Methods: Proteins in ascites from HGSC patients were quantified by the aptamer-based SOMAscan affinity proteomic platform. SOMAscan data were analyzed by bioinformatic methods to reveal clinically relevant links and functional connections, and were validated using the antibody-based proximity extension assay (PEA) Olink platform. Mass spectrometry was used to identify proteins in extracellular microvesicles released by HGSC cells.Results: Consistent with the clinical features of HGSC, 779 proteins in ascites identified by SOMAscan clustered into groups associated either with metastasis and a short relapse-free survival (RFS), or with immune regulation and a favorable RFS. In total, 346 proteins were linked to OC recurrence in either direction. Reanalysis of 214 of these proteins by PEA revealed an excellent median Spearman inter-platform correlation of ρ=0.82 for the 46 positively RFS-associated proteins in both datasets. Intriguingly, many proteins strongly associated with clinical outcome were constituents of extracellular vesicles. These include proteins either linked to a poor RFS, such as HSPA1A, BCAM and DKK1, or associated with a favorable outcome, such as the protein kinase LCK. Finally, based on these data we defined two protein signatures that clearly classify short-term and long-term relapse-free survivors.Conclusion: The ascites secretome points to metastasis-promoting events and an anti-tumor response as the major determinants of the clinical outcome of HGSC. Relevant proteins include both bone fide secreted and vesicle-encapsulated polypeptides, many of which have previously not been linked to HGSC recurrence. Besides a deeper understanding of the HGSC microenvironment our data provide novel potential tools for HGSC patient stratification. Furthermore, the first large-scale inter-platform validation of SOMAscan and PEA will be invaluable for other studies using these affinity proteomics platforms.

YAP induces high-grade serous carcinoma in fallopian tube secretory epithelial cells.

Accumulating evidence indicates that ovarian high-grade serous carcinoma (HGSC) originates from Fallopian tube secretory epithelial cells (FTSECs). However, the molecular mechanisms underlying the initiation and progression of HGSC derived from FTSECs remains unclear. In the present study, we found that the Hippo/YAP signaling pathway plays a critical role in the initiation and progression of Fallopian tube and ovarian HGSC. Importantly, YAP was overexpressed in inflammatory and cancerous Fallopian tube tissues. Further, overexpression of wild-type YAP, or constitutively active YAP in immortalized FTSECs, induced cell proliferation, migration, colony formation, and tumorigenesis. Moreover, the Hippo/YAP and the fibroblast growth factor (FGF) signaling pathways formed an autocrine/paracrine positive feedback loop to drive the progression of the FTSECs-derived HGSC. Evidence in this study strongly suggests that combined therapy with inhibitors of YAP (such as verteporfin) and FGFRs (such as BGJ398) can provide a novel therapeutic strategy to treat Fallopian tube and ovarian HGSC.

Abstract POSTER-BIOL-1308: Macrophage infiltration in high-grade serous carcinomas of humans and mice

Abstract Over the past 10-15 years, focus on the immune system has reinvigorated cancer research and oncology. Both clinical and experimental evidence generated during this time has shown that immune cells and their molecular mediators represent viable targets for therapeutic manipulation. The immune cell composition of high-grade serous carcinoma (HGSC) consists primarily of macrophages and various T cell subsets. However, the functional contribution of each of these cell types is largely unknown. In order to gain insight into whether these cells are pro- or anti-tumorigenic, we generated tissue microarrays containing tumors from 169 patients with pretreated ovarian cancer and quantified the number of CD68+ macrophages in each biopsy. Tumors were divided into high- or low-infiltrated groups based on the median number of macrophages amongst all HGSCs. Interestingly, patients whose tumors were highly infiltrated with macrophages exhibited worsened overall survival, suggesting that macrophages function as pro-tumorigenic cells in these tumors. To investigate the role of macrophages in HGSC progression, we have begun to characterize their abundance and phenotype in tumors of Dicerflox/flox;Ptenflox/flox;Amhr2cre/+ mice, a genetically engineered mouse model of HGSC. Macrophages constituted the predominant stromal and immune cell population in both primary tumors and secondary metastatic lesions. By contrast, macrophages were only found at low frequency in normal oviduct and ovaries. Gene expression analysis of these Dicer/Pten-deficient mouse tumors also revealed the increase in many macrophage-associated genes, as compared with normal oviduct tissue. Taken together, our data from mice and humans strongly indicate a crucial role for macrophages in facilitating ovarian cancer progression. Current efforts are underway to understand how macrophages promote ovarian tumor progression. Citation Format: Tanja Pejovic, Yukie Bean, Jaeyeon Kim, Martin M. Matzuk, Seth B. Coffelt. Macrophage infiltration in high-grade serous carcinomas of humans and mice [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1308.

The cadherin switch in ovarian high-grade serous carcinoma is associated with disease progression

Ovarian high-grade serous carcinoma (HGSC) often has a poor prognosis because of late presentation, lack of sensitivity and specificity of screening modalities and the development of chemoresistance. New targeted therapy is required if survival in these cases is to improve. The profile of E-, P- and N-cadherins in ovarian cancer and its association with survival remain poorly understood. Reduced expression of E-cadherin in prostate cancer associated with increase in the expression of N- and P-cadherins is described as cadherin switch. We hypothesised that there is a switch in the expression of cadherins that regulates the behaviour of HGSC and possibly its outcome. To identify the stages of the cadherin switch in HGSC, we studied the immunoexpression of E-, P- and N-cadherins in a cohort of 177 cases of HGSC. High expression of P-cadherin was associated with poor patient survival and was significantly higher in stage 2 disease when compared with stage 1 and stage 3 disease (P = 0.033). In contrast, loss of E-cadherin was observed in stage 3 HGSC when compared with other stages (P = 0.050). E-, P- and N- cadherin expressions were significantly associated with disease outcome when assessed individually and in various combinations with an interesting profile. Our results indicate that the cadherin switch alters through progression of HGSC. The profile of combined cadherin expressions in association with survival raises expectations in targeted therapy.