Strategy.

While the establishment of an ovarian cancer biobank from patient-derived organoids along with their clinical background information promises advances in research and patient care, standardization remains a challenge due to the heterogeneity of this lethal malignancy, combined with the inherent complexity of organoid technology. This adaptable protocol provides a systematic framework to realize the full potential of ovarian cancer organoids considering a patient-specific variability of progenitors. By implementing a structured experimental workflow to select optimal culture conditions and seeding methods, with parallel testing of direct 3D seeding versus a 2D/3D route, we obtain, in most cases, robust long-term expanding lines suitable for a broad range of downstream applications. Notably, the protocol has been tested and proven efficient in a great number of cases (N = 120) of highly heterogeneous starting material, including high-grade and low-grade ovarian cancer and stages of the disease with primary debulking, recurrent disease, and post-neoadjuvant surgical specimens. Within a low Wnt, high BMP exogenous signaling environment, we observed progenitors being differently susceptible to the activation of the Heregulin 1 ß (HERß-1)-pathway, with HERß-1 promoting organoid formation in some while inhibiting it in others. For a subset of the patient's samples, optimal organoid formation and long-term growth necessitate the addition of fibroblast growth factor 10 and R-Spondin 1 to the medium. Further, we highlight the critical steps of tissue digestion and progenitor isolation and point to examples where brief cultivation in 2D on plastic is beneficial for subsequent organoid formation in the Basement Membrane Extract type 2 matrix. Overall, optimal biobanking requires systematic testing of all main conditions in parallel to identify an adequate growth environment for individual lines. The protocol also describes the handling procedure for efficient embedding, sectioning, and staining to obtain high-resolution images of organoids, which is required for comprehensive phenotyping.

Genetics and beyond: Precision Medicine Real-World Data for Patients with Cervical, Vaginal or Vulvar Cancer in a Tertiary Cancer Center.

Advances in molecular tumor diagnostics have transformed cancer care. However, it remains unclear whether precision oncology has the same impact and transformative nature across all malignancies. We conducted a retrospective analysis of patients with human papillomavirus (HPV)-related gynecologic malignancies who underwent comprehensive molecular profiling and subsequent discussion at the interdisciplinary Molecular Tumor Board (MTB) of the University Hospital, LMU Munich, between 11/2017 and 06/2022. We identified a total cohort of 31 patients diagnosed with cervical (CC), vaginal or vulvar cancer. Twenty-two patients (fraction: 0.71) harbored at least one mutation. Fifteen patients (0.48) had an actionable mutation and fourteen (0.45) received a recommendation for a targeted treatment within the MTB. One CC patient received a biomarker-guided treatment recommended by the MTB and achieved stable disease on the mTOR inhibitor temsirolimus for eight months. Factors leading to non-adherence to MTB recommendations in other patient cases included informed patient refusal, rapid deterioration, stable disease, or use of alternative targeted but biomarker-agnostic treatments such as antibody-drug conjugates or checkpoint inhibitors. Despite a remarkable rate of actionable mutations in HPV-related gynecologic malignancies at our institution, immediate implementation of biomarker-guided targeted treatment recommendations remained low, and access to targeted treatment options after MTB discussion remained a major challenge.

Health-related quality of life and patient-centred outcomes with COVID-19 vaccination in patients with breast cancer and gynaecological malignancies.

Introduction: Safety and tolerability of COVID-19 vaccines were demonstrated by several clinical trials which led to the first FDA/EMA approvals in 2021. Because of mass immunizations, most social restrictions were waived with effects on quality of life. Therefore, our a-priori hypothesis was that COVID-19 vaccination impacted the health-related quality of life (HR-QoL) in patients with breast and gynecological cancer. Methods: From March 15th until August 11th, 2022, fully vaccinated patients with breast and gynecological cancer treated in the oncological outpatient clinics of the Department of Obstetrics and Gynecology, LMU University Hospital, Munich, Germany filled out a vaccine related QoL survey. Patients were asked about demographics (age, comorbidities), clinical parameters related to previous COVID-19 infections, and HR-QoL related parameters (living situation, responsibilities in everyday life). Subsequently, a questionnaire with 12 items was designed using a 5-point Likert scale (0 - strongly disagree/4 - strongly agree), covering the aspects health and therapy, social environment, participation in everyday life and overall assessment. Results: By August 11th, 2022, 108 out of 114 (94.7%) patients had received at least three doses of COVID-19 vaccine and six patients at least two doses. More than half of the surveyed patients were >55y (52.6%; mean: 55.1y, range 29-86y). Patients with breast cancer (n= 83) had early (59.0%) or metastatic cancer (41.0%); gynecological cancers (n=31) also included metastatic (54.8%) and non-metastatic cancer (45.2%). 83.3% of the patients stated that COVID-19 vaccination had a positive impact on their HR-QoL. Furthermore, 29 patients (25.4%) had undergone a COVID-19 infection. These patients reported self-limiting symptoms for a median duration of 5.9 days and no hospital admissions were registered. Conclusions: Our study demonstrates that vaccination against COVID-19 was positively associated with HR-QoL in patients with breast and gynecological cancer. Furthermore, vaccinated patients who underwent COVID-19 disease experienced only self-limiting symptoms.

Protocol to optimize the biobanking of ovarian cancer organoids by accommodating patient-specific differences in stemness potential.

We present a protocol for effective biobanking of epithelial ovarian cancer organoids, considering the heterogeneous clinical presentation and high recurrence rates. Our protocol involves parallel testing of three media to identify patient-specific optimal conditions. We describe steps for tissue dissociation, differential seeding, organoid cultivation, and biobanking. We outline procedures for fixation, embedding, and staining for confocal imaging. Furthermore, we demonstrate that brief cultivation of isolates in 2D on plastic enhances organoid-forming potential in selected lines, expanding their application scope. For complete details on the use and execution of this protocol, please refer to Hoffmann et al.1.

Nuclear receptor co-repressor NCOR2 and its relation to GPER with prognostic impact in ovarian cancer.

PURPOSE: The significance of the non-classical G-protein-coupled estrogen receptor (GPER) as positive or negative prognostic factor for ovarian cancer patients remains still controversial. Recent results indicate that an imbalance of both co-factors and co-repressors of nuclear receptors regulates ovarian carcinogenesis by altering the transcriptional activity through chromatin remodeling. The present study aims to investigate whether the expression of the nuclear co-repressor NCOR2 plays a role in GPER signaling which thereby could positively impact overall survival rates of ovarian cancer patients. METHODS: NCOR2 expression was evaluated by immunohistochemistry in a cohort of 156 epithelial ovarian cancer (EOC) tumor samples and correlated with GPER expression. The correlation and differences in clinical and histopathological variables as well as their effect on prognosis were analyzed by Spearman's correlation, Kruskal-Wallis test and Kaplan-Meier estimates. RESULTS: Histologic subtypes were associated with different NCOR2 expression patterns. More specifically, serous and mucinous EOC demonstrated a higher NCOR2 expression (P = 0.008). In addition, high nuclear NCOR2 expression correlated significantly with high GPER expression (cc = 0.245, P = 0.008). A combined evaluation of both high NCOR2 (IRS > 6) and high GPER (IRS > 8) expression revealed an association of a significantly improved overall survival (median OS 50.9 versus 105.1 months, P = 0.048). CONCLUSION: Our results support the hypothesis that nuclear co-repressors such as NCOR2 may influence the transcription of target genes in EOC such as GPER. Understanding the role of nuclear co-repressors on signaling pathways will allow a better understanding of the factors involved in prognosis and clinical outcome of EOC patients.

KLF11 is an independent negative prognostic factor for breast cancer from a cohort study and induces proliferation and inhibits apoptosis in vitro.

BACKGROUND: The therapy concepts that target several members of krüppel like factor (KLF) family have been achieved in breast cancer (BC). However, the role of KLF11 in BC remains unclear. This study explored the prognostic significance of KLF11 in BC patients and investigated its functional roles in this malignancy. METHODS: Immunohistochemistry (IHC) staining of KLF11 in 298 patients' samples was performed to determine the prognostic role of the KLF11. Then the protein level was correlated to clinicopathological characteristics and survival outcomes. Afterward, the function of KLF11 was explored in vitro with siRNA-mediated loss-of-function of cell viability, proliferation, and apoptosis. RESULTS: From the cohort study, we found that the expression of KLF11 was positively associated with highly proliferative BC of BC. Furthermore, prognostic analysis demonstrated that KLF11 was an independent negative factor for disease-free survival (DFS) and distant-metastasis-free survival (DMFS) of BC. The KLF11-related prognostic model for DFS and DMFS showed high accuracy in predicting the 3-,5- and 10 -year survival probability of BC patients. Additionally, the knockdown of KLF11 inhibited cell viability and proliferation, as well as induced cell apoptosis in MCF7 and MDA-MB-231 cells, while only inhibited cell viability and induced cell apoptosis in SK-BR-3 cells. CONCLUSIONS: Our study indicated that targeting KLF11 is an interesting therapeutic concept and further research could lead to a new therapeutic improvement in BC, especially in highly aggressive molecular subtypes.

PLA2G7/PAF-AH as Potential Negative Regulator of the Wnt Signaling Pathway Mediates Protective Effects in BRCA1 Mutant Breast Cancer.

Past studies have confirmed that aberrant activation of the Wnt/ß-catenin signaling is associated with tumorigenesis and metastasis in breast cancer, while the role of platelet-activating factor acetylhydrolase (PLA2G7/PAF-AH) in this signaling pathway remains unclear. In this study, we analyze the functional impact of PAF-AH on BRCA1 mutant breast cancer and explore its relationship to the Wnt signaling pathway. By performing immunohistochemistry, PAF-AH expression and ß-catenin expression were examined in both BRCA1 WT and BRCA1 mutant breast cancer specimens. The BRCA1 mutant breast cancer cell line HCC1937 was used for in vitro experiments to assess the impact of PAF-AH on cellular functions. The intracellular distribution of ß-catenin depending on PLA2G7/PAF-AH expression was investigated by immunocytochemistry. Significantly higher nuclear expression levels of PAF-AH were found in BRCA1 mutant tissue specimens than in BRCA1 WT samples. Cell viability, proliferation, and the motility rate of HCC1937 were significantly enhanced after PLA2G7 silencing, which indicated a protective role of PAF-AH in breast cancer. Nuclear PAF-AH expressed correlatedly with membranous ß-catenin. PLA2G7 silencing provoked the ß-catenin translocation from the membrane to the nucleus and activated Wnt signaling downstream genes. Our data showed a protective effect of high PAF-AH expression in BRCA1 mutant breast cancer. PAF-AH may achieve its protective effect by negatively regulating the Wnt pathway. In conclusion, our research sheds new light on the regulatory pathways in BRCA1 mutant breast cancer.

PARP inhibitors: risk factors for toxicity and matching patients to the proper poly (ADP-ribose) polymerase inhibitor (PARPi) therapy.

The past 5 years have seen several fundamental advances in ovarian cancer, with important new insights towards novel therapeutic opportunities within the DNA repair pathway. With the incorporation of poly (ADP-ribose) polymerase inhibitors (PARPi) into maintenance treatment regimens, the management of short- and long-term adverse events are key clinical priorities. Currently, three different PARPi are clinically beneficial and have been approved for primary and recurrent ovarian cancer: olaparib, niraparib, and rucaparib. The duration of treatment with PARPi in patients with ovarian cancer varies; patients can receive treatment for up to 2 or 3 years in first-line setting, or continue treatment until unacceptable toxicity or progression occurs in recurrent disease. Despite their similar mechanisms of action, these three inhibitors have specific toxicity profiles, which may lead to dose interruptions or discontinuation of treatment. This review summarizes the current indications for PARPi, including their role in recurrent and first-line maintenance treatment for advanced ovarian cancer. We also outline dose modifications leading to treatment disruption and potential changes in quality of life after prolonged treatment. Finally, we highlight the patient groups most likely to benefit from each of the three different PARPi.

Impact of BRCA Mutation Status on Tumor Dissemination Pattern, Surgical Outcome and Patient Survival in Primary and Recurrent High-Grade Serous Ovarian Cancer: A Multicenter Retrospective Study by the Ovarian Cancer Therapy-Innovative Models Prolong Survival (OCTIPS) Consortium.

BACKGROUND: This study seeks to evaluate the impact of breast cancer (BRCA) gene status on tumor dissemination pattern, surgical outcome and survival in a multicenter cohort of paired primary ovarian cancer (pOC) and recurrent ovarian cancer (rOC). PATIENTS AND METHODS: Medical records and follow-up data from 190 patients were gathered retrospectively. All patients had surgery at pOC and at least one further rOC surgery at four European high-volume centers. Patients were divided into one cohort with confirmed mutation for BRCA1 and/or BRCA2 (BRCAmut) and a second cohort with BRCA wild type or unknown (BRCAwt). Patterns of tumor presentation, surgical outcome and survival data were analyzed between the two groups. RESULTS: Patients with BRCAmut disease were on average 4 years younger and had significantly more tumor involvement upon diagnosis. Patients with BRCAmut disease showed higher debulking rates at all stages. Multivariate analysis showed that only patient age had significant predictive value for complete tumor resection in pOC. At rOC, however, only BRCAmut status significantly correlated with optimal debulking. Patients with BRCAmut disease showed significantly prolonged overall survival (OS) by 24.3 months. Progression-free survival (PFS) was prolonged in the BRCAmut group at all stages as well, reaching statistical significance during recurrence. CONCLUSIONS: Patients with BRCAmut disease showed a more aggressive course of disease with earlier onset and more extensive tumor dissemination at pOC. However, surgical outcome and OS were significantly better in patients with BRCAmut disease compared with patients with BRCAwt disease. We therefore propose to consider BRCAmut status in regard to patient selection for cytoreductive surgery, especially in rOC.

Trends among patients with endometriosis over a 7-year period and the impact of the COVID-19 pandemic: experience from an academic high-level endometriosis centre in Germany.

PURPOSE: Endometriosis is known to be an underestimated disease. Lately the awareness of the disease seems to have improved. Aim of this analysis is to provide an overview of the development of treatment of patients diagnosed with endometriosis. This includes a special scope on implications of the COVID-19 pandemic since in multiple settings postponed treatments resulting in negative impact on prognosis were reported. MATERIALS AND METHODS: We analysed the development of numbers of patients treated for endometriosis in an academic centre within a 7-year period, 01/2015-12/2021, performing a systematic analysis of ICD-10-Codes from our computer system used in clinical routine. RESULTS: Treatment numbers increased over the past 7 years, i.e., 239 treated cases in 2015 vs. 679 in 2021. Following restrictions for outpatient evaluation and surgical capacity at our centre, during COVID-19 pandemic the numbers of treated patients were reduced, especially in the first lockdown period (03/22/2020-05/05/2020 vs. same period in 2019: outpatient clinic (9 vs. 36; p < 0.001), patients surgically treated (27 vs. 52; p < 0,001)). The comparison of 2020 to 2019 showed a reduction in April 2020 of - 37% in outpatient department and up to - 90% for surgically treated patients. Comparing to 2019, we found a reduction of surgical interventions in 2020 by - 9% and an increase by 83% in 2021. CONCLUSIONS: Raising numbers of patients treated for endometriosis point to a new awareness for the disease. After the decline during the lockdown period numbers raised again, leading to a delay, but not an omission of treatment. A certified endometriosis centre with established and well-organized structures is required to improve not only treatment results but also quality of life of those affected.

High RIG-I and EFTUD2 expression predicts poor survival in endometrial cancer.

PURPOSE: Endometrial cancer is the most common gynecological malignancy. The helicase RIG-I, a part of the innate immune system, and EFTUD2, a splicing factor which can upregulate RIG-I expression, are shown to influence tumor growth and disease progression in several malignancies. For endometrial cancer, an immunogenic cancer, data about RIG-I and EFTUD2 are still missing. The aim of this study was to examine the expression of RIG-I and EFTUD2 in endometrial cancer. METHODS: 225 specimen of endometrial cancer were immunohistochemically stained for RIG-I and EFTUD2. The results were correlated to clinicopathological data, overall survival (OS) and progression-free survival (PFS). RESULTS: High RIG-I expression correlated with advanced tumor stages (FIGO: p = 0.027; pT: p = 0.010) and worse survival rates (OS: p = 0.009; PFS: p = 0.022). High EFTUD2 expression correlated to worse survival rates (OS: p = 0.026; PFS: p < 0.001) and was determined to be an independent marker for progression-free survival. CONCLUSION: Our data suggest that the expression of RIG-I and EFTUD2 correlates with survival data, which makes both a possible therapeutic target in the future.

Presence of regulatory T-cells in endometrial cancer predicts poorer overall survival and promotes progression of tumor cells.

PURPOSE: Endometrial cancer (EC) is one of the most common gynaecologic malignancies. Tumor infiltrating regulatory T-cells (Treg) have been reported to have a prognostic impact in many malignancies. Immunotherapeutic strategies are gaining interest for advanced and recurrent EC cases, where treatment options are rare. Our study was aimed at determining the value of Treg in EC progression. METHODS: EC specimens from 275 patients and 28 controls were screened immunohistochemically for the presence of Treg represented by FoxP3. Correlations with clinicopathological and survival parameters were performed. Functional assays were performed using EC cell lines Ishikawa + and RL95-2 after co-culturing with isolated CD4 + CD25 + CD127dim Treg. To assess the influence of EC on the composition of peripheral blood mononuclear cells (PBMC), flow cytometric analyses were performed. RESULTS: We found that an increased infiltration of Treg was associated with high grades and a reduced overall survival. Treg were almost absent in endometrium tissues from healthy control patients. Co-culture of tumor cells with CD4 + CD25 + CD127dim Treg led to functional changes: enhanced invasion, migration and viability indicated that increased levels of Treg in the tumor microenvironment may promote tumor growth. Furthermore, we found that the presence of EC cells led to phenotypic changes in PBMC, showing significantly increased levels of CD25 and FoxP3. CONCLUSION: Our results indicate that the presence of Treg in the EC tumor environment is associated with a poorer outcome. A remarkable impact of Treg on tumor cell behaviour and vice versa of tumor cells on PBMC subpopulations support this notion mechanistically. Our findings provide a basis for focusing on Treg as potential future therapeutic targets in EC.

Blood group antigens SLeX, SLeA, and LeY as prognostic markers in endometrial cancer.

PURPOSE: Endometrial cancer (EC) is the most common gynecological cancer worldwide. Treatment has been improved in recent years, but, in advanced stages, therapeutical options are still limited. It has been reported that the expression of the blood group antigens Sialyl Lewis X (SLeX), Sialyl Lewis A (SLeA) and Lewis Y (LeY) is associated with prognosis in several tumors. Large studies on endometrial and cervical cancer are still pending. METHODS: Specimens of 234 patients with EC were immunohistochemically stained with antibodies for SLeX, SLeA and LeY. Expression was correlated to histopathological variables. RESULTS: High expression of SLeX was correlated to low pT-stage (p = 0.013), low grade (p < 0.001), low FIGO-stage (p = 0.006) and better overall survival rates (OS; p = 0.023). High expression of SLeA was associated with low pT-stage (p = 0.013), low grade (p = 0.001) and better progression-free survival (PFS; p = 0.043). LeY staining was correlated to pN + (p = 0.038), low grade (p = 0.005) and poorer PFS (p = 0.022). CONCLUSION: This is the first study examining the expression of SLeX, SLeA and LeY in EC, which can serve as additional future prognostic markers. Further studies are necessary to understand the underlying mechanisms. The study was approved by the local ethics committee of the Ludwig-Maximilians University Munich (reference number 19-249).

Clinical outcome of combined intracavitary / interstitial brachytherapy using a hybrid applicator in locally advanced cervical cancer.

OBJECTIVE: The aim of this study was to evaluate the clinical outcome in locally advanced cervical cancer (LACC) after image-guided adaptive brachytherapy (IGABT) with combined intracavitary and interstitial (IC/IS) techniques using the hybrid Venezia applicator (Elekta AB, Sweden). METHODS: LACC patients (UICC Stage IIB - IVB) treated with radiochemotherapy followed by IGABT with the hybrid IC/IS Venezia applicator at a single institution were retrospectively analyzed. Treatment comprised EBRT of the pelvis with 45 Gy and concomitant weekly cisplatin chemotherapy (40 mg/m2) followed by MRI-based IGABT. Dosimetry, oncological outcome and toxicity were investigated. RESULTS: Forty-six patients underwent a total of 184 fractions of IGABT between 2017 and 2020. Median follow-up was 24 months. Combined IC/IS techniques were used in 40 patients (87%). The median HRCTV volume was 31.2 cm3 and the median HRCTV D90% was 92.3 Gy (EQD210). The median D2cm3 was 74.8 Gy for bladder, 57.9 Gy for rectum, 60.0 Gy for sigmoid and 52.2 Gy for bowel (EQD23). The 3-yr actuarial rates were 97.6% for local control, 97.6% for pelvic control, 59.9% for distant metastasis-free survival and 81.6% for overall survival. The crude rate for G2 and G3 late toxicity was 21.7% and 4.3%. CONCLUSIONS: IGABT with the hybrid Venezia applicator and a pronounced use of a combined IC/IS technique achieved high target doses, while maintaining low doses to organs at risk, leading to excellent local control and overall survival rates with acceptable toxicity.

Galectin-8 and -9 as prognostic factors for cervical cancer.

PURPOSE: Galectins are carbohydrate-binding proteins with multiple effects on cell biology. Research shows that they play an important role in tumor development and progression. Therefore, in this study, the presence of Galectin-8 and -9 (Gal), both already known as prognostic factors in other tumor entities, were investigated in cervical cancer. Our aim was to examine the association of Gal-8 and -9 expression with histopathological markers and survival of the patients. METHODS: Gal-8 and -9 expression was investigated in 250 cervical cancer samples by immunohistochemistry. The staining was evaluated using the immunoreactive score (IRS). The results were correlated to clinical and pathological data. The correlation of Gal-8 and -9 expression with overall and relapse-free survival was analyzed. RESULTS: Expression of Gal-8 was associated with negative N-status and lower FIGO status. Detection of Gal-9 was connected to negative N-status and lower grading regarding all specimens. A correlation of Gal-9 with lower FIGO status was detected for squamous cell carcinoma (SCC) only. Expression of Gal-8 was associated with relapse-free survival of SCC patients in a positive manner. Gal-9 expression was associated with better overall survival. CONCLUSION: Our results suggest that expression of both galectins is inversely associated with tumor stage and progression. Gal-8 expression is associated with relapse-free survival of patients with SCC, while presence of Gal-9 in cervical cancer is associated with a better prognosis in regard of overall survival.

Subcellular Distribution of Thyroid Hormone Receptor Beta in Ovarian Cancer.

Background: Since the most well-known function of thyroid hormone receptors (TRs) relies on their ability to act as ligand-activated transcription factors, their subcellular localization has been recognized to be relevant for their biological meaning. The current study aimed to determine the prevalence and subcellular distribution of TR beta and TR beta-1 in ovarian cancer (OC). Methods: Tissue was collected from 153 patients that had undergone surgery due to OC at the Department of Obstetrics and Gynaecology of the Ludwig-Maximilians-University Munich. Immunohistochemistry detecting TR beta and TR beta-1 was performed. Staining signals were quantified and tested for association with clinico-pathological parameters including overall survival (OS). Results: The subcellular distribution of TR beta and TR beta-1 differed among histologic subtypes, grade and FIGO stage. TR beta positivity was strongly linked to shortened overall survival (p < 0.001). Strikingly, this shortened OS was mainly attributed to those cases showing complete (p = 0.005) or incomplete shift of TR beta to the cytoplasm (p < 0.001). Significance was lost in multivariate testing. Conclusions: Cytoplasmatic localization of TR beta was associated with reduced OS, at least in univariate analysis. Since TRs have long been supposed to mainly function via the regulation of gene transcription in the nucleus, cytoplasmatic shifting might be interpreted as a regulator of their activity.

A combination of immunohistochemical markers, MUC1, MUC5AC, PAX8 and growth pattern for characterization of mucinous neoplasm of the ovary.

OBJECTIVE: Because mucinous carcinomas are rare tumors that affect several organ sites and are known to originate from different tissues, leading to frequent misdiagnoses, the objective was to characterize the differences between primary mucinous tumors of the ovary and metastatic mucinous cancer to the ovary by studying the expression pattern of several candidate biomarkers. METHODS: Tissue samples of mucinous histology were obtained between 1985 and 2015. Individual ovary and colon tissue samples were analyzed, including standard (PAX8, CK20, CK7, CDX2, SATB2, estrogen/progesterone) and new (MUC1, MUC5AC) biomarkers, which were then scored for immunoreactivity semi-quantitatively. RESULTS: The study cohort included 98 mucinous tumor samples, including benign mucinous cystadenoma (n=24), mucinous borderline tumors (n=24), mucinous carcinomas (n=40), and metastatic mucinous ovarian carcinomas (n=10). A strong positive correlation was found between PAX8 scoring (p=0.003), CK7 scoring (p=0.0001), and MUC1 scoring (p=0.001) in primary mucinous ovarian cancer. Tumors of increasing invasiveness were analyzed and a significant decrease in the scoring of MUC5AC (p=0.001) was observed, with a stronger expression in adenomas (87%) and borderline tumors (75%), and a lower expression in mucinous cancers (42%). Patients survived significantly longer when their tumors expressed high PAX8 and showed an expansile invasion pattern (p=0.005 and p=0.015, respectively) compared with patients with PAX8-negative tumors and destructive invasion pattern. CONCLUSION: The study data support the diagnostic value of MUC1 as a new biomarker to differentiate between primary and metastatic mucinous ovarian cancer. In addition, the tumor growth pattern along with the PAX8 immunophenotype might represent potential prognostic biomarkers for primary mucinous ovarian carcinomas.