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Purpose: To investigate the clinical significance of programmed cell death ligand 1 (PD-L1) expression in ovarian clear cell carcinoma (CCC)., Materials and Methods: Patients with CCC who underwent primary surgery at our hospital between 1984 and 2014 were enrolled in this study. PD-L1 and mismatch repair (MMR) protein expression in tumor cells, tumor-infiltrating lymphocytes (TILs), including cluster of differentiation (CD) 8, CD4, forkhead box P3 (FOXP3), programmed cell death 1 (PD-1), and BAF250a, were evaluated using immunohistochemistry. The association between PD-L1 expression, clinicopathological features, prognosis, and expression of several proteins was investigated., Results: Of the 125 patients with CCC, 17 had negative PD-L1 and 108 had positive PD-L1. Patients with positive PD-L1 expression showed a lower response to chemotherapy (p = 0.01). In addition, patients with positive PD-L1 showed worse progression-free survival (PFS, p = 0.01) and overall survival (OS, p = 0.01) than that in patients with negative PD-L1 expression. Multivariate analyses for PFS and OS showed that PD-L1 expression was an independent prognostic factor for PFS (hazard ratio [HR] 7.81, p < 0.01) and OS (HR 12.90, p < 0.01). PD-L1 expression was not associated with the expression of several TILs or proteins., Conclusion: The expression of PD-L1 was related to a lower response to chemotherapy and worse prognosis in CCC. These results may be useful for the development of new treatments., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Clear cell endometrial carcinoma represents an uncommon and poorly understood entity. Data from molecular/genomic profiling highlighted the importance of various signatures in assessing the prognosis of endometrial cancer according to four classes of risk (POLE mutated, MMRd, NSMP, and p53 abnormal). Unfortunately, data specific to clear cell histological subtype endometrial cancer are lacking. More recently, data has emerged to suggest that most of the patients (more than 80%) with clear cell endometrial carcinoma are characterized by p53 abnormality or NSMP type. This classification has important therapeutic implications. Although it is an uncommon entity, clear cell endometrial cancer patients with POLE mutation seem characterized by a good prognosis. Chemotherapy is effective in patients with NSMP (especially in stage III and IV) and patients with p53 abnormal disease (all stages). While, preliminary data suggested that patients with MMRd are less likely to benefit from chemotherapy. The latter group appears to benefit much more from immune checkpoint inhibitors: recent data from clinical trials on pembrolizumab plus lenvatinib and nivolumab plus cabozantinib supported that immunotherapy plus tyrosine kinase inhibitors (TKI) would be the most appropriate treatment for recurrent non-endometrioid endometrial cancer (including clear cell carcinoma) after the failure of platinum-based chemotherapy. Moreover, ongoing clinical trials testing the anti-tumor activity of innovative products will clarify the better strategies for advanced/recurrent clear cell endometrial carcinoma. Further prospective evidence is urgently needed to better characterize clear cell endometrial carcinoma., Competing Interests: Declaration of Competing Interest Giorgio Bogani: Novartis AG Pharma (C/A, H), Italian Ministry of Health (RG). Nicole Concin: AstraZeneca (C/A, SH), Seattle Genetics (C/A, SH), MSD (SAB), Mersana (C/A, SH), eTheRNA immunotherapies NV (C/A, SH), Roche (travel expenses), Genmab (travel expenses), Amgen (travel expenses). Isabelle Ray-Coquard: Honoraria from AstraZeneca, Clovis, GSK/Tesaro and PharmaMar; Consulting/advisory board fees from AstraZeneca, Roche, Clovis, GSK/Tesaro, Genmab, PharmaMar, MSD, Mersana, Deciphera, OncXea, Esai, BMS, Novartis and Pfizer; Research funding from MSD;Travel expenses from AstraZeneca, GSK and Roche. Yakir Segev: AstraZeneca (CA), GSK (CA). Pauline Wimberger: Amgen (SH, RF, SAB), AstraZeneca (SH, RF, H, SAB), Clovis (SH, RF, SAB), Eisai (SH, SAB), GSK (SH, SAB), Lilly (SH, SAB), MSD (SH, RF, SAB), Novartis (SH, RF, SAB), Pfizer (SH, RF, SAB), Roche (SH, RF, H, SAB), TEVA (SH, SAB). Natalie YL Ngoi: AstraZeneca (SH), Janssen (SH). Kazuhiro Takehara: AstraZeneca (SH), Chugai (SH, RF), Eisai (SH), MSD (SH), Mochida (SH), Takeda (SH). Takayuki Enomoto: Takeda (SH), Astra Zeneca (SH), Eisai (SH), Chugai Pharma (SH, RF), MSD (SH), Mochida (SH). Domenica Lorusso: AstraZeneca (H, CA), Clovis (H, CA, RF), GSK/Tesaro (H, CA), Roche (CA), Genmab (CA), PharmaMar (CA, RF), MSD (CA, RF), Esai (CA), Merck Serono (CA), Novartis (CA) and PharmaMar (H); Consulting/advisory board fees from AstraZeneca, Roche, Clovis, GSK/Tesaro. Diane Provencher: AstraZeneca (CA, SH, SAB), GSK (CA, SH, SAB). Nadeem Abu-Rustum: NIH/NCI Cancer Center Support Grant P30 CA008748 (F). Hannelore Denys: Roche (CA, SH, SAB), Pfizer (CA, SH, SAB), AstraZeneca (SH, SAB), Lily (SAB), GSK (SAB), Novartis (SH), Pharmamar (SH). Bradley J Monk: AstraZeneca (SH, SAB), GSK (SH, SAB), Incyte (SAB), Merck (SH, SAB), Roche/Genentech (SH, SAB), Eisai (SAB), GOG-Foundation (E), US Oncology (E). The other authors indicated no financial relationship. Legend: consulting/advisory relationship (CA); speaker honoraria (SH); honoraria (H); research funding (RF); ownership interest (OI); intellectual propriety/patent holder (IP); scientific advisory board (SAB)., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Ascites cytology is important for determining the stage and treatment methods for ovarian clear cell carcinoma (CCC) as defined by the 2014 International Federation of Obstetrics and Gynecology classification., Methods: Patients with CCC who underwent surgery at our hospital between January 2012 and December 2019 and who received cytodiagnosis of their ascites using Papanicolaou (Pap) and May-Grünwald-Giemsa (MGG) staining, and cell block methods were identified. The cell block technique was performed using hematoxylin-eosin (H&E) staining and immunohistochemical staining for hepatocyte nuclear factor-1β (HNF-1β), estrogen receptor (ER), progesterone receptor (PR), and Wilms tumor-1 (WT-1). Cancer cells of CCC were defined as tumor cells that were positive for HNF-1β and negative for ER, PR, and WT-1. The diagnostic accuracy of ascites cytology using Pap and MGG staining and cell block methods was examined., Results: Based on cytological data, our study included 17 patients: seven (41.1%) with malignant (MAL) ascites, eight (47.1%) with negative for malignancy (NFM), and two (11.8%) with atypia of undetermined significance (AUS) because of a few atypical cells based on Pap and MGG staining. Malignant cells diagnosed by cell blocks were detected in 7/7 patients with MAL ascites based on PAP and MGG staining, 2/8 (25.0%) patients with NFM, and 1/2 (50%) patients with AUS., Conclusion: These findings show that the cell block method combined with the immunohistochemical investigation may be useful for increasing the diagnostic accuracy of malignant cells in CCC., (© 2021 Wiley Periodicals LLC.)

Background: This study aimed to examine the clinical significance and risk factors of thromboembolic events (TEEs) in patients with ovarian carcinoma., Methods: Patients with ovarian carcinoma treated at our hospital between 2000 and 2017 were identified. The risk factors of TEEs, including venous TEEs and arterial TEEs, and the association between TEEs and prognosis were investigated. Patients with TEEs were classified into two groups: those with severe TEEs, defined as patients who required urgent treatment for deep vein thrombosis, massive pulmonary embolism, acute myocardial infarction, and symptomatic cerebral infarction, and those with mild TEEs. The risk factors of severe TEEs and the association between severe TEEs and prognosis were investigated., Results: A total of 369 patients were enrolled. Among them, 53 patients (14.4%) were complicated with TEEs. Clear cell carcinoma (CCC) was a greater risk factor of TEEs than serous carcinoma (hazard ratio [HR] = 2.81, p = 0.03). In multivariate analysis for survival, TEEs were a prognostic factor of poor progression-free survival (PFS; HR = 2.90, p < 0.01) and overall survival (OS; HR = 2.89, p < 0.01). Among 53 patients with TEEs, 17 (32.1%) developed severe TEEs. CCC was strongly associated with severe TEEs (HR = 42.6, p = 0.02). Multivariate analysis for survival demonstrated that severe TEEs were a risk factor of worse PFS (HR = 4.34, p < 0.01) and OS (HR = 3.30, p = 0.03)., Conclusion: TEEs induced poor prognosis and was associated with CCC. A standard treatment for CCC should be included in the strategy of TEEs.

Purpose: To compare the efficacy, safety, and tolerability profiles of pegylated liposomal doxorubicin and carboplatin (PLDC) with those of gemcitabine and carboplatin (GC) for the treatment of patients with platinum-sensitive recurrent ovarian cancer., Methods: Ovarian cancer patients with recurrence > 6 months after first-line platinum and taxane-based therapies were randomly assigned to PLDC [pegylated liposomal doxorubicin 30 mg/m 2 plus carboplatin area under the curve (AUC) 5 mg/mL/min on day 1] every 4 weeks or GC (gemcitabine 1000 mg/m 2 on days 1 and 8 plus carboplatin AUC 4 mg/mL/min on day 1) every 3 weeks for at least 6 cycles. The primary endpoint was progression-free survival, and overall response rate, overall survival, toxicity, and dose administration were secondary endpoints., Results: One-hundred patients (49 PLDC; 51 GC) were randomly assigned. Over a median follow-up of 24 months, the median progression-free survival was 12.0 months (95% CI 9.2-15.0) for PLDC and 9.8 months (8.9-12.3) for GC [HR 0.69 (0.455-1.047)] with a difference of 2.2 months. The response rate was 57.1% (41.0-72.3) for PLDC and 56.4% (39.6-72.2) for GC. No obvious differences in toxicity (G3/4) were noted between arms. The median relative dose intensity of planned dose per week was 88.9% for pegylated liposomal doxorubicin and 53.1% for gemcitabine (p < 0.0001)., Conclusions: PLDC and GC are both good treatment candidates for platinum-sensitive recurrent ovarian cancer patients; however, the dose intensity was lower for GC than for PLDC. PLDC had a more favorable risk-benefit profile than that of GC for patients.

L-type amino acid transporter 1 (LAT1) is a Na + -independent neutral amino acid transporter that plays a key role in cancer cell growth and survival. To determine the significance of LAT1 in prognosis and resistance to chemotherapy in ovarian carcinoma, we investigated the LAT1 expression in 245 ovarian carcinoma patients by immunohistochemistry using tissue microarray. High expression of LAT1 was detected in 85 (34.7%) patients. The ratio of high expression of LAT1 was significantly high in clear cell carcinoma and low in serous carcinoma compared to other histological types (P < 0.0001). High expression of LAT1 in ovarian carcinoma was associated with poorer prognosis as per log-rank test (P = 0.008). Cox's univariate and multivariate analysis revealed that high expression of LAT1 is an independent marker indicating poor prognosis (hazard ratio = 2.810, P < 0.0001) as well as the FIGO stage III/IV (vs. I/II) and suboptimal surgery. High LAT1 expression was also found to be associated with resistance to chemotherapy (P = 0.016) notably in clear cell carcinoma. In conclusion, we demonstrate that LAT1 is not only associated with poor prognosis of ovarian carcinoma, but also associated with chemoresistance in ovarian carcinoma.

Background/aim: To investigate whether XIAP down-regulation and autophagy inhibition sensitize ovarian clear cell cancer cells to cisplatin., Materials and Methods: The ovarian clear cancer cell line KK was used for in vitro analysis. Hydroxychloroquine (HCQ) and phenoxodiol (PXD) or embelin were used as autophagy and XIAP inhibitors, respectively. Non-specific and XIAP-specific siRNAs were transfected using Lipofectamine. Cytotoxicity was assessed by MTT assays. Protein expression was confirmed by western blotting., Results: In KK, down-regulation of XIAP using specific siRNAs together with HCQ treatment enhanced the anti-tumor effect of cisplatin. Although embelin sensitized KK to cisplatin through XIAP down-regulation, it induced autophagy. However, PXD increased cisplatin sensitivity through XIAP down-regulation and autophagy inhibition. Expression of Atg7, Atg12, and Beclin 1 was decreased after PXD treatment., Conclusion: PXD increased cisplatin sensitivity through XIAP down-regulation and autophagy inhibition and could be a new candidate for ovarian clear cell carcinoma treatment., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Objective: Ovarian clear cell carcinoma (CCC) is one of histological subtypes showing poor prognosis due to chemoresistance. The association of autophagy-related proteins and clinical implementation in CCC has not been determined., Methods: The present study investigated whether expression of autophagy-related protein, light chain 3A (LC3A), was related with prognoses in the patients with CCC using immuno-histochemical stainings, and whether inhibition of autophagy modified the sensitivity to cisplatin in CCC cells in vitro., Results: High expression of autophagy-related protein, LC3A, was detected in 78 cases (78%) in all CCC cases. The patients with high LC3A expression showed significantly lower response rate to primary chemotherapy (17% vs. 100%, p<0.010), and had worse progression-free survival (PFS) and overall survival (OS) compared with those with LC3A low expression. Furthermore, multivariate analyses revealed that high expression of LC3A was identified as independent worse prognostic factors for PFS and OS. Inhibition of autophagy protein LC3A using hydroxychloroquine (HCQ) increased sensitivity to cisplatin in CCC cells in vitro., Conclusion: High expression of LC3A proteins was associated with lower response to platinum therapy, leading to worse prognoses in CCC. Although further studies are needed to confirm the results, inhibition of autophagy by HCQ was associated with platinum sensitivity. Autophagy protein LC3A could be a promising target for treatment for CCC., Competing Interests: No potential conflict of interest relevant to this article was reported., (Copyright © 2017. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology)

Clear cell carcinoma of the ovary (CCC) is a histologic subtype of epithelial ovarian cancer with a distinct clinical behavior. There are marked geographic differences in the prevalence of CCC. The CCC is more likely to be detected at an early stage than high-grade serous cancers, and when confined within the ovary, the prognosis is good. However, advanced disease is associated with a very poor prognosis and resistance to standard treatment. Cytoreductive surgery should be performed for patients with stage II, III, or IV disease. An international phase III study to compare irinotecan/cisplatin and paclitaxel/carboplatin as adjuvant chemotherapy for stage IIV CCC has completed enrollment (GCIG/JGOG3017). Considering the frequent PIK3CA mutation in CCC, dual inhibitors targeting PI3K, AKT in the mTOR pathway, are promising. Performing these trials and generating the evidence will require considerable international collaboration.

Clear cell carcinoma of the ovary has shown an exceedingly chemo-resistant phenotype, especially in cases that are recurrent or refractory to previous therapy. Also, progression-free survival was less than 6 months, even in the patients that achieved response when they were treated with conventional anti-cancer cytotoxic agents. We present a case with recurrent and refractory ovarian clear cell carcinoma that achieved complete remission using a combination of bevacizumab, trabectedin and oxaliplatin. The progression-free interval of the patient is over 30 months, and she is still receiving the combination therapy without toxicities of more than grade 2., (© 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.)

Several clinical trials to establish standard treatment modality for ovarian cancers included a high abundance of patients with serous histologic tumors, which were quite sensitive to platinum-based chemotherapy. On the other hand, ovarian tumor with rare histologic subtypes such as clear cell or mucinous tumors have been recognized to show chemo-resistant phenotype, leading to poorer prognosis. Especially, clear cell carcinoma of the ovary (CCC) is a distinctive tumor, deriving from endometriosis or clear cell adenofibroma, and response rate to platinum-based therapy is extremely low. It was implied that complete surgical staging enabled us to distinguish a high risk group of recurrence in CCC patients whose disease was confined to the ovary (pT1M0); however, complete surgical staging procedures could not lead to improved survival. Moreover, the status of peritoneal cytology was recognized as an independent prognostic factor in early-staged CCC patients, even after complete surgical staging. In advanced cases with CCC, the patients with no residual tumor had significantly better survival than those with the tumor less than 1 cm or those with tumor diameter more than 1 cm. Therefore, the importance of achieving no macroscopic residual disease at primary surgery is so important compared with other histologic subtypes. On the other hand, many studies have shown that conventional platinum-based chemotherapy regimens yielded a poorer prognosis in patients with CCC than in patients with serous subtypes. The response rate by paclitaxel plus carboplatin (TC) was slightly higher, ranging from 22% to 56%, which was not satisfactory enough. Another regimen for CCC tumors is now being explored: irinotecan plus cisplatin, and molecular targeting agents. In this review article, we discuss the surgical issues for early-staged and advanced CCC including possibility of fertility-sparing surgery, and the chemotherapy for CCC disease.

Aims:   Actinin-4, encoded by the ACTN4 gene located on chromosome 19q13.2, enhances cell motility by bundling the actin cytoskeleton. We assessed how ACTN4/actinin-4 alterations contribute to the tumorigenesis of ovarian clear-cell adenocarcinomas (CCAs)., Methods and Results:   Fluorescence in-situ hybridization analysis demonstrated that ACTN4 amplification (≥4 ACTN4 copies in ≥40% of cells) occurred in 27 (33%) of 81 CCAs and genomic gains of ACTN4 were associated strongly with immunohistochemical actinin-4 overexpression, poorly differentiated tumour histology and shorter patient survival (all P < 0.05). From the 27 ACTN4-amplified CCAs, 23 tumours with adjacent putative precursor lesions were selected and examined for ACTN4/actinin-4 alterations with respect to their intratumoral heterogeneity. In this selected cohort, none of the precursors lacking cytological atypia exhibited gains of ACTN4 or actinin-4 overexpression; 50% of the atypical endometrioses and 75% of the borderline CCAFs showed low-level gains of ACTN4 and actinin-4 overexpression, respectively. In 12 of 23 ACTN4-amplified CCAs, intratumoral heterogeneity for ACTN4 alterations was documented in carcinomatous components; the better differentiated carcinoma components exhibited fewer alterations than those with poorly differentiated histology., Conclusion:   Accumulative genomic gains of ACTN4, causing actinin-4 protein overexpression, drive the development and progression of ovarian CCAs with high-grade histology., (© 2012 Blackwell Publishing Ltd.)

Ovarian clear-cell adenocarcinoma (CCA) is known to be a type of cancer in humans with a high frequency of expression of the mammalian target of rapamycin (mTOR), hypoxia-inducible factor-1 (HIF-1), and glucose transporter 1 (Glut1). In this study, we aimed to determine how these alterations contribute to tumor development of CCAs. Immunohistochemical expressions of phosphorylated-mTOR (p-mTOR), HIF-1α, and Glut1 were analyzed in 36 CCAs and 60 coexistent putative precursor lesions: 19 nonatypical and 16 atypical endometriotic lesions, and 11 benign and 14 borderline clear-cell adenofibroma (CCAF) components. Twenty-one cases with solitary endometriosis were also examined. The frequencies of immunopositivity for p-mTOR (in cytoplasm or nucleus), HIF-1α (in nucleus), and Glut1 increased in accordance with higher cytological atypia in the putative precursors: 58%, 5%, and 16% in the nonatypical endometriosis; 63%, 37%, and 50% in the atypical endometriosis; 77%, 95%, and 95% in the endometriosis-associated CCAs; 27%, 0%, and 0% in the benign-CCAF components; 64%, 79%, and 43% in the borderline CCAF components; and 71%, 100%, and 93% in the CCAF-associated CCAs, respectively. p-mTOR, HIF-1α (in the nucleus), and Glut1 were positive in 10%, 5%, and 19% of the solitary endometriosis, respectively. In the putative precursor lesions coexisting with CCA, a strong correlation in the expression between p-mTOR and HIF-1α and between HIF-1α and Glut1 was identified. Expressions of p-mTOR, HIF-1α, and Glut1 have already been evident in the putative precursor lesions of CCA, and these alterations cumulatively occur in the development of ovarian CCA.

In this study, we aimed to develop a histological grading system for ovarian clear cell adenocarcinoma (CCA), based on the tumor growth architectures. Cases were defined as Group A if ≥90% of a tumor examined was composed of well-differentiated tubulocystic and/or papillary architectures; Group C if at least 10% of the tumor was composed of very poorly differentiated histology (i.e. solid masses or individual infiltrating tumor cells with no or little glandular/papillary differentiation); and tumors not corresponding to the first 2 descriptions were defined as Group B. The interobserver reproducibility and prognostic value of the assigned groups were analyzed for 159 CCAs from 5 institutions. The level of agreement in assigning the groups between 2 pathologists was 88.7% (=0.82). After consensus was reached, 46 (29%), 79 (50%), and 34 (21%) tumors were classified in Groups A, B, and C, respectively. In early-stage cases [International Federation of Gynecology and Obstetrics (FIGO) stage I-II], Group A tumors had significantly better outcomes (100% 5-yr survival) than Group B tumors (82% 5-yr survival, P=0.024 by log-rank test) or Group C tumors (56% 5-yr survival, P=0.00054 by log-rank test). Moreover, early-stage Group B tumors had significantly better outcomes than Group C tumors (P<0.001 by a generalized Wilcoxon test). In advanced cases (FIGO stage III-IV), Group A tumors had significantly better outcomes than Group C tumors (52% vs. 16% 5-yr survival, respectively, P=0.043). Group A and C tumors defined with our system were identified to have favorable and unfavorable prognostic factors, respectively, independent of the clinical stage of the disease and presence of residual tumors after the initial surgery. The proposed grouping system could divide patients with CCA into 3 subgroups with distinct prognostic indications, providing a 3-tier histological grading system for ovarian CCA.

Somatic mutations of PIK3CA and ARID1A are the most common genetic alterations observed in ovarian clear cell adenocarcinomas (CCA). In a previous report, we showed that PIK3CA gene mutations and loss of ARID1A expression occur early during the development of CCA. In the present study, using direct genomic DNA sequencing for exons 9 and 20 of PIK3CA and immunohistochemistry for ARID1A protein expression, we analyzed the association of these molecular alterations with various clinicopathological parameters in a total of 90 cases of primary ovarian CCA, including 42 previously examined cases. The presence of PIK3CA mutations, identified in 34 (39%) of the 88 informative cases, was significantly associated with a grossly cystic tumor, the presence of adjacent endometriosis, prominent papillary architecture of tumor growth, the presence of hyalinized and mucoid stroma, and the absence of clear cell adenofibroma components (P < 0.05, each). There was no significant association of PIK3CA mutations with other clinical variables, such as age, clinical stage, or clinical outcome of the patients. The intensity of immunoreactivity for ARID1A was assigned as negative, weakly positive, and strongly positive in 44%, 22%, and 33% of tumors, respectively. Compared to tumors immunoreactive for ARID1A, ARID1A-negative tumors were significantly associated with the presence of adjacent endometriosis (P = 0.025), but there was no statistically supported association with other examined clinicopathological parameters. Compared with CCAs strongly positive for ARID1A, CCAs negative for ARID1A more frequently harbor PIK3CA mutations (P = 0.013). PIK3CA gene mutations and ARID1A immunohistochemistry lacked prognostic significance. These data further support the idea that these molecular alterations occur as very early events during tumor development of ovarian CCA.

Our previous study demonstrated that, among ovarian carcinomas, amplification of the MET gene and overexpression of MET specifically and commonly occur in clear-cell adenocarcinoma histology. This study was conducted to address how these alterations contribute to development and progression of this highly chemoresistant form of ovarian cancer. We histologically reviewed 21 previously described MET amplification-positive clear-cell adenocarcinoma cases, and selected 11 tumors with synchronous endometriosis and 2 tumors with adjacent clear-cell adenofibroma (CCAF) components. Using double in situ hybridization and immunohistochemistry, copy number alterations of the MET gene and levels of MET protein expression were analyzed in these putative precursor lesions and the corresponding invasive carcinoma components in this selected cohort. All of the non-atypical precursor lesions analyzed (ie, non-atypical endometrioses and the benign CCAFs) were negative for MET gain. However, low-level (≥3 MET copies in ≥10% and ≥4 MET copies in 10-40% of tumor cells) gain of MET was detected in 4 (40%) of the 10 atypical endometrioses and 1 of the 2 borderline CCAFs. Moreover, high-level (≥4 MET copies in ≥40% of tumor cells) gain of MET were detected in five (50%) of the atypical endometrioses. In 4 (31%) of the 13 cases enrolled, intratumoral heterogeneity for MET gain was documented in invasive carcinoma components, wherein all the relatively differentiated carcinoma components showed low-level gain of MET and all the corresponding poorly differentiated carcinomas showed high-level gain. The overall incidence of MET overexpression gradually increased from the precursors of non-atypical form (0%), through those of atypical form (67%) and the relatively differentiated carcinoma components (92%), to the poorly differentiated carcinoma components (100%). These results suggest that accumulative MET gene copy number alterations causing MET overexpression are associated with higher tumor grade and might drive the development and progression of the MET amplification-positive ovarian clear-cell adenocarcinoma.

Clear cell adenocarcinoma (CCA), a highly lethal histological subtype of ovarian carcinoma, is a type of human cancer with a high frequency of activating mutations in the PIK3CA gene. In this study, we aimed to determine how these mutations contribute to tumour development of CCAs. Exons 9 and 20 of the PIK3CA gene were analysed by direct genomic DNA sequencing of 23 CCAs with synchronous putative precursor lesions (ie endometriosis adjacent to carcinoma, with or without cytological atypia) and their mutational statuses were compared. Somatic mutations of the PIK3CA gene were detected in 10/23 (43%) carcinomas and in all cases the type of mutation was H1047R in the kinase domain. The identical H1047R mutation was also detected in the coexisting endometriotic epithelium, adjacent to the CCAs, in nine of ten (90%) cases. Moreover, in six of the nine lesions, the H1047R mutation was identified even in the endometrioses lacking cytological atypia. These findings provide evidence that mutations of the PIK3CA gene occur in the putative precursor lesions of CCA, strongly suggesting that they are very early events in tumourigenesis, probably initiating the malignant transformation of endometriosis. A specific kinase inhibitor to mutated PIK3CA may potentially be an effective therapeutic reagent against these carcinomas., (Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Clear cell carcinoma (CCC) of the ovary is well-known to be chemotherapy resistant compared with other histologic subtypes. An inhibitor against the mammalian target of rapamycin, temsirolimus (TEM) has been reported to be effective in renal CCC. Therefore, we investigated the effects of TEM in patients with CCC of the ovary. Six patients with CCC of the ovary who had been heavily pretreated by more than 4 regimens were given TEM: the cycle consisted of weekly TEM (10 mg/m(2)) for 3 weeks followed by 1 week off. The treatment was continued until development of either progressive disease, or unmanageable adverse effects. Response evaluation was based upon the Response Evaluation Criteria in Solid Tumors version 1.0. Adverse effects were analyzed according to Common Terminology Criteria for Adverse Events version 3.0. The median cycle of weekly TEM was 3 (range 2-14). Among five cases in which responses could be evaluated, partial response was observed in one case (20%) and stabilized disease was seen in another case (20%). There were no toxicities greater than grade 3, and no case developed severe toxicity requiring discontinuation of weekly TEM. The patient who showed a partial response obtained a progression-free period of 14 months. In conclusion, weekly TEM shows a potential therapeutic benefit for patients with CCC of the ovary. Further studies including a translational approach are needed to select candidates for whom TEM therapy would be beneficial.

In this study, we aimed to determine whether the presence of poorly differentiated histologic components in ovarian clear cell adenocarcinoma (CCA) affects patient prognosis. Pathologic slides from 159 patients with CCA were studied, and the tumors were classified as Por(+) in the event of poorly differentiated histology; that is, if solid masses or cords, or individual infiltrating tumor cells with little or no glandular/papillary differentiation were present in >5% of the tumor area examined. All other tumors were classified as Por(-). The prognostic value and interobserver reproducibility of this assignment were analyzed. The agreement level in the assignment between 2 pathologists was 93.7% (κ=0.86). After a consensus was reached, 53 (33%) and 106 (67%) tumors were classified as Por(+) and Por(-), respectively. Patients with Por(+) tumors showed a significantly worse outcome than those with Por(-) tumors, both in the early stages (stages I/II, 5-year survival rate 53.9% vs. 96.3%, P<0.0001 by log-rank test) and advanced stages (stages III/IV, 5-year survival rate 26.5% vs. 49.2%, P<0.001 by generalized Wilcoxon test). Por(-) tumors showed an effective response to postoperative platinum-based first-line chemotherapy more frequently compared with Por(+) tumors (48% vs. 14%, P=0.042). The Por(+) tumor was found to be an independent prognostic factor for survival irrespective of the clinical stage or presence of residual tumor after the initial surgery. These results suggest that the tumor with a poorly differentiated histology is an adverse prognostic subgroup in ovarian CCA. On the basis of the prognostic impact and interobserver reproducibility, the present binary classification system for CCAs was deemed to be highly superior to the compared conventional histologic grading system.

The aim of this study was to assess protein overexpression and gene copy number alterations of MET in ovarian clear-cell adenocarcinoma, and to assess its potential as a novel therapeutic target. Ninety cases of clear-cell adenocarcinoma were analyzed for MET protein overexpression and copy number alterations of the MET gene by immunohistochemistry and brightfield double in situ hybridization, respectively. In addition, 101 cases of the non-clear-cell type ovarian carcinomas at advanced stages were also evaluated for comparison. MET overexpression was assigned when complete membrane staining with moderate or strong intensity was observed in at least 10% of the tumor cells examined. Double in situ hybridization was determined as positive when the tumor exhibited high-level polysomy (≥4 copies in ≥40% of tumor cells) or MET gene amplification. MET overexpression was detected in 20 of 90 clear-cell adenocarcinomas (22%) and none of 111 non-clear-cell type ovarian carcinomas. Double in situ hybridization was positive in 21 of 89 informative clear-cell adenocarcinomas (24%) and only 3 non-clear-cell type ovarian carcinomas (3%). In the whole population, true amplification of the MET gene was detected only in the clear-cell adenocarcinoma histology (five cases, 6%). In clear-cell adenocarcinomas, double in situ hybridization positivity was highly correlated with the presence of MET overexpression and a poorly differentiated histology of tumors (P=0.0105 and 0.00038, respectively). For the patients with clear-cell adenocarcinomas, MET overexpression, as well as advanced clinical stage and the poorly differentiated histology of tumors, was identified as an independent unfavorable prognostic factor for overall survival. In conclusion, among ovarian carcinomas, the amplification of the MET proto-oncogene is highly selective and commonly occurs in clear-cell adenocarcinoma. MET could serve as a biomarker for the prognostication of patients with clear-cell adenocarcinoma and tumor progression, and has potential as a novel therapeutic target for this carcinoma.

Pathologic slides from 150 patients with clear cell adenocarcinoma from the collaborating institutions were reviewed independently by 2 pathologists, and each tumor was graded histologically using the Shimizu-Silverberg and International Federation of Gynecology and Obstetrics (FIGO) grading systems. For the Shimizu-Silverberg grading system, 3 parameters-architectural pattern, nuclear pleomorphism, and mitotic activity-were assessed and scored as 1 to 3. When the summed scores of these parameters were 3 to 5, 6 to 7, and 8 to 9, grades 1, 2, and 3 were assigned, respectively. The FIGO grade was based on the ratio of glandular/papillary growth versus solid growth: grade 1, less than 5% solid tumor; grade 2, 5% to 50% solid tumor; grade 3, greater than 50% solid tumor. Interobserver agreement levels for assignment of both gradings were fair (κ=0.32 and 0.24, respectively). After consensus had been acquired, 82 (55%), 56 (37%), and 12 (8%) tumors were classified as grades 1, 2, and 3 by the Shimizu-Silverberg grading system, and 88 (59%), 38 (25%), and 24 (16%) were classified as grades 1, 2, and 3 by the FIGO grading system, respectively. Survival analyses indicated that patients with grade 3 tumors, as defined by both the grading systems, tended to have a poor outcome, but any differences between them were not statistically significant. Multivariate analysis showed that only the presence of residual tumor after initial surgery was an independent prognostic factor for overall survival. These results suggest that the 2 tested grading systems have limited value for the prognostication of patients with clear cell adenocarcinoma, and that a more effective grading system for this tumor may be required.

Introduction: Ovarian clear cell carcinoma (CCC) is regarded as grade 3 tumor, and the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines recommend adjuvant chemotherapy for the tumor even at stage IA. However, CCC often showed chemo-resistant phenotype, and the effect of adjuvant chemotherapy still remained uncertain., Methods: Clear cell carcinoma cases treated at collaborating institutions during the period 1992-2005 were retrospectively identified. After a central pathological review, survival analysis was estimated by the Kaplan-Meier method, and prognostic factors were evaluated using a Cox regression model., Results: Among 219 patients with stage I CCC, 195 patients received adjuvant chemotherapy (C+) and 24 patients (C-) did not. The C+ group had 77 pT1a and 118 pT1c cases, and the C- group included 18 pT1a and 6 pT1c tumors (P < 0.001). The median age was 52 years in the C+ group and 57 years in C- group (P = 0.04). During the median follow-up period of 48 months (range, 7-160 years), relapse was observed in one patient (4%) in the C- group and in 35 patients (18%) in the C+ group. There were no statistical differences of progression-free survival and overall survival between the C+ and the C- groups. Multivariate analysis revealed that peritoneal cytology status (P = 0.02) and pT status (P = 0.04) were independent prognostic factors for progression-free survival; however, adjuvant chemotherapy was not a prognostic factor (P = 0.80)., Conclusions: Although the present study was a limited retrospective investigation, it suggested that adjuvant chemotherapy had little impact on the survival of stage I CCC patients. Further strategy, such as a molecular targeting agent, is needed to improve survival of CCC, especially in cases with positive peritoneal washing.

Aims: To identify the key cell-cycle dysregulations in the development of endometriosis-associated ovarian clear cell adenocarcinoma (CCA)., Methods and Results: Expression of p27(Kip1)-interacting cell-cycle regulators, such as p27(Kip1) itself, Skp2, cyclin-dependent kinase subunit 1 (Cks1), cyclin A and cyclin E, and Ki67 labelling index (LI), were analysed by immunohistochemistry in 23 CCAs with 36 endometriotic or atypical endometriotic lesions adjacent to CCA from a cohort of 23 patients, and in 31 cases of solitary endometriosis. The cell-cycle regulators examined were overexpressed (Skp2, Cks1, cyclin A and cyclin E; P < 0.01, each) or down-regulated (p27(Kip1), P = 0.044) significantly more frequently in the CCAs than in the adjacent endometriosis. The frequency of Skp2 overexpression was significantly higher in atypical endometriosis than in endometriosis, and the frequency of Skp2 and cyclin A overexpression was significantly higher in CCA than in atypical endometriosis (P < 0.01, each). Mean Ki67 LI increased from endometriosis (8.4%) through atypical endometriosis (21.4%) to CCA (46.9%), with statistical significance between each component (P < 0.01, each). The frequency of cell-cycle regulator expression and mean Ki67 LIs were not significantly different between solitary endometriosis and endometriosis adjacent to CCA., Conclusions: Alteration of the p27(Kip1)-interacting cell-cycle regulators appeared strongly involved in the progression of endometriosis-associated ovarian clear cell carcinogenesis through increasing cell proliferative activity.

Introduction: Paclitaxel plus carboplatin (TC) is generally considered to be the "gold standard" regimen for treatment of epithelial ovarian carcinomas. Little data are available, however, on the use of this regimen in patients with clear cell adenocarcinoma of the ovary (CCC). Combination chemotherapy with irinotecan hydrochloride plus cisplatin has been reported to be effective for primary and recurrent or resistant CCC. We compared these 2 combinations in patients with CCC., Methods: Patients (n = 99) with CCC were randomly assigned to receive either 180 mg/m2 paclitaxel on day 1 plus AUC 6 mg/mL x minute carboplatin on day 1 every 21 days (TC arm) or 60 mg/m2 irinotecan hydrochloride on days 1, 8, 15 plus 60 mg/m2 cisplatin on day 1 every 28 days (CPT-P arm)., Results: Percentages of patients receiving the scheduled 6 cycles of chemotherapy in the TC and CPT-P arms were 70.8% and 72.0%, respectively. Although toxicity was well tolerated in both arms, the toxicity profile of each arm differed. Progression-free survival (PFS) showed no significant difference between the 2 treatment groups. Because there were more patients with large residual disease in the CPT-P arm, we performed a subset analysis by removing those patients, and then compared the PFS with that of patients without residual disease or with residual disease less than 2 cm. The PFS tended to be longer in the CPT-P group, although the difference was not statistically significant., Conclusions: A phase III randomized trial is required to elucidate the effectiveness of CPT-P combination chemotherapy for CCC.

Objectives: Epithelial ovarian cancer (EOC) can be classified into 5 major histological types. Among them, clear cell adenocarcinoma (CCC) has a poor response to chemotherapy and poor prognosis compared with other histological types. Previously, we reported that the hypoxia-inducible protein 2 (HIG2) gene might be a new biomarker for CCCs, based on its expression profile. In this study, we generated a polyclonal antiserum to HIG2 to explore the use of HIG2 as a predictive biomarker in EOC. In addition, HIG2 expression was evaluated in uterine endometrial and renal CCCs., Methods: Hypoxia-inducible protein 2 expression was analyzed by immunohistochemistry in formalin-fixed surgical samples from 254 EOC, 17 endometrial, and 29 renal CCC patients., Results: Hypoxia-inducible protein 2 is expressed in 175 of 254 ovarian cancer cases. Cytoplasmic HIG2 expression is significantly more frequent in ovarian CCC (83.1%) than in serous (54.9%, P = 0.0001), mucinous (40%, P = 0.00002), or endometrioid (58.1%, P = 0.003) adenocarcinoma. The chemoresponse rate was higher in 24 ovarian CCC patients with cytoplasmic HIG2 expression than in 6 CCC patients without HIG2 expression (62.5% [15/24] vs 0% [0/6], P = 0.02). In contrast, there was no relationship between nuclear HIG2 expression and chemoresponse. Cytoplasmic and nuclear HIG2 expressions are significantly more frequent in ovarian and uterine than renal CCC (P = 0.04)., Conclusions: Hypoxia-inducible protein 2 may be used as a marker for early detection of ovarian CCCs or for prediction of response to chemotherapy, but HIG2 expression does not predict survival of patients with CCC.

We have previously reported that alterations of p27(Kip1)-interacting cell-cycle proteins frequently occur during the development of endometriosis-associated ovarian clear cell adenocarcinoma (CCA; Yamamoto et al., Histopathology in press, 20). However, CCA also occurs in association with clear cell adenofibroma (CCAF). In this study, the expressions of p27(Kip1)-interacting proteins, i.e., p27(Kip1), Skp2, Cks1, cyclin A, cyclin E, and the Ki-67 labeling index (LI), were analyzed in 25 CCAFs (11 benign and 14 borderline) and 15 CCAF-associated CCAs, and compared with the expression status of each protein in the 23 previously studied endometriosis-associated CCAs. Although aberrant expression of all p27(Kip1)-interacting proteins was more frequent in the CCAF-associated CCAs than in the benign CCAFs, statistical significance was found only for Cks1 overexpression. The frequencies of p27(Kip1) downregulation and overexpression of Skp2 and cyclin A were significantly lower in CCAF-associated than in endometriosis-associated CCAs (P < 0.05, respectively). The frequencies of p27(Kip1) downregulation and Skp2 overexpression in borderline CCAFs were significantly lower than those in atypical endometriosis components in endometriosis-associated CCAs (P < 0.05, respectively). Mean Ki-67 LI increased significantly through benign (4.9%) to borderline (11.1%) CCAF and to CCAF-associated CCA (30.6%), but the latter two values were significantly lower than those in atypical endometriosis (21.4%) and endometriosis-associated CCA (46.9%; P < 0.05, respectively). These data suggest that accumulated alterations of p27(Kip1)-interacting proteins may accelerate the development of CCAs regardless of their carcinogenetic pathways, but that tumor cells in the CCAF-associated pathway appear to show slower cell-cycle progression than those in the endometriosis-associated pathway, possibly accounting for the distinct clinicopathological features of the two CCA subtypes.

Pure-type clear cell carcinoma (CCC) has been recognized as a distinct subtype of ovarian cancer, showing resistance to conventional platinum-based chemotherapy and resulting in poor prognosis. The aim of the study was to evaluate the effects of complete surgical staging procedures for early-stage CCC patients in a retrospective multi-institutional analysis. During the period 1992 to 2002, a total of 199 patients with pT1 M0 CCC were identified. Survival analysis was estimated by Kaplan-Meier methods, and prognostic factors were evaluated using a Cox regression model. Among pT1 M0 tumors, retroperitoneal lymph node status was negative in 125 cases (pN0, 63%), positive in 10 cases (pN1, 5%), and unknown in 64 cases (pNx, 32%). Progression-free survival of pN1 was significantly worse than that of pN0 (P < 0.05), whereas there was no significant difference between pN1 and pNx. There was no significant difference of overall survival (OS) among the 3 groups. Multivariate analysis revealed that peritoneal cytology status was the only independent prognostic factor for progression-free survival (P = 0.04), but completion of surgical staging procedures was not a prognostic factor. There was no significant prognostic factor for OS. Our study implied that complete surgical staging enabled us to distinguish a high-risk group of recurrence in pT1 M0 CCC; however, the procedure could not improve OS. Although the study was a limited retrospective study, the impact of peritoneal cytology status was more important than complete surgical staging procedure in CCC patients. More effective treatment modality was warranted, especially for CCC cases positive for malignant peritoneal cytology.

Patterns of allele loss (loss of heterozygosity (LOH)) were studied to identify the genetic backgrounds underlying the two putative carcinogenic pathways of ovarian clear-cell adenocarcinoma: carcinomas thought to arise in endometriosis (endometriosis-associated carcinomas, 20 cases) and carcinomas thought to be derived from clear-cell adenofibroma ((CCAF)-associated carcinomas, 14 cases). Each tumor was assessed for LOH at 24 polymorphic loci located on 12 chromosomal arms: 1p, 3p, 5q, 8p, 9p, 10q, 11q, 13q, 17p, 17q, 19p, and 22q. For all informative loci, the frequency of LOH was not statistically different between the two carcinoma groups: 38% (66/172 loci) in the endometriosis-associated carcinomas and 35% (40/113 loci) in the CCAF-associated carcinomas. In the endometriosis-associated carcinomas, LOH was detected at high frequencies (>50%) at 3p, 5q, and 11q and at low frequencies (<20%) at 8p, 13q, and 17p. In the CCAF-associated carcinomas, LOH was detected at high frequencies at 1p, 10q, and 13q and at low frequencies at 3p, 9p, 11q, and 17q. The frequencies of LOH at chromosomes 3p, 5q, and 11q were significantly higher in the endometriosis-associated carcinomas than in the CCAF-associated carcinomas (P = 0.026, 0.007, and 0.011, respectively). Immunohistochemical analysis demonstrated a close association between the allelic status of the 3p25-26 locus and levels of von Hippel-Lindau (VHL) protein expression (P = 0.0026). These data further support the presence of two distinct carcinogenic pathways to ovarian clear-cell adenocarcinoma; the allelic status of the 3p, 5q, and 11q loci may provide a means to identify the precursor lesions of these carcinomas.

Pure-type clear cell carcinoma (CCC) has been recognized as a distinct subtype of ovarian cancer, showing a resistance to chemotherapy and resulting in poor prognosis. Our aim was to evaluate the effects of complete surgical procedures followed by adjuvant chemotherapy for CCC patients whose tumors were confined to the ovary (pT1M0). During the period of 1987-2005, 56 patients with stage I CCC were identified and two cases were excluded due to retroperitoneal lymph node metastasis. A total of 54 patients were enrolled in the study and divided into two groups: Group A (n=38, 1993-2005) underwent complete surgical staging including pelvic and para-aortic lymphadenectomy. Group B (n=16, 1987-1992) underwent a hysterectomy, bilateral salpingo-oopherectomy, omentectomy without comprehensive lymphadenectomy. Every patient received six courses of adjuvant chemotherapy using a platinum agent. Survival analysis was estimated by the Kaplan-Meier method and prognostic factors were evaluated using a Cox regression model. The clinical characteristics of the two groups were similar, except for the rate of conventional platinum-based chemotherapy (p=0.02). Multiple regression survival analysis revealed that the completion of a comprehensive staging operation was the only independent factor for progression-free survival of stage I CCC patients (p=0.03) and that the chemotherapeutic regimen was not a prognostic factor (p=0.43). The present study indicates that we should accomplish complete surgical staging procedures for CCC confined to the ovary.

Recent studies have shown that platelet-derived growth factors and their receptors are frequently co-expressed in ovarian cancers. Herein, we investigated the role of the platelet-derived growth factor pathway in the development of ovarian clear-cell adenocarcinoma, a highly chemoresistant form of ovarian cancer. Immunohistochemical expression of platelet-derived growth factor receptor-alpha and receptor-beta, platelet-derived growth factor A-chain and B-chain was examined in 31 cases of clear-cell adenocarcinoma and 56 coexisting putative precursor lesions: 17 non-atypical and 19 atypical endometrioses, and 10 non-atypical and 10 atypical clear-cell adenofibroma components. Twenty-one solitary endometrioses were also examined. Vascular endothelial cells were always positive for all the markers examined, and were used as positive controls. The frequencies of positivity for platelet-derived growth factor receptor-alpha and receptor-beta, and platelet-derived growth factor A-chain increased in accordance with higher cytologic atypia in the putative precursors: 71, 47, and 59% in the 17 non-atypical endometrioses, 84, 73, and 84% in the 19 atypical endometrioses, 0% each in the 10 non-atypical clear-cell adenofibromas, 100, 90, and 90% in the 10 atypical clear-cell adenofibromas, and 97, 97, and 100% in the 31 clear-cell adenocarcinomas, respectively. Positivity for platelet-derived growth factor B-chain increased in accordance with increased atypia in clear-cell adenofibroma: 0% in non-atypical clear-cell adenofibromas, 30% in atypical clear-cell adenofibromas, and 60% in coexisting carcinomas. However, in contrast, positivity for platelet-derived growth factor B-chain decreased in accordance with increased atypia in endometriosis coexisting with clear-cell adenocarcinomas: 35% in non-atypical endometrioses, 11% in atypical endometrioses, and 5% in coexisting carcinomas. Platelet-derived growth factor receptor-alpha and receptor-beta, and their ligands A-chain and B-chain were positive in 14, 29, 19, and 62% of the solitary endometrioses, respectively. These results indicate activation of the platelet-derived growth factor pathway in ovarian clear-cell adenocarcinomas and suggest biological differences between carcinomas that arise in association with clear-cell adenofibroma vs endometriosis.

Background: Irinotecan hydrochloride, a topoisomerase I inhibitor, has been preliminarily recognized as an effective agent against clear cell carcinoma of the ovary (CCC), but there are few clinical data. Our aim was to compare progression-free survival (PFS) between patients treated with irinotecan hydrochloride and cisplatin (CPT-P) and those with treated with paclitaxel and carboplatin (TC)., Methods: One hundred and seventeen patients at International Federation of Gynecology and Obstetrics (FIGO) stages Ic (ascites/malignant washing) - IV were identified by scanning the medical records of ten Japanese hospitals. After complete surgical staging procedures including lymphadenectomy, 35 patients received CPT-P and 82 patients received TC. The PFS and overall survival of the two groups were compared using the Kaplan-Meier method., Results: There was no significant difference in median age, performance status, FIGO stage, rate of optimal cytoreduction, or follow-up period between the CPT-P and TC groups. Two-year and 5-year PFS was 48% and 40%, respectively, in the TC group and 55% and 55%, respectively, in the CPT-P group (P = 0.31). Multiple regression analysis revealed that only residual tumor was an independent prognostic factor for PFS (P < 0.01)., Conclusion: CPT-P showed a potential therapeutic effect, at least no less than that of TC therapy. Although there was no significant survival benefit in the present retrospective analysis, we recommend that the CPT-P regimen be evaluated in a larger, prospective, clinical trial.

Clear cell carcinoma (CCC) of the ovary has distinct characteristics showing resistance to conventional platinum-based regimen. Our aim was to evaluate the effects of combination therapy with irinotecan hydrochloride and cisplatin (CPT-P), comparing to regimen with paclitaxel and platinum (TP). We retrospective reviewed 172 patients with complete surgical staging procedures including lymphadenenctomy. Forty-six patients received CPT-P and 126 patients were treated with TP. Survival of the two groups was compared. Between CPT-P group and TP group, there was no significant difference in median age, performance status, FIGO stage, rate of optimal cytoreduction, and follow-up period. There was no significant difference in progression-free survival of patients with stage I tumors (p=0.95) and suboptimally debulked stage II-IV tumors (p=0.92). Although there was no significant difference of overall survival, progression-free survival of CPT-P group was significantly better than that of TP group in optimally debulked stage II-IV (p=0.03). Multiple regression survival analysis revealed CPT-P regimen (p=0.02) and residual tumor diameter (p<0.01) were both independent prognostic factors in stage II-IV tumors. The combination of CPT-P was shown to have a potential therapeutic benefit for advanced CCC of the ovary, especially for cases with optimal debulking surgery. However, this is a limited retrospective study, therefore we recommend that the CPT-P regimen be evaluated in a larger prospective study.