Short response duration even in responders to chemotherapy using conventional cytotoxic agents in recurrent or refractory clear cell carcinomas of the ovary

Survival and biomarker analysis for cancer‑associated thromboembolism in ovarian clear cell carcinoma

The present study aimed to investigate the impact of cancer-associated thromboembolism (CAT) on the survival and biomarkers of ovarian clear cell carcinoma (OCCC). Patients with OCCC who underwent surgery at the National Defense Medical College Hospital (Tokorozawa, Japan) between January 2000 and December 2019 were included in the current study. Associations among CAT, clinicopathological features and prognosis were retrospectively compared. Furthermore, immunohistochemical staining was conducted in all patients to compare differences between patients with and without CAT. Among 111 patients with OCCC, 20 patients (18.0%) had CAT complications. CAT was detected in 12 patients (10.8%) before primary treatment and in 8 patients (7.2%) after primary surgery. Patients with CAT experienced more tumor recurrence (P=0.048) and platinum resistance (P=0.025), had worse progression-free survival (PFS; P<0.01) and overall survival (OS; P<0.01), and multivariate analysis showed that CAT was a prognostic factor for worse PFS [hazard ratio (HR)=2.10, P=0.039] and OS (HR=4.26, P<0.01). Moreover, immunohistochemical analysis revealed that more OCCC cases with CAT were positive for tissue factor (TF; P=0.030) and phosphorylated-Janus kinase 2 (JAK2; P=0.034) expression than those without CAT. In conclusion, CAT may be associated with platinum resistance and poor prognosis in patients with OCCC. Furthermore, TF and JAK2 could be considered potential novel therapeutic targets for OCCC complicated by CAT.

The Analysis of Cell Cycle-related Proteins in Ovarian Clear Cell Carcinoma Versus High-grade Serous Carcinoma

In Japan, the frequency of ovarian clear cell carcinoma (CCC) is twice as high as that in the United States and Europe. Often, patient prognosis with CCC is poor because of chemoresistance. Here, we focus on the cell cycle, which is one of the mechanisms of chemoresistance. To detect the informative markers and improve the strategy of chemotherapy for CCC, we performed immunohistochemical staining of cell cycle-related proteins in ovarian malignant tumors. We detected that each of the 29 samples of CCC and high-grade serous carcinoma (HGSC) were necessary to reveal the significant differences in immunostaining and prognosis. We performed the immunostaining analysis using the antibodies of cell cycle-related proteins such as Ki-67, Cdt1, MCM7, and geminin. The positive rate of Cdt1 in the CCC group was significantly higher than that in the HGSC group (P<0.0001). However, the positive rate of geminin in the HGSC group was significantly higher than that in the CCC group (P<0.0001). The overall survival of CCC patients with high labeling index of Cdt1 was significantly worse than that of CCC patients with low labeling index of Cdt1 (P=0.004). The study results suggested that the cancer cells of CCC and HGSC exist in the G1 phase and S, G2, and M phases, respectively. The differences in cell cycle of CCC might be one of the reasons for chemotherapy resistance. Further investigations are necessary to reveal the usefulness of Cdt1 as a biomarker in CCC.

Role of endometriosis as a prognostic factor for post-progression survival in ovarian clear cell carcinoma

The clinical significance of coexistence of endometriosis (EM) in ovarian clear cell carcinoma (CCC) has not yet been determined. The aim of the present study was to analyze the correlation of endometriosis with clinicopathological factors in CCC. The cases with CCC that received primary debulking surgery at the present hospital between 1990 and 2013 were identified. Retrospective analysis was conducted to evaluate the association between complications with EM and clinicopathological features in CCC. Of the 105 cases enrolled in the study, 45 cases were complicated with EM, and 60 cases did not have EM (non-EM). The patients with EM were diagnosed at a younger age (P=0.03), and at earlier stages (P<0.01) compared with non-EM cases. Although there was no significant difference of progression-free survival (P=0.36), complications with EM were identified as an independent prognostic factor for overall survival (OS; P<0.01) by multivariate analysis. A total of 48 patients (45.7%) developed recurrence: 18 patients in EM-group and 30 patients in non-EM group. There were no significant differences of clinicopathological factors in the treatment at recurrence between both groups. Recurrent cases in EM had significantly worse post-progression survival (PPS) compared with recurrent non-EM group (P<0.01). Multivariate analysis for PPS demonstrated that complications with EM (P<0.01) were identified as a worse prognostic factor. In CCC, the complication with EM was identified as a significant worse prognostic factor for PPS in recurrent cases. Additionally, EM was significantly associated with OS in all cases with CCC. Novel treatment strategies are therefore necessary for recurrent CCC, particularly for cases exhibiting EM.

The role of immune checkpoint inhibition in the treatment of ovarian cancer

The introduction of immune checkpoint inhibitors has revolutionized treatment of multiple cancers and has bolstered interest in this treatment approach. So far, emerging clinical data show limited clinical efficacy of these agents in ovarian cancer with objective response rates of 10–15% with some durable responses. In this review, we present emerging clinical data of completed trials of immune checkpoint inhibitors and review ongoing studies. In addition we examine the current knowledge of the tumor microenvironment of ovarian cancers with a focus on the significance of PD-L1 expression and tumor-infiltrating lymphocytes on predicting response to immune checkpoint blockade. We evaluate approaches to improve treatment outcomes through the use of predictive biomarkers and patient selection. Finally, we review management considerations including immune related adverse events and response criteria.

Radiation Therapy for Recurrent Clear-Cell Cancer of the Ovary

OBJECTIVE

Given the relative chemo-resistant nature of clear-cell gynecologic cancers, we investigated the utility of radiation therapy (RT) to treat recurrent clear-cell carcinoma (CCC) of the ovary.

METHODS

A retrospective chart review of patients with recurrent CCC managed from 1994-2012 was conducted at 2 academic medical centers. Demographic and clinicopathologic factors were abstracted and evaluated using Pearson χ or t tests, Kaplan-Meier and Cox regression analyses.

RESULTS

Fifty-three patients had recurrent CCC, and 24 (45.3%) of these patients received RT. There were no significant differences in age, stage, optimal cytoreduction, platinum response, or the percentage of patients that received more than 3 regimens of chemotherapy between the 2 groups. Patients who received RT for recurrent CCC were more likely to have had a focal recurrence (62.5% vs 10.3%, P ≤ 0.001) and to have undergone secondary cytoreduction (70.8% vs 10.3%, P ≤ 0.001). Of patients who received RT, 73.9% underwent surgery with or before their treatment. Five-year survival after recurrence was significantly higher in the group that received RT, 62.9% versus 18.8% (P = 0.002). In a multivariate analysis, platinum-sensitive disease and RT were associated with improved survival from recurrence, (hazard ratio, 0.26; 95% confidence interval, 0.08-0.81; P = 0.02 and hazard ratio, 0.28; 95% confidence interval, 0.09-0.90, P = 0.03, respectively).

CONCLUSIONS

In this cohort of patients with recurrent CCC, platinum-sensitive disease and RT are associated with improved survival. However, it is important to note that the majority of these patients underwent surgery along with RT, and it may be that the benefit of RT is limited to those who undergo secondary cytoreduction.

Efficacy of glypican-3-derived peptide vaccine therapy on the survival of patients with refractory ovarian clear cell carcinoma

Compared with other epithelial ovarian carcinoma subtypes, ovarian clear cell carcinoma (OCCC) has been recognized to show chemoresistance. Therefore, new treatment modalities are required for patients with OCCC that is refractory to chemotherapy. The carcinoembryonic antigen glypican-3 (GPC3) is expressed by approximately half of OCCC and is a promising immunotherapeutic target. The purpose of this study was to evaluate the effect of GPC3 peptide vaccine against refractory OCCC patients. We conducted a phase II trial with a GPC3-derived peptide vaccine in OCCC patients. Immunological responses were analyzed by ex vivo IFNγ ELISPOT assay. We also evaluated control subjects, who received best supportive care without vaccinations during the same period.

Thirty-two patients with refractory OCCC were enrolled between July 2010 and September 2015, and underwent GPC3 peptide vaccination. Fifteen patients were vaccinated less than six times because their general condition progressively deteriorated, and 17 patients were vaccinated at least six times. Three patients showed a partial response as the best overall response. The GPC3 peptide vaccine induced a GPC3-specific CTL response in 15 out of 24 patients who had PBMCs collected three times or more. The prognosis of palliative care patients without GPC3 peptide vaccinations was significantly poorer than that of those with GPC3 peptide vaccinations (post cancer-treatment survival: p = 0.002).

Although the disease control rate was not high, our results suggest that GPC3 peptide vaccinations may hold a significant impact to prolong survival of patients with refractory OCCC, allowing them to maintain quality of life with no serious toxicities.

X-chromosome-linked inhibitor of apoptosis as a key factor for chemoresistance in clear cell carcinoma of the ovary

Background:

X-chromosome-linked inhibitor of apoptosis (XIAP) is one of the anti-apoptotic proteins leading to chemoresistance in several cancers. The aim of this study is to evaluate the impact of XIAP expression upon ovarian clear cell carcinoma (CCC) that has a platinum-resistant phenotype.

Methods:

Tissue microarrays made from 90 CCC patients were analysed for immunohistochemical expression levels of XIAP, c-Met, p-Akt and Bcl-XL. In addition, CCC cell lines were evaluated whether XIAP silencing could modulate sensitivity to platinum agent in vitro.

Results:

High XIAP expression was observed in 30 (33%) of 90 CCC cases, and was associated with c-Met (<0.01) and Bcl-XL (<0.01) expression. Cases with high XIAP expression had lower response rate to primary platinum-based chemotherapy (10% vs 65%, P=0.02). In stages II–IV tumours, high XIAP expression was related with worse progression-free survival (PFS, P=0.02). Furthermore, high XIAP expression was identified as an independent worse prognostic factor for PFS and overall survival. Finally, downregulation of XIAP using XIAP-specific small interfering RNA increased sensitivity to cisplatin in human cancer cells derived from CCC.

Conclusions:

X-chromosome-linked inhibitor of apoptosis expression was correlated with chemoresistance of primary chemotherapy, and identified as a prognostic marker for CCC. X-chromosome-linked inhibitor of apoptosis could be a candidate for new therapeutic target in CCC.

Significant clinical response of progressive recurrent ovarian clear cell carcinoma to glypican-3-derived peptide vaccine therapy: two case reports

Carcinoembryonic antigen glypican-3 (GPC3) is expressed by>40% of ovarian clear cell carcinoma (CCC) and is a promising immunotherapeutic target. We previously reported the safety of and immunological and clinical responses to a GPC3-derived peptide vaccine in a phase I clinical trial of patients with advanced hepatocellular carcinoma (HCC). Although the efficacy of the GPC3-derived peptide vaccine against HCC patients was evaluated, other GPC3-positive cancer patients have not yet been investigated. Therefore, we conducted a phase II trial to evaluate the clinical outcome of ovarian CCC patients treated with a GPC3-derived peptide vaccine. The GPC3 peptide was administered at a dose of 3 mg per body. Patients received an intradermal injection of the GPC3 peptide emulsified with incomplete Freund's adjuvant. Vaccinations were performed biweekly from the first until the 6th injection and were then repeated at 6-week intervals after the 7th injection. Treatment continued until disease progression. We herein present two patients with chemotherapy-refractory ovarian CCC who achieved a significant clinical response in an ongoing trial of a GPC3 peptide vaccine. Case 1, a 42-year-old patient with advanced recurrent ovarian CCC with liver and retroperitoneal lymph node metastases, received the HLA-A24-restricted GPC3 peptide vaccine. Contrast-enhanced CT at week 10 revealed a partial response (PR) using RECIST criteria. Case 2 was a 67-year-old female with multiple lymph node metastases. She was injected with the HLA-A2-restricted GPC3 peptide vaccine. According to RECIST, PR was achieved at week 37. The stabilization of their diseases over one year provided us with the first clinical evidence to demonstrate that GPC3 peptide-based immunotherapy may significantly prolong the overall survival of patients with refractory ovarian CCC.