Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) Applied to Platinum-Resistant Recurrence of Ovarian Tumor: A Single-Institution Experience (ID: PARROT Trial)

BACKGROUND

We aimed to investigate the therapeutic efficacy and safety of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) in platinum-resistant recurrence of ovarian cancer and peritoneal carcinomatosis, while our secondary endpoint was to establish any changes in quality of life estimated via the EORTC QLQ-30 and QLQ-OV28 questionnaires.

METHODS

In this monocentric, single-arm, phase II trial, women were prospectively recruited and every 28-42 days underwent courses of PIPAC with doxorubicin 2.1 mg/m2 followed by cisplatin 10.5 mg/m2 via sequential laparoscopy.

RESULTS

Overall, 98 PIPAC procedures were performed on 43 women from January 2016 to January 2020; three procedures were aborted due to extensive intra-abdominal adhesions. The clinical benefit rate (CBR) was reached in 82% of women. Three cycles of PIPAC were completed in 18 women (45%), and 13 (32.5%) and 9 (22.5%) patients were subjected to one and two cycles, respectively. During two PIPAC procedures, patients experienced an intraoperative intestinal perforation. There were no treatment-related deaths. Nineteen patients showed no response according to the Peritoneal Regression Grading Score (PRGS) and 8 patients showed minor response according to the PRGS. Median time from ovarian cancer relapse to disease progression was 12 months (95% confidence interval [CI] 6.483-17.517), while the median overall survival was 27 months (95% CI 20.337-33.663). The EORTC QLQ-28 and EORTC QLQ-30 scores did not worsen during therapy.

CONCLUSIONS

PIPAC seems a feasible approach for the treatment of this subset of patients, without any impact on their quality of life. Since this study had a small sample size and a single-center design, future research is mandatory, such as its application in addition to systemic chemotherapy.

Evaluation of secondary cytoreduction surgery in platinum-resistant ovarian cancer patients within three-line recurrent: a multicenter, randomized controlled study

BACKGROUND

Epithelial ovarian cancer is the leading cause of death among gynecological malignancies. Platinum resistance remains a dilemma and bottleneck in treatment, and salvage chemotherapy has limited effectiveness. Recently, the role of secondary cytoreductive surgery (SCS) in patients with platinum-resistant recurrent ovarian cancer (ROC) has caused attention especially in patients with oligometastases. However, there is neither high-quality evidence-based evidence nor standardized criteria for selecting SCS for patients with platinum-resistant ROC until now.

METHODS

This multicenter, randomized, controlled clinical trial is to evaluate the value of SCS and to clarify reliable criteria of utilizing SCS in women with ROC, which is led by Gynecologic Oncology Group, Women's Hospital, Zhejiang University School of Medicine. Recruitment has started on January 1st, 2023, and is scheduled to end in December 2026. One hundred and forty participants with platinum-resistant ROC who meet the "RSCS criteria" will be randomized assigned at a ratio of 1:1 to either the experimental arm or the standard arm. Patients in the experimental arm will receive SCS followed by non-platinum single agent chemotherapy (paclitaxel, gemcitabine or liposomal adriamycin) for at least 4 cycles while patients in the standard arm will be provided with only non-platinum single agent chemotherapy. The primary outcome is progression-free survival. The secondary outcomes are overall survival, adverse events and health-related cancer-specific quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05633199.

Cytoreductive surgery is feasible in patients with limited regional platinum-resistant recurrent ovarian cancer

INTRODUCTION

To evaluate the efficacy of cytoreductive surgery versus chemotherapy for the treatment of limited regional, platinum-resistant ovarian cancer (PROC).

MATERIALS AND METHODS

The clinical records of all patients with PROC treated in our center between March 2015 and March 2022 were retrospectively reviewed. We compared the oncology outcomes of patients who received cytoreduction or chemotherapy alone at relapse and presented information about postoperative adjuvant chemotherapy.

RESULTS

Among 52 patients with limited regional recurrence, 40.4% (21/52) underwent cytoreduction because of platinum resistance, and 59.6% (31/52) received chemotherapy alone. No residual disease (R0) was achieved in 20 patients (95.2%). The severe morbidity rate within 30 days after the surgery was 15%. The median follow-up was 70.6 months. Compared with the chemotherapy alone group, the surgery group with R0 had better progression-free survival (PFS) (10.6 vs. 5.1 months; hazard ratio (HR) = 0.421; P = 0.0035) and post-relapse survival (PRS) (32.6 vs. 16.3 months; HR = 0.478; P = 0.047), but there was no difference in overall survival (OS) between the two groups. Laparoscopy is associated with lesser intraoperative blood loss with no differences in survival and postoperative complications compared to the open approach (P = 0.0042). Subgroup survival analysis showed that compared with chemotherapy alone, surgery prolonged PFS in patients regardless of tumor size (greater than or equal to 4 cm or less). Surgery group patients who achieved R0 had an objective response rate (ORR) of 36.8% (7/19), among whom 40% (4/10) received platinum rechallenge chemotherapy and 33.3% (3/9) were administered non-platinum chemotherapy.

CONCLUSION

When well-selected PROC patients with limited regional recurrence achieved R0, their outcomes were superior to those of patients who received only chemotherapy with an acceptable morbidity rate. Laparoscope technology could be a reliable alternative surgical approach. The reintroduction of platinum agents may be considered following surgery. Further analyses in a larger population are warranted to elucidate the risks and benefits of this surgery and adjuvant chemotherapy strategy.

ATR Inhibitors in Platinum-Resistant Ovarian Cancer

Platinum-resistant ovarian cancer (PROC) is one of the deadliest types of epithelial ovarian cancer, and it is associated with a poor prognosis as the median overall survival (OS) is less than 12 months. Targeted therapy is a popular emerging treatment method. Several targeted therapies, including those using bevacizumab and poly (ADP-ribose) polymerase inhibitor (PARPi), have been used to treat PROC. Ataxia telangiectasia and RAD3-Related Protein Kinase inhibitors (ATRi) have attracted attention as a promising class of targeted drugs that can regulate the cell cycle and influence homologous recombination (HR) repair. In recent years, many preclinical and clinical studies have demonstrated the efficacy of ATRis in PROC. This review focuses on the anticancer mechanism of ATRis and the progress of research on ATRis for PROC.

Surgery in platinum-resistant recurrent epithelial ovarian carcinoma

BACKGROUND

Ovarian cancer is one of the three most common malignant tumors of the female reproductive tract and ranks first in terms of mortality among gynecological tumors. Epithelial ovarian carcinoma (EOC) is the most common ovarian malignancy, accounting for 90% of all primary ovarian tumors. The clinical value of cytoreductive surgery in patients with platinum-resistant recurrent EOC remains largely unclear.

AIM

To evaluate the feasibility of secondary cytoreductive surgery for treating platinum-resistant recurrent EOC.

METHODS

This was a retrospective study of the clinical data of patients with platinum-resistant EOC admitted to the Cancer Hospital of the University of Chinese Academy of Sciences between September 2012 and June 2018. Patient baseline data were obtained from clinical records. Routine follow-up of disease progression was performed as follows. CA125 assessment and physical examination were performed every 3 wk during treatment, including gynecological examination. Imaging assessment was carried out every 12 wk by B-mode ultrasound, computed tomography, or magnetic resonance imaging. The primary outcome was progression-free survival (PFS). Secondary outcomes included overall survival (OS), chemotherapy-free interval (CFI), and complications. Follow-up ended on April 15, 2019.

RESULTS

A total of 38 patients were included. R0 resection was achieved in 25 (65.8%) patients and R1/2 in 13 (34.2%). Twenty-five (65.8%) patients required organ resection. Nine (23.7%) patients had operative complications, 36 (94.7%) received chemotherapy, and five (13.2%) had targeted therapy. Median PFS and OS were 10 (95%CI: 8.27-11.73) months and 28 (95%CI: 12.75-43.25) months, respectively; median CFI was 9 (95%CI: 8.06-9.94) months. R0 resection and postoperative chemotherapy significantly prolonged PFS and OS (all P < 0.05), and R0 resection also significantly prolonged CFI (P < 0.05). Grade ≥ 3 complications were observed, including rectovaginal fistula (n = 1), intestinal and urinary fistulas (n = 1), and renal failure-associated death (n = 1). Except for the patient who died after surgery, all other patients with complications were successfully managed. Two patients developed intestinal obstruction and showed improvement after conservative treatment.

CONCLUSION

Secondary cytoreductive surgery is feasible for treating platinum-resistant recurrent EOC. These findings provide important references for the selection of clinical therapeutic regimens.

Suprarenal lymphadenectomy with nephrectomy for refractory ovarian cancer

The effect of debulking surgery is not vague in patients with refractory ovarian cancer because of drug-resistant tumor biology showing rapid growth. However, it can be considered to be beneficial for selected patients expected to show tumor response by postoperative treatment because the better perfused small tumors may favor the action of cytotoxic therapy. Among them, patients with enlarged lymph nodes and BRCA mutations can show a relatively high rate of response and improved survival by systematic lymphadenectomy followed by poly ADP ribose polymerase (PARP) inhibitors. However, the resection of enlarged lymph nodes above the renal vein may not be familiar to gynecologic oncologists, in particular, for patients who had undergone previous debulking surgery followed by repetitive chemotherapy. Thus, this video will show the step by step procedure of suprarenal lymphadenectomy and en bloc resection of kidney and suprahilar lymph nodes for complete resection of refractory ovarian cancer.

The role of surgery in platinum-resistant ovarian cancer: A call to the scientific community

In the last decade, a growing attention has been focused on identifying effective therapeutic strategies also in the orphan clinical setting of women with platinum-resistant disease. In this context, secondary cytoreductive surgery (SCS) remains a potential approach only in women with platinum sensitive relapse, but experimental data have been published supporting the role of SCS also in patients with platinum-resistant recurrence. In particular, surgery is emerging as a potential option in specific subgroups of women, such as those patients with low-grade serous histology, or low-volume relapse with disease located in the so-called pharmacological sanctuaries. Furthermore, contrasting evidences have suggested a potential role in this clinical setting of SCS combined with intraperitoneal hyperthermic chemotherapy. In this complex scenario we review here the available evidences regarding the role surgery in ovarian cancer patients with platinum resistant disease, trying also to understand which patients may benefit from this challenging, experimental approach.

Surgery vs. chemotherapy for ovarian cancer recurrence: what is the best treatment option

Nowadays, the best treatment option for ovarian cancer recurrence is often subjective, can vary in the different centers and depend on personal experience. Arbeitsgemeinschaft Gynaekologische Onkologie (AGO)-DESKTOP studies have identified a population of patients who could benefit from secondary surgery. The results of the Gynecologic Oncology Group (GOG)-0213 study were recently published, which showed no advantage in terms of overall survival (OS) in patients with platinum-sensitive recurrent epithelial ovarian undergoing secondary cytoreductive surgery (SCS) compared to chemotherapy alone. Aim of this narrative review is to summarize the best aspects that can make ovarian cancer recurrence patients suitable for SCS. A narrative review analyzing all the literature of the past 30 years has been performed. PubMed, Scopus, Web of Science and Ovid MEDLINE were used for research. All non-English-language articles have been excluded. The following keywords were searched: 'recurrent ovarian cancer', 'secondary surgery', 'secondary cytoreductive surgery', 'platinum-sensitive ovarian cancer', 'platinum-resistant ovarian cancer'. We divided eligible patients for secondary cytoreduction in relation to the following factors: platinum-sensitivity, AGO-score or Tian model, unresectable lesions, surgical generic contraindication, woman's personal choice. The selection of truly suitable patients for surgery seems an essential requirement for the patient's best therapeutic choice. In case of absent post-surgical residual tumor, good performance status, single recurrence, and platinum-sensitive ovarian recurrence, surgery could be performed.

Cytoreductive Surgery for Heavily Pre-Treated, Platinum-Resistant Epithelial Ovarian Carcinoma: A Two-Center Retrospective Experience

Few retrospective studies have shown a benefit in selected patients affected by heavily pre-treated, platinum-resistant ovarian carcinomas (PROCs) who have undergone cytoreduction at relapse. However, the role of tertiary and quaternary cytoreductive surgery is not fully defined. Our aim was to evaluate survival and surgical morbidity and mortality after maximal cytoreduction in this setting. We evaluated all consecutive patients undergoing cytoreduction for platinum-resistance over an 8-year period (2010–2018) in two different centers. Fifty patients (median age 52.5 years, range 34–75) were included; the median number of previous chemotherapy lines was three (range 1–7) and the median number of previous surgeries was one (range 1–4). Completeness of cytoreduction (CC = 0) was achieved in 22 patients (44%). Rates of major operative morbidity and 30-day mortality were 38% and 8%, respectively. Median follow-up was 35 months. The absence of tumor residual (CC = 0) was associated with a significantly better overall survival (OS) compared to the CC > 0 subgroup (median OS 32.9 months (95% CI 21.6–44.2) vs. 4.8 months (95% CI n.a.–9.8), hazard ratio (HR) 4.21 (95% CI 2.07–8.60), p < 0.001). Optimal cytoreduction is feasible and associated with promising OS in selected, heavily pre-treated PROCs. Further prospective studies are required to better define the role of surgery in platinum-resistant disease.

Effect of platinum sensitivity on the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) in recurrent epithelial ovarian cancer

INTRODUCTION

Hyperthermic intraperitoneal chemotherapy following cytoreductive surgery (CRS) is a treatment strategy that has been evaluated in recurrent ovarian cancer. The aim of this study was to examine if survival was similar regardless of platinum sensitivity.

METHODS

A retrospective study of women with recurrent platinum sensitive or resisteant epithelial ovarian cancer who were treated with cytoreductive surgery (CRS) and HIPEC between the years 2010-2018 was performed. Recurrence free (RFS) and overall survival (OS) were calculated using the Kaplan-Meier method.

RESULTS

Thirty-five (72.9 %) were platinum sensitive (PS) and 13 (27.1 %) were platinum resistant (PR). The complete cytoreduction (R0) rate was higher in the PS patients as compared to PR (85.7 % vs 53.8 %; p = 0.017). Median follow-up was 16.9 (range, 11.7-34.5) months. The median recurrence free survival in the patients who had a R0 resection was 22.3 months in PS and 11.1 months in PR patients (p = 0.017), respectively. Median overall survival was 26.9 months in the PR patients, while it had not been reached in the PS patients. In the patients with PS recurrence, the mean treatment free interval (TFI) prior to HIPEC was 1.6 years and following HIPEC, 40 % of those patients were recurrence free at 2 years. In the patients with PR recurrence, the mean TFI prior to HIPEC was 4.6 months and following HIPEC, 61.5 % of those patients had a longer TFI, with a mean increase of 10.1 months.

CONCLUSION

Although surgery is not considered standard treatment in PR ovarian cancer, in carefully selected patients, surgery with HIPEC could extend the treatment-free interval.

Salvage lymphadenectomy in recurrent ovarian cancer patients: Analysis of clinical outcome and BRCA1/2 gene mutational status

OBJECTIVE

This study is aimed to analyze the clinical outcome of recurrent ovarian cancer patients bearing isolated lymph-node recurrence (ILNR) who underwent salvage lymphadenectomy (SL). The prognostic role of clinicopathological variables and the mutational status of BRCA1/2 have also been investigated.

METHODS

This retrospective, single-institutional study included women with platinum-sensitive lymph node recurrence underwent to SL between June 2008 and June 2018. Univariate and multivariate analysis was performed to evaluate the impact of clinical parameters, and BRCA1/2 mutational status on post salvage lymphadenectomy progression-free survival (PSL-PFS).

RESULTS

As of June 2019, the median follow-up after SL was 30 months, and the relapse has been documented in 48 (56.5%) patients. In the whole series, the median PSL-PFS was 21 months, and the 3-year PSL-PFS was 36.7%. The median PSL-PFS, according to patients with ILNR (N = 71) versus patients with lymph-nodes and other sites of disease (N = 14), was 27 months versus 12 months, respectively. Univariate analysis of variables conditioning PSL-PFS showed that platinum-free interval (PFI) ≥12 months, normal Ca125 serum levels, and number of metastatic lymph-nodes ≤3 played a statistically significant favorable role. In multivariate analysis, PFI duration ≥12 months and the number of metastatic lymph nodes ≤3 were shown to keep their favorable, independent prognostic value on PSL-PFS.

CONCLUSIONS

In the context of SL, the patients with long PFI and low metastatic lymph node numbers at ILNR diagnosis have the best outcome. The BRCA mutational status seems not associated with clinical variables and PSL-PFS, differently from other sites of disease in ROC patients.

Ovarian cancer relapse: From the latest scientific evidence to the best practice

Ovarian cancer (OC) is the fifth most common cause of cancer death in women worldwide. Despite treatment options have continued to improve in recent years, the recurrence rate is still high; in fact around 80% of patients relapses within 18 months. Recently, the scientific landscape is agree in asserting that the ovarian cancer is not a single disease but the outcome of patients depends from the molecular and biological characterization of tumor tissue. In this scenario, molecular targeted therapy given alone or in combination with chemotherapy is showing significant results. We review the different options for the treatment of ovarian cancer recurrence, including the role of surgery, in order to try outlining a possible treatment algorithm evaluating the recent scientific literature and the most important trials.

RCC2, a regulator of the RalA signaling pathway, is identified as a novel therapeutic target in cisplatin-resistant ovarian cancer

Currently, cisplatin (DDP) is the first-line chemotherapeutic agent used for treatment of ovarian cancer, but gradually acquired drug resistance minimizes its therapeutic outcomes. We aimed to identify crucial genes associated with DDP resistance in ovarian cancer and uncover potential mechanisms. Two sets of gene expression data were downloaded from Gene Expression Omnibus, and bioinformatics analysis was conducted. In our study, the differentially expressed genes between DDP-sensitive and DDP-resistant ovarian cancer were screened in GSE15709 and GSE51373 database, and chromosome condensation 2 regulator (RCC2) and nucleoporin 160 were identified as 2 genes that significantly up-regulated in DDP-resistant ovarian cancer cell lines compared with DDP-sensitive cell lines. Moreover, RCC2, Ral small GTPase (RalA), and Ral binding protein-1 (RalBP1) expression was found to be significantly higher in DDP-resistant ovarian cancer tissues than in DDP-sensitive tissues. RCC2 plays a positive role in cell proliferation, apoptosis, and migration in DDP-resistant ovarian cancer cell lines in vitro and in vivo. Furthermore, RCC2 could interact with RalA, thus promoting its downstream effector RalBP1. RalA knockdown could reverse the effects of RCC2 overexpression on DDP-resistant ovarian cancer cell proliferation, apoptosis, and migration. Similarly, RalA overexpression could alleviate the effects of RCC2 knockdown in DDP-resistant ovarian cancer cells. Taken together, RCC2 may function as an oncogene, regulating the RalA signaling pathway, and intervention of RCC2 expression might be a promising therapeutic strategy for DDP-resistant ovarian cancer.-Gong, S., Chen, Y., Meng, F., Zhang, Y., Wu, H., Li, C., Zhang, G. RCC2, a regulator of the RalA signaling pathway, is identified as a novel therapeutic target in cisplatin-resistant ovarian cancer.

HE4 and eIF3a Expression Correlates with Surgical Outcome and Overall Survival in Ovarian Cancer Patients with Secondary Cytoreduction

For recurrent ovarian cancer (ROC), secondary cytoreductive surgery (SCS) is recommended as one optional treatment. However, little is known about the expression and clinical significance of biomarkers during SCS. Human epididymis protein 4 (HE4) is a clinical biomarker for ovarian cancer. Eukaryotic translation initiation factor 3a (eIF3a) is investigated extensively as a potential biomarker for malignancy. The purpose of this study was to investigate the expressions of HE4 and eIF3a at SCS, as well as their associations with surgical outcome and survival in ROC patients. Immunohistochemistry was performed to determine the expressions of HE4 and eIF3a in ovarian tumors taken from both initial and secondary cytoreductive surgery of 35 ROC patients. eIF3a levels were significantly increased at SCS, compared to those at initial cytoreductive surgery (ICS), while HE4 levels were similar. Both HE4 and eIF3a expressions were associated with surgical outcome, in terms of residual tumor. For ICS, patients with high HE4 expression achieved a higher incidence of optimal cytoreduction than those with low HE4 expression (81.0% vs. 33.3%, P = 0.015). A similar result happened in SCS, indicated by higher incidence of no residual tumor in patients with high HE4 expression (76.4% vs. 44.4%, P = 0.046). And high HE4 expression at SCS was more likely to enhance surgical outcome of SCS (77.8% vs. 29.4%, P = 0.038). Therefore, high HE4 expression at either surgery is a predictor of better overall survival (OS) (P = 0.011 and 0.002). Furthermore, patients with an elevated total score (TS) of HE4 between the two surgeries tended to have prolonged OS, compared to those with a non-elevated TS of HE4 (P = 0.076). For eIF3a, initial eIF3a expression was associated with secondary residual tumor (P = 0.035), and the difference in eIF3a expression between the two surgeries correlated with OS (P = 0.052). The expressions of HE4 and eIF3a in tumor specimens correlated with surgical outcome and predicted OS in ROC patients with SCS, thus meriting further investigation.

53BP1 inhibits the migration and regulates the chemotherapy resistance of ovarian cancer cells

The major problems faced during the treatment of ovarian cancer are metastasis and the development of intrinsic or acquired drug resistance. The present study assessed whether tumor protein p53 binding protein 1 (53BP1) regulated migration and modulated chemotherapy resistance in SKOV3 cells and identified proteins associated with the molecular mechanisms underlying this coordinate regulation. SKOV3 cells were transfected using a 53BP1-expressing vector, which induced 53BP1 overexpression. The migration of the transfected cells was observed using a Transwell assay. The expression of matrix metalloproteinase (MMP)-2 and MMP-9 were assayed using gelatin zymography. In addition, the effects of 53BP1 on the chemosensitivity of SKOV3 cells to cisplatin were evaluated using MTT and western blot assays. Compared with the control, the average number of migrating SKOV3/pLPC-53BP1 cells was decreased from 230±58 to 45±12 (P<0.05) and the protein expression of MMP-9 was significantly inhibited. However, the chemosensitivity of SKOV3/pLPC-53BP1 to cisplatin decreased significantly: Cisplatin half maximal inhibitory concentration (IC⁵⁰) for SKOV3/pLPC-53BP1=7.58±0.51 µg/ml; cisplatin IC⁵⁰ for control=2.98±0.27 µg/ml (P<0.01). Decreased chemosensitivity to cisplatin may be associated with increased expression of phosphorylated-protein kinase B and cyclin dependent kinase 2 and with decreased expression of p21 and the B cell lymphoma (Bcl)-2 associated X/Bcl-2 ratio. The results of the present study demonstrated that 53BP1 may inhibit migration but upregulate chemoresistance to cisplatin in SKOV3 cells.

Surgical management of recurrent ovarian cancer

Most patients with advanced-stage epithelial ovarian cancer will experience a relapse of disease despite a complete response after surgical cytoreduction and platinum-based chemotherapy. Treatment of recurrent ovarian cancer mainly comprises various combinations of systemic chemotherapy with or without targeted agents. The role of cytoreductive surgery for recurrent ovarian cancer is not well established. Although the literature on survival benefit of cytoreductive surgery for recurrent disease has expanded steadily over the past decade, most studies were retrospective, single-institution series with small numbers of patients. Given the balance between survival benefit and surgery-related morbidity during maximum cytoreductive surgical effort, it is essential to establish the optimal selection criteria for identifying appropriate candidates who will benefit from surgery without worsening quality of life. Three phase III randomized trials for this issue are currently underway. Herein, we present contemporary evidence supporting the positive role of cytoreductive surgery and offer selection criteria for optimal candidates for surgery in the treatment of recurrent ovarian cancer.

Cytoreductive Surgery Plus Platinum-Based Hyperthermic Intraperitoneal Chemotherapy in Epithelial Ovarian Cancer: A Promising Integrated Approach to Improve Locoregional Control

Epithelial ovarian cancer (EOC) remains the most lethal among gynecological malignancies. Evidence strongly suggests that administration of platinum-based hyperthermic intraperitoneal chemotherapy after cytoreductive surgery may represent an effective strategy to adequately treat both visible and microscopic disease, thus improving locoregional control.

Leukotriene B4 receptor-2 contributes to chemoresistance of SK-OV-3 ovarian cancer cells through activation of signal transducer and activator of transcription-3-linked cascade

Inflammation and inflammatory mediators are intimately linked with chemoresistance through complex pathways in the tumor microenvironment. However, the mechanism by which inflammatory mediators (e.g., eicosanoids) contribute to chemoresistance remains elusive. In this study, we found that the low-affinity leukotriene B4 receptor-2 (BLT2) and its ligand leukotriene B4 were highly up-regulated in cisplatin-resistant SK-OV-3 ovarian cancer cells and play critical roles in mediating the chemoresistance through the activation of signal transducer and activator of transcription-3 (STAT-3) and the subsequent up-regulation of interleukin-6 (IL-6). BLT2 depletion with siRNA clearly abolished the chemoresistance to cisplatin in SK-OV-3 ovarian cancer cells and further increased cell sensitivity to cisplatin chemotherapy by down-regulating the 'STAT-3-IL-6' cascade. Enlarged tumor formation due to the cisplatin resistance of SK-OV-3 cells in cisplatin-treated athymic mice was also substantially reduced by co-treatment with the BLT2 inhibitor in vivo. Our study demonstrates that BLT2 is a novel contributor to cisplatin resistance in SK-OV-3 ovarian cancer cells and thus may be a potential therapeutic target for the treatment of cisplatin-resistant ovarian cancer.