Checkpoint-inhibition in ovarian cancer: rising star or just a dream?

New Achievements from Molecular Biology and Treatment Options for Refractory/Relapsed Ovarian Cancer-A Systematic Review

Ovarian cancer (OC) has a high rate of mortality and is the fifth most common cause of death in females all over the world. The etiology is still unclear. Numerous factors such as smoking, obesity, and unhealthy diet may affect the risk of OC. Having a family history of breast and OC is one of the main risks for developing OC. Mutations of BRCA1/2 are associated with OC risk as well. The histopathological classification of OC reveals the four most common types: serous, clear cell, endometrioid, and mucinous; these are epithelial OC types, and other types are rare. Furthermore, OC can be subdivided into types I and II. Type I tumors are most probably caused by atypical proliferative tumors. Type II tumors include high-grade carcinoma of the serous type, carcinosarcoma, and carcinoma, which are not differentiated and generally originate from tubal intraepithelial carcinoma of the serous type. Typically, type I tumors are present in early stages, usually with good prognosis. Type II tumors are classified as high-grade tumors and are most often diagnosed at advanced FIGO stages with poor prognosis. High-grade serous OC accounts for 90% of serous OC. Tumor heterogeneity aggravates OC treatment. The standard care for primary epithelial ovarian cancer (EOC) is cytoreductive surgery followed by platinum-based chemotherapy. Neoadjuvant chemotherapy can be used in certain cases followed by cytoreductive surgery. The main prognostic factor is complete tumor resection. However, about 70% of patients relapse. Resistance to chemotherapeutic agents remains a major challenge in EOC treatment, in which many different factors are involved. In recent years, the examination of molecular parameters and their prognostic impact has become increasingly relevant in EOC, and furthermore, the use of immunotherapy has expanded the therapeutic range. As the clinical need is greatest for relapsed patients, this systematic review will focus on recent advances in molecular biology with prognostic and predictive markers and treatment options for recurrent/refractory OC. Inclusion criteria for the review: potential prospective or predictive biomarkers in preclinical or clinical use in relapsed and refractory OC, prognostic impact, clinical and preclinical trials, and immunotherapy. Exclusion criteria for the review: primary OC, no full text or abstract available, not the topic mentioned above, and text not available in English. Risk of bias: the included studies were evaluated descriptively for the topics mentioned above, and data were not compared with each other. The objective is to highlight the molecular mechanisms of the most promising targeted agents under clinical investigation to demonstrate their potential relevance in recurrent/refractory OC.

The MYBL2-CCL2 axis promotes tumor progression and resistance to anti-PD-1 therapy in ovarian cancer by inducing immunosuppressive macrophages

BACKGROUND

An immunosuppressive tumor microenvironment in ovarian cancer facilitates tumor progression and resistance to immunotherapy. The function of MYB Proto-Oncogene Like 2 (MYBL2) in the tumor microenvironment remains largely unexplored.

METHODS

A syngeneic intraovarian mouse model, flow cytometry analysis, and immunohistochemistry were used to explore the biological function of MYBL2 in tumor progression and immune escape. Molecular and biochemical strategies-namely RNA-sequencing, western blotting, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay, multiplex immunofluorescence, chromatic immunoprecipitation assay (CHIP) and luciferase assay-were used to reveal the mechanisms of MYBL2 in the OVC microenvironment.

RESULTS

We found tumor derived MYBL2 indicated poor prognosis and selectively correlated with tumor associated macrophages (TAMs) in ovarian cancer. Mechanically, C-C motif chemokine ligand 2 (CCL2) transcriptionally activated by MYBL2 induced TAMs recruitment and M2-like polarization in vitro. Using a syngeneic intraovarian mouse model, we identified MYBL2 promoted tumor malignancyand increased tumor-infiltrating immunosuppressive macrophages. Cyclin-dependent kinase 2 (CDK2) was a known upstream kinase to phosphorylate MYBL2 and promote its transcriptional function. The upstream inhibitor of CDK2, CVT-313, reprogrammed the tumor microenvironment and reduced anti-PD-1 resistance.

CONCLUSIONS

The MYBL2/CCL2 axis contributing to TAMs recruitment and M2-like polarization is crucial to immune evasion and anti-PD-1 resistance in ovarian cancer, which is a potential target to enhance the efficacy of immunotherapy.

Epithelial ovarian cancer is infiltrated by activated effector T cells co-expressing CD39, PD-1, TIM-3, CD137 and interacting with cancer cells and myeloid cells

Introduction

Despite predicted efficacy, immunotherapy in epithelial ovarian cancer (EOC) has limited clinical benefit and the prognosis of patients remains poor. There is thus a strong need for better identifying local immune dynamics and immune-suppressive pathways limiting T-cell mediated anti-tumor immunity.

Methods

In this observational study we analyzed by immunohistochemistry, gene expression profiling and flow cytometry the antigenic landscape and immune composition of 48 EOC specimens, with a focus on tumor-infiltrating lymphocytes (TILs).

Results

Activated T cells showing features of partial exhaustion with a CD137+CD39+PD-1+TIM-3+CD45RA-CD62L-CD95+ surface profile were exclusively present in EOC specimens but not in corresponding peripheral blood or ascitic fluid, indicating that the tumor microenvironment might sustain this peculiar phenotype. Interestingly, while neoplastic cells expressed several tumor-associated antigens possibly able to stimulate tumor-specific TILs, macrophages provided both co-stimulatory and inhibitory signals and were more abundant in TILs-enriched specimens harboring the CD137+CD39+PD-1+TIM-3+CD45RA-CD62L-CD95+ signature.

Conclusion

These data demonstrate that EOC is enriched in CD137+CD39+PD-1+TIM-3+CD45RA-CD62L-CD95+ T lymphocytes, a phenotype possibly modulated by antigen recognition on neoplastic cells and by a combination of inhibitory and co-stimulatory signals largely provided by infiltrating myeloid cells. Furthermore, we have identified immunosuppressive pathways potentially hampering local immunity which might be targeted by immunotherapeutic approaches.

Immunohistochemical Profiling of PD-1, PD-L1, CD8, MSI, and p53 and Prognostic Implications in Advanced Serous Ovarian Carcinoma: A Retrospective Study

Advanced high-grade serous ovarian carcinoma is a serious malignant neoplasm with a late diagnosis and high mortality rate. Even when treated with standard therapy, such as surgery followed by carboplatin and paclitaxel chemotherapy, the prognosis remains unfavorable. Immunotherapy is a treatment alternative that requires further study. Therefore, we aimed to evaluate the expression of PD-1, PD-L1, CD8, MSI (MLH1, MSH2, MSH6, and PMS2), and p53 in the paraffin samples of high-grade serous ovarian carcinoma. A retrospective study of 28 southern Brazilian patients with advanced serous ovarian carcinoma (EC III or IV) was conducted between 2009 and 2020. The expression of these proteins was evaluated using immunohistochemistry, and the results were correlated with the patients' clinicopathological data. At diagnosis, the mean age was 61 years, and the most common clinical stage (60%) was EC III. Among the cases, 84.6% exhibited p53 overexpression, 14.8% had MSI, 92.0% were sensitive to platinum, and more than 50.0% relapsed after treatment. Patients with MSI had a lower CD8/PD-1 ratio and more relapses (p = 0.03). In conclusion, analysis of immunotherapeutic markers in paraffin-embedded advanced serous ovarian carcinoma samples is feasible and may assist in prognosis.

Research progress of neoantigens in gynecologic cancers

The incidence and mortality of gynecological cancers have increased over the past decade. In the absence of effective treatment strategies, many advanced patients develop resistance to conventional therapies and have poor prognosis. Neoantigens have emerged as a novel tumor-specific antigen (TSA) that arises from genomic mutations in tumor cells. With higher immunogenicity than tumor-associated antigens (TAA), they have no risk of developing autoimmune response, leading them an attractive candidate for tumor therapeutic vaccines. With the development of next-generation sequencing (NGS) technology, the identification of neoantigens has been gradually improved, and the scope of application of neoantigen vaccines has continued to expand. Combined with other therapies such as immune-checkpoint inhibitors (ICIs) or adoptive cell therapy (ACT), the application of neoantigen in gynecological cancers has extended to clinical practice. Here, we reviewed the preclinical and clinical studies of neoantigens in gynecological cancers.

Combined lumbar muscle block and perioperative comprehensive patient-controlled intravenous analgesia with butorphanol in gynecological endoscopic surgery

BACKGROUND

Laparoscopic surgery has become a common surgical approach for the clinical treatment of intra-abdominal lesions in recent years. We hypothesized that lumbar block with postoperative patient-controlled intravenous analgesia (PCIA) by butorphanol after gynecological surgery under general anesthesia would be more effective than PCIA by butorphanol alone.

AIM

To investigate the effect of lumbar block with PCIA by butorphanol after gynecological surgery under general anesthesia.

METHODS

This study assessed 120 women scheduled for laparoscopic surgery at our hospital between May 2017 and May 2020. They were divided using a random number table into a research group (those who received quadratus lumborum block combined with PCIA analgesia by butorphanol) and a control group (those who received only PCIA analgesia by butorphanol), with 60 patients in each group. Demographic factors, visual analog scale scores for pain, serum inflammatory markers, PCIA compressions, Ramsay scores, and adverse events were compared between groups using a t-test, analysis of variance, or χ² test, as appropriate.

RESULTS

There were no significant differences in demographic factors between groups (all P > 0.05). The visual analog scale scores of the research group in the resting state 12 h and 24 h postoperatively were significantly lower than those of the control group (P < 0.05). Two hours after surgery, there were no significant differences in the levels of serum tumor necrosis factor-α, interleukin (IL)-6, or IL-8 between groups (P > 0.05). The serum tumor necrosis factor-α levels of the research group 24 h postoperatively were significantly lower than those of the control group (P < 0.05). The levels of serum IL-6 and IL-8 in the study group 24 h and 48 h postoperatively were significantly lower than those in the control group (P < 0.05).

CONCLUSION

Lumbar block with PCIA with butorphanol after gynecological surgery under general anesthesia significantly improves the analgesic effect and reduces the degree of inflammation, instances of PCIA compression, and adverse reactions.

Immunotherapy of Ovarian Cancer with Particular Emphasis on the PD-1/PDL-1 as Target Points

Simple Summary

Ovarian cancer has remained the leading cause of death among gynecologic malignancies. The current standard of treatment, in most cases, is a combination of surgery and chemotherapy, based on platinum agents and taxanes. Despite the increasing usage of newer drug groups, such as bevacizumab and PARP inhibitors, and the expansion of patient groups for these drugs, ovarian cancer is characterized by recurrences, particularly in the form of peritoneal implants. This review focuses on immunotherapy for ovarian cancer. It considers the current state of knowledge in areas such as cancer vaccines, adoptive cell therapy, CAR-T therapy, and anti-CTLA-4 monotherapy. The paper specifically considers PD-1/PDL-1 as drug targets. Anti-PD-1/PD-L1 monotherapy, and anti-PD-1/PD-L1 immunotherapy in combination with other agents, are analyzed.

Abstract

Ovarian cancer is one of the most fatal cancers in women worldwide. Cytoreductive surgery combined with platinum-based chemotherapy has been the current first-line treatment standard. Nevertheless, ovarian cancer appears to have a high recurrence rate and mortality. Immunological processes play a significant role in tumorigenesis. The production of ligands for checkpoint receptors can be a very effective, and undesirable, immunosuppressive mechanism for cancers. The CTLA-4 protein, as well as the PD-1 receptor and its PD-L1 ligand, are among the better-known components of the control points. The aim of this paper was to review current research on immunotherapy in the treatment of ovarian cancer. The authors specifically considered immune checkpoints molecules such as PD-1/PDL-1 as targets for immunotherapy. We found that immune checkpoint-inhibitor therapy does not have an improved prognosis in ovarian cancer; although early trials showed that a combination of anti-PD-1/PD-L1 therapy with targeted therapy might have the potential to improve responses and outcomes in selected patients. However, we must wait for the final results of the trials. It seems important to identify a group of patients who could benefit significantly from treatment with immune checkpoints inhibitors. However, despite numerous trials, ICIs have not become part of routine clinical practice for the treatment of ovarian cancer.

PD-L1 Expression in Different Segments and Histological Types of Ovarian Cancer According to Lymphocytic Infiltrate

Background and Objectives: Ovarian cancer is the leading cause of death among gynecological tumors. PD-1/PD-L1 immunoregulatory mechanism is activated in ovarian cancers. Lymphocyte infiltration is a significant factor that affects its expression. We analyzed the correlation between localization of lymphocytic infiltrate and PD-L1 expression in epithelial ovarian tumors. Materials and Methods: PD-L1 expression was analyzed in 328 subjects, 122 with epithelial ovarian carcinoma, 42 with atypical proliferative tumor, and 164 with benign epithelial ovarian tumor. Expression in central and invasive tumor parts in epithelial ovarian carcinoma was combined with the most pronounced lymphocyte reaction. Immunohistochemical analysis was performed using the tissue microarray and correlated with a set of histopathology parameters. Results: PD-L1 expression was most prominent in epithelial ovarian carcinoma with different levels of expression observed between invasive and central tumor segments. A high level of PD-L1 expression on tumor cells was more frequently present in the invasive than in the central tumor parts (p < 0.001) only in high-grade serous ovarian carcinoma (HGSC). There was no significant correlation between peritumoral lymphocytic infiltrate and PD-L1 expression regardless of tumor segment. In the central tumor parts of HGSC, there was a correlation of intratumoral lymphocytic infiltrate with a higher level of PD-L1 expression (p = 0.003). Conclusions: The most prominent PD-L1 expression was observed in the invasive tumor parts of HGSC. Only the central parts of the HGSC exhibited significant PD-L1 expression in association with considerable intratumoral lymphocytic infiltrate.

The injury response to DNA damage in live tumor cells promotes antitumor immunity

Although immune checkpoint blockade (ICB) has strong clinical benefit for treating some tumor types, it fails in others, indicating a need for additional modalities to enhance the ICB effect. Here, we identified one such modality by using DNA damage to create a live, injured tumor cell adjuvant. Using an optimized ex vivo coculture system, we found that treating tumor cells with specific concentrations of etoposide, mitoxantrone, or doxorubicin markedly enhanced dendritic cell–mediated T cell activation. These immune-enhancing effects of DNA damage did not correlate with immunogenic cell death markers or with the extent of apoptosis or necroptosis; instead, these effects were mediated by live injured cells with activation of the DNA-PK, ATR, NF-κB, p38 MAPK, and RIPK1 signaling pathways. In mice, intratumoral injection of ex vivo etoposide–treated tumor cells in combination with systemic ICB (by anti-PD-1 and anti-CTLA4 antibodies) increased the number of intratumoral CD103+ dendritic cells and circulating tumor-antigen–specific CD8+ T cells, decreased tumor growth, and improved survival. These effects were absent in Batf3−/− mice and in mice in which the DNA-damaging drug was injected directly into the tumor, due to DNA damage in the immune cells. The combination treatment induced complete tumor regression in a subset of mice that were then able to reject tumor rechallenge, indicating that the injured cell adjuvant treatment induced durable antitumor immunological memory. These results provide a strategy for enhancing the efficacy of immune checkpoint inhibition in tumor types that do not respond to this treatment modality by itself.

Integration of scRNA-Seq and Bulk RNA-Seq to Analyse the Heterogeneity of Ovarian Cancer Immune Cells and Establish a Molecular Risk Model

Background

Considerable evidence suggests that the heterogeneity of ovarian cancer (OC) is a major cause of treatment failure. Single-cell RNA sequencing (scRNA-seq) is a powerful tool to analyse the heterogeneity of the tumour at the single-cell level, leading to a better understanding of cell function at the genetic and cellular levels.

Methods

OC scRNA-seq data were extracted from the Gene Expression Omnibus (GEO) database and the FindCluster () package used for cell cluster analysis. The GSVA package was used for single-sample gene set enrichment analysis (ssGSEA) analysis to obtain a Hallmark gene set score and bulk RNA-seq data were used to analyse the key genes of OC-associated immune cell subsets. CIBERSORT was used to identify immune scores of cells and the “WGCNA” package for the weighted correlation network analysis (WGCNA). KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO (Gene Ontology) analyses of subtype groups were performed by GSEA. Then, univariate Cox and lasso regression were performed to further establish a signature. Finally, qPCR and immunohistochemistry staining were used to evaluate the expression of signature genes in OC.

Results

Two scRNA-seq (GSE154600 and GES158937) datasets were integrated to obtain 20 cell clusters. T cells or NK cells (cluster 5, 6, 7, 11), B cells (cluster 16, 19, 20) and myeloid cells (cluster 4, 9, 10) were clustered according to immune cell markers. The ssGSEA revealed that M1- and M2-like myeloid cell-related genes were significantly upregulated in P3 and P4 patients in the GSE154600 data. Immune cell analysis in TCGA-OC showed that a high abundance of M1-like tumour-associated macrophages (TAMS) predicts better survival. WGCNA, univariate Cox and lasso Cox regression established a two-gene signature (RiskScore=-0.059*CXCL13-0.034*IL26). Next, the TCGA-test and TCGA-OC were used to test the risk prediction ability of the signature, showing a good effect in the datasets. Moreover, the qPCR and immunohistochemistry staining revealed that the expression of CXCL13 and IL26 was reduced in OC tissues.

Conclusion

A two-gene signature prognostic stratification system (CXCL13 and IL26) was developed based on the heterogeneity of OC immune cells to accurately evaluate the prognostic risk.

Neutralization of PD-L2 is Essential for Overcoming Immune Checkpoint Blockade Resistance in Ovarian Cancer

PURPOSE

Ovarian cancer represents a major clinical hurdle for immune checkpoint blockade (ICB), with reported low patient response rates. We found that the immune checkpoint ligand PD-L2 is robustly expressed in patient samples of ovarian cancers and other malignancies exhibiting suboptimal response to ICB but not in cancers that are ICB sensitive. Therefore, we hypothesize that PD-L2 can facilitate immune escape from ICB through incomplete blockade of the PD-1 signaling pathway.

EXPERIMENTAL DESIGN

We engineered a soluble form of the PD-1 receptor (sPD-1) capable of binding and neutralizing both PD-L2 and PD-L1 with ×200 and ×10,000 folds improvement in binding affinity over wild-type PD-1 leading to superior inhibition of ligand-mediated PD-1 activities.

RESULTS

Both in vitro and in vivo analyses performed in this study demonstrated that the high-affinity sPD-1 molecule is superior at blocking both PD-L1- and PD-L2-mediated immune evasion and reducing tumor growth in immune-competent murine models of ovarian cancer.

CONCLUSIONS

The data presented in this study provide justification for using a dual targeting, high-affinity sPD-1 receptor as an alternative to PD-1 or PD-L1 therapeutic antibodies for achieving superior therapeutic efficacy in cancers expressing both PD-L2 and PD-L1.

Prognostic value of HHLA2 expression in solid tumors: A meta-analysis based on the Chinese population

BACKGROUND

Human endogenous retrovirus-H long terminal repeat-associating protein 2 (HHLA2), a newly discovered member of the B7 family, is overexpressed in numerous tumors. However, the prognostic impact of HHLA2 in human cancers remains controversial. Thus, we performed this meta-analysis to explore the prognostic value of HHLA2 in Chinese patients with solid tumors.

METHODS

PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, and WanFang databases were systematically searched for eligible studies that evaluated the impact of HHLA2 on overall survival (OS) in patients with cancer. Hazard ratios (HRs) and 95% confidence intervals (CIs) were combined to evaluate the association between HHLA2 expression and OS in solid tumors. Odds ratios (ORs) and 95% CIs were pooled to assess the correlation between HHLA2 expression and clinicopathological characteristics in solid tumors.

RESULTS

A total of 12 studies, including 15 cohorts and 1747 patients, were included in this meta-analysis. We found that high HHLA2 expression was significantly associated with shorter OS (HR = 1.65, 95% CI: 1.12-2.43). Subgroup analysis by cancer type demonstrated that high HHLA2 expression was associated with poor OS in patients with clear cell renal cell carcinoma (HR = 3.42, 95% CI: 2.39-4.91), gastric cancer (HR = 2.03, 95% CI: 1.31-3.16), intrahepatic cholangiocarcinoma (HR = 1.77, 95% CI: 1.24-2.53), lung cancer (HR = 2.14, 95% CI: 1.33-3.44) and other cancer types (HR = 2.08, 95% CI: 1.34-3.24), but not in patients with epithelial ovarian cancer (HR = 0.52, 95% CI: 0.08-3.56). Nevertheless, high HHLA2 expression was associated with better OS in patients with pancreatic ductal adenocarcinoma (HR = 0.45, 95% CI: 0.32-0.64). Furthermore, high HHLA2 expression was associated with old age (OR = 1.30, 95% CI: 1.03-1.63), lymph node metastasis (OR = 1.99, 95% CI: 1.41-2.81), and vascular invasion (OR = 1.69, 95% CI: 1.18-2.42).

CONCLUSIONS

HHLA2 may serve as a potential prognostic biomarker for solid tumors in Chinese population, by predict the prognosis of cancer patients based on their tumor types.

A Review of the Clinical Characteristics and Novel Molecular Subtypes of Endometrioid Ovarian Cancer

Ovarian cancer is one of the most common gynecologic cancers that has the highest mortality rate. Endometrioid ovarian cancer, a distinct subtype of epithelial ovarian cancer, is associated with endometriosis and Lynch syndrome, and is often accompanied by synchronous endometrial carcinoma. In recent years, dysbiosis of the microbiota within the female reproductive tract has been suggested to be involved in the pathogenesis of endometrial cancer and ovarian cancer, with some specific pathogens exhibiting oncogenic having been found to contribute to cancer development. It has been shown that dysregulation of the microenvironment and accumulation of mutations are stimulatory factors in the progression of endometrioid ovarian carcinoma. This would be a potential therapeutic target in the future. Simultaneously, multiple studies have demonstrated the role of four molecular subtypes of endometrioid ovarian cancer, which are of particular importance in the prediction of prognosis. This literature review aims to compile the potential mechanisms of endometrioid ovarian cancer, molecular characteristics, and molecular pathological types that could potentially play a role in the prediction of prognosis, and the novel therapeutic strategies, providing some guidance for the stratified management of ovarian cancer.

KAT6A, a novel regulator of β-catenin, promotes tumorigenicity and chemoresistance in ovarian cancer by acetylating COP1

Background: Ovarian cancer is a fatal gynecologic malignancy that is found worldwide and exhibits an insidious onset and a lack of early warning symptoms. Despite ongoing studies, the mechanistic basis of the aggressive phenotypes of ovarian cancer remains unclear. Lysine acetyltransferase 6A (KAT6A) is a MYST-type histone acetyltransferase (HAT) enzyme identified as an oncogene in breast cancer, glioblastoma and leukemia. However, the specific functions of KAT6A in ovarian cancer remain unclear. Methods: Immunohistochemistry (IHC) staining and western blotting were performed to characterize KAT6A protein expression in ovarian cancer tissues and cell lines. The biological functions of KAT6A in ovarian cancer were evaluated by cell proliferation, wound healing and transwell invasion assays in vitro. Tumorigenesis and metastasis assays were performed in nude mice to detect the role of KAT6A in vivo. Mass spectrometry and immunoprecipitation assays were performed to detect the KAT6A-COP1 interaction. An in vivo ubiquitination assay was performed to determine the regulation of β-catenin by KAT6A. Results: In the present study, we revealed that KAT6A expression is upregulated in ovarian cancer and is associated with patient overall survival. Downregulation of KAT6A markedly inhibited the proliferation and migration abilities of ovarian cancer cells in vivo and in vitro. Additionally, the inhibition of KAT6A induced apoptosis and enhanced the sensitivity of ovarian cancer cells to cisplatin. Furthermore, KAT6A bound to and acetylated COP1 at K294. The acetylation of COP1 impaired COP1 function as an E3 ubiquitin ligase and led to the accumulation and enhanced activity of β-catenin. Conclusions: Our findings suggest that the KAT6A/COP1/β-catenin signaling axis plays a critical role in ovarian cancer progression and that targeting the KAT6A/COP1/β-catenin signaling axis could be a novel strategy for treating ovarian cancer.

Development and Validation of the Gene Expression Predictor of High-grade Serous Ovarian Carcinoma Molecular SubTYPE (PrOTYPE)

PURPOSE

Gene expression-based molecular subtypes of high-grade serous tubo-ovarian cancer (HGSOC), demonstrated across multiple studies, may provide improved stratification for molecularly targeted trials. However, evaluation of clinical utility has been hindered by nonstandardized methods, which are not applicable in a clinical setting. We sought to generate a clinical grade minimal gene set assay for classification of individual tumor specimens into HGSOC subtypes and confirm previously reported subtype-associated features.

EXPERIMENTAL DESIGN

Adopting two independent approaches, we derived and internally validated algorithms for subtype prediction using published gene expression data from 1,650 tumors. We applied resulting models to NanoString data on 3,829 HGSOCs from the Ovarian Tumor Tissue Analysis consortium. We further developed, confirmed, and validated a reduced, minimal gene set predictor, with methods suitable for a single-patient setting.

RESULTS

Gene expression data were used to derive the predictor of high-grade serous ovarian carcinoma molecular subtype (PrOTYPE) assay. We established a de facto standard as a consensus of two parallel approaches. PrOTYPE subtypes are significantly associated with age, stage, residual disease, tumor-infiltrating lymphocytes, and outcome. The locked-down clinical grade PrOTYPE test includes a model with 55 genes that predicted gene expression subtype with >95% accuracy that was maintained in all analytic and biological validations.

CONCLUSIONS

We validated the PrOTYPE assay following the Institute of Medicine guidelines for the development of omics-based tests. This fully defined and locked-down clinical grade assay will enable trial design with molecular subtype stratification and allow for objective assessment of the predictive value of HGSOC molecular subtypes in precision medicine applications.See related commentary by McMullen et al., p. 5271.

Association of PD-L1 expression by immunohistochemistry and gene microarray with molecular subtypes of ovarian tumors

Identifying patients who respond to immune checkpoint blockade (ICB) is a significant challenge in oncology. While PD-L1 expression by immunohistochemistry (IHC) is the current diagnostic gold standard for patient selection, it nevertheless does not capture all patients who may respond to ICB. Recent gene expression studies in high-grade serous ovarian carcinoma have defined an immunoreactive molecular subtype that has a measurable difference in patient survival compared with non-immunoreactive subtypes, but no studies have yet demonstrated its impact on predicting response to ICB. As a step toward establishing the predictive value of gene expression classifiers in ICB, we assessed the relationship between PD-L1 IHC and molecular subtypes of ovarian epithelial cancer. This was done by analyzing a total of 93 tissue specimens from patients with stage III and IV disease, and comparing PD-L1 IHC with gene expression by Agilent microarrays using TCGA-defined subtypes. We showed that ovarian tumors with elevated IHC PD-L1 expression are most strongly associated with immunoreactive subtype as compared with other molecular subtypes, reaching statistical significance against differentiated (Dunn's test, 33.39, p = 0.0003) and mesenchymal (39.63, p < 0.0001) subtypes. Comparing PD-L1 scoring with CPS vs. TPS showed similar trends, but with stronger correlation strength when using CPS (Kruskal-Wallis, H = 27.52, p < 0.0001), as opposed to TPS (H = 25.04, p < 0.0001). Interestingly, while PD-L1 gene expression by microarray was significantly increased in the immunoreactive subtype (H = 20.25, p = 0.0002), it showed a positive but relatively poor correlation to IHC. Overall, the results demonstrate potential value in use of the molecular classifier to select patients for ICB, pending further studies that assess its ability to predict treatment outcomes. In the future, integration of cellular, protein, and genomic biomarkers in the tumor and tumor microenvironment may improve current methods of predicting treatment response.

Impact of age-, cancer-, and treatment-driven inflammation on T cell function and immunotherapy

Many cancers are predominantly diagnosed in older individuals and chronic inflammation has a major impact on the overall health and immune function of older cancer patients. Chronic inflammation is a feature of aging, it can accelerate disease in many cancers and it is often exacerbated during conventional treatments for cancer. This review will provide an overview of the factors that lead to increased inflammation in older individuals and/or individuals with cancer, as well as those that result from conventional treatments for cancer, using ovarian cancer (OC) and multiple myeloma (MM) as key examples. We will also consider the impact of chronic inflammation on immune function, with a particular focus on T cells as they are key targets for novel cancer immunotherapies. Overall, this review aims to highlight specific pathways for potential interventions that may be able to mitigate the impact of chronic inflammation in older cancer patients.

Molecular classification and immunologic characteristics of immunoreactive high‐grade serous ovarian cancer

High‐grade serous ovarian cancer (HGS‐OvCa) is one of the most lethal gynaecological malignancies. Molecular classification identified an immunoreactive subtype of HGS‐OvCa; however, the immunologic characteristics of immunoreactive HGS‐OvcA remain unclear. In this study, 121 immunoreactive HGS‐OvCa samples were identified from a meta‐analysis of 5 large transcriptome profiling data sets using a cross‐platform immunoreactive HGS‐OvCa subgroup‐specific classifier. By comparing the gene expression profiles of immunoreactive HGS‐OvCa samples and normal tissues, 653 differentially expressed genes (DEGs) were identified. KEGG pathway analysis revealed that the leukocyte transendothelial migration pathways were significantly enriched in the immunoreactive HGS‐OvCa. Protein‐protein interaction analysis identified a module that showed strong involvement of the immune‐related chemokine signalling pathway. Moreover, the GSEA enrichment analysis showed a T‐cell subgroup and M1 macrophages were significantly enriched in immunoreactive OvCa compared with normal samples. Macrophage infiltration levels were significantly elevated in immunoreactive HGS‐OvCa compared with other OvCa subtypes. In addition, expression of immune checkpoint molecules VTCN1 and IDO1 was significantly increased in immunoreactive HGS‐OvCa. In summary, our results suggest that the immunoreactive HGS‐OvCa has unique molecular characteristics and a tumour‐associated immune microenvironment featured by increased infiltration of macrophages, rather than lymphocytes. VTCN1 could be potential targets for the treatment of immunoreactive HGS‐OvCa.

Infiltration of T cells promotes the metastasis of ovarian cancer cells via the modulation of metastasis-related genes and PD-L1 expression

Due to its high ability to disseminate, ovarian cancer remains one of the largest threats to women's health, worldwide. Evidence showed that the immune cells infiltrating the tumor microenvironment are crucial in mediating metastasis. Therefore, it is necessary to understand which types of immune cells are involved in metastasis, and to determine the mechanisms by which they influence the process. By immunohistochemistry, we found that higher concentrations of intratumoral CD8⁺ T cells were found to be correlated with an advanced grade and stage of ovarian cancer. Additionally, the infiltration of stromal CD8⁺ T cells was also significantly higher in tissues with advanced stages and metastatic tumors. A positive correlation between the infiltration of FoxP3⁺ Treg cells and histological grade was also observed, regardless of location. PD-L1 expression in metastatic tumors was also higher than that in paired primary ovarian tumors. Transwell migration and invasion assays revealed the increased migration and invasion of ovarian cancer cell lines (A2780CP and ES2) and ascites-derived ovarian cancer cells following co-culturing with CD8⁺ T cells. Enhanced expression of MMP-9, uPA, VEGF, bFGF, IL-8, IL-10, and PD-L1 by cancer cells following co-culturing with CD8⁺ T cells were also detected by qPCR, ELISA or flow cytometry. In conclusion, our findings suggest that the infiltrated T cells could promote the development of ovarian cancer, and provide another mechanism of immune evasion mediated by T cells.

Harnessing natural killer cells for the treatment of ovarian cancer

INTRODUCTION

Adoptive cellular immunotherapy could be an interesting new treatment option for ovarian carcinoma (OC), as research has demonstrated that OC is an immunogenic disease. In particular, natural killer (NK) cells have attracted attention due to their ability to kill tumor cells without prior sensitization. The therapeutic value of allogeneic NK cells has been first observed in hematological cancers and is increasingly being explored in solid tumors.

METHODS

To substantiate the rationale for NK cell therapy in OC we performed a literature search in the Pubmed database and in the international trial register clinicaltrials.gov with attention for the effect of OC on NK cell function, the effect of current treatment on NK cell biology and the evidence on the therapeutic value of NK cell therapy against OC.

RESULTS

In six clinical trials only 31 OC patients have been reported that received NK cell adoptive transfer. The majority of patients reached stable disease after NK cell therapy, with a mild pattern of side effects. In patients who received repeated infusions, more complete responses are described. All reported studies investigated the intravenous infusion of NK cells. Whereas the studies that are currently recruiting, investigate intraperitoneal infusion of allogeneic NK cells.

CONCLUSION

In this review the pre-clinical evidence and current trials on NK cell immunotherapy in OC patients are summarized. Furthermore, challenges that have to be overcome for NK cell adoptive therapy to have a significant impact on disease outcome are discussed.

Human ovarian cancer intrinsic mechanisms regulate lymphocyte activation in response to immune checkpoint blockade

Immune checkpoint blocking antibodies are currently being tested in ovarian cancer (OC) patients and have shown some responses in early clinical trials. However, it remains unclear how human OC cancer cells regulate lymphocyte activation in response to therapy. In this study, we have established and optimised an in vitro tumour-immune co-culture system (TICS), which is specifically designed to quantify the activation of multiple primary human lymphocyte subsets and human cancer cell killing in response to PD-1/L1 blockade. Human OC cell lines and treatment naïve patient ascites show differential effects on lymphocyte activation and respond differently to PD-1 blocking antibody nivolumab in TICS. Using paired OC cell lines established prior to and after chemotherapy relapse, our data reveal that the resistant cells express low levels of HLA and respond poorly to nivolumab, relative to the treatment naïve cells. In accordance, knockdown of IFNγ receptor expression compromises response to nivolumab in the treatment naïve OC cell line, while enhanced HLA expression induced by a DNA methyltransferase inhibitor promotes lymphocyte activation in TICS. Altogether, our results suggest a ‘cross resistance’ model, where the acquired chemotherapy resistance in cancer cells may confer resistance to immune checkpoint blockade therapy through down-regulation of antigen presentation machinery. As such, agents that can restore HLA expression may be a suitable combination partner for immunotherapy in chemotherapy-relapsed human ovarian cancer patients.

Immunotherapy: Checkpoint Inhibitors in Lynch-Associated Gynecologic Cancers

OPINION STATEMENT

Research into novel therapies for gynecologic cancers is underfunded, and as a result, we are still playing catchup with other solid tumors in the realm of immune checkpoint inhibition. This is despite the fact that two of the most common gynecologic cancers in the USA have strong biologic rationales for response to these agents. Work is now underway to demonstrate safe and effective therapies for our patients. As we better understand the immune system, and more specifically the tumor microenvironment, we will be able to achieve complete responses. The immune system can learn, adapt, and provide ongoing surveillance; if only we could mimic its abilities.

Pseudo- or real progression? An ovarian cancer patient under nivolumab: A case report

BACKGROUND

Checkpoint-Inhibition has revolutionized the treatment for several entities such as melanoma and renal cell carcinoma. The first encouraging experience in ovarian cancer was reported for nivolumab, a fully humanized anti-programmed death-1 antibody. Pseudoprogression is a new phenomenon associated with these novel immuno-oncologic agents. It can be explained by infiltrating leucocytes and edema that result in a temporary increase in tumor size and delayed subsequent shrinkage due to tumor cell destruction.

CASE SUMMARY

We report on a 47-year old patient with platinum-resistant ovarian cancer that was treated off-label with nivolumab 3mg/kg iv d1q14d. She first experienced classic pseudoprogression with inguinal lymph node swelling after cycle two and subsequent shrinkage. After 6 cycles she presented with rectal bleeding and progressive disease was diagnosed due to new tumor infiltration into the rectum.

CONCLUSION

Clinicians should be aware of pseudoprogression, its underlying mechanisms and strategies to discriminate pseudo- from real progression in ovarian cancer.

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT): a challenge for clinicopathological diagnosis

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an extremely aggressive ovarian tumor, with a poor prognosis and high mortality for young women. This paper aims to inform clinical physicians of new clinical improvements and further understanding of SCCOHT. Two cases diagnosed with SCCOHT from our medical database were reconfirmed and immunohistochemically stained with vimentin, CK, EMA, S-100, ER, PR, and SMARCA4. Diffuse small, round cells with scant cytoplasms, small nucleoli, hyperchromatic nuclei, and active nuclear divisions were detected in the microscopy. The immunohistochemical markers indicated minor positive but notably were SMARCA4 negative, which led to the final diagnosis. SCCOHT is a rare and lethal ovarian tumor in young women. The loss of SMARCA4 or the presence of SMARCA2 is a specific marker for the disease. Susceptibility to CDK4/6 inhibitors associated with downregulation of SMARCA4 targeted cyclin D1 may be a probable therapeutical mechanism for the disease.

Immunotherapies based on PD-1/PD-L1 pathway inhibitors in ovarian cancer treatment

Immunotherapies based on anti-programmed death 1/programmed death ligand 1 (PD-1/PD-L1) pathway inhibitors may turn out effective in ovarian cancer (OC) treatment. They can be used in combination with standard therapy and are especially promising in recurrent and platinum-resistant OC. There is growing evidence that the mechanism of the PD-1/PD-L1 pathway can be specific for a particular histological cancer type. Interestingly, the data have shown that the PD-1/PD-L1 pathway blockade may be effective, especially in the endometrioid type of OC. It is important to identify the cause of anti-tumor immune response suppression and exclude its other mechanisms in OC patients. It is also necessary to conduct subsequent studies to confirm in which OC cases the treatment is effective and how to select patients and combine drugs to improve patient survival.