Targetable Immune Regulatory Molecule Expression in High-Grade Serous Ovarian Carcinomas in African American Women: A Study of PD-L1 and IDO in 112 Cases From the African American Cancer Epidemiology Study (AACES)

Racial and socioeconomic disparities in survival among women with advanced-stage ovarian cancer who received systemic therapy

PURPOSE

The purpose of this study was to assess the association between race/ethnicity and all-cause mortality among women with advanced-stage ovarian cancer who received systemic therapy.

METHODS

We analyzed data from the National Cancer Database on women diagnosed with advanced-stage ovarian cancer from 2004 to 2015 who received systemic therapy. Race/ethnicity was categorized as Non-Hispanic (NH) White, NH-Black, Hispanic, NH-Asian/Pacific Islander, and Other. Income and education were combined to form a composite measure of socioeconomic status (SES) and categorized into low-, mid-, and high-SES. Multivariable Cox proportional hazards models were used to assess whether race/ethnicity was associated with the risk of death after adjusting for sociodemographic, clinical, and treatment factors. Additionally, subgroup analyses were conducted by SES, age, and surgery receipt.

RESULTS

The study population comprised 53,367 women (52.4% ages ≥ 65 years, 82% NH-White, 8.7% NH-Black, 5.7% Hispanic, and 2.7% NH-Asian/Pacific Islander) in the analysis. After adjusting for covariates, the NH-Black race was associated with a higher risk of death versus NH-White race (aHR: 1.12; 95% CI: 1.07,1.18), while Hispanic ethnicity was associated with a lower risk of death compared to NH-White women (aHR: 0.87; 95% CI: 0.80, 0.95). Furthermore, NH-Black women versus NH-White women had an increased risk of mortality among those with low-SES characteristics (aHR:1.12; 95% CI:1.03-1.22) and mid-SES groups (aHR: 1.13; 95% CI:1.05-1.21).

CONCLUSIONS

Among women with advanced-stage ovarian cancer who received systemic therapy, NH-Black women experienced poorer survival compared to NH-White women. Future studies should be directed to identify drivers of ovarian cancer disparities, particularly racial differences in treatment response and surveillance.

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.

Prognostic Significance of Programmed Cell Death Ligand 1 Expression in High-Grade Serous Ovarian Carcinoma: A Systematic Review and Meta-Analysis

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.

PD-L1 is highly expressed in ovarian cancer and associated with cancer stem cells populations expressing CD44 and other stem cell markers

BACKGROUND

Immune checkpoint inhibitors, including PD-L1 (programmed death ligand-1) inhibitors have well documented anticancer therapeutic effect in most types of cancers but its use in the treatment of ovarian cancer is not yet proven. The aim of our study is to explore the predictive biomarkers in ovarian cancer and its association with the outcomes. We have investigated the role of PD-L1 expressions in the tumor microenvironment cells including immune cells and cancer stem cells in different types of ovarian cancer.

METHODS

A total of 119 surgical archived ovarian cancer samples were collected from the pathology department at King Fahad Specialist Hospital, Dammam, Saudi Arabia that included serous carcinomas, clear cell carcinomas, mucinous carcinomas, endometrioid carcinomas, and granulosa cell tumors. Immunohistochemistry (IHC) staining was performed using (i) PD-L1 antibodies to detect PD-L1 expressions; (ii) CD8 and CD4 to detect Tumor Infiltrating Lymphocytes (TILs); and (iii) CD44, LGR5, and ALDH2 to detect stem cell markers. The clinicopathological data were collected from patients' medical record to investigate the association with PD-L1, TILs, and stem cells expressions.

RESULTS

We report high PD-L1 expressions in 47.8% of ovarian cancer samples. PD-L1 expressions were detected in different types of epithelial ovarian cancer and were not associated with poor prognosis of ovarian cancer. However, determining the expression levels of TILs in the ovarian cancer tissues found that 81% (n = 97) of ovarian cancer samples have TILs that express both of CD8 and CD4 and significantly associated with high PD-L1 expressions. Interestingly, we have found that ovarian cancer tissues with high expressions of PD-L1 were associated with high expressions of stem cells expressing CD44 and LGR5.

CONCLUSIONS

PD-L1 is highly expressed in the serous type of ovarian carcinomas and the overall expression of PD-L1 is not associated with poor survival rate. Furthermore, PD-L1 expressions are strongly associated with TILs and stem cell markers in ovarian cancer. Inhibiting the PD-L1 using immune checkpoint inhibitors might downregulate stem cell population that known to be associated with cancer recurrence.

A durable response to programmed cell death 1 blockade in a multidrug-resistant recurrent ovarian cancer patient with HLA-B44 supertype: A case report

Relapsed/refractory ovarian cancer, especially platinum resistance recurrence, remains a major therapeutic challenge. Here, we present the case of a patient with recurrent ovarian clear cell carcinoma (OCCC) who failed to respond to multiline chemotherapy and target therapy but achieved an immune complete response (iCR) with programmed cell death 1 (PD-1) inhibitor treatment. The overall survival (OS) was 59 months, and the recurrence-free survival (RFS) was 34 months after immunotherapy, which was counting. Meantime, molecular testing results revealed that traditional biomarkers for immunotherapy, including PD-L1 expression, microsatellite instability (MSI), and tumor mutational burden (TMB), were negative. HLA-B44 (B*18:01) supertype was confirmed by sequence-based HLA typing. This case raises the possibility that ovarian cancer patients with multidrug resistance may still benefit from PD-1 inhibitor therapy, even if PD-L1 pathology is negative.

Targeting immunometabolism mediated by the IDO1 Pathway: A new mechanism of immune resistance in endometrial cancer

Immunotherapy is acquiring a primary role in treating endometrial cancer (EC) with a relevant benefit for many patients. Regardless, patients progressing during immunotherapy or those who are resistant represent an unmet need. The mechanisms of immune resistance and escape need to be better investigated. Here, we review the major mechanisms of immune escape activated by the indolamine 2,3-dioxygenase 1 (IDO1) pathway in EC and focus on potential therapeutic strategies based on IDO1 signaling pathway control. IDO1 catalyzes the first rate-limiting step of the so-called “kynurenine (Kyn) pathway”, which converts the essential amino acid l-tryptophan into the immunosuppressive metabolite l-kynurenine. Functionally, IDO1 has played a pivotal role in cancer immune escape by catalyzing the initial step of the Kyn pathway. The overexpression of IDO1 is also associated with poor prognosis in EC. These findings can lead to advantages in immunotherapy-based approaches as a rationale for overcoming the immune escape. Indeed, besides immune checkpoints, other mechanisms, including the IDO enzymes, contribute to the EC progression due to the immunosuppression induced by the tumor milieu. On the other hand, the IDO1 enzyme has recently emerged as both a promising therapeutic target and an unfavorable prognostic biomarker. This evidence provides the basis for translational strategies of immune combination, whereas IDO1 expression would serve as a potential prognostic biomarker in metastatic EC.

Racial Differences in the Tumor Immune Landscape and Survival of Women with High-Grade Serous Ovarian Carcinoma

BACKGROUND

Tumor-infiltrating lymphocytes (TIL) confer a survival benefit among patients with ovarian cancer; however, little work has been conducted in racially diverse cohorts.

METHODS

The current study investigated racial differences in the tumor immune landscape and survival of age- and stage-matched non-Hispanic Black and non-Hispanic White women with high-grade serous ovarian carcinoma (HGSOC) enrolled in two population-based studies (n = 121 in each racial group). We measured TILs (CD3+), cytotoxic T cells (CD3+CD8+), regulatory T cells (CD3+FoxP3+), myeloid cells (CD11b+), and neutrophils (CD11b+CD15+) via multiplex immunofluorescence. Multivariable Cox proportional hazard regression was used to estimate the association between immune cell abundance and survival overall and by race.

RESULTS

Overall, higher levels of TILs, cytotoxic T cells, myeloid cells, and neutrophils were associated with better survival in the intratumoral and peritumoral region, irrespective of tissue compartment (tumor, stroma). Improved survival was noted for T-regulatory cells in the peritumoral region and in the stroma of the intratumoral region, but no association for intratumoral T-regulatory cells. Despite similar abundance of immune cells across racial groups, associations with survival among non-Hispanic White women were consistent with the overall findings, but among non-Hispanic Black women, most associations were attenuated and not statistically significant.

CONCLUSIONS

Our results add to the existing evidence that a robust immune infiltrate confers a survival advantage among women with HGSOC; however, non-Hispanic Black women may not experience the same survival benefit as non-Hispanic White women with HGSOC.

IMPACT

This study contributes to our understanding of the immunoepidemiology of HGSOC in diverse populations.

Targeting immune checkpoints in gynecologic cancer: updates & perspectives for pathologists

Checkpoint inhibitor-based immunotherapy is increasingly used in the treatment of gynecologic cancers, and most often targets the PD-1/PD-L1 axis. Pathologists should be familiar with the biomarkers required to determine candidacy for these treatments based on existing FDA approvals, including mismatch repair protein immunohistochemistry, microsatellite instability testing, tumor mutation burden testing, and PD-L1 immunohistochemistry. This review summarizes the rationale behind these treatments and their associated biomarkers and delivers guidance on how to utilize and readout these tests. It also introduces additional biomarkers which may provide information regarding immunotherapeutic vulnerability in the future such as neoantigen load; POLE mutation status; and immunohistochemical expression of immunosuppressive checkpoints like LAG-3, TIM-3, TIGIT, and VISTA; immune-activating checkpoints such as CD27, CD40, CD134, and CD137; enzymes such as IDO-1 and adenosine-related compounds; and MHC class I.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Programmed death ligand-1 and CD8 tumor-infiltrating lymphocytes (TILs) as prognostic predictors in ovarian high-grade serous carcinoma (HGSC)

BACKGROUND

P D-L1 is expressed in tumor cells and plays a crucial role in tumor immune escape. Tumor-infiltrating lymphocytes (TILs) as CD8 T cells contribute to reduced tumor growth. Few studies investigated the prognostic effect of PD-L1 and CD8 TILs in ovarian high-grade serous carcinoma (HGSC). In the present study, we analyzed the expression of PD-L1 and CD8 TILs in HGSC by immunohistochemistry, and results were correlated to prognosis. It was carried on 54 cases of ovarian HGSC who attended the Oncology Centre, Mansoura University, Egypt, from 2012 till 2019.

RESULTS

Nearly 60% of cases showed positive PD-L1 expression in tumor cells. Regarding the clinicopathological characteristics, higher PD-L1 expression was found among patients with residual tumor (82.4%) compared to patients with no residual tumor (54.5%), with marginal statistical significance (p 0.07). PD-L1 was significantly associated with CD8 TILs expression. Higher PD-L1 expression was found among tumors with low expression of CD8 TILs with statistically significant difference (p≤0.001). Disease-free survival (DFS) was significantly lower among the group with positive expression of PD-L1 compared to the group with negative expression of PD-L1 (p 0.01), while overall survival (OS) was not associated with PD-L1 expression. On the other hand, the overall survival (OS) in patients with high CD8 expression was significantly higher than patients with low CD8 expression (p 0.043), while DFS was not significantly different among both CD8 TILS groups.

CONCLUSIONS

PD-L1 and CD8 TILs may become a promising therapeutic target for patients with ovarian HGSC. More studies are needed to further validate their prognostic effect. Precise identification of patients who will benefit from PD-L1 checkpoint blockade and TILs adaptive immunotherapy is mandatory.

Immunotherapy in endometrial cancer: rationale, practice and perspectives

Tumor immunotherapy has attracted more and more attention nowadays, and multiple clinical trials have confirmed its effect in a variety of solid tumors. Immune checkpoint inhibitors (ICIs), cancer vaccines, adoptive cell transfer (ACT), and lymphocyte-promoting cytokines are the main immunotherapy methods. Endometrial cancer (EC) is one of the most frequent tumors in women and the prognosis of recurrent or metastatic EC is poor. Since molecular classification has been applied to EC, immunotherapy for different EC subtypes (especially POLE and MSI-H) has gradually attracted attention. In this review, we focus on the expression and molecular basis of the main biomarkers in the immunotherapy of EC firstly, as well as their clinical application significance and limitations. Blocking tumor immune checkpoints is one of the most effective strategies for cancer treatment in recent years, and has now become the focus in the field of tumor research and treatment. We summarized clinical date of planned and ongoing clinical trials and introduced other common immunotherapy methods in EC, such as cancer vaccine and ACT. Hormone aberrations, metabolic syndrome (MetS) and p53 mutant and that affect the immunotherapy of endometrial cancer will also be discussed in this review.

IDO1 Expression in Melanoma Metastases Is Low and Associated With Improved Overall Survival

Indoleamine 2-3 dioxygenase 1 (IDO1) expression may contribute to immunologic escape by melanoma metastases. However, a recent clinical trial failed to identify any clinical benefits of IDO1 inhibition in patients with unresectable metastatic melanoma, and prior characterizations of IDO1 expression have predominately studied primary lesions and local metastases, generating uncertainty regarding IDO1 expression in distant metastases. We hypothesized that IDO1 expression in such lesions would be low and correlated with decreased overall survival (OS). Metastases from patients (n=96) with stage IIIb to IV melanoma underwent tissue microarray construction and immunohistochemical staining for IDO1. Th1-related gene expression was determined quantitatively. Associations between OS and IDO1 expression were assessed with multivariate models. Of 96 metastatic lesions, 28% were IDOpos, and 85% exhibited IDO1 expression in <10% of tumor cells. IDOpos lesions were associated with improved OS (28.9 vs. 10.5 mo, P=0.02) and expression of Th1-related genes. OS was not associated with IDO1 expression in a multivariate analysis of all patients; however, IDO1 expression (hazard ratio=0.25, P=0.01) and intratumoral CD8+ T-cell density (hazard ratio=0.99, P<0.01) were correlated with OS in patients who underwent metastasectomy with curative-intent. IDOpos metastases were less likely to recur after metastasectomy (54% vs. 16%, P=0.01). IDO1 expression was low in melanoma metastases and correlated with OS after metastasectomy with curative-intent. Intratumoral CD8+ T cells and Th1-related genes were correlated with IDO1 expression, as was tumor recurrence. These suggest that IDO1 expression may be a marker of immunologic tumor control, and may inform participant selection in future trials of IDO1 inhibitors.

Expression of the Immune Checkpoints LAG-3 and PD-L1 in High-grade Serous Ovarian Carcinoma: Relationship to Tumor-associated Lymphocytes and Germline BRCA Status

Ovarian high-grade serous carcinomas (HGSC) have shown lackluster responses to immunotherapies targeting the PD-1/PD-L1 axis, perhaps due to the coexistence of other mechanisms of immune evasion in this tumor type. Lymphocyte activation gene-3 (LAG-3) is another inhibitory immune checkpoint often expressed on tumor-associated lymphocytes which is targeted by drugs currently in clinical trials. Forty-eight HGSC with known germline BRCA mutation status were immunohistochemically stained for LAG-3, CD8, and FOXP3. Positive tumor-associated lymphocytes were enumerated and averaged over 10 high-power fields (HPF). PD-L1 immunostaining was also preformed and expression was evaluated on tumor cells and using the combined positive score (CPS). The average number of LAG-3-positve tumor-associated lymphocytes was 6/HPF (range: 0-25.6). Cytotoxic (CD8) T cells averaged 30/HPF (range: 0-168.9), and regulatory (FOXP3) cells averaged 6.6/HPF (range: 0-76.3). Tumoral PD-L1 expression of ≥1% was observed in 27% (13/48) of cases, with only 8% (4/48) showing >5% staining; 81% (39/48) cases had a CPS ≥1. LAG-3-positive lymphocytes and PD-L1 expression were positively correlated, even after controlling for the overall level of CD8 and FOX3P lymphocyte infiltration. Germline BRCA status was not significantly associated with LAG-3, CD8, FOXP3, or PD-L1 expression. These findings indicate that immunotherapies targeting LAG-3 may benefit some ovarian HGSC patients, particularly when used in conjunction with anti-PD-1/PD-L1 approaches. The typically limited expression of LAG-3 and PD-L1 suggests that immunotherapeutic response may be muted in most HGSC even with a combination approach.

Race as a Contributor to Stromal Modulation of Tumor Progression

Stromal cells play crucial roles in tumor development and are increasingly attractive targets for therapy. There are considerable racial disparities in the incidence and progression of many tumors, reflecting both environmental exposure and genetic differences existing between races. Tumorigenesis and tumor progression are linked to both the propensity to suffer an initiating event and the host response to such an event once it occurs, contributing to incidence and outcomes. In this review, we focused on racial disparities in the tumor microenvironment (TME) of different cancers as potential modulators of growth, metastasis, and response to treatment. Several studies suggest that the TME in AA has a distinct tumor biology and may facilitate both early onset and aggressive tumor growth while inhibiting anti-tumorigenic properties. The TME of AA patients often exhibits an immunosuppressive microenvironment with a substantial enrichment of immune inflammatory pathways and genes. As a result, AA patients can potentially benefit more from treatment strategies that modulate the immune system. Focusing on TME components for diagnostic and therapeutic purposes to address racial disparities is a promising area of investigation. Future basic and clinical research studies on personalized cancer diagnosis and treatment should acknowledge the significance of TME in racial disparities.

Expression of B7-H4 and IDO1 is associated with drug resistance and poor prognosis in high-grade serous ovarian carcinomas

High-grade serous ovarian carcinoma (HGSC) is the most lethal gynecologic malignancy. While immune checkpoint inhibitors against PD-L1 and CTLA-4 have shown significant effects in multiple tumor types, the response rate to single-agent immune checkpoint inhibitors is low in HGSC. Alternative biomarkers and targets must be identified to guide patient selection and new therapeutic strategies in HGSC. Here, we aim to investigate the clinical significance of novel immune modulators, including B7-H4, IDO1, Tim3, IL6, and IL-8, in patients with HGSC. A total of 48 patients with HGSCs, comprising 24 cases that were sensitive and 24 that were resistant to standard paclitaxel and carboplatin chemotherapy, were selected for our initial analysis. A NanoString assay including 33 immune-related genes was used to compare the expression of different immune regulatory molecules in the sensitive and resistant groups. Differentially expressed proteins were verified using multiplex immunohistochemical staining on tissue arrays of 202 patients with HGSCs who underwent primary surgery at MDACC. We analyzed the expression levels of immune checkpoints and compared expression profiles with clinicopathologic features including response, progression-free survival, and overall survival. HGSC tumors resistant to therapy expressed higher levels of B7-H4 (69.3%), IDO1 (71.8%), Tim3 (89.1%), and inflammatory factors IL-6 and IL-8, and expressed higher Tim3 in stromal components. High expression of B7-H4 and IDO1 was associated with significantly lower overall survival and progression-free survival. B7-H4 and IDO1 were co-expressed in 49.1% of studied cases. A panel of immunomodulatory proteins including B7-H4, IDO1, Tim3, IL-6, and IL-8 are expressed at high levels in HGSCs. These modulators represent novel targets to enhance immunotherapy in patients with HGSCs.

The Dual Role of STAT1 in Ovarian Cancer: Insight Into Molecular Mechanisms and Application Potentials

The signal transducer and activator of transcription 1 (STAT1) is a transducer protein and acts as a transcription factor but its role in ovarian cancer (OC) is not completely understood. Practically, there are two-faced effects of STAT1 on tumorigenesis in different kinds of cancers. Existing evidence reveals that STAT1 has both tumor-suppressing and tumor-promoting functions involved in angiogenesis, cell proliferation, migration, invasion, apoptosis, drug resistance, stemness, and immune responses mainly through interacting and regulating target genes at multiple levels. The canonical STAT1 signaling pathway shows that STAT1 is phosphorylated and activated by the receptor-activated kinases such as Janus kinase in response to interferon stimulation. The STAT1 signaling can also be crosstalk with other signaling such as transforming growth factor-β signaling involved in cancer cell behavior. OC is often diagnosed at an advanced stage due to symptomless or atypical symptoms and the lack of effective detection at an early stage. Furthermore, patients with OC often develop chemoresistance and recurrence. This review focuses on the multi-faced role of STAT1 and highlights the molecular mechanisms and biological functions of STAT1 in OC.

MHC class I loss in endometrial carcinoma: a potential resistance mechanism to immune checkpoint inhibition

Major histocompatibility complex (MHC) class I is a membrane-bound protein complex expressed on nucleated human cells. MHC class I presents intracellular protein fragments to cytotoxic T cells and triggers an activation cascade upon neoantigen detection by these cells. MHC class I loss by tumor cells decreases tumor neoantigen presentation to the immune system and therefore represents a possible mechanism of immunotherapeutic resistance even among cancers that otherwise appear to be good candidates for checkpoint inhibition, such as mismatch repair (MMR)-deficient and PD-L1-positive malignancies. We herein assess MHC class I expression in a range of endometrial carcinomas, including MMR-deficient and PD-L1-positive cancers. Immunohistochemical staining for combined MHC class I A-, B-, and C-heavy chains was performed on 76 cases of endometrial carcinoma and was classified as present, subclonally lost, or diffusely lost. Tumoral PD-L1 expression, PD-L1 combined positive score, and CD3-positive T lymphocytes were also quantified. Forty-two percent of tumors showed loss of MHC class I expression, either in a subclonal (26%) or diffuse (16%) pattern. This included 46% of MMR-deficient and 25% of PD-L1-positive cancers. These findings suggest that tumoral MHC class I status may be an important factor to consider when selecting endometrial cancer patients for checkpoint inhibition.

The footprint of kynurenine pathway in every cancer: a new target for chemotherapy

Treatment of cancers has always been a challenge for physicians. Typically, several groups of anti-cancer medications are needed for effective management of an invasive and metastatic cancer. Recently, therapeutic potentiation of immune system markedly improved treatment of cancers. Kynurenine pathway has an interwoven correlation with immune system. Kynurenine promotes T Reg (regulatory) differentiation, which leads to increased production of anti-inflammatory cytokines and suppression of cytotoxic activity of T cells. Overactivation of kynurenine pathway in cancers provides an immunologically susceptible microenvironment for mutant cells to survive and invade surrounding tissues. Interestingly, kynurenine pathway vigorously interacts with other molecular pathways involved in tumorigenesis. For instance, kynurenine pathway interacts with phospoinosisitide-3 kinase (PI3K), extracellular signal-regulated kinase (ERK), Wnt/β-catenin, P53, bridging integrator 1 (BIN-1), cyclooxygenase 2 (COX-2), cyclin-dependent kinase (CDK) and collagen type XII α1 chain (COL12A1). Overactivation of kynurenine pathway, particularly overactivation of indoleamine 2,3-dioxygenase (IDO) predicts poor prognosis of several cancers such as gastrointestinal cancers, gynecological cancers, hematologic malignancies, breast cancer, lung cancer, glioma, melanoma, prostate cancer and pancreatic cancer. Furthermore, kynurenine increases the invasion, metastasis and chemoresistance of cancer cells. Recently, IDO inhibitors entered clinical trials and successfully passed their safety tests and showed promising therapeutic efficacy for cancers such as melanoma, brain cancer, renal cell carcinoma, prostate cancer and pancreatic cancer. However, a phase III trial of epacadostat, an IDO inhibitor, could not increase the efficacy of treatment with pembrolizumab for melanoma. In this review the expanding knowledge towards kynurenine pathway and its application in each cancer is discussed separately.

Changes in the Tumor Immune Microenvironment during Disease Progression in Patients with Ovarian Cancer

Simple Summary

Immunotherapy has been a successful treatment for many cancers. However, no immunotherapy treatment has been approved for ovarian cancer due to low efficacy in this patient group. This study investigated the cellular and molecular changes from primary ovarian tumors, at the time of diagnosis, to recurrence, where the disease returns after surgery and chemotherapies. Here we examined the immune contexture to better understand subdued responses to immunotherapy and identify additional, potentially complimentary, therapeutic targets. Indications of the development of adaptive immune resistance during disease progression were observed, with increases in immune and stromal cell infiltration accompanied by the expression of immune suppressive markers. We observed high gene expression of the immune checkpoint genes LAG3 and HAVCR2 (TIM3) in most tumors and increased expression of the immune checkpoint genes TIGIT and CTLA4 in recurrent tumors, compared to the primaries. These markers may be potential candidates for immunotherapy targeting in ovarian cancer.

Abstract

Anti-PD1/PDL1 therapy has proven efficacious against many cancers but only reached modest objective response rates against recurrent ovarian cancer. A deeper understanding of the tumor microenvironment (TME) may reveal other immunosuppressive mechanisms that warrant investigation as immunotherapeutic targets for this challenging disease. Matched primary and recurrent tumors from patients with high-grade serous ovarian carcinoma (HGSC) were analyzed by multicolor immunohistochemistry/immunofluorescence for the presence of T cells, B cells, macrophages, and for the expression of immunosuppressive and HLA molecules. Cancer- and immune-related gene expression was assessed by NanoString analysis. Recurrent tumors showed increased infiltration by immune cells, displayed higher expression of PDL1, IDO, and HLA molecules, and contained more stromal tissue. NanoString analysis demonstrated increased expression of gene signatures related to chemokines and T cell functions in recurrent tumors. The ovarian tumors showed high gene expression of LAG3 and HAVCR2 (TIM3) and enhanced levels of TIGIT and CTLA4 in recurrent tumors compared to primary tumors. The majority of HGSC developed into a more inflamed phenotype during progression from primary to recurrent disease, including indications of adaptive immune resistance. This suggests that recurrent tumors may be particularly sensitive to inhibition of adaptive immune resistance mechanisms.

Clinical and pathological significance of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) expression in high grade serous ovarian cancer

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PD-L1 expression in HGSOC requires further study with modern antibody reagents and platforms.

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The association of PD-L1 positive cases with CD8+ immune cells is more prominent.

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The checkpoint value in HGSOC is not yet clear, but there is an importance meaningful when the threshold is ≥5%.

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PD-L1 expression shows two immunohistochemical staining patterns, patchy/diffuse and patchy/focal.

We investigated programmed cell death 1 (PD-1) / programmed cell death ligand 1 (PD-L1) expression in high grade serous ovarian cancer (HGSOC) and its relationship to tumor infiltrating lymphocytes (TIL) and prognosis. Formalin fixed paraffin embedded (FFPE) samples of 94 HGSOC cases were included in the study. Immunohistochemical analysis (CD3, CD4, CD8, PD-1 and PD-L1) was performed. Samples were analyzed for expression of immune proteins in the peritumoral stromal and intratumoral areas, scored, and expression was correlated with overall survival, stage, and age. PD-L1 staining ratio with a score greater than 0 was found to have lower survival. There were two positive staining patterns, patchy/diffuse and patchy/focal patterns, in 24 (25.5%) cases. Considering the threshold value ≥5%, we demonstrated that the PD-L1 positive cancer cell membrane immunoreactivity rate and patchy/diffuse PD-L1 expression were 9.6% (n = 9). There was statistically significant relationship between high PD-1 scores and PD-L1 cases of ≥ 5%. A statistically significant difference was found between PD-L1 staining and survival in patients with a threshold ≥ 5%. However an appropriate rate for treatment was determined in 9.6% cases. There was a statistically significant correlation between PD-1 positive TIL score and intratumoral CD3, peritumoral stromal CD3, intratumoral CD4 and intratumoral CD8 positive cells. Survival was lower in cases with higher PD-L1 positive stromal TIL score.

Expression of STAT1 is positively correlated with PD-L1 in human ovarian cancer

Signal transducer and activator of transcription 1 (STAT1) is related to the immune microenvironment of tumorigenesis. The programmed cell death 1 (PD-1) and its ligand (PD-L1) have been reported to be important in immunotherapy by mediating tumor immune evasion. Blocking the PD-1/PD-L1 pathway can restore the endogenous anti-tumor immune response. This study aimed to examine the expression of STAT1, PD-1, and PD-L1 and the correlation between selected markers in human epithelial ovarian cancer (EOC). The results showed that malignant tumors contained more STAT1, PD-1, and PD-L1 positive cells. The expression of STAT1 and PD-L1 was associated with age, whereas PD-1 and PD-L1 associated with histopathological type, in patients with ovarian tumors. Moreover, the expression of STAT1 was found to be associated with disease stages and the grade of serous carcinoma. STAT1 expression was higher in OC cells than normal ovarian surface epithelial cells and was positively correlated with PD-L1 expression. The knockdown of STAT1 decreased PD-L1 expression, whereas overexpression of STAT1 increased PD-L1 expression. Furthermore, the expression of STAT1, PD-1, and PD-L1 was lower in paclitaxel-resistant cells than sensitive cells. Finally, STAT1 affected the overall survival and progression-free survival of patients with EOC. These findings suggest that STAT1, PD-1, and PD-L1 are the tissue markers of EOC and imply the possibility that the high level of STAT1, PD-1, and PD-L1 may favor the checkpoint immunotherapy in patients with EOC, but may have a limit in paclitaxel-resistant patients because of the low expression of STAT1, PD-1, and PD-L1 in paclitaxel-resistant cells.

Correlation Patterns Among B7 Family Ligands and Tryptophan Degrading Enzymes in Hepatocellular Carcinoma

Mechanisms of dysfunctional T cell immunity in Hepatocellular Carcinoma (HCC) need to be well defined. B7 family molecules provide both co-stimulatory and co-inhibitory signals to T cells while tryptophan degrading enzymes like Indoleamine 2,3 dioxygenase (IDO) and Tryptophan 2,3 Dioxygenase (TDO) mediate tumor immune tolerance. It is necessary to identify their in situ correlative expression, which informs targets for combined immunotherapy approaches. We investigated B7 family molecules, IDO, TDO and immune responsive effectors in the tumor tissues of patients with HCC (n = 28) using a pathway-focused quantitative nanoscale chip real-time PCR. Four best correlative expressions, namely (1) B7-1 & PD-L2, (2) B7-H2 & B7-H3, (3) B7-2 & PD-L1, (4) PD-L1 & PD-L2, were identified among B7 family ligands, albeit they express at different levels. Although TDO expression is higher than IDO, PD-L1 correlates only with IDO but not TDO. Immune effector (Granzyme B) and suppressive (PD-1 and TGF-β) genes correlate with IDO and B7-1, B7-H5, PD-L2. Identification of the in situ correlation of PD-L1, PD-L2 and IDO suggest their cumulative immuno suppressive role in HCC. The distinct correlations among B7-1, B7-2, B7-H2, and B7-H3, correlation of PD-1 with non-cognate ligands such as B7-1 and B7-H5, and correlation of tumor lytic enzyme Granzyme B with IDO and PD-L2 suggest that HCC microenvironment is complexly orchestrated with both stimulatory and inhibitory molecules which together neutralize and blunt anti-HCC immunity. Functional assays demonstrate that both PDL-1 and IDO synergistically inhibit T cell responses. Altogether, the present data suggest the usage of combined immune checkpoint blocking strategies targeting co-inhibitory B7 molecules and IDO for HCC management.

Accumulation of blood-circulating PD-L1-expressing M-MDSCs and monocytes/macrophages in pretreatment ovarian cancer patients is associated with soluble PD-L1

BACKGROUND

Previous studies have shown clinical relevance of programmed death-ligand 1 (PD-L1) and soluble PD-L1 (sPD-L1) in human cancers. However, still contradictory results exist. Our aim was evaluation of PD-L1-expressing monocytic myeloid-derived suppressor cells (M-MDSCs), monocytes/macrophages (MO/MA), tumour cells (TC) and immune/inflammatory cells (IC) as well as investigation of the sPD-L1 in ovarian cancer (OC) patients.

METHODS

The group of 74 pretreatment women were enrollment to the study. The expression of PD-L1 on M-MDSCS and MO/MA was assessed by flow cytometry. The profile of sPD-L1 was examined with ELISA. The expression of PD-L1 in mononuclear cells (MCs) was analyzed using real time PCR. PD-L1 immunohistochemical analysis was prepared on TC and IC. An in silico validation of prognostic significance of PD-L1 mRNA expression was performed based microarray datasets.

RESULTS

OC patients had significantly higher frequency of MO/MA versus M-MDSC in the blood, ascites and tumour (each p < 0.0001). In contrast, PD-L1 expression was higher on M-MDSCs versus MO/MA in the blood and ascites (each p < 0.0001), but not in the tumour (p > 0.05). Significantly higher accumulation of blood-circulating M-MDSC, MO/MA, PD-L1⁺M-MDSC, PD-L1⁺MO/MA and sPD-L1 was observed in patients versus control (p < 0.001, p < 0.05, p < 0.001, p < 0.001 and p < 0.0001, respectively). Accumulation of these factors was clinicopathologic-independent (p > 0.05). The expression of PD-L1 was significantly higher on IC versus TC (p < 0.0001) and was clinicopathologic-independent (p > 0.05) except higher level of PD-L1⁺TC in the endometrioid versus mucinous tumours. Interestingly, blood-circulating sPD-L1 positively correlated with PD-L1⁺M-MDSCs (p = 0.03) and PD-L1⁺MO/MA (p = 0.02) in the blood but not with these cells in the ascites and tumours nor with PD-L1⁺TC/IC (each p > 0.05). PD-L1 and sPD-L1 were not predictors of overall survival (OS; each p > 0.05). Further validation revealed no association between PD-L1 mRNA expression and OS in large independent OC patient cohort (n = 655, p > 0.05).

CONCLUSIONS

Although PD-L1 may not be a prognostic factor for OC, our study demonstrated impaired immunity manifested by up-regulation of PD-L1/sPD-L1. Furthermore, there was a positive association between PD-L1⁺ myeloid cells and sPD-L1 in the blood, suggesting that sPD-L1 may be a noninvasive surrogate marker for PD-L1⁺myeloid cells immunomonitoring in OC. Overall, these data should be under consideration during future clinical studies/trials.

Prognostic value of programmed cell death ligand-1 expression in ovarian cancer: an updated meta-analysis

Objective

To investigate the prognostic significance of programmed cell death ligand-1 (PD-L1) in ovarian cancer.

Methods

PubMed, Embase, and Cochrane Library databases were searched to identify studies that examined the prognostic significance of immunohistochemically assessed PD-L1 expression in histologically confirmed ovarian cancer. Eleven studies on PD-L1 expression involving 1,296 patients with ovarian cancer were included in this meta-analysis. Pooled hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were analyzed. Relationship between PD-L1 expression, and overall survival (OS) or progression-free survival (PFS) among patients with ovarian cancer was assessed. Subgroup analysis was performed based on the race, histologic type, and tumor International Federation of Gynecology and Obstetrics stage to evaluate the source of heterogeneity. Begg's Funnel plot and Egger's linear test were used to evaluate publication bias. Random-effects model was implemented when significant between-study heterogeneity (I²>50%) was observed.

Results

We found no correlation between PD-L1 expression, and OS (HR, 1.13; 95% CI, 0.95–1.36; I²=78%) or PFS (HR, 1.07; 95% CI, 0.88–1.30; I²=75%) in ovarian cancer. Subgroup analyses showed that higher PD-L1 expression was associated with poor OS in non-Asian patients with ovarian cancer (HR, 1.26; 95% CI, 1.07–1.481; I²=59%). We found that upregulated PD-L1 expression to be a positive predictor for OS in serous ovarian cancer (HR, 0.98; 95% CI, 0.76–1.26; I²=74%) and a negative predictor for OS in non-serous ovarian cancer (HR, 1.29; 95% CI, 1.03–1.61; I²=64%) Furthermore, high PD-L1 expression was found to be a negative predictor for PFS of patients with non-serous ovarian cancer (HR, 1.12; 95% CI, 0.96–1.29; I²=37%).

Conclusion

Our meta-analysis suggests that PD-L1 expression is not associated with patient risk for ovarian cancer.

VISTA expression is associated with a favorable prognosis in patients with high-grade serous ovarian cancer

Blockading programmed death ligand 1 (PD-L1) shows promising results in patients with some cancers, but not in those with ovarian cancer. V-domain Ig suppressor of T cell activation (VISTA) is a recently discovered immune checkpoint protein that suppresses T cell activation. This study aimed to investigate the expression and clinical significance of VISTA in ovarian cancer as well as its relationship with PD-L1. VISTA and PD-L1 levels in 146 ovarian cancer samples were assessed using immunohistochemistry. We investigated the association between VISTA and other clinicopathological variables, including survival. The associations between the VISTA-encoding C10orf54 gene, other immune checkpoints, and survival were analyzed. VISTA was detected in 51.4% of all samples and 46.6% of PD-L1-negative samples; it was expressed in 28.8%, 35.6%, and 4.1% of tumor cells (TCs), immune cells (ICs), and endothelial cells, respectively. Furthermore, VISTA expression was associated with pathologic type and PD-L1 expression. Moreover, VISTA expression in TCs, but not in ICs, was associated with prolonged progression-free and overall survival in patients with high-grade serous ovarian cancer. The expression of C10orf54 mRNA was associated with prolonged overall survival and immune escape-modulating genes. These results showed that VISTA expression in ovarian tumor cells was associated with a favorable prognosis in patients with high-grade serous ovarian cancer; however, additional studies are required to better understand the expression and role of VISTA in ovarian cancer.

Prognostic effect of programmed death-ligand 1 (PD-L1) in ovarian cancer: a systematic review, meta-analysis and bioinformatics study

BACKGROUND

The expression of PD-L1 has been reported in ovarian cancer. However, the prognostic role of PD-L1 expression in ovarian carcinoma remained controversial. This study was performed to assess the prognostic value of PD-L1 expression on ovarian cancer.

METHODS

The PubMed, Embase, EBSCO, and Cochrane Library databases were searched to identify available publications. The pooled odds ratio (OR) or hazard ratios (HRs: multivariate analysis) with their 95% confidence intervals (95% CIs) were calculated in this analysis. A bioinformatics study based on The Cancer Genome Atlas (TCGA) sequencing and microarray datasets was used to further validate the results of PD-L1 mRNA expression. Kaplan-Meier (KM) survival curves were performed to evaluate the prognostic effect of PD-L1 mRNA expression.

RESULTS

Twelve studies with 1630 ovarian cancers regarding PD-L1 immunohistochemical expression were identified. Meta-analysis showed that PD-L1 protein expression was not associated with tumor grade, clinical stage, lymph node status, tumor histology, overall survival (OS), and progression-free survival (PFS). TCGA data showed no association between PD-L1 mRNA expression and ovarian cancer. Further validation using microarray data suggested that no association between PD-L1 mRNA expression and OS was found in large independent patient cohorts (1310 cases). PD-L1 mRNA expression was significantly linked to worse PFS in 1228 patients with ovarian cancer (227458_at: HR = 1.55, 95% CI = 1.28-1.88, P < 0.001; 223834_at: HR = 1.41, 95% CI = 1.14-1.75, P = 0.0015).

CONCLUSIONS

Meta-analysis showed that PD-L1 may not be a prognostic factor for ovarian cancer. But a bioinformatics study showed that PD-L1 expression was significantly associated with worse PFS of ovarian cancer. More clinical studies are needed to further validate these findings.

Prognostic effect of programmed death-ligand 1 (PD-L1) in ovarian cancer: a systematic review, meta-analysis and bioinformatics study

BACKGROUND

The expression of PD-L1 has been reported in ovarian cancer. However, the prognostic role of PD-L1 expression in ovarian carcinoma remained controversial. This study was performed to assess the prognostic value of PD-L1 expression on ovarian cancer.

METHODS

The PubMed, Embase, EBSCO, and Cochrane Library databases were searched to identify available publications. The pooled odds ratio (OR) or hazard ratios (HRs: multivariate analysis) with their 95% confidence intervals (95% CIs) were calculated in this analysis. A bioinformatics study based on The Cancer Genome Atlas (TCGA) sequencing and microarray datasets was used to further validate the results of PD-L1 mRNA expression. Kaplan-Meier (KM) survival curves were performed to evaluate the prognostic effect of PD-L1 mRNA expression.

RESULTS

Twelve studies with 1630 ovarian cancers regarding PD-L1 immunohistochemical expression were identified. Meta-analysis showed that PD-L1 protein expression was not associated with tumor grade, clinical stage, lymph node status, tumor histology, overall survival (OS), and progression-free survival (PFS). TCGA data showed no association between PD-L1 mRNA expression and ovarian cancer. Further validation using microarray data suggested that no association between PD-L1 mRNA expression and OS was found in large independent patient cohorts (1310 cases). PD-L1 mRNA expression was significantly linked to worse PFS in 1228 patients with ovarian cancer (227458_at: HR = 1.55, 95% CI = 1.28-1.88, P < 0.001; 223834_at: HR = 1.41, 95% CI = 1.14-1.75, P = 0.0015).

CONCLUSIONS

Meta-analysis showed that PD-L1 may not be a prognostic factor for ovarian cancer. But a bioinformatics study showed that PD-L1 expression was significantly associated with worse PFS of ovarian cancer. More clinical studies are needed to further validate these findings.

Prognostic effect of programmed death-ligand 1 (PD-L1) in ovarian cancer: a systematic review, meta-analysis and bioinformatics study

BACKGROUND

The expression of PD-L1 has been reported in ovarian cancer. However, the prognostic role of PD-L1 expression in ovarian carcinoma remained controversial. This study was performed to assess the prognostic value of PD-L1 expression on ovarian cancer.

METHODS

The PubMed, Embase, EBSCO, and Cochrane Library databases were searched to identify available publications. The pooled odds ratio (OR) or hazard ratios (HRs: multivariate analysis) with their 95% confidence intervals (95% CIs) were calculated in this analysis. A bioinformatics study based on The Cancer Genome Atlas (TCGA) sequencing and microarray datasets was used to further validate the results of PD-L1 mRNA expression. Kaplan-Meier (KM) survival curves were performed to evaluate the prognostic effect of PD-L1 mRNA expression.

RESULTS

Twelve studies with 1630 ovarian cancers regarding PD-L1 immunohistochemical expression were identified. Meta-analysis showed that PD-L1 protein expression was not associated with tumor grade, clinical stage, lymph node status, tumor histology, overall survival (OS), and progression-free survival (PFS). TCGA data showed no association between PD-L1 mRNA expression and ovarian cancer. Further validation using microarray data suggested that no association between PD-L1 mRNA expression and OS was found in large independent patient cohorts (1310 cases). PD-L1 mRNA expression was significantly linked to worse PFS in 1228 patients with ovarian cancer (227458_at: HR = 1.55, 95% CI = 1.28-1.88, P < 0.001; 223834_at: HR = 1.41, 95% CI = 1.14-1.75, P = 0.0015).

CONCLUSIONS

Meta-analysis showed that PD-L1 may not be a prognostic factor for ovarian cancer. But a bioinformatics study showed that PD-L1 expression was significantly associated with worse PFS of ovarian cancer. More clinical studies are needed to further validate these findings.

PD-L1 and IDO expression in cervical and vulvar invasive and intraepithelial squamous neoplasias: implications for combination immunotherapy

AIMS

The immunoregulatory enzyme indoleamine dioxygenase 2,3 (IDO) has been implicated in cervical and vulvar squamous carcinomas (SCC) and may represent a mechanism of resistance to anti-PD-1/anti-PD-L1 therapy. However, the relationship between IDO and PD-L1 has not been well-investigated.

METHODS AND RESULTS

Sixty-five cases of cervical and vulvar intraepithelial neoplasia and SCC were assessed for IDO and PD-L1 expression. Overall, tumoral PD-L1 expression was seen in 72% of SCC, while 50% expressed IDO; co-expression was seen in 42%. Using the combined positive score (CPS) threshold of 1 to account for both tumoral and immune staining, 83% of SCC expressed PD-L1, 61% expressed IDO and 53% showed co-expression. Cervical SCCs were significantly more likely than human papillomavirus (HPV)-related vulvar SCCs to express tumoral IDO (75% versus 13%, P < 0.001) and demonstrate an IDO CPS ≥ 1 (88% versus 25%, P < 0.001); no significant differences were seen for PD-L1. Additionally, there were no significant differences in IDO and PD-L1 expression in dVIN-associated versus HPV-associated vulvar SCC. In contrast to SCC, the majority of intraepithelial lesions were entirely negative for tumoral PD-L1 and IDO and had a CPS score of <1.

CONCLUSIONS

In summary, IDO and PD-L1 co-expression is common in cervical SCCs and, to a lesser extent, vulvar SCCs. These data suggest a role for combination immunotherapy in a subset of cervical SCCs as well as select vulvar SCCs. Expression for both markers is less common in intraepithelial lesions, providing no strong support for this form of immunotherapy in the absence of invasion.

Indoleamine 2,3-Dioxygenase Expression Pattern in the Tumor Microenvironment Predicts Clinical Outcome in Early Stage Cervical Cancer

The indoleamine 2,3-dioxygenase (IDO) enzyme can act as an immunoregulator by inhibiting T cell function via the degradation of the essential amino acid tryptophan (trp) into kynurenine (kyn) and its derivates. The kyn/trp ratio in serum is a prognostic factor for cervical cancer patients; however, information about the relationship between serum levels and IDO expression in the tumor is lacking. IDO expression was studied in 71 primary and 14 paired metastatic cervical cancer samples by various immunohistochemical (IHC) techniques, including 7-color fluorescent multiparameter IHC, and the link between the concentration of IDO metabolites in serum, clinicopathological characteristics, and the presence of (proliferating) T cells (CD8, Ki67, and FoxP3) was examined. In addition, we compared the relationships between IDO1 and IFNG gene expression and clinical parameters using RNAseq data from 144 cervical tumor samples published by The Cancer Genome Atlas (TCGA). Here, we demonstrate that patchy tumor IDO expression is associated with an increased systemic kyn/trp ratio in cervical cancer (P = 0.009), whereas marginal tumor expression at the interface with the stroma is linked to improved disease-free (DFS) (P = 0.017) and disease-specific survival (P = 0.043). The latter may be related to T cell infiltration and localized IFNγ release inducing IDO expression. Indeed, TCGA analysis of 144 cervical tumor samples revealed a strong and positive correlation between IDO1 and IFNG mRNA expression levels (P < 0.001) and a significant association with improved DFS for high IDO1 and IFNG transcript levels (P = 0.031). Unexpectedly, IDO+ tumors had higher CD8⁺Ki67⁺ T cell rates (P = 0.004). Our data thus indicate that the serum kyn/trp ratio and IDO expression in primary tumor samples are not clear-cut biomarkers for prognosis and stratification of patients with early stage cervical cancer for clinical trials implementing IDO inhibitors. Rather, a marginal IDO expression pattern in the tumor dominantly predicts favorable outcome, which might be related to IFNγ release in the cervical tumor microenvironment.