Programmed Death Ligand Research Articles

ATR inhibition activates cancer cell cGAS/STING-interferon signaling and promotes antitumor immunity in small-cell lung cancer.

Patients with small-cell lung cancer (SCLC) have poor prognosis and typically experience only transient benefits from combined immune checkpoint blockade (ICB) and chemotherapy. Here, we show that inhibition of ataxia telangiectasia and rad3 related (ATR), the primary replication stress response activator, induces DNA damage-mediated micronuclei formation in SCLC models. ATR inhibition in SCLC activates the stimulator of interferon genes (STING)-mediated interferon signaling, recruits T cells, and augments the antitumor immune response of programmed death-ligand 1 (PD-L1) blockade in mouse models. We demonstrate that combined ATR and PD-L1 inhibition causes improved antitumor response than PD-L1 alone as the second-line treatment in SCLC. This study shows that targeting ATR up-regulates major histocompatibility class I expression in preclinical models and SCLC clinical samples collected from a first-in-class clinical trial of ATR inhibitor, berzosertib, with topotecan in patients with relapsed SCLC. Targeting ATR represents a transformative vulnerability of SCLC and is a complementary strategy to induce STING-interferon signaling-mediated immunogenicity in SCLC.

Lymphocyte Function in Tertiary Lymphoid Structures Predicts Hepatocellular Carcinoma Outcome

An increasing number of studies have revealed a correlation between tertiary lymphoid structures (TLSs) and the outcome of hepatocellular carcinoma (HCC). Nevertheless, the associations between the heterogeneity of cellular composition and the overall survival (OS) in HCC remain unexplored. Here, we evaluated the cancer tissues from 150 HCC individuals treated at the Tumor Hospital Affiliated with Nantong University using multiplex immunofluorescence to determine the presence and characteristics of TLS and to investigate the relationship between intra-TLS immunologic activity, TLS maturation, and intratumoral immune cell infiltration. Prognostic factors influencing the outcome were identified through both univariate and multivariate analyses. Additionally, the levels of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death 1, programmed death-ligand 1, and lymphocyte activation gene-3 were determined, as well as their relationship with TLS features were determined. TLS was detected in 71 (47.3%) of the 150 HCC cases and was related to higher intratumoral infiltration levels of lymphocytes. Additionally, intra-TLS lymphocyte proliferation correlated with that of intratumoral lymphocytes, and the presence of TLS and a high proportion of mature TLS demonstrated a significant correlation with better prognosis (P = .013 and P = .03, respectively). Among TLS-positive tumors, a high proportion of B cells expressing activation-induced cytidine deaminase and a high proportion of CD8+ T cells expressing CD45RO were significantly related to improved OS (P = .01 and P < .001, respectively). Comparatively, a high proportion of CD21+CD20+ B cells demonstrated a significant correlation with poorer OS (P < .002). A markedly reduced number of CTLA-4+ cells in the stromal regions in TLS-negative tumors was observed compared with TLS-positive tumors (P = .01). These findings reveal a correlation between TLS presence and improved OS in HCC patients. However, TLS exhibited significant variation in maturation state, T- and B-cell proliferation, and expression of markers related to B- and T-cell function. Notably, these characteristics were also found to possess prognostic significance, indicating that certain TLS might hinder tumor immunity by inhibiting immune cells, whereas others may foster antigen-driven immune responses, likely influenced by the composition and functional status of intra-TLS lymphocytes.

Adverse reactions of immune checkpoint inhibitors combined with Proton pump inhibitors: a pharmacovigilance analysis of drug-drug interactions

BackgroundCombining immune checkpoint and proton pump inhibitors is widely used in cancer treatment. However, the drug-drug interactions of these substances are currently unknown. This study aimed to explore drug-drug interactions associated with concomitant immune checkpoint and proton pump inhibitors.MethodsData were obtained from the US Food and Drug Administration Adverse Event Reporting System from 2014 to 2023. Disproportionality analysis was used for data mining by calculating the reporting odds ratios (RORs) with 95% confidence intervals (95%Cls). The adjusted RORs (RORadj) were then analysed using logistic regression analysis, considering age, sex, and reporting year. Drug-drug interactions occur when a combination treatment enhances the frequency of an event. Further confirmation of the robustness of the findings was achieved using additive and multiplicative models, which are the two statistical methodologies for signal detection of DDIs using spontaneous reporting system.ResultsThe total number of reports on immune checkpoint combined with proton pump inhibitors was 4,276. Median patient age was 66 years (interquartile range [IQR]: 60–74 years). Significant interaction signals were observed for congenital, familial and genetic disorders (RORadj = 2.66, 95%CI, 1.38–5.14, additive models = 0.7322, multiplicative models = 3.5142), hepatobiliary disorders (RORcrude = 6.64, 95%CI, 5.82–7.58, RORadj = 7.10, 95%CI, 6.16–8.18, additive models = 2.0525, multiplicative models = 1.1622), metabolism and nutrition disorders (RORcrude = 3.27, 95%CI, 2.90–3.69, RORadj = 2.66, 95%CI, 2.30–3.08, additive models = 0.6194), and skin and subcutaneous tissue disorders (RORcrude = 1.41, 95%CI, 1.26–1.58, RORadj = 1.53, 95%CI, 1.34–1.75, additive models = 0.6927, multiplicative models = 5.3599). Subset data analysis showed that programmed death-1 combined with proton pump inhibitors was associated with congenital, familial, and genetic disorders; hepatobiliary disorders; and skin and subcutaneous tissue disorders. Programmed death ligand-1 combined with proton pump inhibitors was associated with adverse reactions of metabolism and nutrition disorders. Cytotoxic T-lymphocyte antigen-4 combined with proton pump inhibitors was associated with congenital, familial, and genetic disorders, and skin and subcutaneous tissue disorders.ConclusionsBased on real-world data, four Standardized MedDRA Query System Organ Class toxicities were identified as drug-drug interactions associated with combining immune checkpoint and proton pump inhibitors. Clinicians should be cautious when administering these drugs concomitantly. Preclinical trials and robust clinical studies are required to explore the mechanisms and relationships underlying interactions, thus improving understanding of drug-drug interactions associated with this combination therapy.

Expression of Programmed Death Ligand 1 and Indoleamine 2,3-Dioxygenase in Oral Lichen Planus and Oral Lichenoid Lesions.

Oral lichen planus (OLP) and oral lichenoid lesions (OLL) are inflammatory T-cell mediated disorders of the oral mucosa (OM). Both are associated with an increased risk of oral squamous cell carcinoma, with OLL possibly having a higher rate of malignant transformation than OLP. Programmed death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase (IDO) are immunosuppressive molecules possessing inhibitory effect on T-cells and have been implicated in carcinogenesis. The aim of this study was to examine the expression of PD-L1 and IDO in OLP and OLL. Sixty-eight formalin-fixed, paraffin-embedded tissue samples diagnosed as OLP, compatible with OLP, or OLL were divided into OLP (n = 39) or OLL (n = 29) groups based on both clinical and histopathological diagnostic criteria. Samples of healthy OM (n = 9) served as controls. Samples were immunohistochemically stained for PD-L1 and IDO, and staining distribution and intensity were evaluated. Immunohistochemical expression of PD-L1 was increased in the basal and intermediate layers of epithelium in OLP and in lamina propria in both OLP and OLL compared to controls. OLP and OLL showed increased expression of IDO in epithelium and lamina propria compared to controls. PD-L1 staining intensity in the basal epithelial layer, and IDO staining intensity in lamina propria were increased in OLP compared to OLL. The results indicate that the expression of PD-L1 and IDO increases in OLP and OLL, suggesting that these molecules may play a role in the pathogenesis of both disorders.

Association between microsatellite instability status, clinicopathological features and mitochondrial DNA amplification in patients with colorectal cancer.

The relationship between BRAF-V600E mutations, mitochondrial DNA amplification and microsatellite instability-high (MSI-H) in colorectal cancer (CRC) has yet to be fully elucidated. The aim of the present study was to assess the association between the MSI status and BRAF-V600E gene mutations/clinicopathological features/mitochondrial DNA amplification in CRC. A non-interventional study analysis was performed using the clinicopathological features of 455 patients with CRC. Immunohistochemistry was used to evaluate four mismatch repair proteins (MutS homolog 2, MutS homolog 6, MutL homolog 1 and postmeiotic segregation increased 2), Ki-67 index, and programmed cell death protein 1 (PD-1) and programmed cell death-ligand 1 (PD-L1) expression. Additionally, PCR coupled with capillary electrophoresis were used to ascertain the MSI status. Moreover, amplification refractory mutation system-PCR was used to detect BRAF-V600E gene mutation and fluorescence in situ hybridization analysis was used to assess mitochondrial DNA. A total of 455 patients were divided into the MSI high (MSI-H) group (n=52) and microsatellite stability (MSS) group (n=403) based on their MSI status. Compared with the results of immunohistochemistry of four mismatch repair proteins, the consistency rate between mismatch repair protein deficiency and MSI was 94.23%. There were significant differences in PD-L1, primary tumor site, clinical stage, degree of differentiation, tumor size, lymph node metastasis and the occurrence of multiple primary tumors between the MSI-H group and MSS group (P<0.05 or P<0.001). However, there were no significant differences for sex, age, PD-1, Ki-67 expression and BRAF-V600E. The 24-60-month survival rate of the patients in the MSI-H group was significantly higher than that of those in the MSS group (P<0.05). Furthermore, the number of mitochondrial DNA was significantly amplified in the MSI-H group. In conclusion, the present study demonstrated that the combined detection of PD-L1 and MSI in patients with CRC can provide more accurate and effective guidance for personalized treatment.

Claudin-9 (CLDN9) promotes gastric cancer progression by enhancing the glycolysis pathway and facilitating PD-L1 lactylation to suppress CD8+ T cell anti-tumor immunity

BackgroundGastric cancer (GC) is a common malignancy characterized by the absence of reliable prognostic indicators and effective therapeutic targets. Claudin-9 (CLDN9) has been demonstrated to be upregulated in various cancers. However, its prognostic value, biological function, and regulatory mechanisms in GC remain unclear. Therefore, this study aimed to elucidate the role of CLDN9 in GC progression and its underlying mechanisms. MethodsWe utilized consensus cluster, random survival forest, and multivariate Cox regression analyses to identify CLDN9 in GC. Subsequently, we evaluated the mRNA and protein levels of CLDN9 in GC using quantitative real-time polymerase chain reaction (PCR) (qRT-PCR), western blotting (WB), and immunohistochemistry (IHC). Furthermore, the role of CLDN9 in GC progression was investigated using a series of functional in vivo and in vitro experiments. Finally, we elucidated the molecular mechanisms of CLDN9 using bioinformatics, molecular biology, animal models, and patient tissue specimens. ResultsTwo GC subtypes with survival and functional differences were identified based on glycolytic metabolic genes in the Cancer Genome Atlas (TCGA)- Stomach adenocarcinoma (STAD) dataset. A prognostic risk score was calculated using seven genes to assess the overall survival (OS) in GC. Using random survival forest and multivariate Cox analyses, we identified CLDN9 as the key gene linked to the glycolytic subtype and prognosis of GC. CLDN9 expression was significantly upregulated in patients with GC as well as in GC cells. CLDN9 knockdown inhibited tumor proliferation, invasion, and metastasis both in vivo and in vitro. Mechanistically, CLDN9 was found to regulate lactate dehydrogenase A (LDHA) expression and promote glycolytic metabolism by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/hypoxia-inducible factor 1-alpha (HIF1α) signaling pathway. Additionally, lactate, a glycolytic metabolite, enhanced programmed cell death ligand 1 (PD-L1) lactylation and stability, which suppressed anti-tumor immunity in CD8+ T cells, thereby contributing to GC progression. ConclusionsCLDN9 expression is associated with GC development and progression. Mechanistically, CLDN9 enhances the glycolysis pathway and facilitates PD-L1 lactylation through the PI3K/AKT/HIF1α signaling pathway, thereby suppressing anti-tumor immunity in CD8+ T cells. CLDN9 has the potential to serve as a novel prognostic marker and therapeutic target for GC.

Evaluation of PD-1 and interleukin-10-receptor expression by T lymphocytes in malignant and benign pleural effusions

PD-1 (programmed cell death protein-1)/PD-L1 (programmed cell death ligand 1) as well as IL-10 (interleukin-10)/IL-10R (interleukin-10 receptor) interactions play a major role in tumor immune evasion in various malignancies. Several studies investigated the expression of PD-1 on T lymphocytes in pleural effusions (PE) in patients with malignant diseases. However, results in malignant pleural effusions (MPE) compared to benign PE (BPE) are underreported. In this prospective study, 51 patients (median age 66 years, IQR 54–78, 47% male) with PE of malignant or benign origin at the Medical University of Vienna between March 2021 and November 2022 were enrolled and divided into three groups according to the cytological results (group 1: MPE [n = 24, 47%]; group 2: BPE in malignant disease [n = 22, 43%]; group 3: BPE in benign disease [n = 5, 10%]). In the cytological samples, T cells were analyzed for the expression of PD-1 and IL-10R via flow cytometry. In MPE, the proportion of PD-1+ T lymphocytes on CD4+ cells was significantly lower than in BPE (40.1 vs. 56.3 in group 1 vs. 3, p = 0.019). Moreover, a significantly lower expression of PD-1+ IL-10R+ CD8+ (9.6 vs. 35.2 in group 1 vs. 2, p = 0.016; 9.6 vs. 25.0 in group 1 vs. 3, p = 0.032) and a significantly higher expression of PD-1-IL-10R-CD8+ T lymphocytes (43.7 vs. 14.0 in group1 vs. 2, p = 0.045; 43.7 vs. 23.3 in group 1 vs. 3, p = 0.032) were observed in MPE when compared to BPE. The frequency of T cells expressing PD-1 and IL-10R on CD8+ T cells is significantly lower in MPE compared to BPE regardless of the underlying disease indicating a different microenvironment in PE driven by the presence of tumor cells. Our observation spotlights the possible involvement of PD-1 and IL-10R in MPE.

Gamabufotalin loaded micro-nanocomposites for multimodal therapy of metastatic TNBC by efficiently inducing ICD

Gamabufotalin (CS-6), a main active compound derived from Chinese medicine Chansu, exhibits a robust inhibitory effect on programmed death-ligand 1 (PD-L1) in triple-negative breast cancer (TNBC) cells. Despite its potential for tumor therapy, the medical application of CS-6 is constrained by its hydrophobic nature, lack of targeting capability, and weak immunogenic cell death (ICD) effect. To address these limitations and improve the therapeutic efficiency of this drug against metastatic TNBC, we designed a new kind of CS-6@CPB-S.lux that integrates carboxy-Prussian blue nanoparticles (CPB NPs), CS-6, and attenuated Salmonella typhimurium (S.lux) for TNBC therapy. In vitro and in vivo results have confirmed that CS-6@CPB NPs were efficiently delivered to neoplastic tissue by the tumor hypoxic chemotaxis property of S.lux, wherein the nanomedicine induced significant tumor cell necroptosis and apoptosis via photothermal therapy (PTT) of CPB NPs and chemotherapy of CS-6, which elicited ICD and inhibited PD-L1 expression, resulting in dendritic cells (DCs) maturation and effector T cells activation to comprehensively eliminate tumors. Additionally, the CS-6@CPB-S.lux + Laser treatment significantly transformed the immunosuppressive tumor microenvironment (TME), enhancing antitumor immunity through promoting the polarization of tumor-associated macrophages into antitumorigenic M1 and reducing Tregs recruitment. Consequently, this comprehensive therapy not only inhibited primary and abscopal tumor progression but also prevented TNBC metastasis, which significantly prolonged survival time in animal models. In summary, these findings indicated an alternative approach for metastatic TNBC therapy.

Immunotherapy in Basal Cell Carcinoma.

Basal cell carcinoma (BCC) is the most frequent of all cancers, with an increasing incidence. The first line therapy is surgical excision, but topical therapies can be used in low-risk superficial BCCs, while the more advanced, unresectable, or metastatic BCCs benefit from systemic therapies with hedgehog inhibitors and immunotherapy. The purpose of this review is to highlight local and systemic immunotherapies and their efficacy in the management of BCCs. Local therapies can be considered in superficial and low-risk nodular BCCs, with imiquimod frequently used for its antitumor and immunoregulatory properties. Imiquimod alone demonstrated higher histological clearance rates, but patients treated with imiquimod experienced more adverse events than ones treated with other therapies. Imiquimod can be used as an adjuvant before Mohs micrographic surgery and can also be combined with other local therapies, like curettage, electrodesiccation, cryosurgery, and photodynamic therapy, with some treatment methods yielding results comparable with the surgery. Interferons and Interleukin-2 were evaluated in a small number of studies with different results. Systemic immunotherapies with programmed death-ligand 1 (PD-L1) inhibitors showed inconsistent results in patients with advanced BCCs, being effective in some patients that progressed on or were intolerant to hedgehog pathway inhibitors (HHI).

Specific isolation and quantification of PD-L1 positive tumor derived exosomes for accurate breast cancer discrimination via aptamer-functionalized magnetic composites and SERS immunoassay

PD-L1 positive tumor derived exosomes (TEXsPD−L1) play a significant role in disease progression, tumor metastasis and cancer immunotherapy. However, the overlap of PD-L1 between TEXs and non-tumor derived exosomes (non-TEXs) restricts the specific isolation and quantification of TEXPD−L1 from clinical samples. Herein, a new aptamer-functionalized and hydrophilic immunomagnetic substrate was designed by decorating generation 5 polyamidoamine dendrimers (G5 PAMAM), zwitterionic trimethylamine N-oxide (TMAO) and EpCAM (Epithelial cell adhesion molecule) aptamers on magnetic cores sequentially (Fe3O4@PAMAM@TMAO@Aptamer, named as FPTA) for rapid target and efficient capture of TEXs. The FPTA substrate gathered excellent characters of strong magnetic responsiveness of Fe3O4, abundant affinity sites of PAMAM, strong hydrophilicity of TMAO and enhanced affinity properties of EpCAM aptamers. Because of these advantages, FPTA can isolate TEXs quickly within 30min with high capture efficiency of 90.5 % ± 3.0 % and low nonspecific absorption of 8.2 % ± 2.0 % for non-TEXs. Furthermore, PD-L1 (Programmed cell death-ligand 1) positive TEXs (TEXsPD−L1) from the captured TEXs were recognized and quantitatively analyzed by utilizing SERS (surface-enhanced Raman spectroscopy) reporter molecules 4-NTP (4-Nitrothiophenol) on PD-L1 aptamers-functionalized gold immunoaffinity probe. The signal of TEXsPD−L1 was converted to SERS signal of 4-NTP at 1344 cm−1 which exhibited a linear correlation to concentration of TEXsPD−L1(R2 = 0.9905). With these merits, this strategy was further applied to clinical plasma samples from breast cancer (BC) patients and healthy controls (HC), exhibited an excellent diagnosis accuracy with area under curve (AUC) of receiver operating characteristic (ROC) curve reaching 0.988. All these results demonstrate that the FPTA immunomagnetic substrate combined with SERS immunoaffinity probe may become a generic tool for specific isolation and quantitative analysis of PD-L1 positive tumor-derived exosomes in clinics.

Distinct characteristics of BTLA/HVEM axis expression on Tregs and its impact on the expansion and attributes of Tregs in patients with active pulmonary tuberculosis.

Pulmonary tuberculosis (PTB) remains one of the deadliest infectious diseases. Understanding PTB immunity is of potential value for exploring immunotherapy for treating chemotherapy-resistant PTB. CD4+CD25+Foxp3+ regulatory T cells (Tregs) are key players that impair immune responses to Mycobacteria tuberculosis (MTB). Currently, the intrinsic factors governing Treg expansion and influencing the immunosuppressive attributes of Tregs in PTB patients are far from clear. Here, we employed flow cytometry to determine the frequency of Tregs and the expression of B and T lymphocyte attenuator (BTLA) and its ligand, herpesvirus entry mediator (HVEM), on Tregs in patients with active PTB. Furthermore, the expression of conventional T cells and of programmed death-ligand 1 (PD-L1) and programmed death-1 (PD-1) on Tregs in patients with active PTB was determined. We then examined the characteristics of BTLA/HVEM expression and its correlation with Treg frequency and PD-L1 and PD-1 expression on Tregs in PTB patients. The frequency of Tregs was increased in PTB patients and it had a relevance to PTB progression. Intriguingly, the axis of cosignal molecules, BTLA and HVEM, were both downregulated on the Tregs of PTB patients compared with healthy controls (HCs), which was the opposite of their upregulation on conventional T cells. Unexpectedly, their expression levels were positively correlated with the frequency of Tregs, respectively. These seemingly contradictory results may be interpreted as follows: the downregulation of BTLA and HVEM may alleviate BTLA/HVEM cis-interaction-mediated coinhibitory signals pressing on naïve Tregs, helping their activation, while the BTLA/HVEM axis on effector Tregs induces a costimulatory signal, promoting their expansion. Certainly, the mechanism underlying such complex effects remains to be explored. Additionally, PD-L1 and PD-1, regarded as two of the markers characterizing the immunosuppressive attributes and differentiation potential of Tregs, were upregulated on the Tregs of PTB patients. Further analysis revealed that the expression levels of BTLA and HVEM were positively correlated with the frequency of PD-1+Tregs and PD-L1+Tregs, respectively. Our study illuminated distinct characteristics of BTLA/HVEM axis expression on Tregs and uncovered its impact on the expansion and attributes of Tregs in patients with active PTB. Therefore, blockade of the BTLA/HVEM axis may be a promising potential pathway to reduce Treg expansion for the improvement of anti-MTB immune responses.

Real-World Outcomes in Patients with Advanced Penile Squamous Cell Carcinoma Receiving Immune Checkpoint Inhibitors: A Single Institution Experience

ABSTRACT Introduction Advanced penile squamous cell carcinoma (pSCC) is a rare and aggressive malignancy with a poor prognosis and an unmet need for biomarkers. We performed a retrospective evaluation of real-world efficacy, safety outcomes, and baseline inflammatory biomarkers in patients with advanced pSCC treated with immune checkpoint inhibitors (ICIs). Methods We performed a retrospective review of patients with advanced pSCC who received ICIs from 2012 to 2023 at the Winship Cancer Institute of Emory University in Atlanta, GA. Demographics, disease characteristics, and optimal cutoffs of baseline biomarkers obtained before ICI initiation were described. Human papillomavirus (HPV)/p16+ status was determined by immunohistochemistry. Programmed death-ligand 1 (PD-L1) positivity was defined as &amp;gt;1%. Immune-related adverse events (irAEs) were graded per Common Terminology Criteria for Adverse Events criteria and captured through clinical documentation. Clinical benefit was defined as complete response, partial response, or stable disease based on Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Overall survival (OS) and progression-free survival (PFS) were assessed by Kaplan-Meier method and univariate Cox regression (UVA) using a significance level set at p &amp;lt; 0.05. Neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), platelet-to-lymphocyte (PLR), and neutrophil-to-eosinophil ratios (NER) were collected from complete blood count data. Results Twenty-one patients were included of whom 71.4% were White and 28.6% were Black. Median age at ICI initiation was 56 years (38–76 years). Most patients had Eastern Cooperative Oncology Group performance status ≥2 (61.9%). At diagnosis, 4.8%, 33.3%, and 61.9% were stage 2, 3, and 4, respectively, of whom eight patients had initial distal metastases. Of patients with available data, 7 of 11 patients (63.6%) were PD-L1+ and 8 of 9 (89%) patients were HPV+. Median follow-up was 8.4 months and median time to ICI treatment from diagnosis was 15.6 months. ICI was first line (1L) in 1 patient (4.8%), 2L in 13 (61.9%), 3L in 6 (28.6%), and 4L in 1 (4.8%). Five patients achieved clinical benefit of whom three had partial response and two had stable disease. Median OS was 8.2 months (95% CI, 2.3–15.7) and PFS was 1.9 months (95% CI, 1.3–3.2). Notably, three patients with PD-L1 positivity, microsatellite instability (MSI)-high, or high tumor mutational burden (TMB) demonstrated response to ICI. Higher baseline NLR (hazard ratio, 10.0; 95% CI, 2.73–54.2) at optimal cutoff was associated with shorter OS and PFS on UVA. Three patients (14.3%) developed grade 3/4 ICI-related adverse events. Conclusions Our real-world analysis summarizes our institutional experience and provides granular clinical and molecular attributes of patients with therapeutic response, which may aid in patient stratification within ICI-based clinical trials. Overall, we confirm poor response rates of pSCC to ICI in an unselected approach, consistent with multicenter studies. ICIs may be effective and tolerable therapy in a subset of patients. NLR may be a potential biomarker to assess ICI response in pSCC.

Sarcopenia predicts immune-related adverse events due to anti-PD-1/PD-L1 therapy in patients with advanced lung cancer.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of a number of patients with advanced cancer, and while this has resulted in increased survival times, it has also led to the emergence of novel immune-related adverse events (irAEs). In individuals with advanced cancer, sarcopenia is a significant symptom of cachexia and is linked to poor nutritional status and increased mortality. The present study aimed to evaluate sarcopenia and other risk variables that can affect the emergence of irAEs in patients with lung cancer. A single-center retrospective analysis of 129 patients with advanced lung cancer treated with programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) checkpoint inhibitors was conducted from August 2020 to August 2022. Data on baseline characteristics and adverse events of participants were collected. Computed tomography was used to determine the skeletal muscle index at the third lumbar vertebra (L3-SMI) and whether sarcopenia is present. The median age of all participants was 60 years old (range, 52-66 years), with men accounting for 68.9% of the total patient cohort. The present study showed that 44 (34%) participants presented with any degree of irAEs, and 79 (61.2%) patients presented with sarcopenia. There were no statistically significant differences in baseline characteristics, such as age and sex, between patients who presented with irAEs and those without irAEs. Using logistic regression analysis, individuals with sarcopenia were 2.635-times more likely to experience any grade of irAEs than those without sarcopenia. irAEs are prevalent side effects of PD-1/PD-L1 inhibitor therapy for patients with cancer. By diagnosing and treating sarcopenia early, it is possible to lower the potential risk of irAEs in patients with advanced cancer. Furthermore, sarcopenia can be utilized as a predictor of irAEs.

The Importance of Predictive Biomarkers and Their Correlation with the Response to Immunotherapy in Solid Tumors-Impact on Clinical Practice.

Background/Objectives: Immunotherapy has changed the therapeutic approach for various solid tumors, especially lung tumors, malignant melanoma, renal and urogenital carcinomas, demonstrating significant antitumor activity, with tolerable safety profiles and durable responses. However, not all patients benefit from immunotherapy, underscoring the need for predictive biomarkers that can identify those most likely to respond to treatment. Methods: The integration of predictive biomarkers into clinical practice for immune checkpoint inhibitors (ICI) holds great promise for personalized cancer treatment. Programmed death ligand 1 (PD-L1) expression, tumor mutational burden (TMB), microsatellite instability (MSI), gene expression profiles and circulating tumor DNA (ctDNA) have shown potential in predicting ICI responses across various cancers. Results: Challenges such as standardization, validation, regulatory approval, and cost-effectiveness must be addressed to realize their full potential. Predictive biomarkers are crucial for optimizing the clinical use of ICIs in cancer therapy. Conclusions: While significant progress has been made, further research and collaboration among clinicians, researchers, and regulatory institutes are essential to overcome the challenges of clinical implementation. However, little is known about the relationship between local and systemic immune responses and the correlation with response to oncological therapies and patient survival.

Abstract C149: Relationship between PD-L1 expression and clinicopathological characteristics in Hispanic/ Latino women with breast cancer

Abstract Background: Programmed death ligand 1 (PD-L1) expression in breast cancer serves as a prognostic marker, particularly in aggressive subtypes like triple-negative breast cancer (TNBC), where it helps in predicting response to immune checkpoint inhibitors and guides immunotherapy use. Although several studies have assessed the prevalence of PD-L1 expression in breast cancer, data from the Hispanic population, especially in Latin American countries, is lacking. This study evaluates PD-L1 expression and its correlation with pathological features in Colombian women. Methods: Women with breast cancer tested for PD-L1 were selected from the archives of the Oncologic Pathology Department at the National Cancer Institute of Colombia from September 2021 to May 2024. Information from their pathology reports was extracted, and correlation analyses were carried out using Fisher's exact test Results: A total of 60 reports were screened, comprising 56 cases of ductal invasive breast carcinoma and 1 case of lobular invasive breast carcinoma. 48 individuals were tested using the PD-L1 22C3 antibody, with 41.67% of them being positive for PD-L1 expression. Among the 48 tumors tested with 22C3, 35 cases were classified as TNBC, and 13 cases corresponded to luminal B subtype with a low positive expression (1-10%) of estrogen receptors. The percentage of positive PD-L1 cases was 37.14% for TNBC and 53.85% for the luminal B subtype. Furthermore, 5 HER2-low cases were identified with 2 of them being positive for PD-L1 expression. In the correlation analyses, PD-L1 positive expression was significantly associated with a more aggressive histologic grade compared to PD-L1 negative tumors (p = 0.007). No significant association was found between PD-L1 expression and HR, HER2, or KI67 status, nor with age, necrosis, lymphovascular involvement, perineural invasion, desmoplastic response, or immune cell infiltration. Among the 12 individuals tested for PD-L1 with the SP142 antibody, none showed positive expression, precluding correlation analyses. Conclusion: This study highlights a significant association between PD-L1 expression and aggressive histologic grade in Colombian women with breast cancer. The findings underscore the potential of PD-L1 as a prognostic marker and its relevance in guiding immunotherapy in this population. Further research is needed to explore PD-L1 expression in broader Hispanic groups to better understand its clinical implications. Citation Format: Daniel Mendivelso-González, Patricia López- Correa, Nicolás Prada-Aceros, Alfredo E Romero-Rojas, Rafael Parra-Medina. Relationship between PD-L1 expression and clinicopathological characteristics in Hispanic/ Latino women with breast cancer [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C149.

Abstract C067: Immune thrombocytopenia induced by PD-1/PD-L1 inhibitors in a patient with non-small cell lung adenocarcinoma: A case report and literature review

Abstract Introduction: The introduction of immunotherapy, particularly programmed cell death protein 1 (PD-1) and programmed cell death-ligand 1 (PD-L1) inhibitors, has transformed the treatment paradigm for non-small cell lung adenocarcinoma (NSCLC), significantly improving patient survival rates. However, alongside their immune-activating effects, these agents can also lead to immune-related adverse events (irAEs), affecting various organ systems. Among these, immune thrombocytopenia (ITP) is a rare but potentially life-threatening complication characterized by the destruction of platelets by autoantibodies, resulting in decreased platelet counts and an increased risk of bleeding. While ITP has been identified as a complication of immunotherapy, particularly PD-1 or PD-L1 inhibitors, its incidence, clinical presentation, and management remain poorly understood. Case Presentation: The 73-year-old female with stage IIIA poorly differentiated NSCLC who received chemotherapy with Taxol/Carboplatin and concurrent radiation therapy followed by a right upper lobectomy, initiated on immunotherapy with durvalumab, a PD-L1 inhibitor, developed severe thrombocytopenia (grade 4) after receiving two cycles of durvalumab. Despite steroid treatment, her condition persisted, indicating immune-related adverse events (irAEs). After confirming the diagnosis through further investigation, including molecular analysis, the patient was treated with intravenous immunoglobulin (IVIG), which significantly increased her platelet counts. Durvalumab was discontinued, and fostamatinib, a spleen tyrosine kinase (SYK) inhibitor, was initiated to manage the irAEs effectively. Discussion: ITP is recognized as an immune-related adverse event (irAE) associated with PD-1 or PD-L1 inhibitors, although it remains rare and poorly understood. Several case reports have highlighted the occurrence of ITP induced by these inhibitors, demonstrating varied clinical presentations and responses to treatment. Mechanisms underlying ITP induction by PD-1/PD-L1 inhibitors are not fully elucidated but may involve immune dysregulation, including CD4+ and CD8+ T cell activation, production of antiplatelet antibodies, and increased expression of PD-L1 on platelets. Management strategies for ITP induced by PD-1/PD-L1 inhibitors include steroids, intravenous immunoglobulin (IVIG) therapy, recombinant human thrombopoietin (TPO), interleukin-6 (IL-6) receptor antagonists, and immunosuppressive agents. However, the effectiveness of these treatments varies among patients, highlighting the need for individualized approaches and further research to optimize management strategies. Conclusion: The prompt recognition and management of ITP induced by PD-1/PD-L1 inhibitors are essential for ensuring favorable patient outcomes. Further research is needed to understand the underlying mechanisms and develop effective prevention and management strategies for this rare but serious immune-related adverse event. Citation Format: Aliya M Khan, Richa Dawar. Immune thrombocytopenia induced by PD-1/PD-L1 inhibitors in a patient with non-small cell lung adenocarcinoma: A case report and literature review [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C067.

Concordance of PD-L1 Expression in Metastatic Triple-negative Breast Cancer Between the 22C3 and E1L3N Antibodies Using Combined Positive Scoring.

For patients with metastatic triple-negative breast cancer (TNBC), treatment with pembrolizumab is dependent on the accurate determination of programmed death ligand 1 (PD-L1) expression using immunohistochemistry (IHC). This study evaluated the interobserver concordance in assessing PD-L1 expression on TNBC samples using the commercial 22C3 IHC assay and an in-house assay based on the E1L3N antibody. Concordance between the 22C3 and the E1L3N IHC assays was evaluated on TNBC samples read by a commercial laboratory and a Brigham and Women's Hospital breast pathologist (BWH reader). Each slide was given a PD-L1 combined positive score (CPS) and was considered PD-L1 positive or negative based on the CPS cutoff of 10. Interobserver concordance for the assays was also evaluated on a subset of samples between 2 and 3 independent readers. On 71 samples, 2 independent readers (1 BWH reader and commercial laboratory) using E1L3N and 22C3, respectively, reached agreement on PD-L1 status (positive/negative) on 64 samples (90.1%). Using 22C3, 2 independent readers reached agreement on PD-L1 status on 30 of 36 samples (83.3%), and 3 independent readers reached agreement on 16 of 27 samples (59.3%). Using E1L3N, 2 BWH readers reached agreement on PD-L1 status on 18 of 27 samples (66.7%). Three BWH readers reached an agreement on 2 of 12 of the most challenging samples (16.7%). In conclusion, concordance between E1L3N and 22C3 testing using CPS for PD-L1 in metastatic TNBC was >90%. However, certain cases were challenging to agree upon using current threshold criteria, highlighting the need for more standardized evidence-based methods to assess PD-L1 expression.

CD38 symmetric dimethyl site R58 promotes malignant tumor cell immune escape by regulating the cAMP-GSK3β-PD-L1 axis

In recent years, immunotherapy has emerged as an effective approach for treating tumors, with programmed cell death ligand 1 (PD-L1)/programmed cell death protein-1 (PD-1) immune checkpoint blockade (ICB) being a promising strategy. However, suboptimal therapeutic efficacy limits its clinical benefit. Understanding the regulation mechanism of PD-L1 expression is crucial for improving anti-PD-L1/PD-1 therapy and developing more effective tumor immunotherapy. Previous studies have revealed that resistance to PD-L1/PD-1 blockade therapy arises from the upregulation of CD38 on tumor cells induced by ATRA and IFN-β, which mediates the inhibition of CD8+ T cell function through adenosine receptor signaling, thereby promoting immune evasion.Yet, the precise role of CD38 in regulating PD-L1 on malignant tumor cells and its impact on CD8+ T cells through PD-L1 remain unclear. Here, we demonstrate that CD38 is highly expressed in malignant tumors (lung cancer, nasopharyngeal carcinoma, cervical cancer) and upregulates PD-L1 protein expression, impairing CD8+ T cell function. Mechanistically, CD38 phosphorylates GSK3β via the adenosine-activated cAMP-PKA signaling pathway, leading to GSK3β inactivation and enhanced PD-L1 stability and expression, facilitating tumor immune escape. Furthermore, we identify PRMT5 as a novel CD38-interacting molecule that symmetrically dimethylates CD38 arginine position 58, augmenting PD-L1 stability and expression through the ADO-cAMP-GSK3β signaling axis. This inhibits CD8+ T cell-mediated tumor cell killing, enabling tumor cells to evade immune surveillance. Our findings suggest that targeting the CD38 R58 site offers a new avenue for enhancing anti-PD-L1/PD-1 therapy efficacy in tumor treatment.

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of Type 1 Diabetes.

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death-1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesized that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death. Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry, and ELISA. EV PD-L1: PD-1 binding was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8 T cells. Plasma EV and soluble PD-L1 were assayed in plasma of individuals with islet autoantibody positivity (Ab+) or recent-onset type 1 diabetes and compared to non-diabetic controls. PD-L1 protein colocalized with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. 24-h IFN-α or IFN-γ treatment induced a two-fold increase in EV PD-L1 cargo without a corresponding increase in number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8 T cells. Plasma EV PD-L1 levels were increased in islet Ab+ individuals, particularly in those with single Ab+, Additionally, in from individuals with either Ab+ or type 1 diabetes, but not in controls, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV-PD-L1 could be protective for residual beta cell function. IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8 T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in islet autoantibody positive patients compared to controls. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Cutaneous Basal Cell Carcinoma In Situ: A Review of the World Literature.

Cutaneous basal cell carcinoma (BCC) in situ is a recently recognized subtype of the skin neoplasm in which the abnormal cells are confined to the epidermis. BCC in situ of the skin was previously referred to as a superficial BCC. A review of the world literature has revealed 10 cutaneous BCCs in situ that have been described in nine patients but likely reflect a more general phenomenon. The neoplasm typically presents as an asymptomatic red plaque on the abdomen, upper extremity, back, and chest. Pathologic changes frequently show confluent tumor cells along the epidermal basal layer or superficial aggregates of neoplastic cells that are contiguous with the epidermis and extend into the dermis. Genomic evaluation has been performed in neoplasms from one individual with cutaneous BCC in situ and metastatic BCC; like other variants of BCC, an aberration of the PTCH1 gene was observed. In contrast to his liver metastasis, the in situ carcinoma had a lower tumor mutational burden, lacked programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2) amplification and had a distinct PTCH1 mutation, suggesting that the in situ BCC of his skin and the metastatic BCC of his liver were derived from different clones of cells.