Blood Of Lung Cancer Patients Research Articles

B-356 Siemens CYFRA 21-1: an assay for measurement of cytokeratin fragment 21-1

Abstract Background Cytokeratins are structural proteins forming the subunits of epithelial intermediary filaments. The soluble fragment of cytokeratin 19, cytokeratin fragment 21-1 (CYFRA 21-1), can be found in the blood of lung cancer patients, primarily those with non-small cell lung cancer (NSCLC). CYFRA 21-1 is the preferred biomarker in the management of NSCLC, particularly squamous cell and large cell carcinoma subtypes. An assay for CYFRA 21-1 on Siemens ADVIA Centaur® XPT and Siemens Atellica® IM (Siemens CYFRA) is being developed and analytical performance is being presented. Methods The Siemens CYFRA 21-1 assay (in development) is a one-step chemiluminescent microparticle immunoassay (CMIA) for the quantitative determination of CYFRA 21-1 in human serum and plasma. The specimen is incubated with paramagnetic microparticles coated with the monoclonal antibody (mAb) BM19.21 and acridinium-labeled mAb KS19.1 conjugate on the Siemens ADVIA Centaur XPT System and Siemens Atellica IM System. After incubation and washing, Acid and Base reagents are added. The resulting relative light units (RLUs) are directly proportional to the amount of CYFRA 21-1 in the sample allowing for the quantitative determination of CYFRA 21-1 in the specimen. Results The following performance were determined using 3 unique lots of reagents and calibrators with the calibration range for the assay being 0.00 to 100.00 ng/mL. For the ADVIA Centaur XPT and Atellica IM systems were shown to be equivalent within 4%. The limit of blank (LoB), limit of detection (LoD), and limit of quantitation at 20% CV (LoQ) were determined and met the goal of ≤ 1.00 ng/mL. Linearity according to CLSI EP06 Ed2 was demonstrated for a range of 0.66 through 100.00 ng/mL. A Precision study of 2 controls and 5 panels spanning the range of the assay demonstrated a total %CV ≤ 8% at all levels. In the sample tube type study, a matrix comparison of 61 matched serum and plasma samples were evaluated. Passing-Bablock slopes of < 5% and r > 0.99 were observed when evaluating samples within the measurement range for plasma (LiHep, LiHep separator, K2EDTA and K3EDTA) tubes and serum separator tubes (SST) compared to the Red Top serum samples. Six endogenous substances were evaluated for interference in the CYFRA 21-1 assay. The average percent difference between test and control samples for all endogenous interferents was < 10%. Percent difference in the presence of 20 potentially interfering drugs was ≤ 4.0%. Conclusions The Siemens CYFRA 21-1 assay currently in development is a sensitive and precise assay for the quantitative determination of CYFRA 21-1 in human serum and plasma.

Circulating RKIP and pRKIP in Early-Stage Lung Cancer: Results from a Pilot Study

Background: Lung cancer (LC) is the leading cause of cancer-related deaths. Although low-dose computed tomography (LD-CT) reduces mortality, its clinical use is limited by cost, radiation, and false positives. Therefore, there is an urgent need for non-invasive and cost-effective biomarkers. The Raf Kinase Inhibitor Protein (RKIP) plays a crucial role in cancer development and progression and may also contribute to regulating the tumor–immune system axis. This protein has recently been described in biological fluids. Therefore, we conducted a pilot case–control study to assess RKIP and phosphorylated RKIP (pRKIP) levels in the urine and blood of LC patients. Methods: A novel enzyme linked immunosorbent assay (ELISA) assay was used to measure RKIP and pRKIP levels in urine and blood samples of two cohorts of LC patients and healthy controls (HSs). Furthermore, the biomarkers levels were correlated with tumor characteristics. Results: Serum, but not urine, levels of RKIP were significantly elevated in LC patients, distinguishing them from low- and high-risk healthy subjects with 93% and 74% accuracy, respectively. The RKIP/pRKIP ratio (RpR score) showed an accuracy of 90% and 79% in distinguishing LC patients from HS and HR-HS, respectively. Additionally, the RpR score correlated better with dimension, stage, and lymph node involvement in the tumor group. Conclusions: The serum RKIP and pRKIP profile may be a promising novel biomarker for early-stage LC.

Detection of Circulating Tumor Cells and EGFR Mutation in Pulmonary Vein and Arterial Blood of Lung Cancer Patients Using a Newly Developed Immunocytology-Based Platform.

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are powerful molecular targeted therapeutic agents for lung cancer. We recently developed an original immunocytology and glass slide-based circulating tumor cell (CTC) detection platform for both CTC enumeration and EGFR mutation analysis with DNA extracted from CTCs. Using this platform, we conducted a pilot clinical study for CTC enumeration in peripheral blood (PB), pulmonary arterial blood (PA), and pulmonary venous blood (PV) from 33 patients with lung cancer (Stage I-III) who underwent surgery, followed by digital PCR-based EGFR mutation analysis of CTCs in PV from 12 patients. The results showed that CTC levels were significantly higher in PV and PA than in PB (p < 0.05, p < 0.01. respectively), with a notably greater number of small and large CTC clusters (p < 0.01). Genetic analysis of EGFR mutations of CTCs from PV (n = 12) revealed six mutations, including three Exon19del and three L856R, in CTCs and eight EGFR mutations, including five Exon19del and three L856R, in lung tumor tissue. CTC mutation status matched that of tissue samples in nine patients, was unmatched in two patients, and controversial in one patient, indicating a sensitivity of 0.75 (6/8) and specificity of 1.0 (4/4) with some false-negative results for the mutation analysis of CTCs. This immunocytology-based CTC detection platform is a convenient method for detecting both CTC number and EGFR mutation status under microscopy, suggesting its potential as a liquid biopsy tool in the hospital for patients with lung cancer in some clinical settings.

Mitochondrial Dynamics in Non-Small Cell Lung Cancer.

In lung cancer patients, two complementary abnormalities were found that can cause disruption of the mitochondrial network: increased fusion and impaired fission, manifested by reduced levels of FIS1, a mitochondrial division regulator, and increased expression of MFN1, a mitochondrial fusion mediator. Immunoexpression studies of MFN1 and FIS1 proteins were performed in serum samples obtained from 47 patients with non-small cell lung cancer (NSCLC) and 21 controls. In the NSCLC patients, the immunoexpression of the MFN1 protein was significantly higher, and the FIS1 protein level was significantly lower than in the control group (p < 0.01; p < 0.001; UMW test). Patients with early, operable lung cancer had significantly lower levels of MFN1 immunoexpression compared to patients with advanced, metastatic lung cancer (p < 0.05; UMW test). This suggests that early stages of the disease are characterized by greater fragmentation of damaged mitochondria and apoptosis. In contrast, lower FIS1 protein levels were associated with a worse prognosis. Increased mitochondrial fusion in the blood of lung cancer patients may suggest an increase in protective and repair mechanisms. This opens up questions about why these mechanisms fail in the context of existing advanced cancer disease and is a starting point for further research into why protective mechanisms fail in lung cancer patients.

Expression of Survivin, CK7, ASH1, HMGB3, L587S, and CLCA2 in Peripheral Blood of Lung Cancer Patients by Real-Time Polymerase Chain Reaction.

Introduction The objective of the present study was to identify gene expression in peripheral blood by a real-time polymerase chain reaction (PCR) technique in patients who have lung carcinoma. Material and methods Peripheral blood samples of patients with non-small cell and small cell lung cancer were collected. Target genes included survivin, CK7, ASH1, HMGB3, L587S, and CLCA2. β-Actin was the reference gene. If the mean CT (threshold cycle) value for a target gene is ≥40, the gene expression is considered undetectable. Results Fifty patients with lung carcinoma were included and 30 healthy controls. Out of the six genes, survivin showed 26.8 times fold change as compared to controls; ASH1 and L587S were 0.54 and 0.06, respectively; and HMGB3, CLCA2, and CK7 had non-significant fold change in comparison to controls. The overall detection rate of the six target genes examined in lung cancer was 84%, with 42 out of 50 patients testing positive. Higherstages andASH1 (p = 0.031), CK7 (p = <0.001), and HMGB3, p = 0.011 were associated significantly. CLCA2 had higher expression in patients without adrenal metastases (p = 0.044). Conclusions Lifestyle and geographical variation might be a probable cause of variable gene expression as compared to other studies. However, further research is needed to determine the clinical implication of these markers, especially in larger groups of early-stage patients.

Engagement of sialylated glycans with Siglec receptors on suppressive myeloid cells inhibits anticancer immunity via CCL2.

The overexpression of sialic acids on glycans, called hypersialylation, is a common alteration found in cancer cells. Sialylated glycans can enhance immune evasion by interacting with sialic acid-binding immunoglobulin-like lectin (Siglec) receptors on tumor-infiltrating immune cells. Here, we investigated the effect of sialylated glycans and their interaction with Siglec receptors on myeloid-derived suppressor cells (MDSCs). We found that MDSCs derived from the blood of lung cancer patients and tumor-bearing mice strongly express inhibitory Siglec receptorsand are highly sialylated. In murine cancer models of emergency myelopoiesis, Siglec-E knockout in myeloid cells resulted in prolonged survival and increased tumorinfiltration of activated T cells. Targeting suppressive myeloid cells by blocking Siglec receptors or desialylation strongly reduced their suppressive potential. We further identified CCL2 as a mediator involved in T-cell suppression upon interaction between sialoglycans and Siglec receptors on MDSCs. Our results demonstrated that sialylated glycans inhibit anticancer immunity by modulating CCL2 expression.

Single-Cell Liquid Biopsy of Lung Cancer: Ultra-Simplified Efficient Enrichment of Circulating Tumor Cells and Hand-Held Fluorometer Portable Testing.

Herein, we propose a paper-based laboratory via enzyme-free nucleic acid amplification and nanomaterial-assisted cation exchange reactions (CERs) assisted single-cell-level analysis (PLACS). This method allowed for the rapid detection of mucin 1 and trace circulating tumor cells (CTCs) in the peripheral blood of lung cancer patients. Initially, an independently developed method requiring one centrifuge, two reagents (lymphocyte separation solution and erythrocyte lysate), and a three-step, 45 min sample pretreatment was employed. The core of the detection approach consisted of two competitive selective identifications: copper sulfide nanoparticles (CuS NPs) to C-Ag+-C and Ag+, and dual quantum dots (QDs) to Cu2+ and CuS NPs. To facilitate multimodal point-of-care testing (POCT), we integrated solution visualization, test strip length reading, and a self-developed hand-held fluorometer readout. These methods were detectable down to ag/mL of mucin 1 concentration and the single-cell level. Forty-seven clinical samples were assayed by fluorometer, yielding 94% (30/32) sensitivity and 100% (15/15) specificity with an area under the curve (AUC) of 0.945. Nine and 15 samples were retested by a test strip and hand-held fluorometer, respectively, with an AUC of 0.95. All test results were consistent with the clinical imaging and the folate receptor (FR)-PCR kit findings, supporting its potential in early diagnosis and postoperative monitoring.

A mesoporous gold biosensor to investigate immune checkpoint protein heterogeneity in single lung cancer cells

Immune checkpoint proteins (ICPs) play a major role in a patient's immune response against cancer. Tumour cells usually express those proteins to communicate with immune cells as a process of escaping the anti-cancer immune response. Detecting the major functional immune checkpoint proteins present on cancer cells (such as circulating tumor cells or CTCs) and examining the heterogeneity in their expression at the single-cell level could play a crucial role in both cancer diagnosis and the monitoring of therapy. In this study, we develop a mesoporous gold biosensor to precisely assess ICP heterogeneity in individual cancer cells within a lung cancer model. The platform utilizes a nanostructured mesoporous gold surface to capture CTCs and a Surface Enhanced Raman Scattering (SERS) readout to identify and monitor the expression of key ICP proteins (PD-L1, B7H4, CD276, CD80) in lung cancer cells. The homogeneous and abundant pores in mesoporous 3D gold nanostructures enable increased antibody loading on-chip and an enhanced SERS signal, which are key to our single cell capture, and accurate analysis of ICPs in cancer cells with high sensitivity. Our lung cancer cell line model data showed that our method can detect single cells and analyse the expression of four lung cancer associated ICPs on individual cell surfaces during treatment. To show the potential of our mesoporous gold biosensor in analysing clinical samples, we tested 9 longitudinal Peripheral Blood Mononuclear Cells (PBMC) samples from lung cancer patient before and after therapy. Our mesoporous biosensor successfully captured single CTCs and found that the expression of ICPs in CTCs is highly heterogeneous in both pre-treatment and treated PBMC samples isolated from lung cancer patient blood. We suggest that our findings will help clinicians in selecting the most appropriate therapy for patients.

Novel conditionally replicating adenovirus-mediated efficient detection of circulating tumor cells in lung cancer patients.

Circulating tumor cells (CTCs) are present in the blood of cancer patients from the early stage of cancer development, and their presence has been correlated with patient prognosis and treatment responses. Accordingly, CTCs have been attracting attention as a novel biomarker for early detection of cancer and monitoring of treatment responses. However, since patients typically have only a few CTCs per milliliter of blood, development of an accurate and highly sensitive CTC detection method is crucial. We previously developed a CTC detection method using a novel conditionally replicating adenovirus (Ad) that expresses green fluorescence protein (GFP) in a tumor cell-specific manner by expressing the E1 gene using a tumor-specific human telomerase reverse transcriptase (hTERT) promoter (rAdF35-142T-GFP). CTCs were efficiently detected using rAdF35-142T-GFP, but GFP expression levels in the CTCs and production efficiencies of rAdF35-142T-GFP were relatively low. In this study, in order to overcome these problems, we developed four types of novel GFP-expressing conditionally replicating Ads and examined their ability to visualize CTCs in the blood samples of lung cancer patients. Among the four types of novel recombinant Ads, the novel conditionally replicating Ad containing the 2A peptide and the GFP gene downstream of the E1A gene and the adenovirus death protein (ADP) gene in the E3 region (rAdF35-E1-2A-GFP-ADP) mediated the highest number of GFP-positive cells in the human cultured tumor cell lines. Titers of rAdF35-E1-2A-GFP-ADP were significantly higher (about 4-fold) than those of rAdF35-142T-GFP. rAdF35-E1-2A-GFP-ADP and rAdF35-142T-GFP efficiently detected CTCs in the blood of lung cancer patients at similar levels. GFP+/CD45- cells (CTCs) were found in 10 of 17 patients (58.8%) for both types of recombinant Ads.

Pro-Tumorigenic and Thrombotic Activities of Platelets in Lung Cancer.

Aside from their key protective roles in hemostasis and innate immunity, platelets are now recognized as having multifaceted, adverse roles in the pathogenesis, progression and outcome of many types of human malignancy. The most consistent and compelling evidence in this context has been derived from the notable association of elevated circulating platelet counts with the onset and prognosis of various human malignancies, particularly lung cancer, which represents the primary focus of the current review. Key topics include an overview of the association of lung cancer with the circulating platelet count, as well as the mechanisms of platelet-mediated, pro-tumorigenic immunosuppression, particularly the role of transforming growth factor beta 1. These issues are followed by a discussion regarding the pro-tumorigenic role of platelet-derived microparticles (PMPs), the most abundant type of microparticles (MPs) in human blood. In this context, the presence of increased levels of PMPs in the blood of lung cancer patients has been associated with tumor growth, invasion, angiogenesis and metastasis, which correlate with disease progression and decreased survival times. The final section of the review addresses, firstly, the role of cancer-related platelet activation and thrombosis in the pathogenesis of secondary cardiovascular disorders and the associated mortality, particularly in lung cancer, which is second only to disease progression; secondly, the review addresses the potential role of antiplatelet agents in the adjunctive therapy of cancer.

Clinical validity of oncogenic driver genes detected from circulating tumor DNA in the blood of lung cancer patients.

This study aimed to evaluate the concordance of oncogenic driver mutations between tumor tissues and circulating tumor DNA (ctDNA) in patients with lung cancer. In addition, this study attempted to reveal the clinical utility of ctDNA in lung cancer treatment. Recurrent or metastatic non-small cell lung cancer (NSCLC) patients were prospectively enrolled in this study. Tumor tissue and serial blood samples were obtained from newly diagnosed patients (Cohort A) or patients treated with targeted therapy (Cohort B) and targeted gene panel sequencing was conducted to identify tumor mutational profiles. At the time of diagnosis, patients in Cohort A with a high cell-free DNA (cfDNA) concentration had poorer overall survival than those with a low cfDNA concentration. The sensitivity and precision of ctDNA analysis in pre-treatment patients compared with those of tissue sequencing were 58.4% and 61.5%, respectively. Known lung cancer-associated variants of oncogenic driver genes, including EGFR and KRAS, and tumor suppressor genes, including TP53 and APC, were frequently detected in the ctDNA of the patients (76.9%). An association between smoking and TP53 mutation status was observed in both tissues and ctDNA (P=0.005 and 0.037, respectively). In addition, the EGFR T790M resistance mutation was detected solely from the ctDNA of two patients after treatment with an EGFR tyrosine kinase inhibitor. ctDNA may be a reliable prognostic biomarker with an additional role in treating patients with lung cancer. Further analyses are necessary to understand the properties of ctDNA and widen its clinical use.

Role of circulating-tumor DNA in the early-stage non-small cell lung carcinoma as a predictive biomarker.

Lung cancer is one of the most common solid malignancies. Tissue biopsy is the standard method for accurately diagnosing lung and many other malignancies over decades. However, molecular profiling of tumors leads to establishing a new horizon in the field of precision medicine, which has now entered the mainstream in clinical practice. In this context, a minimally invasive complementary method has been proposed as a liquid biopsy (LB) which is a blood-based test that is gaining popularity as it provides the opportunity to test genotypes in a unique, less invasive manner. Circulating tumor cells (CTC) captivating the Circulating-tumor DNA (Ct-DNA) are often present in the blood of lung cancer patients and are the fundamental concept behind LB. There are multiple clinical uses of Ct-DNA, including its role in prognostic and therapeutic purposes. The treatment of lung cancer has drastically evolved over time. Therefore, this review article mainly focuses on the current literature on circulating tumor DNA and its clinical implications and future goals in non-small cell lung cancer.

Abstract 1333: A novel and highly efficient biomimetic capture approach for the isolation and characterization of circulating metastatic cancer cell clusters from lung cancer patients

Abstract Capture and isolation of circulating metastatic cancer cell clusters (MCCC) is the essential first step to identify novel therapeutic targets focused on this important route of metastasis. We developed a unique biomimetic capture approach that allows selective isolation of these deadly clusters from the whole blood of lung cancer patients. Utilizing a microfluidic platform we developed a versatile smart-coating that combines biomimicry and immuno-capture for a highly efficient and selective isolation of viable MCCCs. Here we show the capture and characterization of multiple MCCCs from non-small cell lung cancer (NSCLC) patients. Table 1 shows the count of clusters detected in NSCLC patients based on a stringent criterion confirming their identification. The MCCCs were detected in every patient tested but none were detected in normal blood controls from donors of similar age. Isolated MCCC where characterized by immunofluorescence and submitted for genomic analyses. Metastasis remains one of the leading causes of cancer related deaths worldwide. Insights into how the tumor propagates to pre-metastatic sites is necessary to develop focused therapeutic approaches. Circulating metastatic cancer cell clusters (MCCCs) have been established as a primary entity causing distal metastases. Significant advances have been made linking cluster integrity and viability to increased metastatic potential highlighting the unmet need for cluster focused therapies. Our novel approach allows the rapid and easy capture of MCCCs paving the way for the discovery of novel or unique targets that eventually will bring new anti-metastatic therapies to the clinic. Table 1 Patient Age/Sex Staging/Metastasis #MCCC INMC-044.1 82 M IVB/bone 2 INMC-044.2 53 F IV/bone 1 INMC-044.3 59 F IV/bone, brain 2 INMC-044.4 65 M IV/thoracic cav., lung 1 INMC-044.5 67 M IIIa/none 3 Normal Blood 54 F N/A 0 Normal Blood 68 M N/A 0 Citation Format: Kourosh Kouhmareh, Erika Martin, Darren Finlay, Anukriti Bhadada, Francisco Downey, Jeff A. Allen, Peter Teriete. A novel and highly efficient biomimetic capture approach for the isolation and characterization of circulating metastatic cancer cell clusters from lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1333.

Abstract 2300: Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer

Abstract Background: Lung cancer (LC) is the deadliest cancer worldwide, with small cell LC (SCLC) and neuroendocrine (NE) LC being the most aggressive and lethal forms. The transcription factor, achaete-scute homolog 1 (ASCL1), regulates neuronal and NE cell development, and is a hallmark of the ASCL1(+) SCLC subtype. Further, investigating subtype has become increasingly important as new drug candidates emerge for SCLC that may be efficacious in only some patients. ASCL1 by IHC tissue biopsy is highly specific, detecting patients who have transformed from NSCLC to SCLC and have acquired resistance to EGFR tyrosine kinase inhibitor therapy in NSCLC. Quantification of ASCL1 on circulating tumor cells (CTCs) is a blood-based, non-invasive alternative to tissue biopsy that provides functional protein-level expression data to monitor lung cancer patients across the disease continuum, informing patient treatment. Methods: A 4-color immunofluorescence (IF) assay was developed to detect ASCL1 expression in CTCs from routine blood samples, comprising detection of nucleated cells (DAPI), cytokeratin positive CTCs, CD45(+) white blood cells (WBC), and ASCL1(+) cells. During validation, cancer cell lines (SHP-77 [ASCL(+)] and U2-OS [ASCL1(-)]) were spiked into normal blood at a ratio of 1:10,000 (CLC/WBC) and plated onto coated glass slides. Slides were stained, imaged, and CTC candidates were identified with a proprietary imaging algorithm. The threshold of ASCL1 positivity (316 MFI) included 99% of all ASCL1(-), U2-OS cells. Assay specificity, sensitivity, overall accuracy, and subcellular localization of biomarker expression were assessed. The ability of the assay to quantify ASCL1 expression in CTCs was confirmed using 31 samples from 11 Extensive Stage SCLC patients. Results: The ASCL1 CTC assay achieved an overall accuracy of 0.992 (95% CI 0.081, 0.993), and an analytical specificity and sensitivity of 0.990 and 0.995, respectively. The assay displayed a positive predictive value and a negative predictive value of 0.979 and 0.998, respectively, determined by evaluating ASCL1 expression in SHP-77 (N=4062) and U2-OS (N=8645). ASCL1 expression was detected in the nucleus of all SHP-77 and majority of SCLC patient CTCs. Of the 11 Extensive Stage SCLC patients tested, 9 (82%) showed at least one conventional CTC (0.02 - 9.63 CTCs/mL), and all 9 (100%) had at least 1 ASCL1(+) CTC (0.06 - 5.5 CTCs/mL). Conclusion: This blood based ASCL1 assay is a highly specific and sensitive approach to monitor ASCL1 expression on CTCs isolated from the blood of lung cancer patients. Citation Format: Luisa Fernandez, Andrew Kunihiro, Mark Frilles, Alisa Tubbs, Jason Christiansen, David Bourdon. Non-invasive liquid biopsy assay for the detection of ASCL1 expression in CTCs of patients with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2300.

Identification and clinical implications of circulating cancer associated fibroblasts in lung cancer patients

ObjectivesIn tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) are known to expedite cancer progression (metastasis). CAF-secreted cytokines confer a survival advantage to circulating tumor stem cells (CTSCs) (indicators of residual-disease) facilitating immune system evasion. Collectively, CAFs serve as “bio-incubator" by providing favourable "soil" for their subsequent growth in the circulation during EMT and are thus considered as an important target in diagnostic and therapeutic applications. Thus, the aim of this study was to check the presence of circulating CAF (cCAFs) in blood of lung cancer patients as a liquid biopsy approach. Materials and methodsMononuclear cells isolated from the peripheral blood of non-metastatic lung cancer patients were cultured to confirm the presence of cCAF. CAF-specific marker α-SMA and FAP was used to characterise them using Western blot and real time PCR. Furthermore, correlation between expression of cCAFs and various clinico-pathological parameters were examined. ResultsCultured MNCs showed the presence of cCAFs which was further confirmed by western blotting. All patients were found positive for the presence of cCAFs (α-SMA expression), while healthy individuals lacked this, being α-SMA negative. Moreover, significant trend was observed between different stages of lung cancer patients (p < 0.014), suggesting its probable role in lung cancer progression. ConclusionThus, cCAFs could be companion biomarker for the early detection of tumors as well as it could be efficient biomarker for the prediction of metastasis. However, validation of cCAFs as robust marker is still required to be tested in a more number of patients. This should be done using more than one marker associated with CAFs for their clinical application, as it has a potential implication to monitor the effectiveness of a specific cancer therapy and disease progression.

Elevated Levels of Circulating Hsp70 and an Increased Prevalence of CD94+/CD69+ NK Cells Is Predictive for Advanced Stage Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) is the second most frequently diagnosed tumor worldwide. Despite the clinical progress which has been achieved by multimodal therapies, including radiochemotherapy, and immune checkpoint inhibitor blockade, the overall survival of patients with advanced-stage NSCLC remains poor, with less than 16 months. It is well established that many aggressive tumor entities, including NSCLC, overexpress the major stress-inducible heat shock protein 70 (Hsp70) in the cytosol, present it on the plasma membrane in a tumor-specific manner, and release Hsp70 into circulation. Although high Hsp70 levels are associated with tumor aggressiveness and therapy resistance, membrane-bound Hsp70 can serve as a tumor-specific antigen for Hsp70-primed natural killer (NK) cells, expressing the C-type lectin receptor CD94, which is part of the activator receptor complex CD94/NKG2C. Therefore, we investigated circulating Hsp70 levels and changes in the composition of peripheral blood lymphocyte subsets as potential biomarkers for the advanced Union for International Cancer Control (UICC) stages in NSCLC. As expected, circulating Hsp70 levels were significantly higher in NSCLC patients compared to the healthy controls, as well as in patients with advanced UICC stages compared to those in UICC stage I. Smoking status did not influence the circulating Hsp70 levels significantly. Concomitantly, the proportions of CD4+ T helper cells were lower compared to the healthy controls and stage I tumor patients, whereas that of CD8+ cytotoxic T cells was progressively higher. The prevalence of CD3-/CD56+, CD3-/NKp30, CD3-/NKp46+, and CD3-/NKG2D+ NK cells was higher in stage IV/IIIB of the disease than in stage IIIA but were not statistically different from that in healthy individuals. However, the proportion of NK cells expressing CD94 and the activation/exhaustion marker CD69 significantly increased in higher tumor stages compared with stage I and the healthy controls. We speculate that although elevated circulating Hsp70 levels might promote the prevalence of CD94+ NK cells in patients with advanced-stage NSCLC, the cytolytic activity of these NK cells also failed to control tumor growth due to insufficient support by pro-inflammatory cytokines from CD4+ T helper cells. This hypothesis is supported by a comparative multiplex cytokine analysis of the blood in lung cancer patients with a low proportion of CD4+ T cells, a high proportion of NK cells, and high Hsp70 levels versus patients with a high proportion of CD4+ T cells exhibiting lower IL-2, IL-4, IL-6, IFN-γ, granzyme B levels.

Abstract C046: Polymorphonuclear myeloid derived suppressor cells die by ferroptosis in the tumor microenvironment

Abstract Myeloid-derived suppressor cells (MDSC) in the tumor microenvironment (TME) function as an immunosuppressive shield that protects the tumor from the host’s immune system and considered a barrier to effective immunotherapy. Here, we focused on polymorphonuclear (PMN)-MDSCs, the most prevalent MDSCs in the TME, to identify mechanisms regulating their maintenance, turnover, and accumulation. Using four mouse models of cancer including autochthonous pancreatic adenocarcinoma from KPC genetically engineered mice (KrasG12D/p53R172H, PdxCre), we found that PMN-MDSCs spontaneously die by ferroptosis, a non-apoptotic form of regulated cell death triggered by the discoordination of regulatory redox mechanisms culminating in massive peroxidation of polyunsaturated phospholipids. Only PMN-MDSCs within the TME were observed to spontaneously undergo ferroptosis. In mice, ferroptosis-related gene expression in CD11b+L6ClowLy6G+ PMN-MDSC isolated from bone marrow, spleen, and tumor demonstrated tumor-specific ferroptosis across tumor models. In humans, whole transcriptomic analysis of PMN-MDSC sorted from tumors and matched blood of lung cancer patients vs blood of healthy donors revealed up-regulation of genes involved in the regulation of ferroptosis in tumor PMN-MDSC. Ferroptosis gene signatures correlated with the PMN-MDSC signatures in pancreatic cancer patients and was associated with worse overall survival. Thus, ferroptosis is an unappreciated, prominent pathway of cell death of PMN-MDSCs in cancer linked to clinical outcome in patients with pancreatic cancer. Citation Format: Rina Kim, Ayumi Hashimoto, Nune Markosyan, Vladimir A. Tyurin, Yulia Y. Tyurina, Shuyu Fu, Mohit Sehgal, Laura Garcia-Gerique, Gozde Kar, Andrew Kossenkov, Bereket A. Gebregziabher, John W. Tobias, Kristin Hicks, Hui Deng, Laxminarasimha Donthireddy, Andrew Greenberg, Brian Nam, Yulia Nefedova, Valerian E. Kagan, Robert H. Vonderheide, Dmitry Gabrilovich. Polymorphonuclear myeloid derived suppressor cells die by ferroptosis in the tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C046.

The influence of blood sample processing on blood-based DNA methylation signatures

Stability is crucial for the clinical applicable biomarker such as DNA methylation profiles. However, the influence of various blood processing on the DNA methylation signatures have been barely studied. Here, we systematically evaluated the impact of temporary storage and frozen and thaw on the levels of DNA methylation. The methylation intensities of 13 CpG loci from 53 individuals (42 healthy participants and 11 lung cancer patients) whose blood samples were processed by up to 14 various protocols were quantitatively determined by the mass spectrometry, obtaining more than 8,000 quantitative data. We disclosed a trend of accumulatively increased DNA methylation along with time when the blood from healthy people were stored for up to 96 h at room temperature (RT), whereas the storage at 4°C had much weaker effects or no impact. On the contrary, the methylation patterns in the blood of lung cancer patients were more stable at both RT and 4°C even for 96 h. Multiple cycles of frozen and thaw could result in demethylation, but was more significant to the blood than to the extracted DNA. Our study indicated that the blood processing in vitro could influence the DNA methylation signatures and introduce unexpected biases.

Abstract 3377: Immunosuppressive features characterize tumor tissues and peripheral blood of lung cancer patients

Abstract The role of immunity at the local and peripheral level is a recognized hallmark of cancer. The immunosuppressive and inflammatory background of lung cancer (LC), led us to hypothesize that the tumour and the circulating immune cell profiles could be source of biomarkers for LC risk assessment. In this respect we already developed a plasma microRNA-signature classifier (MSC) that stratifies LC screening patients in high, intermediate and low risk groups. To get insight we investigated tumour tissues and peripheral blood immune cell profiles of these patients. The possibility to develop molecular tests reflecting an immunosuppressive status for prognostic and diagnostic purposes was also explored. The immune cell composition of 40 frozen LC tissues collected during screening trials from patients with a different MSC risk profile were assessed by deconvolution analysis using CIBERSORT software. Results were validated by RT-qPCR and IHC, as well as using RNAseq data from the 1000 lung cancer patients of The Cancer Genome Atlas (TCGA) database. From a training set composed by 20 LC patients and 20 matched controls, we analyzed peripheral blood mononuclear cells (PBMCs) by flow cytometry using a 24 marker panel to encompass monocyte and myeloid-derived suppressor cells (MDSC) subsets, regulatory T cells, cytolytic NK cells and activated/exhausted/hyperexausted T cells. Gene signatures of relevant immune cell subsets were then validated and employed to define a RT-qPCR based algorithm using plasma samples collected from an independent set of 40 LC patients and 40 matched controls. At the tumor tissue level, CIBERSORT analysis indicated a significant reduction of cytotoxic T lymphocytes and a concomitant increase of regulatory T cells in MSC high risk patients, characterized by worse prognosis compared to intermediate/low risk patients. A 168 gene signature able to discriminate these two groups was identified. Furthermore, within the LC TCGA datasets the identified signature stratified two groups of patients with different 5-years overall survival (p&amp;lt;0.01). Flow cytometry analysis of PBMC samples confirmed the lower number of lymphocytes at systemic level measured in tumor specimens of MSC high risk patients. This was paralleled by an increase of exhausted T cells as well as classical, inflammatory and monocytic MDSCs. By comparing LC cases and controls an algorithm composed by four immune cell subsets resulted in 0.91 and 0.72 AUC values in the training and validation set, respectively. Based on these results a 14 immune related gene signature was finally developed and tested on samples of the validation set, where an AUC of 0.75 was observed. Overall, these findings suggest that immunosuppressive features at tumour and systemic discriminate LC patients with worse outcome. Molecular-based tests able to recapitulate these features could be easily moved into the clinical practice. Citation Format: Mattia Boeri, Veronica Huber, Orazio Fortunato, Ugo Pastorino, Licia Rivoltini, Gabriella Sozzi. Immunosuppressive features characterize tumor tissues and peripheral blood of lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3377.

CD137 Agonists Targeting CD137-Mediated Negative Regulation Show Enhanced Antitumor Efficacy in Lung Cancer

Negative immune regulation plays a notable role in tumor immunity. This study aimed to confirm that CD137 mediates negative immunoregulation as well as agonist activity in tumor immunity. Soluble CD137 (sCD137), a prominent splice variant of membrane-bound CD137 (mCD137), was identified, and its concentration in the blood of lung cancer patients was increased. The baseline concentration of sCD137 in the blood was negatively correlated with the efficacy of neoadjuvant immunochemotherapy in a pilot study. The percentage of CD137+ regulatory T cells (Tregs) in the blood of lung cancer patients was also increased, and further enriched at the tumor site; Foxp3, CTLA-4, IL-10, IL-35-Ebi3, sCD137 and costimulatory molecules expression were also higher, indicating increased immunosuppressive activity. A high percentage of CD137+ Tregs in the tumor was associated with worse OS outcomes among patients with high CD137+CD8+ T cell infiltration levels. Notably, targeting CD137+ Tregs using an engineered CD137 agonist with wild-type mouse IgG2a Fc clearly decreased the total Treg numbers and eliminated the tumor in the CT26 model and prolonged the survival rate of a Lewis lung carcinoma (LLC) model. These results indicated it may be possible to empower CD137 agonist with ability to abolish CD137-mediated negative regulation to enhance its antitumor efficacy.