Deep Learning-Based H-Score Quantification of Immunohistochemistry-Stained Images

Immunohistochemistry (IHC) is a well-established and commonly used staining method for clinical diagnosis and biomedical research. In most IHC images, the target protein is conjugated with a specific antibody and stained using diaminobenzidine (DAB), resulting in a brown coloration, whereas hematoxylin serves as a blue counterstain for cell nuclei. The protein expression level is quantified through the H-score, calculated from DAB staining intensity within the target cell region. Traditionally, this process requires evaluation by 2 expert pathologists, which is both time consuming and subjective. To enhance the efficiency and accuracy of this process, we have developed an automatic algorithm for quantifying the H-score of IHC images. To characterize protein expression in specific cell regions, a deep learning model for region recognition was trained based on hematoxylin staining only, achieving pixel accuracy for each class ranging from 0.92 to 0.99. Within the desired area, the algorithm categorizes DAB intensity of each pixel as negative, weak, moderate, or strong staining and calculates the final H-score based on the percentage of each intensity category. Overall, this algorithm takes an IHC image as input and directly outputs the H-score within a few seconds, significantly enhancing the speed of IHC image analysis. This automated tool provides H-score quantification with precision and consistency comparable to experienced pathologists but at a significantly reduced cost during IHC diagnostic workups. It holds significant potential to advance biomedical research reliant on IHC staining for protein expression quantification.

Pathomic Features Reveal Immune and Molecular Evolution From Lung Preneoplasia to Invasive Adenocarcinoma

Recent statistics on lung cancer, including the steady decline of advanced diseases and the dramatically increasing detection of early-stage diseases and indeterminate pulmonary nodules, mark the significance of a comprehensive understanding of early lung carcinogenesis. Lung adenocarcinoma (ADC) is the most common histologic subtype of lung cancer, and atypical adenomatous hyperplasia is the only recognized preneoplasia to ADC, which may progress to adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) and eventually to invasive ADC. Although molecular evolution during early lung carcinogenesis has been explored in recent years, the progress has been significantly hindered, largely due to insufficient materials from ADC precursors. Here, we employed state-of-the-art deep learning and artificial intelligence techniques to robustly segment and recognize cells on routinely used hematoxylin and eosin histopathology images and extracted 9 biology-relevant pathomic features to decode lung preneoplasia evolution. We analyzed 3 distinct cohorts (Japan, China, and United States) covering 98 patients, 162 slides, and 669 regions of interest, including 143 normal, 129 atypical adenomatous hyperplasia, 94 AIS, 98 MIA, and 205 ADC. Extracted pathomic features revealed progressive increase of atypical epithelial cells and progressive decrease of lymphocytic cells from normal to AAH, AIS, MIA, and ADC, consistent with the results from tissue-consuming and expensive molecular/immune profiling. Furthermore, pathomics analysis manifested progressively increasing cellular intratumor heterogeneity along with the evolution from normal lung to invasive ADC. These findings demonstrated the feasibility and substantial potential of pathomics in studying lung cancer carcinogenesis directly from the low-cost routine hematoxylin and eosin staining.

New Insights into Macrophage Polarization and its Prognostic Role in Patients with Colorectal Cancer Liver Metastasis

Background

As liver metastasis is the most common cause of mortality in patients with colorectal cancer, studying colorectal cancer liver metastasis (CLM) microenvironment is essential for improved understanding of tumor biology and to identify novel therapeutic targets.

Methods

We used multiplex immunofluorescence platform to study tumor associated macrophage (TAM) polarization and adaptive T cell subtypes in tumor samples from 105 CLM patients (49 without and 56 with preoperative chemotherapy).

Results

CLM exhibited M2 macrophage polarization, and helper T cells were the prevalent adaptive T cell subtype. The density of total, M2 and TGFβ-expressing macrophages, and regulatory T cells was lower in CLM treated with preoperative chemotherapy. CLM with right-sided primary demonstrated enrichment of TGFβ-expressing macrophages, and with left-sided primary had higher densities of helper and cytotoxic T cells. In multivariate analysis, high density of M2 macrophages correlated with longer recurrence-free survival (RFS) in the entire cohort [hazard ratio (HR) 0.425, 95% CI 0.219-0.825, p=0.011) and in patients without preoperative chemotherapy (HR 0.45, 95% CI 0.221-0.932, p=0.032). High pSMAD3-expressing macrophages were associated with shorter RFS in CLM after preoperative chemotherapy.

Conclusions

Our results highlight the significance of a multi-marker approach to define the macrophage subtypes and identify M2 macrophages as a predictor of favorable prognosis in CLM.

Automated Cellular-Level Dual Global Fusion of Whole-Slide Imaging for Lung Adenocarcinoma Prognosis

Histopathologic whole-slide images (WSI) are generally considered the gold standard for cancer diagnosis and prognosis. Survival prediction based on WSI has recently attracted substantial attention. Nevertheless, it remains a central challenge owing to the inherent difficulties of predicting patient prognosis and effectively extracting informative survival-specific representations from WSI with highly compounded gigapixels. In this study, we present a fully automated cellular-level dual global fusion pipeline for survival prediction. Specifically, the proposed method first describes the composition of different cell populations on WSI. Then, it generates dimension-reduced WSI-embedded maps, allowing for efficient investigation of the tumor microenvironment. In addition, we introduce a novel dual global fusion network to incorporate global and inter-patch features of cell distribution, which enables the sufficient fusion of different types and locations of cells. We further validate the proposed pipeline using The Cancer Genome Atlas lung adenocarcinoma dataset. Our model achieves a C-index of 0.675 (±0.05) in the five-fold cross-validation setting and surpasses comparable methods. Further, we extensively analyze embedded map features and survival probabilities. These experimental results manifest the potential of our proposed pipeline for applications using WSI in lung adenocarcinoma and other malignancies.

Cellular and Molecular Mechanisms of Liver Fibrosis in Patients with NAFLD

The expression of immune- and cancer-related genes was measured in liver biopsies from 107 NAFLD patients. The strongest difference in overall gene expression was between liver fibrosis stages F3 and F4, with 162 cirrhosis-associated genes identified. Strong correlations with fibrosis progression from F1 to F4 were observed for 91 genes, including CCL21, CCL2, CXCL6, and CCL19. In addition, the expression of 21 genes was associated with fast progression to F3/F4 in an independent group of eight NAFLD patients. These included the four chemokines, SPP1, HAMP, CXCL2, and IL-8. A six-gene signature including SOX9, THY-1, and CD3D had the highest performance detecting the progressors among F1/F2 NAFLD patients. We also characterized immune cell changes using multiplex immunofluorescence platforms. Fibrotic areas were strongly enriched in CD3+ T cells compared to CD68+ macrophages. While the number of CD68+ macrophages increased with fibrosis severity, the increase in CD3+ T-cell density was more substantial and progressive from F1 to F4. The strongest correlation with fibrosis progression was observed for CD3+CD45R0+ memory T cells, while the most significant increase in density between F1/F2 and F3/F4 was for CD3+CD45RO+FOXP3+CD8- and CD3+CD45RO-FOXP3+CD8- regulatory T cells. A specific increase in the density of CD68+CD11b+ Kupffer cells with liver fibrosis progression was also observed.

Abstract 4525: YAP1 in relapsed pulmonary high-grade neuroendocrine carcinomas (NEC) is associated with CDKN2A loss, intact RB1, EMT and therapeutic vulnerability to MEK1 and CDK4/6 inhibition

Neuroendocrine carcinomas (NECs) are clinically aggressive carcinomas commonly arising from the respiratory and gastrointestinal tracts, typically categorized as large-cell neuroendocrine carcinomas (LCNECs) or small cell carcinomas (most commonly small cell lung cancer (SCLC)). Clinically, pulmonary LCNECs (pLCNECs) mirror the course common to SCLC - initial response followed by rapid and insurmountable resistance to one-size-fits-all approaches. Recently, SCLC has been subdivided into four subtypes with unique vulnerabilities, three of which are defined by the transcription factors ASCL1, NEUROD1, and POU2F3, while a fourth group exhibits an inflamed signature. We hypothesize that pLCNEC may be similarly classified into molecularly distinct subsets with unique therapeutic vulnerabilities - a fundamental step toward personalized medicine. We applied our SCLC 1300 gene signature to pLCNEC patient tumors and, as in SCLC, found three distinct subtypes determined by differential expression of ASCL1, NEUROD1, and POU2F3, but with a unique fourth subtype marked by expression of the transcription factor YAP1. Unlike in treatment-naïve SCLC, where YAP1 is absent, YAP1 expression clearly defines pLCNEC as two, roughly equal subsets with the YAP1-low tumors encompassing tumors expressing the other three transcription factors. Conversely, YAP1-high pLCNEC is more mesenchymal and inflamed, and less neuroendocrine (NE), reminiscent of inflamed SCLC. Additionally, YAP1-high status is associated with smoking exposure (P<0.001, FC=81), high frequency of CDKN2A homozygous deletion and SMARCA4 mutations, as well as intact RB1. These features are distinct from SCLC, wherein transcriptional subtypes lack distinct genomic characteristics. Consistent with CDKN2A deletion, YAP1-high pLCNEC cell lines have increased sensitivity to MEK1 and CDK4/6 inhibition. We also demonstrate that RB1 loss downregulates YAP1 expression, which may account for the absence of YAP1 in treatment-naïve SCLC due to ubiquitous loss of RB1. In contrast to treatment-naïve SCLC, where our group and others have been unable to detect YAP1, single-cell RNAseq analysis of biopsies from patients with relapsed SCLC identified emerging YAP1-positive cancer cell populations, which are similarly associated with increased EMT, immune cell infiltration (CD8+ T-cells), and loss of NE gene expression. This suggests that the ability for cancer cells to acquire YAP1 expression and, perhaps, pLCNEC-like features, may be a resistance mechanism in relapsed SCLC, contributing to the abundant intratumoral heterogeneity and highlighting potential vulnerabilities to overcome resistance. In summary, YAP1 may be a predictive biomarker of intact RB1 and response to cellular and checkpoint immunotherapy and MEK1/CDK4/6 inhibition in pLCNEC and relapsed SCLC.

Citation Format: C. Allison Stewart, Lixia Diao, Yuanxin Xi, Runsheng Wang, Kavya Ramkumar, B. Leticia Rodriguez, Benjamin B. Morris, Li Shen, Bingnan Zhang, Yan Yang, Azusa Tanimoto, Veronica Y. Novegil, Luisa M. Solis Soto, Pedro F. Simoes da Rocha, Natalie Vokes, Don L. Gibbons, Michael Frumovitz, Junya Fujimoto, Jing Wang, Bonnie Glisson, Lauren A. Byers, Carl M. Gay. YAP1 in relapsed pulmonary high-grade neuroendocrine carcinomas (NEC) is associated with CDKN2A loss, intact RB1, EMT and therapeutic vulnerability to MEK1 and CDK4/6 inhibition. [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 4525.

The Single-Cell Immunogenomic Landscape of B and Plasma Cells in Early-Stage Lung Adenocarcinoma

Tumor-infiltrating B and plasma cells (TIB) are prevalent in lung adenocarcinoma (LUAD); however, they are poorly characterized. We performed paired single-cell RNA and B-cell receptor (BCR) sequencing of 16 early-stage LUADs and 47 matching multiregion normal tissues. By integrative analysis of ∼50,000 TIBs, we define 12 TIB subsets in the LUAD and adjacent normal ecosystems and demonstrate extensive remodeling of TIBs in LUADs. Memory B cells and plasma cells (PC) were highly enriched in tumor tissues with more differentiated states and increased frequencies of somatic hypermutation. Smokers exhibited markedly elevated PCs and PCs with distinct differentiation trajectories. BCR clonotype diversity increased but clonality decreased in LUADs, smokers, and with increasing pathologic stage. TIBs were mostly localized within CXCL13+ lymphoid aggregates, and immune cell sources of CXCL13 production evolved with LUAD progression and included elevated fractions of CD4 regulatory T cells. This study provides a spatial landscape of TIBs in early-stage LUAD.

SIGNIFICANCE

While TIBs are highly enriched in LUADs, they are poorly characterized. This study provides a much-needed understanding of the transcriptional, clonotypic states and phenotypes of TIBs, unraveling their potential roles in the immunopathology of early-stage LUADs and constituting a road map for the development of TIB-targeted immunotherapies for the treatment of this morbid malignancy. This article is highlighted in the In This Issue feature, p. 2483.

Follicular Lymphoma Microenvironment Characteristics Associated with Tumor Cell Mutations and MHC Class II Expression

Follicular lymphoma (FL) is a B-cell malignancy with a complex tumor microenvironment that is rich in nonmalignant immune cells. We applied single-cell RNA sequencing to characterize the diverse tumor and immune cell populations of FL and identified major phenotypic subsets of FL T cells, including a cytotoxic CD4 T-cell population. We characterized four major FL subtypes with differential representation or relative depletion of distinct T-cell subsets. By integrating exome sequencing, we observed that somatic mutations are associated with, but not definitive for, reduced MHC expression on FL cells. In turn, expression of MHCII genes by FL cells was associated with significant differences in the proportions and targetable immunophenotypic characteristics of T cells. This provides a classification framework of the FL microenvironment in association with FL genotypes and MHC expression, and informs different potential immunotherapeutic strategies based upon tumor cell MHCII expression.

SIGNIFICANCE

We have characterized the FL-infiltrating T cells, identified cytotoxic CD4 T cells as an important component that is associated with tumor cell-intrinsic characteristics, and identified sets of targetable immune checkpoints on T cells that differed from FLs with normal versus low MHC expression. See related commentary by Melnick, p. 374. This article is highlighted in the In This Issue feature, p. 369.

The Role of Nerve Fibers in the Tumor Immune Microenvironment of Solid Tumors

The importance of neurons and nerve fibers in the tumor microenvironment (TME) of solid tumors is now acknowledged after being unexplored for a long time; this is possible due to the development of new technologies that allow in situ characterization of the TME. Recent studies have shown that the density and types of nerves that innervate tumors can predict a patient's clinical outcome and drive several processes of tumor biology. Nowadays, several efforts in cancer research and neuroscience are taking place to elucidate the mechanisms that drive tumor-associated innervation and nerve-tumor and nerve-immune interaction. Assessment of neurons and nerves within the context of the TME can be performed in situ, in tumor tissue, using several pathology-based strategies that utilize histochemical and immunohistochemistry principles, hi-plex technologies, and computational pathology approaches to identify measurable histopathological characteristics of nerves. These features include the number and type of tumor associated nerves, topographical location and microenvironment of neural invasion of malignant cells, and investigation of neuro-related biomarker expression in nerves, tumor cells, and cells of the TME. A deeper understanding of these complex interactions and the impact of nerves in tumor biology will guide the design of better strategies for targeted therapy in clinical trials.

Targeting de novo lipogenesis and the Lands cycle induces ferroptosis in KRAS-mutant lung cancer

Mutant KRAS (KM), the most common oncogene in lung cancer (LC), regulates fatty acid (FA) metabolism. However, the role of FA in LC tumorigenesis is still not sufficiently characterized. Here, we show that KMLC has a specific lipid profile, with high triacylglycerides and phosphatidylcholines (PC). We demonstrate that FASN, the rate-limiting enzyme in FA synthesis, while being dispensable in EGFR-mutant or wild-type KRAS LC, is required for the viability of KMLC cells. Integrating lipidomic, transcriptomic and functional analyses, we demonstrate that FASN provides saturated and monounsaturated FA to the Lands cycle, the process remodeling oxidized phospholipids, such as PC. Accordingly, blocking either FASN or the Lands cycle in KMLC, promotes ferroptosis, a reactive oxygen species (ROS)- and iron-dependent cell death, characterized by the intracellular accumulation of oxidation-prone PC. Our work indicates that KM dictates a dependency on newly synthesized FA to escape ferroptosis, establishing a targetable vulnerability in KMLC.

Multidimensional single-cell analysis identifies a role for CD2-CD58 interactions in clinical antitumor T cell responses

The in vivo persistence of adoptively transferred T cells is predictive of antitumor response. Identifying functional properties of infused T cells that lead to in vivo persistence and tumor eradication has remained elusive. We profiled CD19-specific chimeric antigen receptor (CAR) T cells as the infusion products used to treat large B cell lymphomas using high-throughput single-cell technologies based on time-lapse imaging microscopy in nanowell grids (TIMING), which integrates killing, cytokine secretion, and transcriptional profiling. Our results show that the directional migration of CD19-specific CAR T cells is correlated with multifunctionality. We showed that CD2 on T cells is associated with directional migration and that the interaction between CD2 on T cells and CD58 on lymphoma cells accelerates killing and serial killing. Consistent with this, we observed that elevated CD58 expression on pretreatment tumor samples in patients with relapsed or refractory large B cell lymphomas treated with CD19-specific CAR T cell therapy was associated with complete clinical response and survival. These results highlight the importance of studying dynamic T cell–tumor cell interactions in identifying optimal antitumor responses.

Overexpression of CD73 in pancreatic ductal adenocarcinoma is associated with immunosuppressive tumor microenvironment and poor survival

BACKGROUND

CD73, a newly recognized immune checkpoint mediator, is expressed in several types of malignancies. However, CD73 expression and its impact on tumor microenvironment and clinical outcomes in pancreatic ductal adenocarcinoma (PDAC) remain unclear.

METHODS

This study included two cohorts: 138 patients from our institution (MDA) and 176 patients from TCGA dataset. CD73 expression, CD4+, CD8+, CD21+ and CD45RO + tumor infiltrating lymphocytes (TILs) were evaluated by immunohistochemistry using tissue microarrays. The results of CD73 expression were correlated with clinicopathologic parameters, survival and TILs.

RESULTS

CD73 overexpression correlated with poor differentiation (P = 0.002) and tumor size (P = 0.049). For CD73-low group, median overall survival (OS) and recurrence-free survival (RFS) were 26.9 ± 3.8 months and 12.6 ± 2.6 months, respectively, compared to 16.9 ± 4.4 months (P = 0.01) and 7.9 ± 1.2 months (P = 0.01), respectively, in CD73-high group. CD73 was an independent predictor for both RFS (P = 0.02) and OS (P = 0.01) by multivariate variate analysis. Similarly, CD73-high tumors had significantly shorter OS than CD73-low tumors in TCGA dataset (P < 0.0001). CD73-high correlated with decreased CD4+ TILs in MDA cohort and decreased CD8A and CR2 (CD21) expression in TCGA cohort.

CONCLUSIONS

CD73 overexpression is associated with poor differentiation, tumor size, and shorter survival, and is an independent prognostic factor in PDAC patients. CD73 overexpression is associated with decreased CD4+, CD8+ and CD21+ TILs. Our data support that CD73 plays an important role in immunosuppressive tumor microenvironment and promote tumor progression in PDAC.

Efficacy, Safety and Biomarker Analysis of Combined PD-L1 (Atezolizumab) and VEGF (Bevacizumab) Blockade in Advanced Malignant Peritoneal Mesothelioma

Malignant peritoneal mesothelioma (MPeM) is a rare but aggressive malignancy with limited treatment options. VEGF inhibition enhances efficacy of immune-checkpoint inhibitors by reworking the immunosuppressive tumor milieu. Efficacy and safety of combined PD-L1 (atezolizumab) and VEGF (bevacizumab) blockade (AtezoBev) was assessed in 20 patients with advanced and unresectable MPeM with progression or intolerance to prior platinum-pemetrexed chemotherapy. The primary endpoint of confirmed objective response rate per RECISTv1.1 by independent radiology review was 40% (8/20; 95%CI:19.1-64.0) with median response duration of 12.8 months. Six (75%) responses lasted for >10 months. Progression-free and overall survival at 1-year were 61% (95%CI:35-80) and 85% (95%CI:60-95), respectively. Responses occurred notwithstanding low tumor mutation burden and PD-L1 expression status. Baseline epithelial-mesenchymal transition gene-expression correlated with therapeutic resistance/response (r=0.80; P=0.0010). AtezoBev showed promising and durable efficacy in patients with advanced MPeM with acceptable safety profile and these results address a grave unmet need for this orphan disease.

Expression of BCL2 alternative proteins and association with outcome in CLL patients treated with venetoclax

Venetoclax, a BCL-2 inhibitor, is highly effective for the treatment of patients with chronic lymphocytic leukemia (CLL) and dependence on alternative proteins may result in resistance to BCL-2 inhibition. Patients with CLL treated with venetoclax as monotherapy at MD Anderson Cancer Center between 05/2012 and 01/2016 were included and pretreatment bone marrow was analyzed by immunohistochemistry (IHC) for BCL-W, BCL-XL, BCL2-A1 and MCL-1. Twenty-seven patients were included. BCL-W + and BCL-2A1+ was found in 15% and 7% of the patients, respectively. Both BCL-XL and MCL-1 were negative in all samples. A higher CR and longer PFS rates were observed in patients with BCL-W+ (p = .60, p = .46), BCL-2A1+ (p = .60, p = .29), and either BCL-W + or BCL-2A1+ (p = .33, p = .20), though not statistically significant. Pretreatment IHC expression of BCL-2 alternative proteins does not predict response to venetoclax in CLL, but may be a surrogate for an indolent biology. Sensitive techniques are needed to explore anti-apoptotic pathways.

STING Pathway Expression Identifies NSCLC With an Immune-Responsive Phenotype

INTRODUCTION

Although the combination of anti-programmed cell death-1 or anti-programmed cell death ligand-1 (PD-L1) with platinum chemotherapy is a standard of care for NSCLC, clinical responses vary. Even though predictive biomarkers (which include PD-L1 expression, tumor mutational burden, and inflamed immune microenvironment) are validated for immunotherapy, their relevance to chemoimmunotherapy combinations is less clear. We have recently reported that activation of the stimulator of interferon genes (STING) innate immune pathway enhances immunotherapy response in SCLC. Here, we hypothesize that STING pathway activation may predict and underlie predictive correlates of antitumor immunity in NSCLC.

METHODS

We analyzed transcriptomic and proteomic profiles in two NSCLC cohorts from our institution (treatment-naive patients in the Profiling of Resistance Patterns and Oncogenic Signaling Pathways in Evaluation of Cancers of the Thorax study and relapsed patients in the Biomarker-Integrated Approaches of Targeted Therapy for Lung Cancer Elimination study) and The Cancer Genome Atlas (N = 1320). Tumors were stratified by STING activation on the basis of protein or mRNA expression of cyclic GMP-AMP synthase, phospho-STING, and STING-mediated chemokines (chemokine ligand 5 [CCL5] and C-X-C motif chemokine 10 [CXCL10]). STING activation in patient tumors and in platinum-treated preclinical NSCLC models was correlated with biomarkers of immunotherapy response.

RESULTS

STING activation is associated with higher levels of intrinsic DNA damage, targetable immune checkpoints, and chemokines in treatment-naive and relapsed lung adenocarcinoma. We observed that tumors with lower STING and immune gene expression show higher frequency of serine-threonine kinase 11 (STK11) mutations; however, we identified a subset of these tumors that are TP53 comutated and display high immune- and STING-related gene expression. Treatment with cisplatin increases STING pathway activation and PD-L1 expression in multiple NSCLC preclinical models, including adeno- and squamous cell carcinoma.

CONCLUSIONS

STING pathway activation in NSCLC predicts features of immunotherapy response and is enhanced by cisplatin treatment. This suggests a possible predictive biomarker and mechanism for improved response to chemoimmunotherapy combinations.

CXCR2 expression in tumor cells is a poor prognostic factor and promotes invasion and metastasis in lung adenocarcinoma

CXCR2 in non-small cell lung cancer (NSCLC) has been studied mainly in stromal cells and is known to increase tumor inflammation and angiogenesis. Here, we examined the prognostic importance of CXCR2 in NSCLC and the role of CXCR2 and its ligands in lung cancer cells. The effect of CXCR2 expression on tumor cells was studied using stable knockdown clones derived from a murine KRAS/p53-mutant lung adenocarcinoma cell line with high metastatic potential and an orthotopic syngeneic mouse model and in vitro using a CXCR2 small-molecule antagonist (SB225002). CXCR2 protein expression was analyzed in tumor cells from 262 NSCLC. Gene expression profiles for CXCR2 and its ligands (CXCR2 axis) were analyzed in 52 human NSCLC cell lines and 442 human lung adenocarcinomas. Methylation of CXCR2 axis promoters was determined in 70 human NSCLC cell lines. Invasion and metastasis were decreased in CXCR2 knockdown clones in vitro and in vivo. SB225002 decreased invasion in vitro. In lung adenocarcinomas, CXCR2 expression in tumor cells was associated with smoking and poor prognosis. CXCR2 axis gene expression profiles in human NSCLC cell lines and lung adenocarcinomas defined a cluster driven by CXCL5 and associated with smoking, poor prognosis, and RAS pathway activation. Expression of CXCL5 was regulated by promoter methylation. The CXCR2 axis may be an important target in smoking-related lung adenocarcinoma.

Abstract 392: CXCR2 expression in tumor cells is associated with an adverse outcome in a large set of non-small-cell lung cancer (NSCLC)

Background: CXCR2 plays an important role in inflammation, and stimulation of CXCR2-expressing endothelial cells by ELR+ CXC chemokines promotes angiogenesis. Our goal was to study the expression of CXCR2 by tumor cells and its impact on prognosis in NSCLC. Material and Methods: CXCR2 expression was determined using immunohistochemistry and a large set of tissue microarray including 458 NSCLC. The association between cytoplasmic CXCR2 (cCXCR2) expression in tumor cells and clinico-pathological factors as well as survival was analyzed. Distribution of CXCR2 and its ligands (IL8, CXCL1, CXCL2, CXCL3, CXCL5, CXCL6 and CXCL7) gene expression was studied using publicly available gene expression profiles from 52 NSCLC cell lines (GSE4824) and 444 lung adenocarcinomas (adc) (NCI Director's Challenge). To summarize the effect of CXCR2/CXCR2 ligands biological axis, Principal Component Analysis (PCA) and unsupervised hierarchical clustering were performed using CXCR2 and its ligands gene expression in both cell lines and lung adc. The first Principal Component (PC1) was correlated (Pearson) with the whole genome in 52 NSCLC cell lines. All genes were ranked according to their correlation with PC1, and used for Gene Set Enrichment Analysis (GSEA) “pre-ranked” analysis. Results: Using the median of expression to dichotomize the patients in a high versus low expression group, 238 (52.1%) tumors expressed high cCXCR2. No association was observed with gender, race, smoking habits, histology, and stage. High cCXCR2 was associated with overall survival (Hazard ratio (HR) 1.5696; confidence interval (CI)=1.176-2.096, p-value=0.002) and recurrence-free survival (HR 1.321; CI=1.027-1.698, p-value=0.030) in a univariate Cox proportional hazards (CPH) model. High cCXCR2 remained significant for overall in a multicovariate CPH after adjusting for age, gender, histology, stage, neoadjuvant chemotherapy for overall survival (HR 1.465; CI=1.088-1.972, p-value=0.012) and a trend was observed for recurrence-free survival (HR 1.261; CI=0.973-1.633, p-value=0.080). Gene expression distribution of CXCR2 and its ligands were strikingly similar in cell lines and lung adc. In both cases, hierarchical clustering showed a cluster mostly driven by CXCR2, CXCL5, and CXCL7, representing 20% of the samples. PC1 accounted for 48.25 and 46.15% of the variation of the PCA in cell lines and lung adc respectively. KRAS and NFKB oncogenic pathways were the top 2 gene sets associated with PC1. Using the median as a cutoff, PC1 was associated with a worse overall survival in 444 lung adc (Log-rank P=0.006). Conclusion: cCXCR2 expression in NSCLC tumor cells is frequent and associated with an adverse outcome. CXCR2/CXCR2 ligands biological axis may be associated with an activation of KRAS and NFKB pathways, and a poor prognosis in lung adc. Funding Source: Department of Defense-VITAL.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 392. doi:10.1158/1538-7445.AM2011-392