Infiltration of NK and plasma cells is associated with a distinct immune subset in non-small cell lung cancer.

Immune cells of the tumor microenvironment are central but erratic targets for immunotherapy. The aim of this study was to characterize novel patterns of immune cell infiltration in non-small cell lung cancer (NSCLC) in relation to its molecular and clinicopathologic characteristics. Lymphocytes (CD3+, CD4+, CD8+, CD20+, FOXP3+, CD45RO+), macrophages (CD163+), plasma cells (CD138+), NK cells (NKp46+), PD1+, and PD-L1+ were annotated on a tissue microarray including 357 NSCLC cases. Somatic mutations were analyzed by targeted sequencing for 82 genes and a tumor mutational load score was estimated. Transcriptomic immune patterns were established in 197 patients based on RNA sequencing data. The immune cell infiltration was variable and showed only poor association with specific mutations. The previously defined immune phenotypic patterns, desert, inflamed, and immune excluded, comprised 30, 13, and 57% of cases, respectively. Notably, mRNA immune activation and high estimated tumor mutational load were unique only for the inflamed pattern. However, in the unsupervised cluster analysis, including all immune cell markers, these conceptual patterns were only weakly reproduced. Instead, four immune classes were identified: (1) high immune cell infiltration, (2) high immune cell infiltration with abundance of CD20+ B cells, (3) low immune cell infiltration, and (4) a phenotype with an imprint of plasma cells and NK cells. This latter class was linked to better survival despite exhibiting low expression of immune response-related genes (e.g. CXCL9, GZMB, INFG, CTLA4). This compartment-specific immune cell analysis in the context of the molecular and clinical background of NSCLC reveals two previously unrecognized immune classes. A refined immune classification, including traits of the humoral and innate immune response, is important to define the immunogenic potency of NSCLC in the era of immunotherapy. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

PD-L1 amplification is associated with an immune cell rich phenotype in squamous cell cancer of the lung.

Gene amplification is considered to be one responsible cause for upregulation of Programmed Death Ligand-1 (PD-L1) in non-small cell lung cancer (NSCLC) and to represent a specific molecular subgroup possibly associated with immunotherapy response. Our aim was to analyze the frequency of PD-L1 amplification, its relation to PD-L1 mRNA and protein expression, and to characterize the immune microenvironment of amplified cases. The study was based on two independent NSCLC cohorts, including 354 and 349 cases, respectively. Tissue microarrays were used to evaluate PD-L1 amplification by FISH and PD-L1 protein by immunohistochemistry. Immune infiltrates were characterized immunohistochemically by a panel of immune markers (CD3, CD4, CD8, PD-1, Foxp3, CD20, CD138, CD168, CD45RO, NKp46). Mutational status was determined by targeted sequencing. RNAseq data was available for 197 patients. PD-L1 amplification was detected in 4.5% of all evaluable cases. PD-L1 amplification correlated only weakly with mRNA and protein expression. About  37% of amplified cases were negative for PD-L1 protein. PD-L1 amplification did not show any association with the mutational status. In squamous cell cancer, PD-L1 amplified cases were enriched among patients with high tumoral immune cell infiltration and showed gene expression profiles related to immune exhaustion. In conclusion, PD-L1 amplification correlates with PD-L1 expression in squamous cell cancer and was associated with an immune cell rich tumor phenotype. The correlative findings help to understand the role of PD-L1 amplification as an important immune escape mechanism in NSCLC and suggest the need to further evaluate PD-L1 amplification as predictive biomarker for checkpoint inhibitor therapy.

Expression of scavenger receptor MARCO defines a targetable tumor-associated macrophage subset in non-small cell lung cancer.

Tumor-associated macrophages (TAMs) are attractive targets for immunotherapy. Recently, studies in animal models showed that treatment with an anti-TAM antibody directed against the scavenger receptor MARCO resulted in suppression of tumor growth and metastatic dissemination. Here we investigated the expression of MARCO in relation to other macrophage markers and immune pathways in a non-small cell lung cancer (NSCLC) cohort (n = 352). MARCO, CD68, CD163, MSR1 and programmed death ligand-1 (PD-L1) were analyzed by immunohistochemistry and immunofluorescence, and associations to other immune cells and regulatory pathways were studied in a subset of cases (n = 199) with available RNA-seq data. We observed a large variation in macrophage density between cases and a strong correlation between CD68 and CD163, suggesting that the majority of TAMs present in NSCLC exhibit a protumor phenotype. Correlation to clinical data only showed a weak trend toward worse survival for patients with high macrophage infiltration. Interestingly, MARCO was expressed on a distinct subpopulation of TAMs, which tended to aggregate in close proximity to tumor cell nests. On the transcriptomic level, we found a positive association between MARCO gene expression and general immune response pathways including strong links to immunosuppressive TAMs, T-cell infiltration and immune checkpoint molecules. Indeed, a higher macrophage infiltration was seen in tumors expressing PD-L1, and macrophages residing within tumor cell nests co-expressed MARCO and PD-L1. Thus, MARCO is a potential new immune target for anti-TAM treatment in a subset of NSCLC patients, possibly in combination with available immune checkpoint inhibitors.

Reaching the limits of prognostication in non-small cell lung cancer: an optimized biomarker panel fails to outperform clinical parameters.

Numerous protein biomarkers have been analyzed to improve prognostication in non-small cell lung cancer, but have not yet demonstrated sufficient value to be introduced into clinical practice. Here, we aimed to develop and validate a prognostic model for surgically resected non-small cell lung cancer. A biomarker panel was selected based on (1) prognostic association in published literature, (2) prognostic association in gene expression data sets, (3) availability of reliable antibodies, and (4) representation of diverse biological processes. The five selected proteins (MKI67, EZH2, SLC2A1, CADM1, and NKX2-1 alias TTF1) were analyzed by immunohistochemistry on tissue microarrays including tissue from 326 non-small cell lung cancer patients. One score was obtained for each tumor and each protein. The scores were combined, with or without the inclusion of clinical parameters, and the best prognostic model was defined according to the corresponding concordance index (C-index). The best-performing model was subsequently validated in an independent cohort consisting of tissue from 345 non-small cell lung cancer patients. The model based only on protein expression did not perform better compared to clinicopathological parameters, whereas combining protein expression with clinicopathological data resulted in a slightly better prognostic performance (C-index: all non-small cell lung cancer 0.63 vs 0.64; adenocarcinoma: 0.66 vs 0.70, squamous cell carcinoma: 0.57 vs 0.56). However, this modest effect did not translate into a significantly improved accuracy of survival prediction. The combination of a prognostic biomarker panel with clinicopathological parameters did not improve survival prediction in non-small cell lung cancer, questioning the potential of immunohistochemistry-based assessment of protein biomarkers for prognostication in clinical practice.

Oligonucleotide gap-fill ligation for mutation detection and sequencing in situ.

In clinical diagnostics a great need exists for targeted in situ multiplex nucleic acid analysis as the mutational status can offer guidance for effective treatment. One well-established method uses padlock probes for mutation detection and multiplex expression analysis directly in cells and tissues. Here, we use oligonucleotide gap-fill ligation to further increase specificity and to capture molecular substrates for in situ sequencing. Short oligonucleotides are joined at both ends of a padlock gap probe by two ligation events and are then locally amplified by target-primed rolling circle amplification (RCA) preserving spatial information. We demonstrate the specific detection of the A3243G mutation of mitochondrial DNA and we successfully characterize a single nucleotide variant in the ACTB mRNA in cells by in situ sequencing of RCA products generated by padlock gap-fill ligation. To demonstrate the clinical applicability of our assay, we show specific detection of a point mutation in the EGFR gene in fresh frozen and formalin-fixed, paraffin-embedded (FFPE) lung cancer samples and confirm the detected mutation by in situ sequencing. This approach presents several advantages over conventional padlock probes allowing simpler assay design for multiplexed mutation detection to screen for the presence of mutations in clinically relevant mutational hotspots directly in situ.

Inconsistent results in the analysis of ALK rearrangements in non-small cell lung cancer.

BACKGROUND: Identification of targetable EML4-ALK fusion proteins has revolutionized the treatment of a minor subgroup of non-small cell lung cancer (NSCLC) patients. Although fluorescence in situ hybridization (FISH) is regarded as the gold standard for detection of ALK rearrangements, ALK immunohistochemistry (IHC) is often used as screening tool in clinical practice. In order to unbiasedly analyze the diagnostic impact of such a screening strategy, we compared ALK IHC with ALK FISH in three large representative Swedish NSCLC cohorts incorporating clinical parameters and gene expression data. METHODS: ALK rearrangements were detected using FISH on tissue microarrays (TMAs), including tissue from 851 NSCLC patients. In parallel, ALK protein expression was detected using IHC, applying the antibody clone D5F3 with two different protocols (the FDA approved Ventana CDx assay and our in house Dako IHC protocol). Gene expression microarray data (Affymetrix) was available for 194 patients. RESULTS: ALK rearrangements were detected in 1.7 % in the complete cohort and 2.0 % in the non-squamous cell carcinoma subgroup. ALK protein expression was observed in 1.8 and 1.4 % when applying the Ventana assay or the in house Dako protocol, respectively. The specificity and accuracy of IHC was high (> 98 %), while the sensitivity was between 69 % (Ventana) and 62 % (in house Dako protocol). Furthermore, only 67 % of the ALK IHC positive cases were positive with both IHC assays. Gene expression analysis revealed that 6/194 (3 %) tumors showed high ALK gene expression (≥ 6 AU) and of them only three were positive by either FISH or IHC. CONCLUSION: The overall frequency of ALK rearrangements based on FISH was lower than previously reported. The sensitivity of both IHC assays was low, and the concordance between the FISH and the IHC assays poor, questioning current strategies to screen with IHC prior to FISH or completely replace FISH by IHC.

The relationship between EMT, CD44high /EGFRlow phenotype, and treatment response in head and neck cancer cell lines.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) tumors are often therapy resistant and may originate from cancer stem cells or tumor cells with an epithelial-to-mesenchymal transition (EMT) phenotype. The aim of this study was to characterize HNSCC cell lines with regard to EMT profile and to investigate the influence of EMT on the response to treatment. METHODS: mRNA expression of the EMT-associated genes CDH1 (E-cadherin), CDH2 (N-cadherin), FOXC2, TWIST1, VIM (vimentin), and FN1 (fibronectin) was determined using quantitative real-time PCR. Cell morphology and migration were investigated by phase-contrast microscopy and Boyden chamber assay, respectively. The cell surface expression of CD44 and epidermal growth factor receptor (EGFR) was examined by flow cytometry. The response to radiotherapy, cetuximab, and dasatinib was assessed by crystal violet staining. RESULTS: A total of 25 cell lines investigated differed greatly with regard to EMT phenotype. Cell lines with an EMT expression profile showed a mesenchymal morphology and a high migratory capacity. In addition, they exhibited a high cell surface expression of CD44 and a low expression of EGFR, a pattern previously associated with stemness. When the EMT inducer transforming growth factor-ß (TGF-ß) was added to non-EMT cells, changes in treatment responses were observed. Moreover, the expression of TWIST1 was found to correlate with radioresistance. CONCLUSIONS: The data presented in this report suggest that EMT is associated with a CD44high /EGFRlow phenotype and possibly negative impact on radiotherapy response in HNSCC cell lines.

Fibroblast subsets in non-small cell lung cancer: Associations with survival, mutations, and immune features.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are molecularly heterogeneous mesenchymal cells that interact with malignant cells and immune cells and confer anti- and protumorigenic functions. Prior in situ profiling studies of human CAFs have largely relied on scoring single markers, thus presenting a limited view of their molecular complexity. Our objective was to study the complex spatial tumor microenvironment of non-small cell lung cancer (NSCLC) with multiple CAF biomarkers, identify novel CAF subsets, and explore their associations with patient outcome. METHODS: Multiplex fluorescence immunohistochemistry was employed to spatially profile the CAF landscape in 2 population-based NSCLC cohorts (n = 636) using antibodies against 4 fibroblast markers: platelet-derived growth factor receptor-alpha (PDGFRA) and -beta (PDGFRB), fibroblast activation protein (FAP), and alpha-smooth muscle actin (αSMA). The CAF subsets were analyzed for their correlations with mutations, immune characteristics, and clinical variables as well as overall survival. RESULTS: Two CAF subsets, CAF7 (PDGFRA-/PDGFRB+/FAP+/αSMA+) and CAF13 (PDGFRA+/PDGFRB+/FAP-/αSMA+), showed statistically significant but opposite associations with tumor histology, driver mutations (tumor protein p53 [TP53] and epidermal growth factor receptor [EGFR]), immune features (programmed death-ligand 1 and CD163), and prognosis. In patients with early stage tumors (pathological tumor-node-metastasis IA-IB), CAF7 and CAF13 acted as independent prognostic factors. CONCLUSIONS: Multimarker-defined CAF subsets were identified through high-content spatial profiling. The robust associations of CAFs with driver mutations, immune features, and outcome suggest CAFs as essential factors in NSCLC progression and warrant further studies to explore their potential as biomarkers or therapeutic targets. This study also highlights multiplex fluorescence immunohistochemistry-based CAF profiling as a powerful tool for the discovery of clinically relevant CAF subsets.

FGFR1 overexpression in non-small cell lung cancer is mediated by genetic and epigenetic mechanisms and is a determinant of FGFR1 inhibitor response.

Amplification of fibroblast growth factor receptor 1 (FGFR1) in non-small cell lung cancer (NSCLC) has been considered as an actionable drug target. However, pan-FGFR tyrosine kinase inhibitors did not demonstrate convincing clinical efficacy in FGFR1-amplified NSCLC patients. This study aimed to characterise the molecular context of FGFR1 expression and to define biomarkers predictive of FGFR1 inhibitor response. In this study, 635 NSCLC samples were characterised for FGFR1 protein expression by immunohistochemistry and copy number gain (CNG) by in situ hybridisation (n = 298) or DNA microarray (n = 189). FGFR1 gene expression (n = 369) and immune cell profiles (n = 309) were also examined. Furthermore, gene expression, methylation and microRNA data from The Cancer Genome Atlas (TCGA) were compared. A panel of FGFR1-amplified NSCLC patient-derived xenograft (PDX) models were tested for response to the selective FGFR1 antagonist M6123. A minority of patients demonstrated FGFR1 CNG (10.5%) or increased FGFR1 mRNA (8.7%) and protein expression (4.4%). FGFR1 CNG correlated weakly with FGFR1 gene and protein expression. Tumours overexpressing FGFR1 protein were typically devoid of driver alterations (e.g. EGFR, KRAS) and showed reduced infiltration of T-lymphocytes and lower PD-L1 expression. Promoter methylation and microRNA were identified as regulators of FGFR1 expression in NSCLC and other cancers. Finally, NSCLC PDX models demonstrating FGFR1 amplification and FGFR1 protein overexpression were sensitive to M6123. The unique molecular and immune features of tumours with high FGFR1 expression provide a rationale to stratify patients in future clinical trials of FGFR1 pathway-targeting agents.

Stromal FAP is an independent poor prognosis marker in non-small cell lung adenocarcinoma and associated with p53 mutation.

OBJECTIVES: Fibroblasts regulate tumor growth and immune surveillance. Here, we study FAP, PDGFßR and α-SMA fibroblast markers in a well-annotated clinical cohort of non-small-cell lung cancer (NSCLC) for analyses of associations with immune cell infiltration, mutation status and survival. MATERIALS AND METHODS: A well-annotated NSCLC cohort was subjected to IHC analyses of stromal expression of FAP, PDGFßR and α-SMA and of stromal CD8 density. Fibroblast markers-related measurements were analyzed with regard to potential associations with CD8 density, cancer genetic driver mutations, survival and PD-L1 expression in the whole NSCLC cohort and in subsets of patients. RESULTS: High stromal FAP expression was identified as an independent poor prognostic marker in the whole study population (HR 1.481; 95 % CI, 1.012-2.167, p = 0.023) and in the histological subset of adenocarcinoma (HR 1.720; 95 % CI, 1.126-2.627, p = 0.012). Among patients with adenocarcinoma, a particularly strong association of FAP with poor survival was detected in patients with low stromal CD8 infiltration, and in other subpopulations identified by specific clinical characteristics; elderly patients, females, non-smokers and patients with normal ECOG performance status. α-SMA expression was negatively associated with CD8 infiltration in non-smokers, but none of the fibroblast markers expression was associated with CD8 density in the whole study population. Significant associations were detected between presence of p53 mutations and high α-SMA (p = 0.003) and FAP expression (p < 0.001). CONCLUSION: The study identifies FAP intensity as a candidate independent NSCLC prognostic biomarker. The study also suggests continued analyses of the relationships between genetic driver mutations and the composition of tumor stroma, as well as continued probing of marker-defined fibroblasts as NSCLC subset-specific modifiers of immune surveillance and outcome.

Targeting MARCO and IL37R on Immunosuppressive Macrophages in Lung Cancer Blocks Regulatory T Cells and Supports Cytotoxic Lymphocyte Function.

The progression and metastatic capacity of solid tumors are strongly influenced by immune cells in the tumor microenvironment. In non-small cell lung cancer (NSCLC), accumulation of anti-inflammatory tumor-associated macrophages (TAM) is associated with worse clinical outcome and resistance to therapy. Here we investigated the immune landscape of NSCLC in the presence of protumoral TAMs expressing the macrophage receptor with collagenous structure (MARCO). MARCO-expressing TAM numbers correlated with increased occurrence of regulatory T cells and effector T cells and decreased natural killer (NK) cells in these tumors. Furthermore, transcriptomic data from the tumors uncovered a correlation between MARCO expression and the anti-inflammatory cytokine IL37. In vitro studies subsequently showed that lung cancer cells polarized macrophages to express MARCO and gain an immune-suppressive phenotype through the release of IL37. MARCO-expressing TAMs blocked cytotoxic T-cell and NK-cell activation, inhibiting their proliferation, cytokine production, and tumor killing capacity. Mechanistically, MARCO+ macrophages enhanced regulatory T (Treg) cell proliferation and IL10 production and diminished CD8 T-cell activities. Targeting MARCO or IL37 receptor (IL37R) by antibody or CRISPR knockout of IL37 in lung cancer cell lines repolarized TAMs, resulting in recovered cytolytic activity and antitumoral capacity of NK cells and T cells and downmodulated Treg cell activities. In summary, our data demonstrate a novel immune therapeutic approach targeting human TAMs immune suppression of NK- and T-cell antitumor activities. SIGNIFICANCE: This study defines tumor-derived IL37 and the macrophage scavenger receptor MARCO as potential therapeutic targets to remodel the immune-suppressive microenvironment in patients with lung cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/4/956/F1.large.jpg.

Programmed Cell Death Ligand 1 Expression in Resected Non-Small Cell Lung Cancer.

BACKGROUND: Recently, anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) immunotherapies have yielded promising outcomes for patients with advanced non-small cell lung cancer (NSCLC) and led to great interest in applying these agents to treat resectable early-stage NSCLC. The objective of our study was to evaluate PD-L1 protein expression in resectable early-stage NSCLC specimens from a large Northern European cohort, examine the relationship to clinical characteristics, and demonstrate the prognostic role in resected NSCLC. MATERIALS AND METHODS: A large cohort of 875 NSCLC tumors consisted of 337 patients from Sweden and 538 patients from Norway was studied. All the patients had undergone pulmonary resection, and most patients had had early-stage NSCLC. PD-L1 protein expression was assessed by immunohistochemistry using the Dako PD-L1 22C3 pharmDx kit. The tumor proportion score for PD-L1 protein expression was compared with comprehensive demographic and clinicopathologic data. RESULTS: The overall prevalence of PD-L1 protein expression in the resectable NSCLC cohort was 9.5% at a tumor proportion score cutoff of ≥ 50%. Stage I NSCLC had lower PD-L1 expression compared with that of the other stages (P = .0012). PD-L1 expression correlated with wild-type EGFR gene expression (P = .0156) and mutated KRAS gene expression (P = .0004). No significant association was found between PD-L1 expression and mortality after multivariable adjustment for clinical characteristics, although the survival curves showed PD-L1 expression significantly correlated with a poor prognosis in the total NSCLC cohort and in the adenocarcinoma subgroup. CONCLUSION: PD-L1 expression in the present large cohort of resectable NSCLC was relatively low compared with data from clinical trials of advanced NSCLC. PD-L1 expression correlated positively with tumor stage, wild-type EGFR, and KRAS mutation. PD-L1 expression was not found as an independent prognostic factor in the present study. These findings could be important in the future when evaluating the role of anti-PD-1/PD-L1 immunotherapy in the setting of neoadjuvant or adjuvant trials for early-stage resectable NSCLC.

Evaluation of NTRK immunohistochemistry as a screening method for NTRK gene fusion detection in non-small cell lung cancer.

PURPOSE: The small molecule inhibitors larotrectinib and entrectinib have recently been approved as cancer agnostic drugs in patients with tumours harbouring a rearrangement of the neurotrophic tropomyosin receptor kinase (NTRK). These oncogenic fusions are estimated to occur in 0.1-3 % of non-small cell lung cancers (NSCLC). Although molecular techniques are most reliable for fusion detection, immunohistochemical analysis is considered valuable for screening. Therefore, we evaluated the newly introduced diagnostic immunohistochemical assay (clone EPR17341) on a representative NSCLC cohort. METHODS: Cancer tissue from 688 clinically and molecularly extensively annotated NSCLC patients were comprised on tissue microarrays and stained with the pan-TRK antibody clone EPR17341. Positive cases were further analysed with the TruSight Tumor 170 RNA assay (Illumina). Selected cases were also tested with a NanoString NTRK fusion assay. For 199 cases, NTRK RNA expression data were available from previous RNA sequencing analysis. RESULTS: Altogether, staining patterns for 617 NSCLC cases were evaluable. Of these, four cases (0.6 %) demonstrated a strong diffuse cytoplasmic and membranous staining, and seven cases a moderate staining (1.1 %). NanoString or TST170-analysis could not confirm an NTRK fusion in any of the IHC positive cases, or any of the cases with high mRNA levels. In the four cases with strong staining intensity in the tissue microarray, whole section staining revealed marked heterogeneity of NTRK protein expression. CONCLUSION: The presence of NTRK fusion genes in non-small cell lung cancer is exceedingly rare. The use of the immunohistochemical NTRK assay will result in a small number of false positive cases. This should be considered when the assay is applied as a screening tool in clinical diagnostics.

Comprehensive analysis of RNA binding motif protein 3 (RBM3) in non-small cell lung cancer.

AIMS: High expression of the RNA-binding motif protein 3 (RBM3) correlates with improved prognosis in several major types of cancer. The aim of the present study was to examine the prognostic value of RBM3 protein and mRNA expression in non-small cell lung cancer (NSCLC). METHODS AND RESULTS: Immunohistochemical expression of RBM3 was evaluated in surgically treated NSCLC from two independent patient populations (n = 213 and n = 306). Staining patterns were correlated with clinicopathological parameters, overall survival (OS), and recurrence-free interval (RFI). Cases with high nuclear RBM3 protein expression had a prolonged 5-year OS in both cohorts when analyzing adenocarcinomas separately (P = .02 and P = .01). RBM3 remained an independent prognostic factor for OS in multivariable analysis of cohort I (HR 0.44, 95% CI 0.21-0.90) and for RFI in cohort II (HR 0.38, 95% CI 0.22-0.74). In squamous cell carcinoma, there was instead an insignificant association to poor prognosis. Also, the expression levels of RBM3 mRNA were investigated in 2087 lung adenocarcinomas and 899 squamous cell carcinomas assembled from 13 and 8 public gene expression microarray datasets, respectively. The RBM3 mRNA levels were not clearly associated with patient outcome in either adenocarcinomas or squamous cell carcinomas. CONCLUSIONS: The results from this study support that high protein expression of RBM3 is linked to improved outcome in lung adenocarcinoma.

WITHDRAWN: Characterization of Patterns of Immune Cell Infiltration in NSCLC.

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Publisher Correction: A clonal expression biomarker associates with lung cancer mortality.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Mutation patterns in a population-based non-small cell lung cancer cohort and prognostic impact of concomitant mutations in KRAS and TP53 or STK11.

OBJECTIVES: Non-small cell lung cancer (NSCLC) is a heterogeneous disease with unique combinations of somatic molecular alterations in individual patients, as well as significant differences in populations across the world with regard to mutation spectra and mutation frequencies. Here we aim to describe mutational patterns and linked clinical parameters in a population-based NSCLC cohort. MATERIALS AND METHODS: Using targeted resequencing the mutational status of 82 genes was evaluated in a consecutive Swedish surgical NSCLC cohort, consisting of 352 patient samples from either fresh frozen or formalin fixed paraffin embedded (FFPE) tissues. The panel covers all exons of the 82 genes and utilizes reduced target fragment length and two-strand capture making it compatible with degraded FFPE samples. RESULTS: We obtained a uniform sequencing coverage and mutation load across the fresh frozen and FFPE samples by adaption of sequencing depth and bioinformatic pipeline, thereby avoiding a technical bias between these two sample types. At large, the mutation frequencies resembled the frequencies seen in other western populations, except for a high frequency of KRAS hotspot mutations (43%) in adenocarcinoma patients. Worse overall survival was observed for adenocarcinoma patients with a mutation in either TP53, STK11 or SMARCA4. In the adenocarcinoma KRAS-mutated group poor survival appeared to be linked to concomitant TP53 or STK11 mutations, and not to KRAS mutation as a single aberration. Similar results were seen in the analysis of publicly available data from the cBioPortal. In squamous cell carcinoma a worse prognosis could be observed for patients with MLL2 mutations, while CSMD3 mutations were linked to a better prognosis. CONCLUSION: Here we have evaluated the mutational status of a NSCLC cohort. We could not confirm any survival impact of isolated driver mutations. Instead, concurrent mutations in TP53 and STK11 were shown to confer poor survival in the KRAS-positive adenocarcinoma subgroup.

A clonal expression biomarker associates with lung cancer mortality.

An aim of molecular biomarkers is to stratify patients with cancer into disease subtypes predictive of outcome, improving diagnostic precision beyond clinical descriptors such as tumor stage1. Transcriptomic intratumor heterogeneity (RNA-ITH) has been shown to confound existing expression-based biomarkers across multiple cancer types2-6. Here, we analyze multi-region whole-exome and RNA sequencing data for 156 tumor regions from 48 patients enrolled in the TRACERx study to explore and control for RNA-ITH in non-small cell lung cancer. We find that chromosomal instability is a major driver of RNA-ITH, and existing prognostic gene expression signatures are vulnerable to tumor sampling bias. To address this, we identify genes expressed homogeneously within individual tumors that encode expression modules of cancer cell proliferation and are often driven by DNA copy-number gains selected early in tumor evolution. Clonal transcriptomic biomarkers overcome tumor sampling bias, associate with survival independent of clinicopathological risk factors, and may provide a general strategy to refine biomarker design across cancer types.

Gene Expression Profiling of Large Cell Lung Cancer Links Transcriptional Phenotypes to the New Histological WHO 2015 Classification.

INTRODUCTION: Large cell lung cancer (LCLC) and large cell neuroendocrine carcinoma (LCNEC) constitute a small proportion of NSCLC. The WHO 2015 classification guidelines changed the definition of the debated histological subtype LCLC to be based on immunomarkers for adenocarcinoma and squamous cancer. We sought to determine whether these new guidelines also translate into the transcriptional landscape of lung cancer, and LCLC specifically. METHODS: Gene expression profiling was performed by using Illumina V4 HT12 microarrays (Illumina, San Diego, CA) on samples from 159 cases (comprising all histological subtypes, including 10 classified as LCLC WHO 2015 and 14 classified as LCNEC according to the WHO 2015 guidelines), with complimentary mutational and immunohistochemical data. Derived transcriptional phenotypes were validated in 199 independent tumors, including six WHO 2015 LCLCs and five LCNECs. RESULTS: Unsupervised analysis of gene expression data identified a phenotype comprising 90% of WHO 2015 LCLC tumors, with characteristics of poorly differentiated proliferative cancer, a 90% tumor protein p53 gene (TP53) mutation rate, and lack of well-known NSCLC oncogene driver alterations. Validation in independent data confirmed aggregation of WHO 2015 LCLCs in the specific phenotype. For LCNEC tumors, the unsupervised gene expression analysis suggested two different transcriptional patterns corresponding to a proposed genetic division of LCNEC tumors into SCLC-like and NSCLC-like cancer on the basis of TP53 and retinoblastoma 1 gene (RB1) alteration patterns. CONCLUSIONS: Refined classification of LCLC has implications for diagnosis, prognostics, and therapy decisions. Our molecular analyses support the WHO 2015 classification of LCLC and LCNEC tumors, which herein follow different tumorigenic paths and can accordingly be stratified into different transcriptional subgroups, thus linking diagnostic immunohistochemical staining-driven classification with the transcriptional landscape of lung cancer.

Profiling cancer testis antigens in non-small-cell lung cancer.

Cancer testis antigens (CTAs) are of clinical interest as biomarkers and present valuable targets for immunotherapy. To comprehensively characterize the CTA landscape of non-small-cell lung cancer (NSCLC), we compared RNAseq data from 199 NSCLC tissues to the normal transcriptome of 142 samples from 32 different normal organs. Of 232 CTAs currently annotated in the Caner Testis Database (CTdatabase), 96 were confirmed in NSCLC. To obtain an unbiased CTA profile of NSCLC, we applied stringent criteria on our RNAseq data set and defined 90 genes as CTAs, of which 55 genes were not annotated in the CTdatabase, thus representing potential new CTAs. Cluster analysis revealed that CTA expression is histology dependent and concurrent expression is common. IHC confirmed tissue-specific protein expression of selected new CTAs (TKTL1, TGIF2LX, VCX, and CXORF67). Furthermore, methylation was identified as a regulatory mechanism of CTA expression based on independent data from The Cancer Genome Atlas. The proposed prognostic impact of CTAs in lung cancer was not confirmed, neither in our RNAseq cohort nor in an independent meta-analysis of 1,117 NSCLC cases. In summary, we defined a set of 90 reliable CTAs, including information on protein expression, methylation, and survival association. The detailed RNAseq catalog can guide biomarker studies and efforts to identify targets for immunotherapeutic strategies.