•Molecular testing determines appropriate targeted therapies for advanced NSCLC.•Country-specific differences exist in molecular testing availability across Europe.•Molecular tumour board and reflex ...molecular testing strategies are desirable.•Next-generation sequencing permits comprehensive molecular testing.•Cell-free DNA-based analysis facilitates re-testing to guide subsequent treatment.
The discovery of oncogenic driver mutations rendering non-small cell lung cancer (NSCLC) targetable by small-molecule inhibitors, and the development of immunotherapies, have revolutionised NSCLC treatment. Today, instead of non-selective chemotherapies, all patients with advanced NSCLC eligible for treatment (and increasing numbers with earlier, less extensive disease) require fast and comprehensive screening of biomarkers for first-line patient selection for targeted therapy, chemotherapy, or immunotherapy (with or without chemotherapy). To avoid unnecessary re-biopsies, biomarker screening before first-line treatment should also include markers that are actionable from second-line onwards; PD-L1 expression testing is also mandatory before initiating treatment.
Population differences exist in the frequency of oncogenic driver mutations: EGFR mutations are more frequent in Asia than Europe, whereas the converse is true for KRAS mutations. In addition to approved first-line therapies, a number of emerging therapies are being investigated in clinical trials. Guidelines for biomarker testing vary by country, with the number of actionable targets and the requirement for extensive molecular screening strategies expected to increase. To meet diagnostic demands, rapid screening technologies for single-driver mutations have been implemented. Improvements in DNA- and RNA-based next-generation sequencing technologies enable analysis of a group of genes in one assay; however, turnaround times remain relatively long. Consequently, rapid screening technologies are being implemented alongside next-generation sequencing.
Further challenges in the evolving landscape of biomarker testing in NSCLC are actionable primary and secondary resistance mechanisms to targeted therapies. Therefore, comprehensive testing on re-biopsies, collected at the time of disease progression, in combination with testing of circulating tumour DNA may provide important information to guide second- or third-line therapies. Furthermore, longitudinal biomarker testing can provide insights into tumour evolution and heterogeneity during the course of the disease. We summarise best practice strategies for Europe in the changing landscape of biomarker testing at diagnosis and during treatment.
•No technical bias between fresh frozen and FFPE samples.•A high fraction of adenocarcinoma patients with activating KRAS mutations.•Mutations in TP53, STK11 and SMARCA4 linked to poor prognosis in ...adenocarcinoma.•Mutations in CSMD3 linked to better prognosis in squamous cell carcinoma.•Co-mutations in TP53 or STK11 confer poor prognosis in KRAS positive patients.
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.
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.
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.
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.
The Blueprint (BP) Programmed Death Ligand 1 (PD-L1) Immunohistochemistry Comparability Project is a pivotal academic/professional society and industrial collaboration to assess the feasibility of ...harmonizing the clinical use of five independently developed commercial PD-L1 immunohistochemistry assays. The goal of BP phase 2 (BP2) was to validate the results obtained in BP phase 1 by using real-world clinical lung cancer samples.
BP2 were conducted using 81 lung cancer specimens of various histological and sample types, stained with all five trial-validated PD-L1 assays (22C3, 28-8, SP142, SP263, and 73-10); the slides were evaluated by an international panel of pathologists. BP2 also assessed the reliability of PD-L1 scoring by using digital images, and samples prepared for cytological examination. PD-L1 expression was assessed for percentage (tumor proportional score) of tumor cell (TC) and immune cell areas showing PD-L1 staining, with TCs scored continuously or categorically with the cutoffs used in checkpoint inhibitor trials.
The BP2 results showed highly comparable staining by the 22C3, 28-8 and SP263 assays; less sensitivity with the SP142 assay; and higher sensitivity with the 73-10 assay to detect PD-L1 expression on TCs. Glass slide and digital image scorings were highly concordant (Pearson correlation >0.96). There was very strong reliability among pathologists in TC PD-L1 scoring with all assays (overall intraclass correlation coefficient ICC = 0.86–0.93), poor reliability in IC PD-L1 scoring (overall ICC = 0.18–0.19), and good agreement in assessing PD-L1 status on cytological cell block materials (ICC = 0.78–0.85).
BP2 consolidates the analytical evidence for interchangeability of the 22C3, 28-8, and SP263 assays and lower sensitivity of the SP142 assay for determining tumor proportion score on TCs and demonstrates greater sensitivity of the 73-10 assay compared with that of the other assays.
The study of human macrophages and their ontogeny is an important unresolved issue. Here, we use a humanized mouse model expressing human cytokines to dissect the development of lung macrophages from ...human hematopoiesis in vivo. Human CD34+ hematopoietic stem and progenitor cells (HSPCs) generated three macrophage populations, occupying separate anatomical niches in the lung. Intravascular cell labeling, cell transplantation, and fate-mapping studies established that classical CD14+ blood monocytes derived from HSPCs migrated into lung tissue and gave rise to human interstitial and alveolar macrophages. In contrast, non-classical CD16+ blood monocytes preferentially generated macrophages resident in the lung vasculature (pulmonary intravascular macrophages). Finally, single-cell RNA sequencing defined intermediate differentiation stages in human lung macrophage development from blood monocytes. This study identifies distinct developmental pathways from circulating monocytes to lung macrophages and reveals how cellular origin contributes to human macrophage identity, diversity, and localization in vivo.
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•A developmental map of human lung macrophages from blood monocytes in vivo•Extravasating CD14+ monocytes give rise to alveolar and interstitial macrophages•Identification of CD14+HLA-DRhi lung monocytes as intermediate differentiation stage•Pulmonary intravascular macrophages originate from CD16+ blood monocytes
Tissue-resident macrophages maintain healthy organ function, but the ontogeny of human macrophages is largely unknown. Using humanized mice and single-cell RNA sequencing, Evren et al. uncover the migration and differentiation of blood monocytes into distinct populations of human lung macrophages in vivo.
The recent development of immune checkpoint inhibitors (ICIs) has led to promising advances in the treatment of patients with NSCLC and SCLC with advanced or metastatic disease. Most ICIs target ...programmed cell death protein 1 (PD-1) or programmed death ligand 1 (PD-L1) axis with the aim of restoring antitumor immunity. Multiple clinical trials for ICIs have evaluated a predictive value of PD-L1 protein expression in tumor cells and tumor-infiltrating immune cells (ICs) by immunohistochemistry (IHC), for which different assays with specific IHC platforms were applied. Of those, some PD-L1 IHC assays have been validated for the prescription of the corresponding agent for first- or second-line treatment. However, not all laboratories are equipped with the dedicated platforms, and many laboratories have set up in-house or laboratory-developed tests that are more affordable than the generally expensive clinical trial–validated assays. Although PD-L1 IHC test is now deployed in most pathology laboratories, its appropriate implementation and interpretation are critical as a predictive biomarker and can be challenging owing to the multiple antibody clones and platforms or assays available and given the typically small size of samples provided. Because many articles have been published since the issue of the IASLC Atlas of PD-L1 Immunohistochemistry Testing in Lung Cancer, this review by the IASLC Pathology Committee provides updates on the indications of ICIs for lung cancer in 2019 and discusses important considerations on preanalytical, analytical, and postanalytical aspects of PD-L1 IHC testing, including specimen type, validation of assays, external quality assurance, and training.
Immune checkpoint inhibitor (ICI) therapies have revolutionized the management of patients with NSCLC and have led to unprecedented improvements in response rates and survival in a subset of patients ...with this fatal disease. However, the available therapies work only for a minority of patients, are associated with substantial societal cost, and may lead to considerable immune-related adverse events. Therefore, patient selection must be optimized through the use of relevant biomarkers. Programmed death-ligand 1 protein expression by immunohistochemistry is widely used today for the selection of programmed cell death protein 1 inhibitor therapy in patients with NSCLC; however, this approach lacks robust sensitivity and specificity for predicting response. Tumor mutation burden (TMB), or the number of somatic mutations derived from next-generation sequencing techniques, has been widely explored as an alternative or complementary biomarker for response to ICIs. In theory, a higher TMB increases the probability of tumor neoantigen production and therefore, the likelihood of immune recognition and tumor cell killing. Although TMB alone is a simplistic surrogate of this complex interplay, it is a quantitative variable that can be relatively readily measured using currently available sequencing techniques. A large number of clinical trials and retrospective analyses, employing both tumor and blood-based sequencing tools, have evaluated the performance of TMB as a predictive biomarker, and in many cases reveal a correlation between high TMB and ICI response rates and progression-free survival. Many challenges remain before the implementation of TMB as a biomarker in clinical practice. These include the following: (1) identification of therapies whose response is best informed by TMB status; (2) robust definition of a predictive TMB cut point; (3) acceptable sequencing panel size and design; and (4) the need for robust technical and informatic rigor to generate precise and accurate TMB measurements across different laboratories. Finally, effective prediction of response to ICI therapy will likely require integration of TMB with a host of other potential biomarkers, including tumor genomic driver alterations, tumor-immune milieu, and other features of the host immune system. This perspective piece will review the current clinical evidence for TMB as a biomarker and address the technical sequencing considerations and ongoing challenges in the use of TMB in routine practice.
Global gene expression profiling has been widely used in lung cancer research to identify clinically relevant molecular subtypes as well as to predict prognosis and therapy response. So far, the ...value of these multigene signatures in clinical practice is unclear, and the biologic importance of individual genes is difficult to assess, as the published signatures virtually do not overlap.
Here, we describe a novel single institute cohort, including 196 non-small lung cancers (NSCLC) with clinical information and long-term follow-up. Gene expression array data were used as a training set to screen for single genes with prognostic impact. The top 450 probe sets identified using a univariate Cox regression model (significance level P < 0.01) were tested in a meta-analysis including five publicly available independent lung cancer cohorts (n = 860).
The meta-analysis revealed 14 genes that were significantly associated with survival (P < 0.001) with a false discovery rate <1%. The prognostic impact of one of these genes, the cell adhesion molecule 1 (CADM1), was confirmed by use of immunohistochemistry on tissue microarrays from 2 independent NSCLC cohorts, altogether including 617 NSCLC samples. Low CADM1 protein expression was significantly associated with shorter survival, with particular influence in the adenocarcinoma patient subgroup.
Using a novel NSCLC cohort together with a meta-analysis validation approach, we have identified a set of single genes with independent prognostic impact. One of these genes, CADM1, was further established as an immunohistochemical marker with a potential application in clinical diagnostics.
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.
What's new?
Because of their dual anti‐ and proinflammatory role, tumor‐associated macrophages (TAMs) are attractive targets for immunotherapy. Treatment with antibodies targeting the scavenger receptor MARCO has previously been shown to result in a more proinflammatory macrophage phenotype and reduced tumor growth. Here, the authors show that MARCO defines a distinct subset of immune‐suppressive TAMs in a large lung cancer cohort. A higher macrophage infiltration was observed in tumors expressing PD‐L1, and transcriptomic data revealed a correlation between MARCO, checkpoint molecules and T‐cell infiltration. MARCO could thus be a potential new immune target for anti‐TAM treatment in a subset of NSCLC patients.
Polarization of tumor-associated macrophages (TAMs) to a proangiogenic/immune-suppressive (M2-like) phenotype and abnormal, hypoperfused vessels are hallmarks of malignancy, but their molecular basis ...and interrelationship remains enigmatic. We report that the host-produced histidine-rich glycoprotein (HRG) inhibits tumor growth and metastasis, while improving chemotherapy. By skewing TAM polarization away from the M2- to a tumor-inhibiting M1-like phenotype, HRG promotes antitumor immune responses and vessel normalization, effects known to decrease tumor growth and metastasis and to enhance chemotherapy. Skewing of TAM polarization by HRG relies substantially on downregulation of placental growth factor (PlGF). Besides unveiling an important role for TAM polarization in tumor vessel abnormalization, and its regulation by HRG/PlGF, these findings offer therapeutic opportunities for anticancer and antiangiogenic treatment.
► HRG represses tumor growth and metastasis by macrophage polarization ► HRG-mediated macrophage polarization is dependent on suppression of PlGF ► HRG-mediated macrophage polarization promote immunomodulation ► Myeloid-derived PlGF monitors tumor vessel functionality and immune response
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