Evolutionary trajectories of small cell lung cancer under therapy

The evolutionary processes that underlie the marked sensitivity of small cell lung cancer (SCLC) to chemotherapy and rapid relapse are unknown1-3. Here we determined tumour phylogenies at diagnosis and throughout chemotherapy and immunotherapy by multiregion sequencing of 160 tumours from 65 patients. Treatment-naive SCLC exhibited clonal homogeneity at distinct tumour sites, whereas first-line platinum-based chemotherapy led to a burst in genomic intratumour heterogeneity and spatial clonal diversity. We observed branched evolution and a shift to ancestral clones underlying tumour relapse. Effective radio- or immunotherapy induced a re-expansion of founder clones with acquired genomic damage from first-line chemotherapy. Whereas TP53 and RB1 alterations were exclusively part of the common ancestor, MYC family amplifications were frequently not constituents of the founder clone. At relapse, emerging subclonal mutations affected key genes associated with SCLC biology, and tumours harbouring clonal CREBBP/EP300 alterations underwent genome duplications. Gene-damaging TP53 alterations and co-alterations of TP53 missense mutations with TP73, CREBBP/EP300 or FMN2 were significantly associated with shorter disease relapse following chemotherapy. In summary, we uncover key processes of the genomic evolution of SCLC under therapy, identify the common ancestor as the source of clonal diversity at relapse and show central genomic patterns associated with sensitivity and resistance to chemotherapy.

MET Fusions in NSCLC: Clinicopathologic Features and Response to MET Inhibition

INTRODUCTION

MET fusions have been described only rarely in NSCLC. Thus, data on patient characteristics and treatment response are limited. We here report histopathologic data, patient demographics, and treatment outcome including response to MET tyrosine kinase inhibitor (TKI) therapy in MET fusion-positive NSCLC.

METHODS

Patients with NSCLC and MET fusions were identified mostly by RNA sequencing within the routine molecular screening program of the national Network Genomic Medicine, Germany.

RESULTS

We describe a cohort of nine patients harboring MET fusions. Among these nine patients, two patients had been reported earlier. The overall frequency was 0.29% (95% confidence interval: 0.15-0.55). The tumors were exclusively adenocarcinoma. The cohort was heterogeneous in terms of age, sex, or smoking status. We saw five different fusion partner genes (KIF5B, TRIM4, ST7, PRKAR2B, and CAPZA2) and several different breakpoints. Four patients were treated with a MET TKI leading to two partial responses, one stable disease, and one progressive disease. One patient had a BRAF V600E mutation as acquired resistance mechanism.

CONCLUSIONS

MET fusions are very rare oncogenic driver events in NSCLC and predominantly seem in adenocarcinomas. They are heterogeneous in terms of fusion partners and breakpoints. Patients with MET fusion can benefit from MET TKI therapy.

KEAP1/NFE2L2 Pathway Signature Outperforms KEAP1/NFE2L2 Mutation Status and Reveals Alternative Pathway-Activating Mutations in NSCLC

INTRODUCTION

Activation of the antioxidant KEAP1/NFE2L2 (NRF2) pathway leads to increased glutamine dependence and an aggressive phenotype in NSCLC. Because this pathway has been explored as a clinical target, we developed a transcriptomic signature for identifying KEAP1/NFE2L2-activated tumors.

METHODS

A total of 971 NSCLC samples were used to train an expression signature (K1N2-score) to predict KEAP1/NFE2L2 mutations. There were 348 in-house NSCLCs that were analyzed using a NanoString expression panel for validation.

RESULTS

The 46-gene K1N2 score robustly predicted KEAP1/NFE2L2 mutations in the validation set irrespective of histology and mutation (area under the curve: 89.5, sensitivity: 90.2%), suggesting that approximately 90% of KEAP1/NFE2L2 mutations are pathway-activating. The K1N2-score outperformed KEAP1/NFE2L2 mutational status when predicting patient survival (score p = 0.047; mutation p = 0.215). In K1N2 score-positive but KEAP1/NFE2L2 wild-type samples, enrichment testing identified SMARCA4/BRG1 and CUL3 mutations as mimics of KEAP1/NFE2L2 mutations.

CONCLUSIONS

The K1N2-score identified KEAP1/NFE2L2-activated NSCLC by robustly detecting KEAP1/NFE2L2mut cases and discovering alternative genomic activators. It is a potential means for selecting patients with a constitutively active KEAP1/NFE2L2 pathway.

Somatic rearrangements causing oncogenic ectodomain deletions of FGFR1 in squamous cell lung cancer

The discovery of frequent 8p11-p12 amplifications in squamous cell lung cancer (SQLC) has fueled hopes that FGFR1, located inside this amplicon, might be a therapeutic target. In a clinical trial, only 11% of patients with 8p11 amplification (detected by FISH) responded to FGFR kinase inhibitor treatment. To understand the mechanism of FGFR1 dependency, we performed deep genomic characterization of 52 SQLCs with 8p11-p12 amplification, including 10 tumors obtained from patients who had been treated with FGFR inhibitors. We discovered somatically altered variants of FGFR1 with deletion of exons 1-8 that resulted from intragenic tail-to-tail rearrangements. These ectodomain-deficient FGFR1 variants (ΔEC-FGFR1) were expressed in the affected tumors and were tumorigenic in both in vitro and in vivo models of lung cancer. Mechanistically, breakage-fusion-bridges were the source of 8p11-p12 amplification, resulting from frequent head-to-head and tail-to-tail rearrangements. Generally, tail-to-tail rearrangements within or in close proximity upstream of FGFR1 were associated with FGFR1 dependency. Thus, the genomic events shaping the architecture of the 8p11-p12 amplicon provide a mechanistic explanation for the emergence of FGFR1-driven SQLC. Specifically, we believe that FGFR1 ectodomain-deficient and FGFR1-centered amplifications caused by tail-to-tail rearrangements are a novel somatic genomic event that might be predictive of therapeutically relevant FGFR1 dependency.

Tumour area infiltration and cell count in endoscopic biopsies of therapy-naive upper GI tract carcinomas by QuPath analysis: implications for predictive biomarker testing

Guidelines regulate how many (tumour-bearing) tissue particles should be sampled during gastric cancer biopsy to obtain representative results in predictive biomarker testing. Little is known about how well these guidelines are applied, how the number of tissue particles correlates with the actual tumour-infiltrated area and how many absolute tumour cells are captured. The study included endoscopic biopsies of untreated carcinomas of the upper gastrointestinal (GI)-tract during the 2016-2020 review period. Archival (H&E)-stained histological sections were digitised and the tumour areas were manually annotated. The tumour-bearing tissue area and absolute carcinoma cell count per case were determined by image analysis and compared with a reference primary surgical specimen. Biopsies from 253 patients were analysed. The following mean values were determined: (a) tumour tissue particle number: 6.5 (range: 1-25, standard deviation (SD) = 3.33), (b) number of tumour-bearing tissue particles: 4.7 (range: 1-20, SD = 2.80), (c) tumour-infiltrated area: 7.5 mm2 (range: 0.18-59.46 mm2, SD = 6.67 mm2), (d) absolute tumour cell count: 13,492 (range: 193-92,834, SD = 14,185) and (e) tumour cell count in a primary surgical specimen (tumour size: 6.7 cm): 105,200,176. The guideline-recommended tissue particle count of 10 was not achieved in 208 patients (82.2%) and the required tumour-bearing tissue particle count of 5 was not achieved in 133 patients (52.6%). Tissue particle count, tumour-infiltrated area and tumour cell count were only weakly correlated. Most cases featured an infiltrated area ≥ 4.5 mm2 (156, 61.7%). Cases with more tissue particles showed only a moderate increase in infiltrated area and tumour cells compared to cases with fewer particles. Biopsies are often used to determine predictive biomarkers, particularly Her2/neu and PD-L1. Diagnostic standards to ensure representative material have been suggested in guidelines to reduce false-negative predictions. However, the real-world practice seems to substantially deviate from recommended standards. To the best of our knowledge, this is the first systematic study describing the relationships between endoscopic tissue fragment number, actual infiltrated tumour area and carcinoma cell number. The data question the tissue particle number as a quality assessment parameter. We advocate histopathological reports indicating on which basis statements on therapy-relevant biomarkers were made. Digital pathology has the potential to objectively quantify the tissue for documentation, quality assessment and future clinical studies.

Abstract HER2-13: HER2-13 Proficiency assessment of HER2-low breast cancer scoring with the Ventana PATHWAY 4B5 and Dako HercepTest HER2 assays and the impact of pathologist training

Background: Based on the results of the DESTINY-Breast04 study, the HER2-targeted antibody-drug conjugate trastuzumab deruxtecan (T-DXd) and the Ventana PATHWAY 4B5 companion diagnostic were recently approved by the US Food and Drug Administrated for the treatment and identification of patients with HER2-low (IHC2+/ISH- or IHC1+) (Modi et al. N Engl J Med 2022). The efficacy of T-DXd in HER2-low mBC highlights the need to distinguish lower ranges of HER2 IHC expression, which has been reported to be more challenging than scoring high HER2 expression (Fernandez et al. JAMA Oncol 2022). Here we report on current real-world HER2-low interpretation proficiency and the impact of training for participating pathologists in HER2-low scoring.

Methods: Pathologists from laboratories across the US, EU, Japan, Australia, and Brazil were invited to use a digital pathology platform (Pathotrainer) to interpret HER2 digital images using ASCO/CAP 2018 scoring criteria. Two whole-slide imaging sample sets of representative study cases were compiled for Ventana PATHWAY 4B5 or Dako HercepTest (HcT) stained tumors. Another sample set (n = 25) was developed for a 4 hour virtual training session based on the ASCO/CAP 2018 guideline with some practical considerations. A steering committee (SC) of 8 pathology experts was formed to guide the study. Pathologists’ score was compared with a reference score as determined by independent review of 3 experts in HER2 pathology. Paired study cases (n = 14) considered challenging due to difficult-to-interpret staining patterns were reevaluated by the SC members. Concordance and efficacy of training were measured by Cohen’s weighted kappa (κ) coefficient, overall rater agreement (ORA), and receiver operating characteristic curve statistics. The primary endpoint was real-world concordance and ORA. The secondary endpoints were post-training concordance and ORA and correct identification of HER2 IHC 0 and HER2-low.

Results: Pre-training baseline or real-world scores were taken by 77 pathologists in 14 countries (n = 49 for 4B5, n = 28 for HcT) and 74 pathologists completed post-training scores (n = 48 for 4B5, n = 26 for HcT). HER2 scoring proficiency of pathologists was high for both assays when assessed on ASCO/CAP binary HER2-negative and -positive status, irrespective of training (4B5: κ = 0.96, ORA =98.9.%; HcT: κ = 0.84, ORA = 94.3%) Concordance per ORA for the new 3-tier classification (HER2 IHC 0 vs HER2-low [IHC 2+/ISH- or IHC 1+] vs HER2-positive [IHC 3+ or IHC 2+/ISH+]) was greater than 80% for both assays at baseline and after training (see Table). In a subgroup analysis assessing training effect for 4B5 assay, concordance rates for HER2 IHC 0 were 74.6% at baseline and 89.2% after training (P < 0.001), and for HER2-low, NPA was 80.6% before and 91.1% after training (P < 0.001); there were no statistically significant changes after training for HcT (data not shown).

Conclusions: Results from this real-world global study demonstrate that overall score concordance with a new category of HER2-low was above the 80% ORA benchmark for both 4B5 and HcT and is higher than previously reported (Fernandez et al. JAMA Oncol 2022). These data demonstrate pathologists’ ability to achieve an acceptable level of accuracy for identifying HER2 IHC 0 and HER2-low patients even after short-term training; however, additional training techniques and experience are needed to further improve accuracy.

Acknowledgment

Judy Yu, a former AstraZeneca employee, provided expertise and technical insights to support the study.

Editorial Acknowledgment

Under guidance of the authors, assistance in medical writing and editorial support was provided by Toinette Labuschagné, MSc, of ApotheCom, and was funded by Daiichi Sankyo.

Funding

This study was funded by Daiichi Sankyo and AstraZeneca.

Table. Summary of Pathologist Concordance and Interobserver Variability

Citation Format: Josef Rüschoff, Alexander Penner, Ian O. Ellis, M. Elizabeth H. Hammond, Annette Lebeau, Robert Y. Osamura, Frédérique Penault-Llorca, Federico Rojo, Neil Atkey, Andreas H. Scheel, Corrado D´Arrigo, Hans-Ulrich Schildhaus, Akira Moh, Chirag Desai, Giuseppe Viale. HER2-13 Proficiency assessment of HER2-low breast cancer scoring with the Ventana PATHWAY 4B5 and Dako HercepTest HER2 assays and the impact of pathologist training [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr HER2-13.

Resistance to MET inhibition in MET-dependent NSCLC and therapeutic activity after switching from type I to type II MET inhibitors

OBJECTIVES

Resistance to MET inhibition occurs inevitably in MET-dependent non-small cell lung cancer and the underlying mechanisms are insufficiently understood. We describe resistance mechanisms in patients with MET exon 14 skipping mutation (METΔ^ex14), MET amplification, and MET fusion and report treatment outcomes after switching therapy from type I to type II MET inhibitors.

MATERIALS AND METHODS

Pre- and post-treatment biopsies were analysed by NGS (next generation sequencing), digital droplet PCR (polymerase chain reaction), and FISH (fluorescense in situ hybridization). A patient-derived xenograft model was generated in one case.

RESULTS

Of 26 patients with MET tyrosine kinase inhibitor treatment, eight had paired pre- and post-treatment biopsies (Three with MET amplification, three with METΔ^ex14, two with MET fusions (KIF5B-MET and PRKAR2B-MET).) In six patients, mechanisms of resistance were detected, whereas in two cases, the cause of resistance remained unclear. We found off-target resistance mechanisms in four cases with KRAS mutations and HER2 amplifications appearing. Two patients exhibited second-site MET mutations (p.D1246N and p. Y1248H). Three patients received type I and type II MET tyrosine kinase inhibitors sequentially. In two cases, further progressive disease was seen hereafter. The patient with KIF5B-MET fusion received three different MET inhibitors and showed long-lasting stable disease and a repeated response after switching therapy, respectively.

CONCLUSION

Resistance to MET inhibition is heterogeneous with on- and off-target mechanisms occurring regardless of the initial MET aberration. Switching therapy between different types of kinase inhibitors can lead to repeated responses in cases with second-site mutations. Controlled clinical trials in this setting with larger patient numbers are needed, as evidence to date is limited to preclinical data and case series.

Screening of FGFR patients for FGFR directed clinical trials in Network Genomic Medicine (NGM): Real-world data

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Background: The fibroblast growth factor receptor (FGFR) 1-4 genes show a heterogenic landscape of alterations in non-small cell lung cancer (NSCLC) whereas only a small amount is yet considered to have oncogenic potential. The frequency of activating FGFR alterations is low, counting for approximately 2% of NSCLC. We have screened NSCLC patients (pts) for FGFR translocations/mutations within NGM and analysed them on FGFR alteration frequency, patient characteristics and outcome. Methods: From 04/2019 to 01/2020 we screened 472 squamous NSCLC for FGFR gene alterations and from 02/2020 to 12/2021 an additional 5286 patients including all NSCLC cases. Of these 5286 pts, 1097 pts were analysed for FGFR fusions. We used DNA-NGS for FGFR-mutations and RNA-NGS for FGFR–translocations. Activating mutations were defined according to the publicly available molecular data bases and published data. Results: Within the cohort of 5758 NSCLC patients, we found 316 (5.5%) patients with FGFR alterations. Sixty-six (20.9% of FGFR, 1.1% of NSCLC) patients had alterations classified as activating, of whom 39 had FGFR point mutations and 27 FGFR translocations. Concerning the patients with activating alterations, they had UICC stage III or IV at time of diagnosis; 22 were females; 58 patients had squamous cell carcinoma, 6 patients had adenocarcinoma and 2 had large cell neuroendocrine carcinoma. Fifty-three patients (80.3%) with activating FGFR alteration had a co-mutation: TP53 (inactivating) co-mutation was seen in 41 cases (62.1%) and 19 cases had either PTEN (7 pts), KRAS (4), EGFR (3), PIK3CA (2), ROS1 (1), ALK (1) or BRAF (1) mutations. Ten patients were included in a FGFR-targeted trial. Sixty patients were available for follow-up. The median overall survival (mOS) was 21.4 month (95%CI: 16.8–25.9) for all patients with activating FGFR alteration, whereas mOS was 18.5 month (95%CI: 13.2-23.9) for FGFR mutation and 25.3 months (95%CI: 17.8-32.9) for FGFR fusions. Conclusions: FGFR 1-4 gene alterations are rare. Large molecular and clinical networks are necessary to identify these pts. Prognostic factors of FGFR patients are currently not defined. Further assessments on molecular and clinical features in FGFR altered NSCLC are needed to identify sensitivity to FGFR inhibition. Clinical trials with specific FGFR inhibitors are ongoing.

Improved Tissue Processing in Esophageal Adenocarcinoma After Ivor Lewis Esophagectomy Allows Histological Analysis of All Surgically Removed Lymph Nodes with Significant Effects on Nodal UICC Stages

BACKGROUND

In esophageal carcinoma, the numbers of metastatic and total removed lymph nodes (LN) are well-established variables of long-term prognosis. The overall rate of retrieved LN depends on neoadjuvant treatment, the extent of surgical lymphadenectomy, and the modality of the pathological workup. The question in this study is whether technically extended histopathological preparation can increase the number of detected (metastatic) LN with an impact on nodal UICC staging.

PATIENTS AND METHODS

A cohort of 77 patients with esophageal adenocarcinoma was treated with Ivor Lewis esophagectomy including standardized two-field lymphadenectomy. The specimens were grossed, and all manually detectable LN were retrieved. The remaining tissue was completely embedded by the advanced "acetone compression" retrieval technique. The primary outcome parameter was the total number of detected lymph nodes before and after acetone workup.

RESULTS

A mean number of 23,1 LN was diagnosed after standard manual LN preparation. With complete embedding of the fatty tissue using acetone compression, the number increased to 40.5 lymph nodes (p < 0.0001). The mean number of metastatic LN increased from 3.2 to 4.2 nodal metastases following acetone compression (p < 0.0001). Additional LN metastases which caused a change in the primary (y)pN stage were found in ten patients (13.0%).

CONCLUSIONS

Advanced lymph node retrieval by acetone compression allows a reliable statement on the real number of removed LN. Results demonstrate an impact on the nodal UICC stage. A future multicenter study will examine the prognostic impact of improved lymph node retrieval on long-term oncologic outcome.

[Brain metastases-Interdisciplinary approach towards a personalized treatment]

The incidence, treatment and prognosis of patients with brain metastases have substantially changed during the last decades. While the survival time after diagnosis of cerebral metastases was on average a maximum of 3-6 months only 10 years ago, the survival time could be significantly improved due to novel surgical, radiotherapeutic and systemic treatment modalities. Only a few years ago, the occurrence of brain metastases led to a withdrawal from systemic oncological treatment and the exclusion of drug therapy studies and to a purely palliatively oriented treatment in the sense of whole brain radiation therapy (WBRT) with or without surgery. The increasing availability of targeted and immunomodulatory drugs as well as adapted radio-oncological procedures enable increasingly more personalized treatment approaches. The aim of this review article is to demonstrate the progress and complexity of the treatment of brain metastases in the context of modern comprehensive interdisciplinary concepts.

"Interchangeability" of PD-L1 immunohistochemistry assays: a meta-analysis of diagnostic accuracy

Different clones, protocol conditions, instruments, and scoring/readout methods may pose challenges in introducing different PD-L1 assays for immunotherapy. The diagnostic accuracy of using different PD-L1 assays interchangeably for various purposes is unknown. The primary objective of this meta-analysis was to address PD-L1 assay interchangeability based on assay diagnostic accuracy for established clinical uses/purposes. A systematic search of the MEDLINE database using PubMed platform was conducted using "PD-L1" as a search term for 01/01/2015 to 31/08/2018, with limitations "English" and "human". 2,515 abstracts were reviewed to select for original contributions only. 57 studies on comparison of two or more PD-L1 assays were fully reviewed. 22 publications were selected for meta-analysis. Additional data were requested from authors of 20/22 studies in order to enable the meta-analysis. Modified GRADE and QUADAS-2 criteria were used for grading published evidence and designing data abstraction templates for extraction by reviewers. PRISMA was used to guide reporting of systematic review and meta-analysis and STARD 2015 for reporting diagnostic accuracy study. CLSI EP12-A2 was used to guide test comparisons. Data were pooled using random-effects model. The main outcome measure was diagnostic accuracy of various PD-L1 assays. The 22 included studies provided 376 2×2 contingency tables for analyses. Results of our study suggest that, when the testing laboratory is not able to use an Food and Drug Administration-approved companion diagnostic(s) for PD-L1 assessment for its specific clinical purpose(s), it is better to develop a properly validated laboratory developed test for the same purpose(s) as the original PD-L1 Food and Drug Administration-approved immunohistochemistry companion diagnostic, than to replace the original PD-L1 Food and Drug Administration-approved immunohistochemistry companion diagnostic with a another PD-L1 Food and Drug Administration-approved companion diagnostic that was developed for a different purpose.

Tumor Vessel Normalization, Immunostimulatory Reprogramming, and Improved Survival in Glioblastoma with Combined Inhibition of PD-1, Angiopoietin-2, and VEGF

Glioblastoma (GBM) is a non-T-cell-inflamed cancer characterized by an immunosuppressive microenvironment that impedes dendritic cell maturation and T-cell cytotoxicity. Proangiogenic cytokines such as VEGF and angiopoietin-2 (Ang-2) have high expression in glioblastoma in a cell-specific manner and not only drive tumor angiogenesis and vascular permeability but also negatively regulate T-lymphocyte and innate immune cell responses. Consequently, the alleviation of immunosuppression might be a prerequisite for successful immune checkpoint therapy in GBM. We here combined antiangiogenic and immune checkpoint therapy and demonstrated improved therapeutic efficacy in syngeneic, orthotopic GBM models. We observed that blockade of VEGF, Ang-2, and programmed cell death protein-1 (PD-1) significantly extended survival compared with vascular targeting alone. In the GBM microenvironment, triple therapy increased the numbers of CTLs, which inversely correlated with myeloid-derived suppressor cells and regulatory T cells. Transcriptome analysis of GBM microvessels indicated a global vascular normalization that was highest after triple therapy. Our results propose a rationale to overcome tumor immunosuppression and the current limitations of VEGF monotherapy by integrating the synergistic effects of VEGF/Ang-2 and PD-1 blockade to reinforce antitumor immunity through a normalized vasculature.

BIOLUMA: A phase II trial of nivolumab in combination with ipilimumab to evaluate efficacy and safety in lung cancer and to evaluate biomarkers predictive for response—Preliminary results from the NSCLC cohort

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Background: Patient selection, dosing regimens and resistance mechanisms for immune checkpoint inhibitor combination therapy remain unmet medical needs in lung cancer. Combining blockade of PD-1 and CTLA-4 can be more effective than monotherapy but is accompanied by an increase in toxicity. Thus, to circumvent unnecessary toxicity it is of great interest to identify patients who will benefit from PD-1/PD-L1 blockade alone and to add ipilimumab only in case of primary or secondary progression. We present interim data from the non-small-cell lung cancer (NSCLC) cohort of the ongoing BIOLUMA trial which evaluates efficacy and safety of nivolumab and ipilimumab in lung cancer with a broad translational program to identify potential biomarkers predictive of response and/or resistance including whole exome sequencing (WES) of serial biopsies, functional analysis of peripheral T-cells and gut microbiome analyses. Methods: BIOLUMA is a multicentre non-randomised phase II trial in 2nd line patients with non-squamous NSCLC. Patients are treated with nivolumab 240 mg until disease progression and subsequently with a combination therapy of nivolumab 3 mg/kg q2w and ipilimumab 1mg/kg q6w. Primary endpoint is overall response rate (ORR) after addition of ipilimumab to nivolumab treatment. Analysis of sequential tumor biopsies, blood and gut microbiome is performed at different timepoints. Results: To date, 26 patients have been enrolled and 9 patients were transferred to the combination therapy after progression on nivolumab monotherapy. Drop out rate between the treatment arms is high, mainly due to rapid disease progression and adverse events which don’t allow addition of ipilimumab. ORR is available for 8 of these patients: 6 patients (75%) had PD as best response, and 1 (12.5%) each had a stable disease and partial response, respectively. The patient who achieved a PR had experienced primary tumor progression on nivolumab monotherapy before. Toxicity rate was similar to what has been reported from other trials. Conclusions: In NSCLC, addition of ipilimumab to nivolumab in nivolumab refractory patients seems to be safe, but the response rate is low and the drop out between the treatment parts high. Given these data, early termination of this cohort is currently discussed. Clinical trial information: NCT03083691.

BIOLUMA: A phase II trial of nivolumab in combination with ipilimumab to evaluate efficacy and safety in lung cancer and to evaluate biomarkers predictive for response—Preliminary results from the SCLC cohort

8563

Background: Patient selection, dosing regimens and resistance mechanisms for immune checkpoint inhibitor combination therapy remain unmet medical needs in lung cancer. We present interim data from the small-cell lung cancer (SCLC) cohort of the ongoing BIOLUMA trial which evaluates efficacy and safety of nivolumab and ipilimumab in lung cancer with a broad translational program to identify potential biomarkers predictive of response and/or resistance including whole exome sequencing (WES) of serial biopsies, functional analysis of peripheral T-cells and gut microbiome analyses. Methods: BIOLUMA is an investigator initiated, multicentre non-randomised phase II trial in 2nd line patients with SCLC. The initial all-comer SCLC cohort was recently amended for inclusion of patients with high tumor mutation burden (TMB) only. Patients are pre-screened for TMB by WES at the time of first diagnosis. After progression on platinum-based therapy, 4 cycles of nivolumab 1 mg/kg q3w in combination with ipilimumab 3 mg/kg q3w and subsequent nivolumab 240 mg flat dose as monotherapy are given. Primary endpoint is overall response rate (ORR) of the upfront combination therapy. Analysis of sequential tumor biopsies, blood and gut microbiome is performed at different timepoints. Results: The SCLC cohort was amended to include TMB high patients only, after two treatment-related deaths had occurred and emerging data indicated treatment benefit depends on high TMB status for the combination therapy. Both patients with treatment-related death had a CT-scan documented partial response (not confirmed according to RECIST due to death). One each died of pneumonitis and encephalitis. From the all-comer cohort, efficacy data are available for 18 patients. ORR was 38.8% with 7 partial and no complete responses. Stable disease occurred in 16.7% (n = 3) resulting in a DCR of 55.5%. TMB pre-screening for the amended cohort is currently ongoing. Conclusions: In the SCLC cohort, upfront combination therapy of nivolumab and ipilimumab shows remarkable ORR but is accompanied by high toxicity rates. In order to ensure a reasonable balance of risks and treatment benefit, only TMB high patients are included after an amendment of the cohort to improve the risk/benefit ratio. Clinical trial information: NCT03083691.

Acquired resistance to MET inhibition in MET driven NSCLC

9030

Background: MET mutations ( MET∆ex14), amplifications or translocations can activate oncogenic signaling in lung cancer and are sensitive to MET inhibition. Acquired resistance to therapy with MET tyrosine kinase inhibitors (TKI) occurs inevitably. Methods: Between 2015 and 2018, eighteen patients with MET-driven NSCLC were treated with capmatinib or crizotinib as single agent at our site. Rebiopsy samples from five patients were analyzed by NGS and fluoreszenz-in-situ hybridization (FISH) at time of progression. Results: Of the five patients with rebiopsy samples at time of progression, two had initially a MET amplification (one patient with low-level and one patient with high-level amplification), two patients had a MET∆ex14 and one patient had a KIF5B-MET fusion. Patient 1 (low-level MET amplification) showed a partial response to crizotinib. The rebiopsy revealed an acquired KRAS mutation as a potential mechanism of resistance. Patient 2 (high-level MET amplification) showed stable disease as best response to capmatinib and patient 3 (MET∆ex14) showed a partial response to capmatinib. Both patients developed acquired HER2 amplifications. Patient 4 ( MET∆ex14) showed initially a partial response to crizotinib. The rebiopsy sample revealed an acquired MET kinase domain mutation (p.D1246N). As preclinical findings suggested that D1246N confers resistance to type I MET inhibitors but remains sensitive to type II inhibitors, cabozantinib was started. A CT six weeks after therapy initiation showed progressive disease. Patient 5 ( KIF5B-MET) had a partial response to crizotinib. An acquired MET p.Y1248H mutation was found at time of progression. Therapy was changed to cabozantinib. A new CT scan is pending. Conclusions: Resistance to MET inhibition is heterogeneous with on- and off-target-mechanisms occurring. We found HER2 amplification as a potential new bypass mechanism. The MET mutation D1246N conferred resistance to type I and type II inhibitors. We describe the first case of an acquired mutation of the MET tyrosine kinase domain in a patient with an oncogenic MET fusion. Further investigations are needed to collect comprehensive data to understand resistance mechanisms in MET inhibition and to develop novel therapeutic strategies.

Clinical impact of PD-L1 and PD-1 expression in squamous cell cancer of the vulva

PURPOSE

Squamous cell carcinoma of the vulva (SQCV) is the fifth most common cancer in women and accounts for about 5% of all genital cancers in women. The PD-L1 signaling pathway is activated in many malignant neoplasms and its blockade enhances anti-cancer immunity. The aim of our study was to examine the protein expression of PD-L1 and PD-1 in squamous cell cancer of the vulva, its correlations with clinicopathologic features and prognostic value.

METHODS

Patients with SQCV treated in one institution were used for the analyses. PD-L1 immunohistochemistry was performed on 4 µm-thick section of the respective FFPE tissue blocks using the 28-8 antibody. PD-L1 scoring was performed separately for tumour cells (TC) and tumour associated immune cells. DNA was extracted to determine HPV status. Kaplan-Meier estimates for disease-free-survival and overall-survival were calculated and compared by log-rank test.

RESULTS

PD-L1 expression in tumour cells could be observed in 32.9% of the patients. The expression of PD-L1 in peritumoural immune cells was confirmed in 91.4% of the patients. A significant correlation between PD-L1 expression in tumour cells and tumour stage was detected (p = 0.007). PD-L1 expression was independent from HPV status. Using the log-rank test we could not prove any significant differences in disease-free survival (p = 0.434) and overall survival (p = 0.858). Regression analysis showed that nodal status is a predictive factor of survival (p < 0.001).

CONCLUSION

The present study showed that a relevant amount of patients with squamous cell cancer of the vulva express PD-L1 in both, tumour cells and tumour-associated immune cells. Furthermore, the significant correlation of PD-L1 expression in TCs with tumour stage indicated the clinical impact of PD-L1 expression during tumour development. These data indicate that SQCV might be amenable to immune checkpoint-inhibition and constitute a rational for the future clinical trials.

Genomic Profiling Identifies Outcome-Relevant Mechanisms of Innate and Acquired Resistance to Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy in Lung Cancer

PURPOSE

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective in acquired resistance (AR) to early-generation EGFR TKIs in EGFR-mutant lung cancer. However, efficacy is marked by interindividual heterogeneity. We present the molecular profiles of pretreatment and post-treatment samples from patients treated with third-generation EGFR TKIs and their impact on treatment outcomes.

METHODS

Using the databases of two lung cancer networks and two lung cancer centers, we molecularly characterized 124 patients with EGFR p.T790M-positive AR to early-generation EGFR TKIs. In 56 patients, correlative analyses of third-generation EGFR TKI treatment outcomes and molecular characteristics were feasible. In addition, matched post-treatment biopsy samples were collected for 29 patients with progression to third-generation EGFR TKIs.

RESULTS

Co-occurring genetic aberrations were found in 74.4% of EGFR p.T790-positive samples (n = 124). Mutations in TP53 were the most frequent aberrations detected (44.5%; n = 53) and had no significant impact on third-generation EGFR TKI treatment. Mesenchymal-epithelial transition factor (MET) amplifications were found in 5% of samples (n = 6) and reduced efficacy of third-generation EGFR TKIs significantly (eg, median progression-free survival, 1.0 months; 95% CI, 0.37 to 1.72 v 8.2 months; 95% CI, 1.69 to 14.77 months; P ≤ .001). Genetic changes in the 29 samples with AR to third-generation EGFR TKIs were found in EGFR (eg, p.T790M loss, acquisition of p.C797S or p.G724S) or in other genes (eg, MET amplification, KRAS mutations).

CONCLUSION

Additional genetic aberrations are frequent in EGFR-mutant lung cancer and may mediate innate and AR to third-generation EGFR TKIs. MET amplification was strongly associated with primary treatment failure and was a common mechanism of AR to third-generation EGFR TKIs. Thus, combining EGFR inhibitors with TKIs targeting common mechanisms of resistance may delay AR.

K-ras Mutation Subtypes in NSCLC and Associated Co-occuring Mutations in Other Oncogenic Pathways

INTRODUCTION

Although KRAS mutations in NSCLC have been considered mutually exclusive driver mutations for a long time, there is now growing evidence that KRAS-mutated NSCLC represents a genetically heterogeneous subgroup. We sought to determine genetic heterogeneity with respect to cancer-related co-mutations and their correlation with different KRAS mutation subtypes.

METHODS

Diagnostic samples from 4507 patients with NSCLC were analyzed by next-generation sequencing by using a panel of 14 genes and, in a subset of patients, fluorescence in situ hybridization. Next-generation sequencing with an extended panel of 14 additional genes was performed in 101 patients. Molecular data were correlated with clinical data. Whole-exome sequencing was performed in two patients.

RESULTS

We identified 1078 patients with KRAS mutations, of whom 53.5% had at least one additional mutation. Different KRAS mutation subtypes showed different patterns of co-occurring mutations. Besides mutations in tumor protein p53 gene (TP53) (39.4%), serine/threonine kinase 11 gene (STK11) (19.8%), kelch like ECH associated protein 1 gene (KEAP1) (12.9%), and ATM serine/threonine kinase gene (ATM) (11.9%), as well as MNNG HOS Transforming gene (MET) amplifications (15.4%) and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) amplifications (13.8%, exclusively in G12C), we found rare co-occurrence of targetable mutations in EGFR (1.2%) and BRAF (1.2%). Whole-exome sequencing of two patients with co-occurring phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA) mutation revealed clonality of mutated KRAS in one patient and subclonality in the second, suggesting different evolutionary backgrounds.

CONCLUSION

KRAS-mutated NSCLC represents a genetically heterogeneous subgroup with a high frequency of co-occurring mutations in cancer-associated pathways, partly associated with distinct KRAS mutation subtypes. This diversity might have implications for understanding the variability of treatment outcome in KRAS-mutated NSCLC and for future trial design.

Genetic instability and recurrent MYC amplification in ALK-translocated NSCLC: a central role of TP53 mutations

The anaplastic lymphoma kinase (ALK) rearrangement defines a distinct molecular subtype of non-small cell lung cancer (NSCLC). Despite the excellent initial efficacy of ALK inhibitors in patients with ALK+ lung cancer, resistance occurs almost inevitably. To date, there is no reliable biomarker allowing the identification of patients at higher risk of relapse. Here, we analysed a subset of 53 ALK+ tumours with and without TP53 mutation and ALK+ NSCLC cell lines by NanoString nCounter technology. We found that the co-occurrence of early TP53 mutations in ALK+ NSCLC can lead to chromosomal instability: 24% of TP53-mutated patients showed amplifications of known cancer genes such as MYC (14%), CCND1 (10%), TERT (5%), BIRC2 (5%), ORAOV1 (5%), and YAP1 (5%). MYC-overexpressing ALK+ TP53-mutated cells had a proliferative advantage compared to wild-type cells. ChIP-Seq data revealed MYC-binding sites within the promoter region of EML4, and MYC overexpression in ALK+ TP53-mutated cells resulted in an upregulation of EML4-ALK, indicating a potential MYC-dependent resistance mechanism in patients with increased MYC copy number. Our study reveals that ALK+ NSCLC represents a more heterogeneous subgroup of tumours than initially thought, and that TP53 mutations in that particular cancer type define a subset of tumours that harbour chromosomal instability, leading to the co-occurrence of pathogenic aberrations. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Physical basis of the 'magnification rule' for standardized Immunohistochemical scoring of HER2 in breast and gastric cancer

Background

Detection of HER2/neu receptor overexpression and/or amplification is a prerequisite for efficient anti-HER2 treatment of breast and gastric carcinomas. Immunohistochemistry (IHC) of the HER2 protein is the most common screening test, thus precise and reproducible IHC-scoring is of utmost importance. Interobserver variance still is a problem; in particular in gastric carcinomas the reliable differentiation of IHC scores 2+ and 1+ is challenging.

Herein we describe the physical basis of what we called the ‘magnification rule’: Different microscope objectives are employed to reproducibly subdivide the continuous spectrum of IHC staining intensities into distinct categories (1+, 2+, 3+).

Methods

HER2-IHC was performed on 120 breast cancer biopsy specimens (n = 40 per category). Width and color-intensity of membranous DAB chromogen precipitates were measured by whole-slide scanning and digital morphometry. Image-analysis data were related to semi-quantitative manual scoring according to the magnification rule and to the optical properties of the employed microscope objectives.

Results

The semi-quantitative manual HER2-IHC scores are correlated to color-intensity measured by image-analysis and to the width of DAB-precipitates. The mean widths ±standard deviations of precipitates were: IHC-score 1+, 0.64 ± 0.1 μm; score 2+, 1.0 ± 0.23 μm; score 3+, 2.14 ± 0.4 μm. The width of precipitates per category matched the optical resolution of the employed microscope objective lenses: Approximately 0.4 μm (40×), 1.0 μm (10×) and 2.0 μm (5×).

Conclusions

Perceived intensity, width of the DAB chromogen precipitate, and absolute color-intensity determined by image-analysis are linked. These interrelations form the physical basis of the ‘magnification rule’: 2+ precipitates are too narrow to be observed with 5× microscope objectives, 1+ precipitates are too narrow for 10× objectives. Thus, the rule uses the optical resolution windows of standard diagnostic microscope objectives to derive the width of the DAB-precipitates. The width is in turn correlated with color-intensity. Hereby, the more or less subjective estimation of IHC scores based only on the staining-intensity is replaced by a quasi-morphometric measurement. The principle seems universally applicable to immunohistochemical stainings of membrane-bound biomarkers that require an intensity-dependent scoring.

Electronic supplementary material

The online version of this article (10.1186/s13000-018-0696-x) contains supplementary material, which is available to authorized users.

Structural Alterations of MET Trigger Response to MET Kinase Inhibition in Lung Adenocarcinoma Patients

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Interlaboratory concordance of PD-L1 immunohistochemistry for non-small-cell lung cancer

AIMS

Programmed death ligand 1 (PD-L1) immunohistochemistry has become a mandatory diagnostic test in the treatment of lung cancer. Several research initiatives have started to harmonise the five PD-L1 immunohistochemistry assays that have been used in clinical trials. Here, we report data on interlaboratory and interassay concordance for commercial assays ('assays') and laboratory-developed tests (LDTs) at 10 German testing sites.

METHODS AND RESULTS

To assess interlaboratory concordance, a tissue microarray containing 21 pulmonary carcinoma specimens was centrally prepared. Pre-cut sections were stained at 10 sites by the use of assays 28-8, 22C3, SP263, and SP142, as well as 11 LDTs. Assay performance was evaluated with a second tissue microarray containing 11 cell lines with defined PD-L1 expression. Quality control was centrally performed by manual and digital analyses. The assays yielded reproducible IHC staining patterns at all sites. In agreement with previous studies, 22C3, 28-8 and SP263 showed similar staining patterns, whereas SP142 was distinct. Among the LDTs, six of 11 protocols showed staining patterns similar to those of assays 22C3 and 28-8. Interlaboratory concordance of tumour cell scoring by use of a six-step system was moderate (Light's κ = 0.43-0.69), whereas the clinically approved cut-offs of ≥1% and ≥50% showed substantial concordance (κ = 0.73-0.89). Immune cell scoring by the use of SP142 yielded moderate concordance (κ = 0.42).

CONCLUSIONS

The data confirm the previously described staining patterns of the assays, and show that they can be reproducibly employed at different sites. LDTs with staining results similar to those of the assays are implementable, but have to be carefully validated.

Drugging the catalytically inactive state of RET kinase in RET-rearranged tumors

Oncogenic fusion events have been identified in a broad range of tumors. Among them, RET rearrangements represent distinct and potentially druggable targets that are recurrently found in lung adenocarcinomas. We provide further evidence that current anti-RET drugs may not be potent enough to induce durable responses in such tumors. We report that potent inhibitors, such as AD80 or ponatinib, that stably bind in the DFG-out conformation of RET may overcome these limitations and selectively kill RET-rearranged tumors. Using chemical genomics in conjunction with phosphoproteomic analyses in RET-rearranged cells, we identify the CCDC6-RETI788N mutation and drug-induced mitogen-activated protein kinase pathway reactivation as possible mechanisms by which tumors may escape the activity of RET inhibitors. Our data provide mechanistic insight into the druggability of RET kinase fusions that may be of help for the development of effective therapies targeting such tumors.

Interlaboratory-concordance of PD-L1 IHC for NSCLC

e20508

Background: Immunohistochemistry (IHC) of the PD-L1 protein has become a mandatory diagnostic test for NSCLC. We conducted a two-step round robin test to analyze interobserver- and interlaboratory-concordance of PD-L1 IHC and to compare four clinical trial assays (CTAs; 28-8, 22C3, SP264, SP142) and laboratory-developed tests (LDTs). Results of step-one showed that reproducible PD-L1 IHC scoring is feasible; here we present the data on interlaboratory concordance Methods: Interlaboratory-concordance was tested by a centrally prepared tissue-microarray containing 21 NSCLC specimens that was stained at ten sites using CTAs and LDTs. Assay-performance was assessed with a second tissue-microarray containing eleven cell-lines with defined PD-L1 expression. Slides were evaluated by central quality-control and image-analysis. Results: The four CTAs yielded reproducible IHC-stainings at all sites while the results of the LDTs were mixed: Six protocols showed appropriate IHC quality with staining patterns similar to 22C3 and 28-8 CTAs, five protocols yielded less DAB-deposits and reduced staining intensity. Interlaboratory-concordance of carcinoma cell scoring using the 6-step system was moderate (κ = 0.43-0.69) while the included cut-offs ≥1% and ≥50% showed substantial concordance for the CTAs (κ = 0.73-0.89) and moderate concordance for the LDTs (κ = 0.50). No significant differences in interlaboratory-concordance were found among the CTAs. However, differences in the resulting staining patterns were noticed: While 22C3 and 28-8 showed similar staining patterns, SP263 showed minor differences in some cases and SP142 showed distinct patterns. Conclusions: The data show that the PD-L1 CTAs can be reproducibly employed and scored at different sites. LDTs with staining patterns similar to the CTAs are possible yet have to be carefully calibrated to match the appropriate intensity-range. The choice of assay and the set-up of the IHC-protocol may strongly influence the resulting staining.

Fibroblast kinase 1-3 inhibitor BGJ398 in patients with FGFR1 amplified squamous non-small cell lung cancer treated in a phase I study: Evaluation of tumor tissue and response at a single center

e20664

Background: Fibroblast growth factor receptor 1 ( FGFR1) amplification in squamous cell non-small cell lung cancer (sqNSCLC) has been described as potential oncogenic and targetable driver in cell lines and murine models. However, a phase I study evaluating FGFR 1-3 inhibitor BGJ398 showed moderate response rate of 11% in FGFR1amplified sgNSCLC treated with dose ≥ 100mg. To identify underlying mechanisms of resistance, we analyzed tumor tissues of selected patients. Methods: Within the phase I BGJ398 study, patients (pts) with FGFR1amplified sqNSCLC were treated orally with escalating dose (5 to 150mg) of BGJ398 once daily (QD) or 50mg twice a day. In the expansion phase, pts received BGJ398 either continuously QD or on a 3-weeks on/1-week off schedule. CT scans for response were performed every 8 weeks. Available tumor tissue of pts treated with BGJ398 at our center was analyzed using hybrid capture–based massively parallel sequencing (CAGE). Results: Twenty-one pts with FGFR1 amplified sqNSCLC were treated with ≥ 100mg BGJ398 at our site. As best response, 3 pts showed partial response (PR), 7 pts stable disease (SD) and 7 pts progressive disease (PD). Two pts withdrew their consents and 2 pts died ahead of first CT scan: one due to infection and one due to sudden death. We performed CAGE covering 256 genes on 9 patients: on 3 pts with PR, 2 pts with SD, 2 pts with PD and 2 pts who died before first CT scan. All analyzed patients harbored mutations in TP53. Additionally, we detected two CDKN2A (one patient with PR and one patient who died before first CT) and three MLL2 stop codon and frame shift mutations (two patients with SD and one patient with PD). Of interest, we identified three patients with two canonical (one patient with SD and one patient who died before first CT) and one non-canonical mutations in PIK3CA(one patient with SD). Conclusions: In our analysis, MLL2 and PIK3CA mutations seem to have a negative impact on response in FGFR1 amplified pts treated with BGJ398. Further analysis with higher patient number is needed to identify the role of MLL2 and PIK3CA mutations in FGFR1 amplified sqNSCLC. Clinical trial information: NCT01004224.

Harmonized PD-L1 immunohistochemistry for pulmonary squamous-cell and adenocarcinomas

Immunohistochemistry of the PD-L1 protein may be predictive for anti-PD-1 and anti-PD-L1 immunotherapy in pulmonary adenocarcinoma and in clinically unselected cohorts of so-called non-small-cell lung cancer. Several PD-L1 immunohistochemistry assays with custom reagents and scoring-criteria are developed in parallel. Biomarker testing and clinical decision making would profit from harmonized PD-L1 diagnostics. To assess interobserver concordance and PD-L1 immunohistochemistry staining patterns, 15 pulmonary carcinoma resection specimens (adenocarcinoma: n=11, squamous-cell carcinoma: n=4) were centrally stained with the assays 28-8, 22C3, SP142, and SP263 according to clinical trial protocols. The slides were evaluated independently by nine pathologists. Proportions of PD-L1-positive carcinoma cells and immune cells were scored according to a 6-step system that integrates the criteria employed by the four PD-L1 immunohistochemistry assays. Proportion scoring of PD-L1-positive carcinoma cells showed moderate interobserver concordance coefficients for the 6-step scoring system (Light's kappa=0.47-0.50). The integrated dichotomous proportion cut-offs (≥1, ≥5, ≥10, ≥50%) showed good concordance coefficients (κ=0.6-0.8). Proportion scoring of PD-L1-positive immune cells yielded low interobserver concordance coefficients both for the 6-step-score (κ<0.2) and the dichotomous cut-offs (κ=0.12-0.25). The assays 28-8 and 22C3 stained similar proportions of carcinoma cells in 12 of 15 cases. SP142 stained fewer carcinoma cells compared to 28-8, 22C3, and SP263 in four cases, whereas SP263 stained more carcinoma cells in nine cases. SP142 and SP263 stained immune cells more intensely. The data indicate that carcinoma cells can be reproducibly scored in PD-L1 immunohistochemistry for pulmonary adenocarcinoma and squamous-cell carcinoma. No differences in interobserver concordance were noticed among the tested assays. The scoring of immune cells yielded low concordance rates and might require specific standardization. The four tested PD-L1 assays did not show comparable staining patterns in all cases. Thus, studies that correlate staining patterns and response to immunotherapy are required to test the significance of the observed differences.

Heterogeneous Mechanisms of Primary and Acquired Resistance to Third-Generation EGFR Inhibitors

PURPOSE

To identify novel mechanisms of resistance to third-generation EGFR inhibitors in patients with lung adenocarcinoma that progressed under therapy with either AZD9291 or rociletinib (CO-1686).

EXPERIMENTAL DESIGN

We analyzed tumor biopsies from seven patients obtained before, during, and/or after treatment with AZD9291 or rociletinib (CO-1686). Targeted sequencing and FISH analyses were performed, and the relevance of candidate genes was functionally assessed in in vitro models.

RESULTS

We found recurrent amplification of either MET or ERBB2 in tumors that were resistant or developed resistance to third-generation EGFR inhibitors and show that ERBB2 and MET activation can confer resistance to these compounds. Furthermore, we identified a KRASG12S mutation in a patient with acquired resistance to AZD9291 as a potential driver of acquired resistance. Finally, we show that dual inhibition of EGFR/MEK might be a viable strategy to overcome resistance in EGFR-mutant cells expressing mutant KRAS CONCLUSIONS: Our data suggest that heterogeneous mechanisms of resistance can drive primary and acquired resistance to third-generation EGFR inhibitors and provide a rationale for potential combination strategies. Clin Cancer Res; 22(19); 4837-47. ©2016 AACR.

Genomic Amplification of CD274 (PD-L1) in Small-Cell Lung Cancer

Purpose: Programmed death ligand-1 (PD-L1), encoded by the CD274 gene, is a target for immune checkpoint blockade; however, little is known about genomic CD274 alterations. A subset of small-cell lung cancer (SCLC) exhibits increased copy number of chromosome 9p24, on which CD274 resides; however, most SCLCs show low expression of PD-L1. We therefore examined whether CD274 is a target of recurrent genomic alterations.Experimental Design: We examined somatic copy number alterations in two patient cohorts by quantitative real-time PCR in 72 human SCLC cases (cohort 1) and SNP array analysis in 138 human SCLC cases (cohort 2). Whole-genome sequencing revealed the detailed genomic structure underlying focal amplification. PD-L1 expression in amplified cases from cohorts 1 and 2 was further examined by transcriptome sequencing and immunohistochemical (IHC) staining.Results: By examining somatic copy number alterations in two cohorts of primary human SCLC specimens, we observed 9p24 copy number gains (where CD274 resides) and focal, high-level amplification of CD274 We found evidence for genomic targeting of CD274, suggesting selection during oncogenic transformation. CD274 amplification was caused by genomic rearrangements not affecting the open reading frame, thus leading to massively increased CD274 transcripts and high level expression of PD-L1.Conclusions: A subset (4/210, 1.9%) of human SCLC patient cases exhibits massive expression of PD-L1 caused by focal amplification of CD274 Such tumors may be particularly susceptible to immune checkpoint blockade. Clin Cancer Res; 23(5); 1220-6. ©2016 AACR.

PD-L1 expression in non-small cell lung cancer: Correlations with genetic alterations

Inhibition of the PD-1/PD-L1 pathway may induce anticancer immune responses in non-small cell lung cancer (NSCLC). Two PD-L1 immunohistochemistry (IHC) assays have been approved as companion diagnostic tests for therapeutic anti-PD-1 antibodies. However, many aspects of PD-L1 prevalence and association with genetically defined subtypes have not been addressed systematically. Here, we analyzed PD-L1 expression in 436 genetically annotated NSCLC specimens enriched for early stages using PD-L1 antibody 5H1. Expression of PD-L1 was detected in the tumor cells (TC) (34% of cases) and in associated immune cells (IC) (49%) across all stages of NSCLC, either alone or in combination. PD-L1 IHC-positive TC, but not IC showed significantly higher PD-L1 RNA expression levels. Expression in TC was associated with TP53, KRAS and STK11 mutational status in adenocarcinomas (AD) and with NFE2L2 mutations in squamous cell carcinomas (SQ). No correlations with histological subtype, clinical characteristics and overall survival were found. The presence of PD-L1-positive IC was significantly associated with patients' smoking status in AD. The findings are in agreement with the emerging concept that tumors with high mutational burden are more likely to benefit from immunotherapy, since TP53 and KRAS mutations are linked to smoking, increased numbers of somatic mutations and expression of neoantigens. Current clinical studies focus on stage IIIB and IV NSCLC; however, PD-L1 expression occurs in earlier stages and might be a predictive biomarker in clinical trials testing (neo-) adjuvant strategies.

Comprehensive lymph node morphometry in rectal cancer using acetone compression

Aims

Acetone compression (AC) is an elution compression technique for the comprehensive pathological examination of fatty tissue. Here AC is combined with digital morphometry to evaluate the impact of preoperative (neoadjuvant) chemoradiotherapy (neoCRT) on lymph node (LN) numbers and morphology in locally advanced rectal cancer. AC is compared with complete embedding of the mesorectal fat (whole mesorectal embedding (WME)) to exclude artificial alterations and to the standard technique, manual dissectioning (MD).

Methods

320 rectal cancer specimens were subjected to LN morphometry. Neoadjuvant CRT was applied in 204 specimens. LNs were prepared either with AC (n=138), WME (n=51) or MD (n=131). 8523 LNs were assessed including 530 nodes with metastases.

Results

LN prepared by AC and WME showed similar morphologies. AC revealed reduced LN sizes in neoCRT specimens compared with primary resection (2.2; 2.4 mm, p=0.049) while the LN number was comparable (27; 30/specimen). AC yielded 28 LN/specimen on average, MD yielded 22 LN (p<0.001). In neoCRT specimens, MD yielded less LN compared with primary resection (19; 25). MD detected less small LN (<2 mm; MD: 25%; AC: 56%) while 24 of the 135 LN metastases found by AC were ≤2 mm in diameter.

Conclusions

AC does not alter LN morphology and is especially suited to retrieve small LN after neoadjuvant CRT of rectal cancer. Neoadjuvant multimodality treatment caused reduced LN sizes while the LN numbers were not affected. When compared with MD, AC proved more reliable in the retrieval of LN from rectal cancer specimens after neoCRT.

Challenging dedifferentiated liposarcoma identified by MDM2-amplification, a report of two cases

Background

Liposarcoma is the most frequent soft tissue sarcoma. Well differentiated liposarcoma may progress into dedifferentiated liposarcoma with pleomorphic histology. A minority additionally features myogenic, osteo- or chondrosarcomatous heterologous differentiation. Genomic amplification of the Mouse double minute 2 homolog (MDM2) locus is characteristic for well differentiated and dedifferentiated liposarcomas. Detection of MDM2 amplification may supplement histopathology and aid to distinguish liposarcoma from other soft tissue neoplasia.

Case presentation

Here we present two cases of dedifferentiated liposarcoma with challenging presentation. Case 1 features a myogenic component. As the tumour infiltrated the abdominal muscles and showed immunohistochemical expression of myogenic proteins, rhabdomyosarcoma had to be ruled out. Case 2 has an osteosarcomatous component resembling extraosseous osteosarcoma. The MDM2 status was determined in both cases and helped making the correct diagnosis. Overexpression of MDM2 and co-overexpression of Cyclin-dependent kinase 4 is demonstrated by immunohistochemistry. The underlying MDM2 amplification is shown by fluorescence in situ hybridisation. Since low grade osteosarcoma may also harbour MDM2 amplification it is emphasised that the amplification has to be present in the lipomatous parts of the tumour to distinguish liposarcoma from extraosseous osteosarcoma.

Conclusions

The two cases exemplify challenges in the diagnoses of dedifferentiated liposarcoma. Liposarcoma often has pleomorphic histology and additionally may feature heterologous components that mimic other soft tissue neoplasms. Amplification of MDM2 is characteristic for well differentiated and dedifferentiated liposarcomas. Determination of the MDM2 status by in situ hybridisation may assist histopathology and help to rule out differential diagnoses.

Cystic endosalpingiosis presenting as chronic back pain, a case report

A 48-year old woman presented with chronic back pain. Previous examinations had been inconclusive. Gynaecological examination revealed large cystic masses on the fundus uteri and left adnexa. Laparoscopy and histopathology showed unusually extensive cystic endosalpingiosis covering the serosa-coated uterine surface as well as the adnexa on both sides. After uneventful laparoscopic-assisted vaginal hysterectomy the patient quickly recovered and was relieved of her chronic backache. Virtual slides: http://www.diagnosticpathology.diagnomx.eu/vs/1501709091077524.

[Angioinvasion by neuroendocrine jejunal tumor. Demonstration of a malignancy sign by acetone compression]

Neuroendocrine neoplasms of the digestive system are classified by current World Health Organization (WHO) guidelines as G1 and G2 neuroendocrine tumors (NET) as well as neuroendocrine carcinoma (NEC) based on proliferation and differentiation. The G1 NET tumors are highly differentiated, low proliferating and usually exhibit a favorable course of the disease without the development of metastases. In the case presented here, angioinvasion by a pT3 NET G1 was demonstrated after complete work-up of the mesenterial fat by acetone compression. The findings indicate an unfavorable course of disease requiring intensive surveillance.

Impact of epidermal growth factor receptor (EGFR) cell surface expression levels on effector mechanisms of EGFR antibodies

The epidermal growth factor receptor (EGFR) is a widely expressed Ag that is successfully targeted in tumor patients by mAbs or tyrosine kinase inhibitors. A clinical study in non-small cell lung cancer patients demonstrated a positive correlation between EGFR expression levels and the therapeutic efficacy of the EGFR mAb cetuximab. However, the impact of EGFR expression on the different mechanisms of action (MoAs) triggered by the EGFR mAb has not been defined. In this study, BHK-21 cells were stably transfected to express different EGFR levels, which were quantified by immunofluorescence and immunohistochemistry and compared with EGFR levels of clinical non-small cell lung cancer samples. These cells were used to systematically investigate the impact of target Ag expression levels on Fab- or Fc-mediated MoAs of EGFR mAb. A negative correlation between EGFR levels and potency of Fab-mediated MoA was observed. Interestingly, Ab-dependent cell-mediated cytotoxicity (ADCC) by NK cells, monocytes, or polymorphonuclear cells as well as complement-dependent cytotoxicity positively correlated with the number of EGFR molecules. In comparison with ADCC by mononuclear cells, polymorphonuclear cell-mediated ADCC and complement-dependent cytotoxicity required higher EGFR expression levels and higher mAb concentrations to trigger significant tumor cell killing. This correlation between EGFR expression levels and Fc-mediated MoA was confirmed in an independent panel of human tumor cell lines carrying diverse genetic alterations. Furthermore, RNA interference-induced knockdown experiments reinforced the impact of EGFR expression on tumor cell killing by EGFR mAb. In conclusion, these results suggest that EGFR expression levels may determine distinct patterns of MoAs that contribute to the therapeutic efficacy of EGFR mAb.