Pulmonary squamous cell carcinoma and lymphoepithelial carcinoma - morphology, molecular characteristics and differential diagnosis

Squamous cell carcinoma (SCC) comprises one of the major groups of non-small-cell carcinoma of the lung, and is subtyped into keratinising, non-keratinising and basaloid SCC. SCC can readily be diagnosed using histomorphology alone in keratinising SCC. Confirmatory immunohistochemical analyses should always be applied in non-keratinising and basaloid tumours to exclude differential diagnoses, most prominently adenocarcinoma and high-grade neuroendocrine carcinoma, which may have important therapeutic consequences. According to the World Health Organisation (WHO) classification 2015, the diagnosis of SCC can be rendered in resections of morphologically ambiguous tumours with squamous immunophenotype. In biopsies and cytology preparations in the same setting the current guidelines propose a diagnosis of 'non-small-cell carcinoma, favour SCC' in TTF1-negative and p40-positive tumours to acknowledge a possible sampling bias and restrict extended immunohistochemical evaluation in order to preserve tissue for molecular testing. Most SCC feature a molecular 'tobacco-smoke signature' with enrichment in GG > TT mutations, in line with the strong epidemiological association of SCC with smoking. Targetable mutations are extremely rare but they do occur, in particular in younger and non- or light-smoking patients, warranting molecular investigations. Lymphoepithelial carcinoma (LEC) is a poorly differentiated SCC with a syncytial growth pattern and a usually prominent lymphoplasmacytic infiltrate and frequent Epstein-Barr virus (EBV) association. In this review, we describe the morphological and molecular characteristics of SCC and LEC and discuss the most pertinent differential diagnoses.

USP13 drives lung squamous cell carcinoma by switching lung club cell lineage plasticity

Lung squamous cell carcinoma (LUSC) is associated with high mortality and limited targeted therapies. USP13 is one of the most amplified genes in LUSC, yet its role in lung cancer is largely unknown. Here, we established a novel mouse model of LUSC by overexpressing USP13 on KrasG12D/+; Trp53flox/flox background (KPU). KPU-driven lung squamous tumors faithfully recapitulate key pathohistological, molecular features, and cellular pathways of human LUSC. We found that USP13 altered lineage-determining factors such as NKX2-1 and SOX2 in club cells of the airway and reinforced the fate of club cells to squamous carcinoma development. We showed a strong molecular association between USP13 and c-MYC, leading to the upregulation of squamous programs in murine and human lung cancer cells. Collectively, our data demonstrate that USP13 is a molecular driver of lineage plasticity in club cells and provide mechanistic insight that may have potential implications for the treatment of LUSC.

Associations of tissue tumor mutational burden and mutational status with clinical outcomes in KEYNOTE-042: pembrolizumab versus chemotherapy for advanced PD-L1-positive NSCLC

BACKGROUND

We evaluated whether tissue tumor mutational burden (tTMB) and STK11, KEAP1, and KRAS mutations have clinical utility as biomarkers for pembrolizumab monotherapy versus platinum-based chemotherapy in patients with programmed death ligand- 1 (PD-L1)-positive (tumor proportion score ≥1%) advanced/metastatic non-small-cell lung cancer (NSCLC) without EGFR/ALK alterations in the phase III KEYNOTE-042 trial.

PATIENTS AND METHODS

This retrospective exploratory analysis assessed prevalence of tTMB and STK11, KEAP1, and KRAS mutations determined by whole-exome sequencing of tumor tissue and matched normal DNA and their associations with outcomes in KEYNOTE-042. Clinical utility of tTMB was assessed using a prespecified cut point of 175 mutations/exome.

RESULTS

Of 793 patients, 345 (43.5%) had tTMB ≥175 mutations/exome and 448 patients (56.5%) had tTMB <175 mutations/exome. No association was observed between PD-L1 expression and tTMB. Continuous tTMB score was associated with improved overall survival (OS) and progression-free survival among patients receiving pembrolizumab (Wald test, one-sided P < 0.001) but not those receiving chemotherapy (Wald test, two-sided P > 0.05). tTMB ≥175 mutations/exome was associated with improved outcomes for pembrolizumab versus chemotherapy, whereas tTMB <175 mutations/exome was not {OS: hazard ratio, 0.62 [95% confidence interval (CI) 0.48-0.80] and 1.09 (95% CI 0.88-1.36); progression-free survival: 0.75 (0.59-0.95) and 1.27 (1.04-1.55), respectively}. Improved OS [hazard ratio (95% CI)] for pembrolizumab versus chemotherapy was observed regardless of STK11 [STK11 mutant (n = 33): 0.37 (0.16-0.86), STK11 wild-type (n = 396): 0.83 (0.65-1.05)]; KEAP1 [KEAP1 mutant (n = 64): 0.75 (0.42-1.35), KEAP1 wild-type (n = 365): 0.78 (0.61-0.99)], or KRAS [KRAS mutant (n = 69): 0.42 (0.22-0.81); KRAS wild-type (n = 232): 0.86 (0.63-1.18)] mutation status.

CONCLUSION

tTMB with a cut point of ≥175 mutations/exome is a potential predictive biomarker for pembrolizumab monotherapy for advanced/metastatic PD-L1 tumor proportion score ≥1% NSCLC. Pembrolizumab is a standard first-line treatment in this setting regardless of STK11, KEAP1, or KRAS mutation status.

Assessment of RANK/RANK-L prevalence and clinical significance in NSCLC European Thoracic Oncology Platform Lungscape cohort and SPLENDOUR randomized clinical trial

BACKGROUND

The primary objective of this study is to evaluate the clinical significance of RANK/L expression, in both a retrospective cohort of surgically resected stage I-III NSCLC (Lungscape) and a randomized clinical trial-cohort (SPLENDOUR) of advanced NSCLC treated with chemotherapy alone or in combination with denosumab.

METHODS

RANK-L expression was assessed on tissue microarrays (TMAs) in Lungscape and whole sections in SPLENDOUR, using immunohistochemistry, with H-scores values > 0 indicating positivity. Prevalence of RANK positivity and its association with clinicopathological characteristics, and patient outcome was explored in a subset of the ETOP Lungscape cohort and in SPLENDOUR. Also investigated were the prevalence of RANK overexpression (proportion of positive cancer cells ≥ 50%) in the Lungscape cohort, and RANK-L in the SPLENDOUR trial.

RESULTS

In the Lungscape cohort, RANK expression was assessed at a median follow-up of 46 months (N = 488 patients; 4 centers); 35% were female, 44/49/6% adenocarcinomas (AC)/squamous cell carcinomas (SCC)/other, 48/27/25% with stage I/II/III. Median RFS/TTR/OS were 58/Not reached/74 months. Prevalence of RANK expression was 31% (95%CI:27%-35%); significantly higher in AC: 50% (95%CI:43%-57%) vs SCC: 12% (95%CI:8%-16%) (p < 0.001); more frequent in females (42% vs 25%, p < 0.001) and tumors ≤ 4 cm (35.3% vs 23.3%, p = 0.0065). No association with outcome was found. In the SPLENDOUR trial (463 patients), the prevalence of membranous and cytoplasmic RANK positivity was 34% (95%CI:30%-38%) and 9% (95%CI:7%-12%), respectively, while prevalence for RANK-L was 5% (95%CI:3%-7%) and 36% (95%CI:31%-40%), respectively. Cytoplasmic RANK-L positivity was more common among females (47% vs 31%, p = 0.001) and in non-SCC histology (45% vs 10%, p < 0.0001). At the pre-specified 1% significance level, no prognostic or predictive effect was found.

CONCLUSIONS

Both cohorts indicate that RANK expression is more common in adenocarcinoma/non-squamous NSCLC and in female patients. No prognostic effect is found, and in the clinical trial involving addition of denosumab to chemotherapy no predictive effect is detected.

Prognostic impact of tumour mutational burden in resected stage I and II lung adenocarcinomas from a European Thoracic Oncology Platform Lungscape cohort

BACKGROUND

The primary objective of this study is to evaluate tumor mutational burden (TMB), its associations with selected clinicopathological and molecular characteristics as well as its clinical significance, in a retrospective cohort of surgically resected stage I-II lung adenocarcinomas, subset of the ETOP Lungscape cohort.

METHODS

TMB was evaluated on tumor DNA extracted from resected primary lung adenocarcinomas, based on FoundationOne®CDx (F1CDx) genomic profiling, centrally performed at the University Hospital Zurich. The F1CDx test sequences the complete exons of 324 cancer-related genes and detects substitutions, insertions and deletions (indels), copy number alterations and gene rearrangements. In addition, the genomic biomarkers TMB and microsatellite instability (MSI) are analyzed.

RESULTS

In the Lungscape cohort, TMB was assessed in 78 surgically resected lung adenocarcinomas from two Swiss centers (62 % males, 55 %/45 % stage I/II). Median TMB was 7.6 Muts/Mb, with TMB high (≥10 Muts/Mb) in 40 % of cases (95 %CI:29 %-52 %). The most frequently mutated genes were TP53/KRAS/EGFR/MLL2 detected in 58 %/38 %/33 %/30 % of samples, respectively. TMB was significantly higher among males (TMB high: 50 % vs 23 % in females, p = 0.032), as well as among current/former smokers (TMB high: 44 % vs 8 % in never smokers, p = 0.023). Furthermore, TMB was significantly higher in TP53 mutated than in non-mutated patients (TMB high: 60 % vs 12 %, p < 0.001), while it was higher in EGFR non-mutated patients compared to EGFR mutated (TMB high: 48 % vs 23 %, p = 0.049). At a median follow-up time of 56.1 months (IQR:38.8-72.0), none of the three outcome variables (OS, RFS, TTR) differed significantly by TMB status (all p-values > 5 %). This was also true when adjusting for clinicopathological characteristics.

CONCLUSIONS

While presence of TP53 mutations and absence of EGFR mutations are associated with high TMB, increased TMB had no significant prognostic impact in patients with resected stage I/II lung adenocarcinoma beyond T and N classification, in both unadjusted and adjusted analyses.

Squamous cell lung cancer: Current landscape and future therapeutic options

Squamous cell lung cancers (lung squamous cell carcinomas [LUSCs]) are associated with high mortality and a lack of therapies specific to this disease. Although recurrent molecular aberrations are present in LUSCs, efforts to develop targeted therapies against receptor tyrosine kinases, signaling transduction, and cell cycle checkpoints in LUSCs were met with significant challenges. The present therapeutic landscape focuses on epigenetic therapies to modulate the expression of lineage-dependent survival pathways and undruggable oncogenes. Another important therapeutic approach is to exploit metabolic vulnerabilities unique to LUSCs. These novel therapies may synergize with immune checkpoint inhibitors in the right therapeutic context. For example, the recognition that alterations in KEAP1-NFE2L2 in LUSCs affected antitumor immune responses created unique opportunities for targeted, metabolic, and immune combinations. This article provides a perspective on how lessons learned from the past influence the current therapeutic landscape and opportunities for future drug development for LUSCs.

Genomic landscape, immune characteristics and prognostic mutation signature of cervical cancer in China

Purpose

This study aimed to analyse the genomic alteration profiles and immune characteristics of a cohort of Chinese cervical cancer patients to understand why certain patients benefited from molecular targeted therapies and immunotherapy as well as their prognostic significance.

Methods

PD-L1 expression and clinicopathological information were obtained from 98 cervical cancer patients. Differences in PD-L1 expression and gene mutations between squamous cell carcinoma (SCC) and adenocarcinoma (AC) were analysed by the chi-square test or Fisher's exact test. Differences in gene mutations between our cohort and The Cancer Genome Atlas (TCGA) cohort were tested by Fisher's exact test. Logistic regression was used to analyse factors influencing TMB-high.

Results

Positive PD-L1 expression was significantly higher in cervical SCC than in cervical AC (87% vs. 39%, p < 0.001). Frequently mutated genes in cervical cancer included the PIK3CA, KMT2D, and KMT2C genes, among others. PIK3CA gene mutation rates were significantly higher in SCC than in AC (p = 0.004). The TERT gene mutation rate was significantly higher in our cohort than in the TCGA cohort (12% vs. 1%, p < 0.001). The independent predictors of high TMB were KMT2C and LRP1B gene mutations (p < 0.05). We also found that PTEN mutations were associated with worse survival (median PFS, 12.16 vs. 21.75 months, p = 0.0024).

Conclusion

Cervical SCC and AC have different molecular profiles and immune characteristics, suggesting that targeted treatments for SCC and AC patients may improve clinical outcomes. KMT2C and LRP1B gene mutations are independent predictors of TMB-high status in cervical cancer. We also proposed the prognostic value of PTEN mutations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01376-9.

Factors affecting outcome in resected EGFR-mutated lung cancer

INTRODUCTION

Long-term data on disease trajectory of EGFR-mutated early-stage non-small cell lung cancer (NSCLC) is still limited. This is relevant in the context of the recently approved introduction of adjuvant EGFR-targeting therapy, specifically osimertinib in resected stage II-III EGFR-mutated NSCLC.

METHODS

Long-term data on patients with resected adenocarcinoma of the lung and known EGFR-status were analysed with focus on site of relapse and detailed cause of death. Patients resected in the period 2006 to 2018 were included.

RESULTS

Of 503 patients (286 (57%) females, median age 67.3 years), 62 (12%) harboured an EGFR-mutation, 286 (57%) were in stage I. After a median follow-up of 8.0 years, 241 (48%) patients relapsed. Recurrence occurred in 30% and 53% of EGFR-positive stage IA and IB patients, respectively. Median overall survival was longer in EGFR-mutated versus non-mutated patients (128 versus 88 months). The recurrence rate, time to recurrence and rate of brain metastases was not different between EGFR-mutated and non-mutated groups. Median time from recurrence to death was longer in EGFR-mutated patients (31 months) compared with non-mutated patients (15 months). More patients without EGFR-mutation succumbed to non-cancer related death (18%) compared to patients with EGFR-mutations (8%).

CONCLUSIONS

The recurrence pattern in EGFR-mutated and non-mutated NSCLC-patients is similar and the rate is high in early stages. Time from recurrence to death and overall survival is longer in the EGFR-mutated group, due to lower risk of non-lung cancer deaths, and efficient treatment upon relapse.

Integration of rapid PCR testing as an adjunct to NGS in diagnostic pathology services within the UK: evidence from a case series of non-squamous, non-small cell lung cancer (NSCLC) patients with follow-up

AIMS

Somatic genetic testing in non-squamous, non-small cell lung carcinoma (NSCLC) patients is required to highlight subgroups eligible for a number of novel oncological therapies. This study aims to determine whether turnaround times for reporting epidermal growth factor receptors (EGFR) by next-generation sequencing (NGS) alone is sufficient to meet the needs of lung cancer patients.

METHODS

We performed a retrospective case series with follow-up. Outcomes of EGFR testing (102 tests) in 96 patients by NGS were compared with a rapid, fully automated PCR-based platform (Idylla) in local histopathology laboratories.

RESULTS

Turnaround time for reporting NGS was 17 calendar days. Reporting using the Idylla EGFR Mutation Test, by contrast, gave a potential turnaround time of 3.8 days from request to authorisation. Three-quarters of patients presenting with stage IV disease had a performance status of 0, 1, or 2 but 18% experienced rapid clinical deterioration (p<0.05). A third of these patients were deceased by the time NGS reports were available.

CONCLUSIONS

We discuss issues around integrating rapid PCR testing alongside NGS in multidisciplinary care pathways and strategies for mitigating against foreseeable difficulties. Dual testing for stage IV non-squamous, NSCLC patients has the potential to improve care and survival outcomes by providing access to the right test at the right time.

KRAS Mutations in Squamous Cell Carcinomas of the Lung

KRAS is one of the most commonly mutated oncogenes in cancer, enabling tumor proliferation and maintenance. After various approaches to target KRAS have failed over the past decades, the first specific inhibitor of the p.G12C mutation of KRAS was recently approved by the FDA after showing promising results in adenocarcinomas of the lung and other solid tumors. Lung cancer, the most common cancer worldwide, is a promising use case for these new therapies, as adenocarcinomas in particular frequently harbor KRAS mutations. However, in squamous cell carcinoma (SCC) of the lung, KRAS mutations are rare and their impact on clinical outcome is poorly understood. In this review, we discuss the current knowledge on the prevalence and prognostic and predictive significance of KRAS mutations in the context of SCC.

Programmed death-ligand 1 expression and its associations with clinicopathological features, prognosis, and driver oncogene alterations in surgically resected lung adenocarcinoma

OBJECTIVES

Programmed death-ligand 1 (PD-L1) expression is a predictive biomarker of response to immunotherapies targeting programmed death-1/PD-L1 in advanced-stage lung adenocarcinoma. The aim of this study was to investigate the associations between PD-L1 expression and clinicopathological features, prognosis, and driver oncogene alterations in patients with lung adenocarcinoma.

MATERIALS AND METHODS

We evaluated PD-L1 expression in 1,005 surgically resected lung adenocarcinoma specimens, by immunohistochemistry using the 22C3 antibody. PD-L1 positivity was defined based on the proportion of stained tumor cells (TPS) on tissue microarrays: <1% (negative), 1-49% (weakly positive), and ≥ 50% (strongly positive). Correlations between PD-L1 expression and clinicopathological features, prognosis, and driver oncogene (EGFR, KRAS, ALK, ROS1, and RET) alterations in lung adenocarcinoma were analyzed.

RESULTS

PD-L1 expression was negative in 726 (72%) of 1,005 tumors, weakly positive in 161 (16%), and strongly positive in 118 (12%). Male sex, smoking, elevated serum carcinoembryonic antigen levels, advanced pathological stages, high-grade tumors, predominantly solid tumors, tumors with lymphatic permeation or vascular or pleural invasion, tumors without EGFR mutations, and tumors with KRAS mutations were more common in patients with PD-L1-positive tumors (TPS ≥ 1%) than in those with PD-L1-negative tumors (TPS < 1%). PD-L1 positivity was not associated with ALK, ROS1, or RET fusion status. Although PD-L1 positivity was associated with poor overall survival and poor relapse-free survival in all patients, this was not statistically significant after adjusting for prognostic factors in the multivariate analysis. In the subgroup analysis according to driver oncogene alterations, PD-L1 positivity was associated with poor relapse-free survival only in patients with EGFR-mutated tumors.

CONCLUSION

Surgically resected lung adenocarcinomas with increased PD-L1 expression were biologically aggressive tumors that frequently occurred in male smokers. PD-L1 expression and its prognostic significance differed according to driver oncogene alterations.

Programmed cell death ligand-1 expression and survival in a cohort of patients with non-small cell lung cancer receiving first-line through third-line therapy in Denmark

BACKGROUND

PD-L1 expression on tumor cells (TCs) or immune cells (ICs) may be used as a prognostic marker for survival in patients with NSCLC. We characterized PD-L1 expression on TCs or ICs in a patient cohort with NSCLC to determine associations between PD-L1 expression and overall survival (OS), according to EGFR and KRAS mutation status.

METHODS

Danish patients aged >18 years diagnosed with NSCLC before 2014 on first- (N = 491), second- (N = 368), or third-line (N = 498) therapy were included. Data were extracted from population-based medical registries. Tumor samples from pathology archives were tested for biomarkers. High PD-L1 expression was defined as expression on ≥25 % of TCs or ICs based on first diagnostic biopsy or surgical resection. KRAS and EGFR mutation status were tested using PCR-based assays. Cox regression analysis was used to compute adjusted HRs and associated 95 % CIs.

RESULTS

PD-L1 TC and IC ≥ 25 % were observed in 24.3 %-31.0 % and 11.7-14.7 % of patients, respectively. EGFR and KRAS mutations were detected in 4.7 %-8.8 % and 26.5 %-30.7 % of patients, respectively. PD-L1 TC ≥ 25 % was not associated with survival advantage in first- (HR = 0.96, 95 % CI: 0.75-1.22), second- (1.08, 0.81-1.42), or third-line (0.94, 0.74-1.20) therapy. PD-L1 IC ≥ 25 % was associated with survival advantage in second-line (HR = 0.56, 95 % CI: 0.36-0.86) and third-line (0.69, 0.49-0.97) but not first-line (1.00, 0.70-1.41) therapy.

CONCLUSION

No association was observed between PD-L1 TC ≥ 25 % and OS in any therapy line. PD-L1 IC ≥ 25 % may confer survival benefit among some patients who reach second-line therapy.

Diving into the Pleural Fluid: Liquid Biopsy for Metastatic Malignant Pleural Effusions

Simple Summary

Malignant pleural effusion is a common complication arising as the natural progression of many tumors, such as lung cancer. When this occurs, the common protocol consists of analyzing the pleural fluid for the presence of malignant cells. However, on many occasions no malignant cells are found despite a clear suspicion of cancer. Thus, the current diagnostic methodology is imperfect and more precise methods for the identification of malignancy are needed. Nonetheless, these methods are often invasive, which may be counterproductive, especially for patients with poor health condition. These concerns have made clinicians consider alternative non-invasive strategies to diagnose cancer using the generally abundant pleural fluid (e.g., liquid biopsy). Thus, a liquid sample can be analyzed for the presence of cancer footprints, such as circulating malignant cells and tumor nucleic acids. Herein, we review the literature for studies considering pleural fluid as a successful source of liquid biopsy.

Abstract

Liquid biopsy is emerging as a promising non-invasive diagnostic tool for malignant pleural effusions (MPE) due to the low sensitivity of conventional pleural fluid (PF) cytological examination and the difficulty to obtain tissue biopsies, which are invasive and require procedural skills. Currently, liquid biopsy is increasingly being used for the detection of driver mutations in circulating tumor DNA (ctDNA) from plasma specimens to guide therapeutic interventions. Notably, malignant PF are richer than plasma in tumor-derived products with potential clinical usefulness, such as ctDNA, micro RNAs (miRNAs) and long non-coding RNAs (lncRNAs), and circulating tumor cells (CTC). Tumor-educated cell types, such as platelets and macrophages, have also been added to this diagnostic armamentarium. Herein, we will present an overview of the role of the preceding biomarkers, collectively known as liquid biopsy, in PF samples, as well as the main technical approaches used for their detection and quantitation, including a proper sample processing. Technical limitations of current platforms and future perspectives in the field will also be addressed. Using PF as liquid biopsy shows promise for use in current practice to facilitate the diagnosis and management of metastatic MPE.

Prognostic Impact of KRAS G12C Mutation in Patients With NSCLC: Results From the European Thoracic Oncology Platform Lungscape Project

INTRODUCTION

KRAS mutations, the most frequent gain-of-function alterations in NSCLC, are currently emerging as potential predictive therapeutic targets. The role of KRAS-G12C (Kr_G12C) is of special interest after the recent discovery and preclinical analyses of two different Kr_G12C covalent inhibitors (AMG-510, MRTX849).

METHODS

KRAS mutations were evaluated in formalin-fixed, paraffin-embedded tissue sections by a microfluidic-based multiplex polymerase chain reaction platform as a component of the previously published European Thoracic Oncology Platform Lungscape 003 Multiplex Mutation study, of clinically annotated, resected, stage I to III NSCLC. In this study, -Kr_G12C mutation prevalence and its association with clinicopathologic characteristics, molecular profiles, and postoperative patient outcome (overall survival, relapse-free survival, time-to-relapse) were explored.

RESULTS

KRAS gene was tested in 2055 Lungscape cases (adenocarcinomas: 1014 [49%]) with I or II or III stage respective distribution of 53% or 24% or 22% and median follow-up of 57 months. KRAS mutation prevalence in the adenocarcinoma cohort was 38.0% (95% confidence interval (CI): 35.0% to 41.0%), with Kr_G12C mutation representing 17.0% (95% CI: 14.7% to 19.4%). In the "histologic-subtype" cohort, Kr_G12C prevalence was 10.5% (95% CI: 9.2% to 11.9%). When adjusting for clinicopathologic characteristics, a significant negative prognostic effect of Kr_G12C presence versus other KRAS mutations or nonexistence of KRAS mutation was identified in the adenocarcinoma cohort alone and in the "histologic-subtype" cohort. For overall survival in adenocarcinomas, hazard ratio (HR)_{G12C versus other KRAS} is equal to 1.39 (95% CI: 1.03 to 1.89, p = 0.031) and HR_{G12C versus no KRAS} is equal to 1.32 (95% CI: 1.03 to 1.69, p = 0.028) (both also significant in the "histologic-subtype" cohort). For time-to-relapse, HR_{G12C versus other KRAS} is equal to 1.41 (95% CI: 1.03 to 1.92, p = 0.030). In addition, among all patients, for relapse-free survival, HR_{G12C versus no KRAS} is equal to 1.27 (95% CI: 1.04 to 1.54, p = 0.017).

CONCLUSIONS

In this large, clinically annotated stage I to III NSCLC cohort, the specific Kr_G12C mutation is significantly associated with poorer prognosis (adjusting for clinicopathologic characteristics) among adenocarcinomas and in unselected NSCLCs.

Neoadjuvant treatment of stage IIIA-N2 in EGFR-Mutant/ALK-rearranged non-small cell lung cancer

Defining the optimal neoadjuvant strategy in early-stage and locoregional (N2) oncogenic-driven lung cancer remains a major challenge for the scientific community. Whereas significant advances have been achieved with the use of personalized medicine and targeted therapies in advanced stages, we are still far from translating the same magnitude of benefits into an earlier-stage disease. Perioperative strategies with neoadjuvant and adjuvant tyrosine kinase inhibitors in patients with EGFR and ALK gene alterations have yielded mixed results and further biomarker-driven trials are needed to shed more light on the significance of inhibiting the oncogenic signaling addiction at earlier stages of the disease and the conceivable value of incorporating more potent targeted inhibitors in this setting. Meanwhile, the landscape of early-stage lung cancer management is progressing rapidly, and we anticipate the incorporation of novel immunotherapeutic agents on the basis of this promising preliminary activity as induction strategies. Whether the benefits observed in the overall population can be translated into specific subsets of oncogenic-driven tumors is still unknown, but it clearly reinforces the importance of incorporating—sooner rather than later—a biomarker-testing strategy into the routine work-up of early-stage non-small cell lung cancer (NSCLC). There are still many challenges to overcome such as the need to stablish standardized surrogate endpoints and to define the optimal duration of perioperative treatment, as well as how to expedite patient recruitment using enrichment strategies for biomarker stratified trials. Despite the difficulties, we are living in exciting times and coming up on a new window of opportunities for achieving the ultimate goal of curing early-stage lung cancer and improving long-term outcomes by eliminating the minimal residual disease and reducing the risk for metastatic recurrence.

Long term follow-up of EGFR mutated NSCLC cases

PURPOSE

A substantial fraction of all non-small cell lung cancers(NSCLC) carry a mutation in the EGFR gene for which an effective treatment with anti-tyrosine kinases(TKIs) is available. We studied the long term survival of these patients following the introduction of TKIs.

EXPERIMENTAL DESIGN

All consecutive cases of NSCLC newly diagnosed with advanced disease were referred for free tumor EGFR mutation testing at Clalit's national personalized medicine laboratory. Mutations and deletions in target codons 18-21 of EGFR were sought using RT-PCR and fragment analysis. Comprehensive EMRs were used to collect full data on treatments and clinical status.

RESULTS

A cohort of 3,062 advanced NSCLC cases, included 481(15.7%) somatic EGFR mutation carriers (17.5% of all adenocarcinomas, 26.7% of females with adenocarcinomas). TKIs treatment to EGFR mutation carriers was provided to 85% of all eligible. After a median follow up period of 15.9 months for EGFR mutated cases the hazard ratio for overall survival of EGFR-mutated NSCLC treated with TKIs was 0.55(0.49-0.63, p<0.0001) when compared with EGFR wild-type(WT) tumors under usual care. After adjusting for age, sex, ethnicity, smoking history and tumor histology, all of which had an independently significant effect on survival, the HR for TKI-treated, EGFR-mutated tumors, was 0.63 (0.55-0.71, p<0.0001). Treating EGFR-WT cases with TKIs yielded a high HR=1.32 (1.19-1.48).

CONCLUSIONS

TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years. Squamous histology, smoking, male sex and Arab ethnicity were associated with higher NSCLC mortality hazard. Treating non-EGFR-mutated NSCLC with TKIs seems detrimental. Statement of Significance: • TKIs given to EGFR mutated advanced NSCLC demonstrated a substantial survival benefit for at least five years but not much longer. • Treating non-EGFR-mutated NSCLC with TKIs seems detrimental and should probably be avoided. • Squamous histology of non-small cell lung cancer, smoking history, male sex and Arab ethnicity were associated with altogether higher NSCLC mortality hazard.

Programmed death-ligand 1 expression influenced by tissue sample size. Scoring based on tissue microarrays' and cross-validation with resections, in patients with, stage I-III, non-small cell lung carcinoma of the European Thoracic Oncology Platform Lungscape cohort

PD-L1, as assessed by immunohistochemistry, is a predictive biomarker for immuno-oncology treatment in lung cancer. Different scoring methods have been used to assess its status, resulting in a wide range of positivity rates. We use the European Thoracic Oncology Platform Lungscape non-small cell lung carcinoma cohort to explore this issue. PD-L1 expression was assessed via immunohistochemistry on tissue microarrays (up to four cores per case), using the DAKO 28-8 immunohistochemistry assay, following a two-round external quality assessment procedure. All samples were analyzed under the same protocol. Cross-validation of scoring between tissue microarray and whole sections was performed in 10% randomly selected samples. Cutoff points considered: ≥1, 50 (primarily), and 25%. At the two external quality assessment rounds, tissue microarray scoring agreement rates between pathologists were: 73% and 81%. There were 2008 cases with valid immunohistochemistry tissue microarray results (50% all cores evaluable). Concordant cases at 1, 25, and 50% were: 85, 91, and 93%. Tissue microarray core results were identical for 70% of cases. Sensitivity of the tissue microarray method for 1, 25, and 50% was: 80, 78, and 79% (specificity: 90, 95, 98%). Complete agreement between tissue microarrays and whole sections was achieved for 60% of the cases. Highest sensitivity rates for 1% and 50% cutoffs were detected for higher number of cores. Underestimation of PD-L1 expression on small samples is more common than overestimation. We demonstrated that classification of PD-L1 on small biopsy samples does not represent the overall expression of PD-L1 in all non-small cell cancer carcinoma cases, although the majority of cases are 'correctly' classified. In future studies, sampling more and larger biopsies, recording the biopsy size and tumor load may permit further refinement, increasing predictive accuracy.

Is there a causal link between PTEN deficient tumors and immunosuppressive tumor microenvironment?

The PTEN tumor suppressor is the second most commonly inactivated gene across cancer types. While it's role in PI3K/AKT and DNA damage pathways are clear, increasing evidences suggest that PTEN may also promote anti-tumor immunity. PTEN-deficient tumors are characterized by (i) reduced levels of cytotoxic T cells, helper T cells and NK cells, (ii) elevated pro-oncogenic inflammatory cytokines like CCL2 and (iii) increased levels of immunosuppressive cells such as MDSCs and Tregs. An intriguing possibility is that link between PTEN and anti-tumor immunity is mediated by the interferon signaling pathway. In this review, we summarize the evidences for the mechanistic link between PTEN deficiency and immunosuppressive tumor microenvironment and the interferon signaling pathway. We further discuss how the link between these pathways can be exploited for development of personalized immunotherapy for patients with PTEN deficient tumors.

A retrospective cohort study of PD-L1 prevalence, molecular associations and clinical outcomes in patients with NSCLC: Results from the European Thoracic Oncology Platform (ETOP) Lungscape Project

INTRODUCTION

The PD-L1 biomarker is an important factor in selecting patients with non-small cell lung cancer for immunotherapy. While several reports suggest that PD-L1 positivity is linked to a poor prognosis, others suggest that PD-L1 positive status portends a good prognosis.

METHODS

PD-L1 positivity prevalence, assessed via immunohistochemistry (IHC) on tissue microarrays (TMAs), and its association with clinicopathological characteristics, molecular profiles and patient outcome- Relapse-free Survival (RFS), Time-to-Relapse (TTR) and Overall Survival (OS)- is explored in the ETOP Lungscape cohort of stage I-III non-small cell lung cancer (NSCLC). Tumors are considered positive if they have ≥1/5/25/50% neoplastic cell membrane staining.

RESULTS

PD-L1 expression was assessed in 2182 NSCLC cases (2008 evaluable, median follow-up 4.8 years, 54.6% still alive), from 15 ETOP centers. Adenocarcinomas represent 50.9% of the cohort (squamous cell: 42.4%). Former smokers are 53.7% (current: 31.6%, never: 10.5%). PD-L1 positivity prevalence is present in more than one third of the Lungscape cohort (1%/5% cut-offs). It doesn't differ between adenocarcinomas and squamous cell histologies, but is more frequently detected in higher stages, never smokers, larger tumors (1/5/25% cut-offs). With ≥1% cut-off it is significantly associated with IHC MET overexpression, expression of PTEN, EGFR and KRAS mutation (only for adenocarcinoma). Results for 5%, 25% and 50% cut-offs were similar, with MET being significantly associated with PD-L1 positivity both for AC (p < 0.001, 5%/25%/50% cut-offs) and SCC (p < 0.001, 5% & 50% cut-offs and p = 0.0017 for 25%). When adjusting for clinicopathological characteristics, a significant prognostic effect was identified in adenocarcinomas (adjusted p-values: 0.024/0.064/0.063 for RFS/TTR/OS 1% cut-off, analogous for 5%/25%, but not for 50%). Similar results obtained for the model including all histologies, but no effect was found for the squamous cell carcinomas.

CONCLUSION

PD-L1 positivity, when adjusted for clinicopathological characteristics, is associated with a better prognosis for non-metastatic adenocarcinoma patients.

KRAS: Reasons for optimism in lung cancer

Despite being the most frequent gain-of-function genetic alteration in human cancer, KRAS mutation has to date offered only limited potential as a prognostic and predictive biomarker. Results from the phase III SELECT-1 trial in non-small cell lung cancer (NSCLC) recently added to a number of historical and more contemporary disappointments in targeting KRAS mutant disease, including farnesyl transferase inhibition and synthetic lethality partners such as STK33. This narrative review uses the context of these previous failures to demonstrate how the knowledge gained from these experiences can be used as a platform for exciting advances in NSCLC on the horizon. It now seems clear that mutational subtype (most commonly G12C) of individual mutations is of greater relevance than the categorical evaluation of KRAS mutation presence or otherwise. A number of direct small molecules targeted to these subtypes are in development and have shown promising biological activity, with some in the late stages of preclinical validation.

In pursuit of synergy: An investigation of the PI3K/mTOR/MEK co-targeted inhibition strategy in NSCLC

Clinical PI3K inhibition has been somewhat disappointing, due to both inadequate patient stratification and compensatory cell signalling through bypass mechanisms. As such, investigation of PI3K-MEK co-targeted inhibition has been recommended. With high mortality rates and a clear need for new therapeutic intervention strategies, non-small cell lung cancer (NSCLC) is an important setting to investigate the effectiveness of this approach.

Here, 174 NSCLC tumours were screened for 150 mutations by Fluidigm technology, with 15 patients being profiled for phosphoprotein expression. The effects of GDC-0941 (a pan PI3K inhibitor), GDC-0980 (a dual PI3K/mTOR inhibitor) and GDC-0973 (a MEK inhibitor) alone and in combination were assessed in 3 NSCLC cell lines.

PIK3CA was mutated in 5.17% of NSCLC patients. GDC-0941 and GDC-0980 treatment induced anti-proliferative and pro-apoptotic responses across all NSCLC cell lines, while GDC-0973 treatment induced only anti-proliferative responses. GDC-0980 and GDC-0973 combined treatment led to significant increases in apoptosis and synergistic reductions in proliferation across the panel of cell lines.

This study found that the PI3K/MEK co-targeted inhibition strategy is synergistic in all 3 molecular subtypes of NSCLC investigated. Consequently, we would advocate clinical trials for NSCLC patients combining GDC-0980 and GDC-0973, each of which are separately under clinical investigation currently.

Comparison of next generation sequencing, SNaPshot assay and real-time polymerase chain reaction for lung adenocarcinoma EGFR mutation assessment

BACKGROUND

The epidermal growth factor receptor (EGFR) mutation status assessment has become increasingly important given the significant impact of tyrosine kinase inhibitors in lung cancer management. Our aim was to compare real life operational characteristics for three EGFR mutation assays - two targeted approaches and a next generation sequencing (NGS) technique.

METHODS

EGFR mutation status was assessed for lung adenocarcinoma samples (formalin fixed- paraffin embedded samples) using qPCR, SNaPshot and NGS (Ion Torrent™) techniques.

RESULTS

A total of 15 high clinical significance mutations were identified by at least one technique from the total of 64 samples. All mutations were identified by the TaqMan qPCR technique while SNaPshot in conjunction with fragment analysis identified 11 EGFR mutations. The NGS approach followed by an automatic analysis using the default calling parameters identified 10 mutations from the SNaPshot/qPCR panel and other three insertions, five point mutations and 58 silent variants; manual data review identified all 15 high significance mutations.

CONCLUSIONS

Performance was similar for high tumor content samples but careful data analysis and post hoc variant calling filter alterations were necessary in order to obtain robust results from low tumor content samples by NGS. NGS is able to generate a comprehensive mutational profile albeit at a higher cost and workload. Result interpretation should take into account not only general run parameters such as mean read depth but also relative coverage and read distribution; currently there is an acute need to define firm recommendations/standards concerning NGS data interpretation and quality control.