Molecular and Histological Changes in Post-Treatment Biopsies of Non-Squamous Non-Small Cell Lung Cancer: A Retrospective Study

Exploring circular MET RNA as a potential biomarker in tumors exhibiting high MET activity

BACKGROUND

MET-driven acquired resistance is emerging with unanticipated frequency in patients relapsing upon molecular therapy treatments. However, the determination of MET amplification remains challenging using both standard and next-generation sequencing-based methodologies. Liquid biopsy is an effective, non-invasive approach to define cancer genomic profiles, track tumor evolution over time, monitor treatment response and detect molecular resistance in advance. Circular RNAs (circRNAs), a family of RNA molecules that originate from a process of back-splicing, are attracting growing interest as potential novel biomarkers for their stability in body fluids.

METHODS

We identified a circRNA encoded by the MET gene (circMET) and exploited blood-derived cell-free RNA (cfRNA) and matched tumor tissues to identify, stratify and monitor advanced cancer patients molecularly characterized by high MET activity, generally associated with genomic amplification.

RESULTS

Using publicly available bioinformatic tools, we discovered that the MET locus transcribes several circRNA molecules, but only one candidate, circMET, was particularly abundant. Deeper molecular analysis revealed that circMET levels positively correlated with MET expression and activity, especially in MET-amplified cells. We developed a circMET-detection strategy and, in parallel, we performed standard FISH and IHC analyses in the same specimens to assess whether circMET quantification could identify patients displaying high MET activity. Longitudinal monitoring of circMET levels in the plasma of selected patients revealed the early emergence of MET amplification as a mechanism of acquired resistance to molecular therapies.

CONCLUSIONS

We found that measurement of circMET levels allows identification and tracking of patients characterized by high MET activity. Circulating circMET (ccMET) detection and analysis could be a simple, cost-effective, non-invasive approach to better implement patient stratification based on MET expression, as well as to dynamically monitor over time both therapy response and clonal evolution during treatment.

Actionable Molecular Alterations Are Revealed in Majority of Advanced Non-Small Cell Lung Cancer Patients by Genomic Tumor Profiling at Progression after First Line Treatment

Background: Genomic profiling in advanced Non-Small Cell Lung cancer (NSCLC) can reveal Actionable Molecular Alterations (AMAs). Our study aims to investigate clinical relevance of re-biopsy after first line treatment, by reporting on acquired and persistent AMAs and potential targeted treatments in a real-time cohort of NSCLC patients. Methods: Patients with advanced NSCLC receiving first-line treatment were prospectively included in an observational study (NCT03512847). Genomic profiling was performed by TruSight Oncology 500 HT gene panel on tumor tissue collected at diagnosis and at time of progression. Results: The 92 patients re-biopsied at progression had received immunotherapy (n = 44), chemotherapy (n = 44), or combination treatment (n = 4). In 87 of these patients (95%), successful genomic profiling was performed at both the diagnostic biopsy and the re-biopsy. In 74 patients (85%), ≥1 AMA were found. The AMAs were acquired in 28%. The most frequent AMAs were observed in TP53 (45%), KRAS (24%), PIK3CA (6%), and FGFR1 (6%). Only five patients (5%) received targeted treatment mainly due to deterioration in performance status. Conclusions: Re-biopsy at progression revealed acquired AMAs in approximately one third of patients, and 85% had at least one AMA with the potential of receiving targeted treatment, thus strengthening the clinical relevance of re-biopsy.

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.

Detailed genomic characterization identifies high heterogeneity and histotype-specific genomic profiles in adrenocortical carcinomas

Molecular characterization of adrenocortical carcinoma has been recently established, but the correlation between molecular profiles and clinical and pathological characteristics is still poorly defined with no data available about genetic heterogeneity along disease progression. In this scenario, a detailed molecular profile was correlated with clinical and pathological characteristics in adrenocortical carcinoma patients to identify potentially novel biomarkers. Targeted next-generation sequencing and copy number variation analyses for 18 most frequently altered genes in adrenocortical carcinoma were assessed on 62 adult cases (including 10 with matched primary and metastatic/recurrence samples) and results correlated with major clinical and pathological characteristics of tumors. A total of 433 somatic deleterious genetic alterations (328 gene mutations and 105 copy number variations) were identified in 57/62 cases, five resulted wild type for all genes tested. TERT, CDK4, ZNRF3,and RB1 were altered in more than 30% of cases. Among histological variants genotypes were significantly different. Lowest mutation burden was found in the oncocytic type (p = 0.006), whereas the highest with a prevalence of RB1 (p = 0.001) and CDK4 (p = 0.002) was found in the conventional and myxoid ones, respectively. None of the 10 cases with matched samples showed a stable genotype along tumor progression, although allelic frequencies or percentages of altered nuclei at fluorescence in situ hybridization were in most cases similar among different tumor samples for genes that were stable along tumor progression. Among individual genes, an altered p53/Rb1 pathway was the strongest adverse molecular signature, being associated with high Ki-67 index, high tumor stage, aggressive disease status, and shorter disease-free survival. The genomic signature in adrenocortical carcinoma is changing along tumor progression and is associated with specific clinical and pathological features, including histological variant and prognosis.

A rare case of squamous cell carcinoma lung with multiple locoregional recurrences and histological transformation

A 52-year-old female nonsmoker with localized squamous cell carcinoma (T3N1M0) of lung underwent lobectomy with adjuvant chemotherapy. Two years later, the patient had her first locoregional recurrence with adenosquamous cell carcinoma, and pneumonectomy with adjuvant chemotherapy rendered her disease free. Subsequent isolated locoregional recurrence with squamous cell carcinoma 18 months later was treated with chemoradiotherapy and had a complete response. Patient yet again had locoregional recurrence after 4 years and had progressive disease despite subsequent multiple line of treatment with platinum-based chemotherapy, stereotactic body radiation therapy, and nivolumab. This case is unique in presentation due to prolonged survival with multiple line of treatment of recurrent locoregional tumor without distant metastasis and alteration in the histology of tumor during illness.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)-from morphology to molecular testing

In recent years, endobronchial ultrasound-guided TBNA (EBUS-TBNA) has emerged as an innovative technique for diagnosis and staging of lung cancer and has been successfully introduced into daily clinical practice with several advantages including minimally invasive approach, safe, cost-effective, real time image guidance, broad sampling capability, and rapid on-site evaluation (ROSE). Both cytological and histological approach could be useful to have material for diagnosis, immunohistochemical and molecular analyses which may be very important for targeted therapy with successful rate ranging from 89% to 98%. The utility of ROSE during EBUS-TBNA has been matter of debate. Indeed, although some evidence concluded that ROSE does not increase the diagnostic efficacy of EBUS-TBNA, other demonstrated that it improves the diagnostic yield of the procedure up to 30%, allows to avoid repetition of additional diagnostic procedures and reduces risk of complications. Furthermore the sample preparation by cytopathologist is optimized with the aid of direct macroscopic inspection, optimal smearing techniques, and triage of the sample permitting to obtain adequate tissue for diagnosis, ancillary techniques and molecular testing, when needed. Some pathological issues on EBUS-TBNA are reviewed and discussed with particular focus on ROSE and molecular testing.

Secondary biopsy of non-oncogenic-driven lung cancer may reveal a clinically sensible histologic change. A brief report of two paradigmatic cases

After an initial benefit, non-small-cell lung cancer (NSCLC) patients receiving therapy with tyrosine kinase inhibitors develop drug resistance through a variety of mechanisms. Among these, tumor histology changes are a mechanism of acquired resistance in epidermal growth factor receptor-mutated and anaplastic lymphoma kinase-rearranged NSCLC cases. The current availability of therapeutic approaches to overcome tyrosine kinase inhibitor resistance in oncogenic-driven lung cancers justifies secondary tumor biopsy in these patients. On the other hand, little is known about the mechanism of disease progression in non-oncogenic driven NSCLC. Nevertheless, NSCLC lacking "druggable" genetic alterations are not considered for secondary biopsy, as it is commonly believed that these tumors cannot develop histologic or molecular changes. Herein, we report two paradigmatic cases of wild-type NSCLC showing histologic "change" on secondary biopsy, allowing for a successful switch in therapeutic strategy.

Mutation testing for directing upfront targeted therapy and post-progression combination therapy strategies in lung adenocarcinoma

Introduction: Advances in the biology of non-small-cell lung cancer, especially adenocarcinoma, reveal multiple molecular subtypes driving oncogenesis. Accordingly, individualized targeted therapeutics are based on mutational diagnostics.

Areas covered: Advances in strategies and techniques for individualized treatment, particularly of adenocarcinoma, are described through literature review. Approved therapies are established for some molecular subsets, with new driver mutations emerging that represent increasing proportions of patients. Actionable mutations are denovo oncogenic drivers or acquired resistance mediators, and mutational profiling is important for directing therapy. Patients should be monitored for emerging actionable resistance mutations. Liquid biopsy and associated multiplex diagnostics will be important means to monitor patients during treatment.

Expert commentary: Outcomes with targeted agents may be improved by integrating mutation screens during treatment to optimize subsequent therapy. In order for this to be translated into impactful patient benefit, appropriate platforms and strategies need to be optimized and then implemented universally.

Genetic changes of non-small cell lung cancer under neoadjuvant therapy

BACKGROUND

Large scale sequencing efforts defined common molecular alterations in non-small cell lung cancer (NSCLC) and revealed potentially druggable mutations. Yet, systematic data on the changes of the respective molecular profiles under standard therapy in NSCLC are limited.

RESULTS

14 out of 68 observed coding mutations (21%) and 6 out of 33 (18%) copy number variations (CNV) were lost or gained during therapy. Mutational and CNV changes clustered in 6/37 (16%) and 3/37 (8%) patients. Changes in clinically relevant mutations were rare but present in single cases for genes such as BRAF and PIK3CA. The type of radiochemotherapy but not the duration of therapy impacted on the frequency of mutational changes.

METHODS

We established a lung cancer specific next-generation sequencing panel covering ~7500 hotspots of 41 genes frequently mutated in NSCLC and performed ultradeep multigene sequencing of 37 corresponding pre- and post-therapeutic formalin fixed paraffin-embedded specimens to discover mutational changes and copy number variations under neo-adjuvant radio- (RTX) and/or chemotherapy (CTX).

CONCLUSION

We unraveled changes in common driver gene candidates in NSCLC under neo-adjuvant therapy. Our data shed first light on the genetic changes of NSCLC under conventional therapy and might be taken into account when the relevance of sequential biopsy approaches is discussed.