Role of next generation sequencing-based liquid biopsy in advanced non-small cell lung cancer patients treated with immune checkpoint inhibitors: impact of STK11, KRAS and TP53 mutations and co-mutations on outcome

Exploring the Role of CBX3 as a Potential Therapeutic Target in Lung Cancer

Epigenetic changes regulate gene expression through histone modifications, chromatin remodeling, and protein translation of these modifications. The PRC1 and PRC2 complexes shape gene repression via histone modifications. Specifically, the CBX protein family aids PRC1 recruitment to chromatin, impacting the progressive multistep process driving chromatin silencing. Among family members, CBX3 is a complex protein involved in aberrant epigenetic mechanisms that drive lung cancer progression. CBX3 promotes lung tumorigenesis by interacting with key pathways such as PI3K/AKT, Ras/KRAS, Wnt/β-catenin, MAPK, Notch, and p53, leading to increased proliferation, inhibition of apoptosis, and enhanced resistance to therapy. Given our current lack of knowledge, additional research is required to uncover the intricate mechanisms underlying CBX3 activity, as well as its involvement in molecular pathways and its potential biomarker evaluation. Specifically, the dissimilar roles of CBX3 could be reexamined to gain a greater insight into lung cancer pathogenesis. This review aims to provide a clear overview of the context-related molecular profile of CBX3, which could be useful for addressing clinical challenges and developing novel targeted therapies based on personalized medicine.

Effects of KRAS, STK11, KEAP1, and TP53 mutations on the clinical outcomes of immune checkpoint inhibitors among patients with lung adenocarcinoma

BACKGROUND

This study aimed to identify the associations between individual KRAS, STK11, KEAP1, or TP53 mutations, as well as the comutation status of these genes, and the tumor mutation burden (TMB) with clinical outcomes of lung adenocarcinoma patients treated with immune checkpoint inhibitors (ICIs).

METHODS

We collected data from patients with lung adenocarcinoma treated with ICIs from the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database between June 2019 and August 2023. The main endpoints were the treatment response and overall survival (OS).

RESULTS

Among 343 patients with lung adenocarcinoma, 61 (18%), 69 (20%), 41 (12%), and 222 (65%) patients had KRAS, STK11, KEAP1, and TP53 mutations, respectively. An overall objective response was observed in 94 of 338 patients (28%), including 2 (1%) who achieved a complete response and 92 (27%) who achieved a partial response. Patients with STK11, KEAP1, or TP53 mutations had a significantly greater TMB (P<0.001). According to the univariate analysis, the treatment response was significantly correlated with TP53 mutation in both the general (P = 0.041) and KRAS wild-type (P = 0.009) populations. KEAP1 and TP53 mutations were associated with worse OS among assessable patients (hazard ratio (HR) = 2.027, P = 0.002; HR = 1.673, P = 0.007, respectively) and among patients without KRAS mutations (HR = 1.897, P = 0.012; HR = 1.908, P = 0.004, respectively). According to the multivariate analysis, KEAP1 (HR = 1.890, P = 0.008) and TP53 (HR = 1.735, P = 0.011) mutations were found to be independent factors for OS.

CONCLUSIONS

STK11, KEAP1, and TP53 mutations are significantly associated with a high TMB. TP53 mutation could affect the treatment response to some degree, and both KEAP1 and TP53 mutations resulted in inferior OS in the general patient population and in those with KRAS-wild-type lung adenocarcinoma, indicating that KEAP1 and TP53 mutations might act as prognostic factors for ICI treatment in lung adenocarcinoma patients.

Sex- and Age-Associated Differences in Genomic Alterations among Patients with Advanced Non-Small Cell Lung Cancer (NSCLC)

Genomic mutations impact non-small cell lung cancer (NSCLC) biology. The influence of sex and age on the distribution of these alterations is unclear. We analyzed circulating-tumor DNA from individuals with advanced NSCLC from March 2018 to October 2020. EGFR, KRAS, ALK, ROS1, BRAF, NTRK, ERBB2, RET, MET, PIK3CA, STK11, and TP53 alterations were assessed. We evaluated the differences by sex and age (<70 and ≥70) using Fisher's exact test. Of the 34,277 samples, 30,790 (89.83%) had a detectable mutation and 19,923 (58.12%) had an alteration of interest. The median age of the ctDNA positive population was 69 (18-102), 16,756 (54.42%) were female, and 28,835 (93.65%) had adenocarcinoma. Females had more alterations in all the assessed EGFR mutations, KRAS G12C, and ERBB2 ex20 ins. Males had higher numbers of MET amp and alterations in STK11 and TP53. Patients <70 years were more likely to have alterations in EGFR exon 19 del/exon 20 ins/T790M, KRAS G12C/D, ALK, ROS1, BRAF V600E, ERBB2 Ex20ins, MET amp, STK11, and TP53. Individuals ≥70 years were more likely to have alterations in EGFR L861Q, MET exon 14 skipping, and PIK3CA. We provided evidence of sex- and age-associated differences in the distribution of genomic alterations in individuals with advanced NSCLC.

Circulating biomarkers as predictors of response to immune checkpoint inhibitors in NSCLC: Are we on the right path?

Immune checkpoints inhibitors (ICIs) have markedly improved the therapeutic management of advanced NSCLC and, more recently, they have demonstrated efficacy also in the early-stage disease. Despite better survival outcomes with ICIs compared to standard chemotherapy, a large proportion of patients can derive limited clinical benefit from these agents. So far, few predictive biomarkers, including the programmed death-ligand 1 (PD-L1), have been introduced in clinical practice. Therefore, there is an urgent need to identify novel biomarkers to select patients for immunotherapy, to improve efficacy and avoid unnecessary toxicity. A deeper understanding of the mechanisms involved in antitumor immunity and advances in the field of liquid biopsy have led to the identification of a wide range of circulating biomarkers that could potentially predict response to immunotherapy. Herein, we provide an updated overview of these circulating biomarkers, focusing on emerging data from clinical studies and describing modern technologies used for their detection.

TP53 co-mutations in advanced lung adenocarcinoma: comparative bioinformatic analyses suggest ambivalent character on overall survival alongside KRAS, STK11 and KEAP1 mutations

Background

Recently, we could show that the co-mutations of KRAS + KEAP1, STK11 + KEAP1 and KRAS + STK11 + KEAP1 lead to a significantly shorter median overall survival (mOS) across treatments by analyzing multiple datasets. TP53, a tumor suppressor gene, plays a crucial role in regulating cell cycle progression. Its mutations occur in approximately 40-50% of non-small lung cancer (NSCLC). Co-occurrence of all four mentioned mutations has been a matter of debate for years. The aim of this study was to assess the distribution of these four mutations and the influence of the different co-mutational patterns on survival.

Methods

We present a comparative bioinformatic analysis and refer to data of 4,109 patients with lung adenocarcinoma (LUAD).

Results

Most of the mutations within the LUAD belong to TP53-only (29.0%), quadruple-negative (25.9%) and KRAS-only (13.4%). Whereas TP53-mutations seem to have protective effects in the context of further KEAP1- and KRAS + KEAP1-alterations (improved mOS), their role seems contrary if acquired in an already existing combination of mutations as KRAS + STK11, KRAS + STK11 + KEAP1 and STK1 + KEAP1. TP53 co-mutationshad a negative influence on KRAS-only mutated LUAD (mOS reduced significantly by more than 30%).

Discussion

These data underline the need for complex mutational testing to estimate prognosis more accurately in patients with advanced LUAD.

Efficacy of osimertinib and the role of sequential liquid biopsy in patients diagnosed with NSCLC harboring EGFR and BRAF mutations at baseline: insights from two case reports

Epidermal Growth Factor Receptor (EGFR) and B-Raf (BRAF) mutations are two of the most important drivers identified in non-small-cell lung cancer (NSCLC). This report highlights two cases of patients diagnosed with metastatic NSCLC bearing concurrent EGFR and BRAF mutations at baseline and treated with osimertinib as first-line treatment. Molecular profiling was conducted in the tissue and plasma at the time of initial diagnosis, and subsequent repeated liquid biopsy examinations were planned after 10 days, 28 days, and at the time of radiological progression in the frame of the prospective translational study REM. These cases suggest that osimertinib may maintain its therapeutic effectiveness even in patients presenting with a baseline BRAF co-mutation. Notably, radiological responses align with liquid biopsy observations: in both instances, follow-up liquid biopsies indicate the clearance of EGFR-mutated circulating tumor DNA (ctDNA).

Deterministic reprogramming and signaling activation following targeted therapy in non-small cell lung cancer driven by mutations or oncogenic fusions

INTRODUCTION

Targeted therapy is used to treat lung adenocarcinoma caused by epidermal growth factor receptor (EGFR) mutations in the tyrosine kinase domain and rare subtypes (<5%) of non-small cell lung cancer. These subtypes include fusion oncoproteins like anaplastic lymphoma kinase (ALK), ROS1, rearranged during transfection (RET), and other receptor tyrosine kinases (RTKs). The use of diverse selective oral inhibitors, including those targeting rat sarcoma viral oncogene homolog (KRAS) mutations, has significantly improved clinical responses, extending progression-free and overall survival.

AREAS COVERED

Resistance remains a critical issue in lung adenocarcinoma, notably in EGFR mutant, echinoderm microtubule associated protein-like 4 (EML4)-ALK fusion, and KRAS mutant tumors, often associated with epithelial-to-mesenchymal transition (EMT).

EXPERT OPINION

Despite advancements in next generation EGFR inhibitors and EML4-ALK therapies with enhanced brain penetrance and identifying resistance mutations, overcoming resistance has not been abated. Various strategies are being explored to overcome this issue to achieve prolonged cancer remission and delay resistance. Targeting yes-associated protein (YAP) and the mechanisms associated with YAP activation through Hippo-dependent or independent pathways, is desirable. Additionally, the exploration of liquid-liquid phase separation in fusion oncoproteins forming condensates in the cytoplasm for oncogenic signaling is a promising field for the development of new treatments.

KRAS G12C-mutant driven non-small cell lung cancer (NSCLC)

KRAS G12C mutations in non-small cell lung cancer (NSCLC) partially respond to KRAS G12C covalent inhibitors. However, early adaptive resistance occurs due to rewiring of signaling pathways, activating receptor tyrosine kinases, primarily EGFR, but also MET and ligands. Evidence indicates that treatment with KRAS G12C inhibitors (sotorasib) triggers the MRAS:SHOC2:PP1C trimeric complex. Activation of MRAS occurs from alterations in the Scribble and Hippo-dependent pathways, leading to YAP activation. Other mechanisms that involve STAT3 signaling are intertwined with the activation of MRAS. The high-resolution MRAS:SHOC2:PP1C crystallization structure allows in silico analysis for drug development. Activation of MRAS:SHOC2:PP1C is primarily Scribble-driven and downregulated by HUWE1. The reactivation of the MRAS complex is carried out by valosin containing protein (VCP). Exploring these pathways as therapeutic targets and their impact on different chemotherapeutic agents (carboplatin, paclitaxel) is crucial. Comutations in STK11/LKB1 often co-occur with KRAS G12C, jeopardizing the effect of immune checkpoint (anti-PD1/PDL1) inhibitors.

Higher TP53 somatic mutation prevalence from liquid biopsy analysis in ever smoker non-small-cell lung cancer patients

OBJECTIVE

Cigarette smoking is a primary risk factor, linked to 80% of LC deaths. TP53, a key gene, is implicated in various cancers, with TP53 alterations in 36.7% of cancers. This research aims to investigate TP53 mutations detected in NSCLC patients by liquid biopsy and explore the relationship between these mutations and smoking history.

MATERIAL AND METHOD

The study enrolled a total of 340 patients diagnosed with non-small cell lung cancer (NSCLC). For sequencing, the Illumina NextSeq 500 system was utilized. The oncogenicity of the variants was assessed according to the ClinGen/CGC/VICC SOP and the variants were categorized into four tiers according to AMP/ASCO/CAP.

RESULTS

The most common mutations were in TP53 (48.7%), followed by EGFR, PIK3CA, and PTEN. Missense mutations were frequent, with TP53 and EGFR having higher rates in ever-smokers. No indels or complex mutations were found in ever-smokers. Patient age ranged from 20 to 86 years. Tier I-II variants were more common in ever-smokers, while Tier III variants were prevalent in never-smokers. TP53 mutations were more frequent in ever-smokers, showing a strong association with smoking. Domain distribution showed differences in PIK3CA. Transversion/transition ratios varied by gene and smoking status.

DISCUSSION

The presence of TP53 mutations is strongly associated with both cigarette smoking and elevated Tv/Ti ratios. The tier status of TP53, EGFR, and PTEN variants does not show a specific domain distribution, but interesting associations are observed between the tier status and domain distribution in PIK3CA variants. Therefore, further comprehensive investigations are needed to explore this entity, as well as the underlying factors contributing to the increased Tv/Ti rates in the TP53 gene. Such research will provide deeper insights into the genetic alterations associated with smoking and tumor heterogeneity, ultimately aiding in the development of targeted therapies.

Real-World Outcomes of Immunotherapy in Second- or Later-Line Non-Small Cell Lung Cancer with Actionable Genetic Alterations

INTRODUCTION

While the efficacy of immune checkpoint inhibitors (ICIs) in treating non-small cell lung cancer (NSCLC) patients with actionable genetic alterations (AGAs) is modest, certain patients demonstrate improved survival. Thus, this study aimed to evaluate the benefits of ICIs in NSCLC patients with diverse AGAs and verify the predictive biomarkers of ICI efficacy.

METHODS

From January 2018 to July 2022, this study compared the progression-free survival (PFS) of NSCLC patients with different AGAs treated with ICI monotherapy as second- or later-line therapy at Samsung Medical Center. To ascertain the predictors of ICIs efficacy, we adjusted ICIs' effects on PFS in terms of clinical and molecular biomarkers.

RESULTS

EGFR (46.0%) was the most prevalent mutation in 324 patients. In multivariate analysis, PD-L1 positivity (tumor proportion score (TPS) ≥ 1%) (HR = 0.41) and the use of steroids for immune-related adverse events (HR = 0.46) were positive factors for ICI therapy in the AGAs group. Co-existing mutation of STK11 with KRAS mutation (HR = 4.53) and TP53 with MET mutation (HR = 9.78) was negatively associated with survival.

CONCLUSIONS

The efficacy of ICI treatment varied across AGA subtypes, but patients with KRAS, MET, and BRAF mutations demonstrated relatively long-duration benefits of ICI therapy. PD-L1 was a significant positive predictive biomarker in all AGA groups.

Effect of liver metastasis on the efficacy of immune checkpoint inhibitors in cancer patients: a systemic review and meta-analysis

Liver metastasis is a frequent phenomenon in advanced tumor disease. Immune checkpoint inhibitors (ICIs) are a new class of therapeutics that can improve the prognosis of cancer patients. The purpose of this study is to elucidate the relationship between liver metastasis and survival outcomes of patients receiving ICIs treatment. We searched four main databases, including PubMed, EMBASE, Cochrane Library, and Web of Science. Overall survival (OS) and progression-free survival (PFS) were the survival outcomes of our concern. Hazard ratio (HR) with 95% confidence interval (CI) were used to evaluate the relationship between liver metastasis and OS/ PFS. Finally, 163 articles were included in the study. The pooled results showed that patients with liver metastasis receiving ICIs treatment had worse OS (HR=1.82, 95%CI:1.59-2.08) and PFS (HR=1.68, 95%CI:1.49-1.89) than patients without liver metastasis. The effect of liver metastasis on ICIs efficacy differed in different tumor types, and patients with urinary system tumors (renal cell carcinoma OS: HR=2.47, 95%CI:1.76-3.45; urothelial carcinoma OS: HR=2.37, 95%CI:2.03-2.76) had the worst prognosis, followed by patients with melanoma (OS: HR=2.04, 95%CI:1.68-2.49) or non-small cell lung cancer (OS: HR=1.81, 95%CI:1.72-1.91). ICIs efficacy in digestive system tumors (colorectal cancer OS: HR=1.35, 95%CI:1.07-1.71; gastric cancer/ esophagogastric cancer OS: HR=1.17, 95%CI:0.90-1.52) was less affected, and peritoneal metastasis and the number of metastases have a greater clinical significance than liver metastasis based on univariate data. For cancer patients receiving ICIs treatment, the occurrence of liver metastasis is associated with poor prognosis. Different cancer types and metastatic sites may hold a different prognostic effect on the efficacy of ICIs treatment in cancer patients.

Liquid Biopsy in NSCLC: An Investigation with Multiple Clinical Implications

Tissue biopsy is essential for NSCLC diagnosis and treatment management. Over the past decades, liquid biopsy has proven to be a powerful tool in clinical oncology, isolating tumor-derived entities from the blood. Liquid biopsy permits several advantages over tissue biopsy: it is non-invasive, and it should provide a better view of tumor heterogeneity, gene alterations, and clonal evolution. Consequentially, liquid biopsy has gained attention as a cancer biomarker tool, with growing clinical applications in NSCLC. In the era of precision medicine based on molecular typing, non-invasive genotyping methods became increasingly important due to the great number of oncogene drivers and the small tissue specimen often available. In our work, we comprehensively reviewed established and emerging applications of liquid biopsy in NSCLC. We made an excursus on laboratory analysis methods and the applications of liquid biopsy either in early or metastatic NSCLC disease settings. We deeply reviewed current data and future perspectives regarding screening, minimal residual disease, micrometastasis detection, and their implication in adjuvant and neoadjuvant therapy management. Moreover, we reviewed liquid biopsy diagnostic utility in the absence of tissue biopsy and its role in monitoring treatment response and emerging resistance in metastatic NSCLC treated with target therapy and immuno-therapy.

A Multicenter Retrospective Chart Review of Clinical Outcomes Among Patients With KRAS G12C Mutant Non-Small Cell Lung Cancer

BACKGROUND

On May 28, 2021, the United States Food and Drug Administration (FDA) granted accelerated approval to sotorasib for second-line or later treatment of patients with locally advanced or metastatic KRAS G12C mutant non-small cell lung cancer (NSCLC). This was the first FDA-approved targeted therapy for this patient population. Due to a paucity of real world data describing clinical outcomes in patients with locally advanced or metastatic KRAS G12C mutated NSCLC in the second-line or later, we sought to compile a large, academic medical center-based historical dataset to clarify clinical outcomes in this patient population.

MATERIALS AND METHODS

The clinical outcomes of 396 patients with stage IV (n = 268, 68%) or recurrent, metastatic (n = 128, 32%) KRAS G12C mutant NSCLC were evaluated in this multicenter retrospective chart review conducted through the Academic Thoracic Oncology Medical Investigator's Consortium (ATOMIC). Patients treated at 13 sites in the United States and Canada and diagnosed between 2006 and 2020 (30% 2006-2015, 70% 2016-2020) were included. Primary outcomes included real-world PFS (rwPFS) and overall survival (OS) from time of stage IV or metastatic diagnosis, with particular interest in patients treated with second-line docetaxel-containing regimens, as well as clinical outcomes in the known presence or absence of STK11 or KEAP1 comutations.

RESULTS

Among all patients with stage IV or recurrent, metastatic KRAS G12C mutant NSCLC (n = 201 with KRAS G12C confirmed prior to first line systemic therapy), the median first-line rwPFS was 9.3 months (95% CI, 7.3-11.8 months) and median OS was 16.8 months (95% CI, 12.7-22.3 months). In this historical dataset, first line systemic therapy among these 201 patients included platinum doublet alone (44%), PD-(L)1 inhibitor monotherapy (30%), platinum doublet chemotherapy plus PD-(L)1 inhibitor (18%), and other regimens (8%). Among patients with documented second-line systemic therapy (n = 123), the second-line median rwPFS was 8.3 months (95% CI, 6.1-11.9 months), with median rwPFS 4.6 months (95% CI, 1.4-NA) among 10 docetaxel-treated patients (9 received docetaxel and 1 received docetaxel plus ramucirumab). Within the total study population, 49 patients (12%) had a co-occurring STK11 mutation and 3 (1%) had a co-occurring KEAP1 mutation. Among the 49 patients with a co-occurring KRAS G12C and STK11 mutation, median rwPFS on first-line systemic therapy (n = 23) was 6.0 months (95% CI, 4.7-NA), and median OS was 14.0 months (95% CI, 10.8-35.3 months).

CONCLUSION

In this large, multicenter retrospective chart review of patients with KRAS G12C mutant NSCLC we observed a relatively short median rwPFS of 4.6 months among 10 patients with KRAS G12C mutant NSCLC treated with docetaxel with or without ramucirumab in the second-line setting, which aligns with the recently reported CodeBreak 200 dataset.

Circulating Biomarkers for Prediction of Immunotherapy Response in NSCLC

Non-small cell lung cancer (NSCLC) constitutes the majority of the lung cancer population and the prognosis is poor. In recent years, immunotherapy has become the standard of care for advanced NSCLC patients as numerous trials demonstrated that immune checkpoint inhibitors (ICI) are more efficacious than conventional chemotherapy. However, only a minority of NSCLC patients benefit from this treatment. Therefore, there is an unmet need for biomarkers that could accurately predict response to immunotherapy. Liquid biopsy allows repeated sampling of blood-based biomarkers in a non-invasive manner for the dynamic monitoring of treatment response. In this review, we summarize the efforts and progress made in the identification of circulating biomarkers that predict immunotherapy benefit for NSCLC patients. We also discuss the challenges with future implementation of circulating biomarkers into clinical practice.

Liquid Biopsy for Lung Cancer: Up-to-Date and Perspectives for Screening Programs

Lung cancer is the deadliest cancer worldwide. Tissue biopsy is currently employed for the diagnosis and molecular stratification of lung cancer. Liquid biopsy is a minimally invasive approach to determine biomarkers from body fluids, such as blood, urine, sputum, and saliva. Tumor cells release cfDNA, ctDNA, exosomes, miRNAs, circRNAs, CTCs, and DNA methylated fragments, among others, which can be successfully used as biomarkers for diagnosis, prognosis, and prediction of treatment response. Predictive biomarkers are well-established for managing lung cancer, and liquid biopsy options have emerged in the last few years. Currently, detecting EGFR p.(Tyr790Met) mutation in plasma samples from lung cancer patients has been used for predicting response and monitoring tyrosine kinase inhibitors (TKi)-treated patients with lung cancer. In addition, many efforts continue to bring more sensitive technologies to improve the detection of clinically relevant biomarkers for lung cancer. Moreover, liquid biopsy can dramatically decrease the turnaround time for laboratory reports, accelerating the beginning of treatment and improving the overall survival of lung cancer patients. Herein, we summarized all available and emerging approaches of liquid biopsy-techniques, molecules, and sample type-for lung cancer.

Comprehensive analysis of T cell receptor repertoire in patients with KRAS mutant non-small cell lung cancer

Background

Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the most frequently mutated oncogenes in non-small cell lung cancer (NSCLC). The administration of immunotherapy has demonstrated significant efficacy in prolonging the overall survival of patients with KRAS mutation in recent years. However, the efficacy of immunotherapy in KRAS mutant NSCLC is variable. Analysis of T cell receptor (TCR) repertoire may contribute to a better understanding of the mechanisms behind such differential outcomes.

Methods

A total of 47 patients with KRAS mutant NSCLC were enrolled in this study. Deep sequencing of the TCR β chain complementarity-determining regions in tumor tissue and paired peripheral blood specimens was conducted. Comprehensive analysis of TCR repertoire metrics was performed with different KRAS mutation subtypes and concomitant mutations. Moreover, the associations between TCR repertoire metrics and tumor mutation burden (TMB), as well as programmed death-ligand 1 were explored, respectively.

Results

TCR repertoire metrics, including Shannon index, Clonality, and Morisita index (MOI), showed no significant differences among different KRAS mutation subtypes. The similar results were observed between patients with tumor protein p53 (TP53) mutation and those with wild-type TP53. In contrast, although no significant differences were found in Shannon index and Clonality, patients with KRAS/serine/threonine kinase 11 (STK11) comutation showed a significantly higher MOI compared to their STK11 wild-type counterparts (P=0.012). In addition, TCR repertoire metrics were neither associated with TMB nor programmed death-ligand 1 expression in KRAS mutant NSCLC.

Conclusions

This retrospective study comprehensively described the TCR repertoire in KRAS mutant NSCLC. A higher MOI represented more overlap of the TCR repertoire between tumor tissue and paired peripheral blood, indicating distinctive immunological features in NSCLC with KRAS/STK11 comutation.

Liquid biopsy and non-small cell lung cancer: are we looking at the tip of the iceberg?

The possibility to analyse the tumour genetic material shed in the blood is undoubtedly one of the main achievements of translational research in the latest years. In the modern clinical management of advanced non-small cell lung cancer, molecular characterisation plays an essential role. In parallel, immunotherapy is widely employed, but reliable predictive markers are not available yet. Liquid biopsy has the potential to face the two issues and to increase its role in advanced NSCLC in the next future. The aim of this review is to summarise the main clinical applications of liquid biopsy in advanced non-small cell lung cancer, underlining both its potential and limitations from a clinically driven perspective.

Emerging Blood-Based Biomarkers for Predicting Immunotherapy Response in NSCLC

Simple Summary

Treatment with immunotherapy has been established as a standard treatment for lung cancer in recent years. Unfortunately, still, only a small proportion of patients benefit from the treatment, being the first leading cause of cancer death worldwide. Therefore, there is an urgent need for predictive biomarkers to help clinicians to discern whose patients are more likely to respond to immunotherapy. Since liquid biopsy opens the door to select patients and monitor the response during the treatment in a non-invasive way, in this review, we focus on the most relevant and recent results based on blood soluble biomarkers.

Abstract

Immunotherapy with Immune Checkpoint Inhibitors (ICIs) has demonstrated a profitable performance for Non-Small Cell Lung Cancer (NSCLC) cancer treatment in some patients; however, there is still a percentage of patients in whom immunotherapy does not provide the desired results regarding beneficial outcomes. Therefore, obtaining predictive biomarkers for ICI response will improve the treatment management in clinical practice. In this sense, liquid biopsy appears as a promising method to obtain samples in a minimally invasive and non-biased way. In spite of its evident potential, the use of these circulating biomarkers is still very limited in the real clinical practice, mainly due to the huge heterogeneity among the techniques, the lack of consensus, and the limited number of patients included in these previous studies. In this work, we review the pros and cons of the different proposed biomarkers, such as soluble PD-L1, circulating non-coding RNA, circulating immune cells, peripheral blood cytokines, and ctDNA, obtained from liquid biopsy to predict response to ICI treatment at baseline and to monitor changes in tumor and tumor microenvironment during the course of the treatment in NSCLC patients.

More to the RAS Story: KRASG12C Inhibition, Resistance Mechanisms, and Moving Beyond KRASG12C

Despite the discovery of RAS oncogenes in human tumor DNA 40 years ago, the development of effective targeted therapies directed against RAS has lagged behind those more successful advancements in the field of therapeutic tyrosine kinase inhibitors targeting other oncogenes such as EGFR, ALK, and ROS1. The discoveries that (1) malignant RAS oncogenes differ from their wild-type counterparts by only a single amino acid change and (2) covalent inhibition of the cysteine residue at codon 12 of KRAS^G12C in its inactive GDP-bound state resulted in effective inhibition of oncogenic RAS signaling and have catalyzed a dramatic shift in mindset toward KRAS-driven cancers. Although the development of allele-selective KRAS^G12C inhibitors has changed a treatment paradigm, the clinical activity of these agents is more modest than tyrosine kinase inhibitors targeting other oncogene-driven cancers. Heterogeneous resistance mechanisms generally result in the restoration of RAS/mitogen-activated protein kinase pathway signaling. Many approaches are being evaluated to overcome this resistance, with many combinatorial clinical trials ongoing. Furthermore, because KRAS^G12D and KRAS^G12V are more prevalent than KRAS^G12C, there remains an unmet need for additional therapeutic strategies for these patients. Thus, our current translational standing could be described as "the end of the beginning," with additional discovery and research innovation needed to address the enormous disease burden imposed by RAS-mutant cancers. Here, we describe the development of KRAS^G12C inhibitors, the challenges of resistance to these inhibitors, strategies to mitigate that resistance, and new approaches being taken to address other RAS-mutant cancers.

TP53 Co-Mutations in Advanced EGFR-Mutated Non-Small Cell Lung Cancer: Prognosis and Therapeutic Strategy for Cancer Therapy

Lung cancer is the leading cause of cancer-related deaths worldwide. As the most prevalent molecular mutation subtypes in non-small cell lung cancer (NSCLC), EGFR-TKIs are currently a standard first-line therapy for targeting the mutated EGFR in advanced NSCLC patients. However, 20-30% of this subset of patients shows primary resistance to EGFR-TKIs. Patients with co-mutations of EGFR and several other genes have a poor response to EGFR-TKIs, whereas the prognostic and predictive significance of EGFR/TP53 co-mutation in NSCLC patients remains controversial. Meanwhile, little is known about how to choose an optimal therapeutic strategy for this subset of patients. Presently, no drugs targeting TP53 mutations are available on the market, and some p53 protein activators are in the early stage of clinical trials. A combination of EGFR-TKIs with antiangiogenic agents or chemotherapy or other agents might be a more appropriate strategy to tackle the problem. In this review, we describe the prognostic and predictive value of EGFR/TP53 co-mutation in NSCLC patients, investigate the mechanisms of this co-mutation affecting the response to EGFR-TKIs, and further explore optimal regimens effectively to prolong the survival time of the NSCLC patients harboring this co-mutation.

Harnessing Liquid Biopsies to Guide Immune Checkpoint Inhibitor Therapy

Immunotherapy (IO), involving the use of immune checkpoint inhibition, achieves improved response-rates and significant disease-free survival for some cancer patients. Despite these beneficial effects, there is poor predictability of response and substantial rates of innate or acquired resistance, resulting in heterogeneous responses among patients. In addition, patients can develop life-threatening adverse events, and while these generally occur in patients that also show a tumor response, these outcomes are not always congruent. Therefore, predicting a response to IO is of paramount importance. Traditionally, tumor tissue analysis has been used for this purpose. However, minimally invasive liquid biopsies that monitor changes in blood or other bodily fluid markers are emerging as a promising cost-effective alternative. Traditional biomarkers have limitations mainly due to difficulty in repeatedly obtaining tumor tissue confounded also by the spatial and temporal heterogeneity of tumours. Liquid biopsy has the potential to circumvent tumor heterogeneity and to help identifying patients who may respond to IO, to monitor the treatment dynamically, as well as to unravel the mechanisms of relapse. We present here a review of the current status of molecular markers for the prediction and monitoring of IO response, focusing on the detection of these markers in liquid biopsies. With the emerging improvements in the field of liquid biopsy, this approach has the capacity to identify IO-eligible patients and provide clinically relevant information to assist with their ongoing disease management.

Daily Practice Assessment of KRAS Status in NSCLC Patients: A New Challenge for the Thoracic Pathologist Is Right around the Corner

Simple Summary

RAS mutation is the most frequent oncogenic alteration in human cancers and KRAS is the most frequently mutated, notably in non-small cell lung carcinomas (NSCLC). Various attempts to inhibit KRAS in the past were unsuccessful in these latter tumors. However, recently, several small molecules (AMG510, MRTX849, JNJ-74699157, and LY3499446) have been developed to specifically target KRAS G12C-mutated tumors, which seems promising for patient treatment and should soon be administered in daily practice for non-squamous (NS)-NSCLC. In this context, it will be mandatory to systematically assess the KRAS status in routine clinical practice, at least in advanced NS-NSCLC, leading to new challenges for thoracic oncologists.

Abstract

KRAS mutations are among the most frequent genomic alterations identified in non-squamous non-small cell lung carcinomas (NS-NSCLC), notably in lung adenocarcinomas. In most cases, these mutations are mutually exclusive, with different genomic alterations currently known to be sensitive to therapies targeting EGFR, ALK, BRAF, ROS1, and NTRK. Recently, several promising clinical trials targeting KRAS mutations, particularly for KRAS G12C-mutated NSCLC, have established new hope for better treatment of patients. In parallel, other studies have shown that NSCLC harboring co-mutations in KRAS and STK11 or KEAP1 have demonstrated primary resistance to immune checkpoint inhibitors. Thus, the assessment of the KRAS status in advanced-stage NS-NSCLC has become essential to setting up an optimal therapeutic strategy in these patients. This stimulated the development of new algorithms for the management of NSCLC samples in pathology laboratories and conditioned reorganization of optimal health care of lung cancer patients by the thoracic pathologists. This review addresses the recent data concerning the detection of KRAS mutations in NSCLC and focuses on the new challenges facing pathologists in daily practice for KRAS status assessment.

Morphological and Molecular Characterization of KRAS G12C-Mutated Lung Adenocarcinomas

Simple Summary

Lung adenocarcinoma is currently the main histological subtype of lung cancer, accounting for more than 60% of diagnosed cases. The most frequent genomic alteration in these tumors is the mutation of the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, which until recently was not accessible to targeted therapy. New phase I, II, and III clinical trials using targeted inhibitors for the specific glycine-to-cysteine mutation at codon 12 (KRAS c.34G>T/KRAS G12C) of the KRAS gene showed promising results in approximately 30% of lung adenocarcinomas harboring a KRAS G12C mutation. In our study, we analyzed the genomic landscape of these tumors using next-generation sequencing technology and characterized new molecular subtypes that could be more susceptible to the new class of KRAS G12C inhibitors.

Abstract

Lung adenocarcinoma (LUAD) is the major subtype of non-small cell lung cancer, accounting for approximately 60% of cases. Molecular analysis of LUADs showed that the KRAS gene is mutated in up to 30% of cases; such cases were previously considered “undruggable”. The KRAS G12C mutation has become a hot topic of research after initial, promising, phase I and II trials with targeted inhibitors. We analyzed the morphological and genomic landscape of 202 KRAS G12C mutated LUADs using next-generation sequencing, and identified a specific subtype of patients that could show an improved response to KRAS G12C inhibitors. The main histological subtype was acinar in 29.7% of cases. Tumor-infiltrating lymphocytes (TILs) were highly or moderately abundant in more than 60% of cases. The immunohistochemical profile showed TTF1 positivity in 78.7% of cases and PD-L1 positivity in 44.1% of cases. The molecular profile showed an association between KRAS G12C and STK11 mutations in 25.2% of cases. This subgroup was associated with a statistically significant lower TTF1 (p = 0.0092) and PD-L1 (p < 0.0001) positivity. This type of combined morphological and molecular analysis can improve our understanding of tumor biology, and help us to identify specific patient subgroups that can achieve the best treatment response.

Targeting KRAS in NSCLC: Old Failures and New Options for "Non-G12c" Patients

Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) gene mutations are among the most common driver alterations in non-small cell lung cancer (NSCLC). Despite their high frequency, valid treatment options are still lacking, mainly due to an intrinsic complexity of both the protein structure and the downstream pathway. The increasing knowledge about different mutation subtypes and co-mutations has paved the way to several promising therapeutic strategies. Despite the best results so far having been obtained in patients harbouring KRAS exon 2 p.G12C mutation, even the treatment landscape of non-p.G12C KRAS mutation positive patients is predicted to change soon. This review provides a comprehensive and critical overview of ongoing studies into NSCLC patients with KRAS mutations other than p.G12C and discusses future scenarios that will hopefully change the story of this disease.

Treatment with immune checkpoint inhibitors after EGFR-TKIs in EGFR-mutated lung cancer

Background

Epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKIs) have become the gold standard for EGFR‐mutated non‐small cell lung cancer (NSCLC) treatment. Immune checkpoint inhibitors (ICIs) have been developed for the treatment of several malignancies, including lung cancer. However, it is known that ICIs have poorer efficacy in EGFR‐mutated NSCLC.

Methods

We collected data for patients with EGFR‐mutated NSCLC receiving monotherapy with ICIs after EGFR‐TKIs between December 2015 and March 2020 in three institutions, and retrospectively analyzed the association between patient characteristics and efficacy of ICIs.

Results

A total of 25 patients were included in this study. We defined responders as patients undergoing 90 days or longer of ICI treatment. Comparing characteristics between responders and non‐responders, more tumors with L858R EGFR mutation were observed in responders than in non‐responders (L858R: 66.7% and 25.0%, respectively, p < 0.05). There was no difference in incidence of T790M resistance mutation before ICI treatment. The PD‐L1 positive rate was slightly higher in responders but not statistically significant (22.2% and 12.5%, respectively). Median duration of EGFR‐TKI pretreatment was shorter in ICI responders compared with nonresponders (13.3 and 19.9 months, respectively). The survival of patients with L858R tumors was significantly longer than that of patients with exon 19 deletion (HR: 0.35, 95% CI: 0.13–0.93, p = 0.026).

Conclusions

ICI treatment tends to have better efficacy in patients with L858R‐mutated tumors. This study suggests that patients with L858R‐mutated NSCLC are candidates for ICI treatment after EGFR‐TKI treatment.

Immunotherapy in Non-Small Cell Lung Cancer With Actionable Mutations Other Than EGFR

While first line targeted therapies are the current standard of care treatment for non-small cell lung cancer (NSCLC) with actionable mutations, the cancer cells inevitably acquire resistance to these agents over time. Immune check-point inhibitors (ICIs) have improved the outcomes of metastatic NSCLC, however, its efficacy in those with targetable drivers is largely unknown. In this manuscript, we reviewed the published data on ICI therapies in NSCLC with ALK, ROS1, BRAF, c-MET, RET, NTRK, KRAS, and HER2 (ERBB2) alterations. We found that the objective response rates (ORRs) associated with ICI treatments in lung cancers harboring the BRAF (0-54%), c-MET (12-49%), and KRAS (18.7-66.7%) alterations were comparable to non-mutant NSCLC, whereas the ORRs in RET fusion NSCLC (less than10% in all studies but one) and ALK fusion NSCLC (0%) were relatively low. The ORRs reported in small numbers of patients and studies of ROS1 fusion, NTRK fusion, and HER 2 mutant NSCLC were 0-17%, 50% and 7-23%, respectively, making the efficacy of ICIs in these groups of patients less clear. In most studies, no significant correlation between treatment outcome and PD-L1 expression or tumor mutation burden (TMB) was identified, and how to select patients with NSCLC harboring actionable mutations who will likely benefit from ICI treatment remains unknown.

Clinical potential of circulating free DNA and circulating tumour cells in patients with metastatic non-small-cell lung cancer treated with pembrolizumab

Immune checkpoint inhibitors, such as pembrolizumab, are revolutionizing therapeutic strategies for different cancer types, including non-small-cell lung cancer (NSCLC). However, only a subset of patients benefits from this therapy, and new biomarkers are needed to select better candidates. In this study, we explored the value of liquid biopsy analyses, including circulating free DNA (cfDNA) and circulating tumour cells (CTCs), as a prognostic or predictive tool to guide pembrolizumab therapy. For this purpose, a total of 109 blood samples were collected from 50 patients with advanced NSCLC prior to treatment onset and at 6 and 12 weeks after the initiation of pembrolizumab. Plasma cfDNA was measured using hTERT quantitative PCR assay. The CTC levels at baseline were also analysed using two enrichment technologies (CellSearch® and Parsortix systems) to evaluate the efficacy of both approaches at detecting the presence of programmed cell death ligand 1 on CTCs. Notably, patients with high baseline hTERT cfDNA levels had significantly shorter progression-free survival (PFS) and overall survival (OS) than those with low baseline levels. Moreover, patients with unfavourable changes in the hTERT cfDNA levels from baseline to 12 weeks showed a higher risk of disease progression. Additionally, patients in whom CTCs were detected using the CellSearch® system had significantly shorter PFS and OS than patients who had no CTCs. Finally, multivariate regression analyses confirmed the value of the combination of CTCs and cfDNA levels as an early independent predictor of disease progression, identifying a subgroup of patients who were negative for CTCs, who presented low levels of cfDNA and who particularly benefited from the treatment.

Associations between tumor mutations in cfDNA and survival in non-small cell lung cancer

INTRODUCTION

Studies have indicated that detection of mutated KRAS or EGFR in circulating tumor DNA (ctDNA) from pre-treatment plasma samples is a negative prognostic factor for non-small cell lung cancer (NSCLC) patients. This study aims to investigate whether this is the case also for NSCLC patients with other tumor mutations.

METHODS

Tumor tissue DNA from 107 NSCLC patients was sequenced and corresponding pre-treatment plasma samples were analyzed using a limited target next-generation sequencing approach validated in this study. Patients without detected mutations in tumor samples were excluded from further analyses.

RESULTS

Mutations were detected in tumor samples from 71 patients. Median age was 68 years, 51% were female, and 88% were current/former smokers, 91% had adenocarcinoma, 4% had squamous cell carcinoma and 6% had other NSCLC. The distribution between stage I, II, III and IV was 33%, 8%, 30%, and 29%, respectively. Between one and three tumor mutation(s) were detected in ctDNA from corresponding plasma samples. Patients with detected ctDNA had shorter PFS (9.6 vs. 41.3 months, HR: 2.9, 95% CI: 1.6-5.2, p = 0.0003) and OS (13.6 vs. 115.0 months, HR: 4.0, 95% CI: 2.1-7.6, p = 0.00002) than patients without detected ctDNA. ctDNA remained a significant negative prognostic factor for OS (HR: 2.5, 95% CI: 1.1-5.7, p=0.0327), but not PFS, in the multivariable analyses adjusting for baseline patient and disease characteristics including stage of disease.

CONCLUSIONS

This study adds further evidence supporting that detectable tumor mutations in cfDNA is associated with a worse prognosis in NSCLC harboring a variety of tumor mutations.

The role of molecular heterogeneity targeting resistance mechanisms to lung cancer therapies

Introduction: The treatment scenario of lung cancer is rapidly evolving through time. In parallel, growing evidence is accumulating on different mechanisms of treatment resistance. Inter- and intra-tumor heterogeneity define the spatial and temporal tumor clonal evolution, that is at the basis of tumor progression and resistance to anticancer treatments.Areas covered: This review summarizes the available evidence on molecular heterogeneity in lung cancer, from diagnosis to the occurrence of treatment resistance. The application of novel molecular diagnostic methods to detect molecular heterogeneity, and the implications of understanding heterogeneity for drug development strategies are discussed, with focus on clinical relevance and impact on patients' survival.Expert opinion: The current knowledge of molecular heterogeneity allows to identify different molecular subgroups of patients within the same conventional tumor type. Deeper understanding of heterogeneity determinants and the possibility to comprehensively investigate tumor molecular patterns will lead to the development of personalized treatment approaches, with the final goal to overcome resistance and prolong survival in lung cancer patients.

Genomic Characterization of Concurrent Alterations in Non-Small Cell Lung Cancer (NSCLC) Harboring Actionable Mutations

An increasing number of driver genomic alterations with potential targeted treatments have been identified in non-small cell lung cancer (NSCLC). Much less is known about the incidence and different distribution of concurrent alterations, as identified by comprehensive genomic profiling in oncogene-addicted NSCLCs. Genomic data from advanced NSCLC consecutively analyzed using a broad next-generation sequencing panel were retrospectively collected. Tumors harboring at least one main actionable gene alteration were categorized according to the presence/absence of concurrent genomic aberrations, to evaluate different patterns among the main oncogene-addicted NSCLCs. Three-hundred-nine actionable gene alterations were identified in 284 advanced NSCLC patients during the study period. Twenty-five tumor samples (8%) displayed concurrent alterations in actionable genes. Co-occurrences involving any pathogenic variant or copy number variation (CNV) were identified in 82.8% of cases. Overall, statistically significant differences in the number of concurrent alterations, and the distribution of TP53, STK11, cyclines and receptor tyrosin kinase (RTK) aberrations were observed across the eight actionable gene groups. NGS analyses of oncogene-addicted NSCLCs showed a different distribution and pattern of co-alteration profiles. Further investigations are needed to evaluate the prognostic and treatment-related impact of these concurrent alterations, hooked to the main gene aberrations.