EGFR 19del Research Articles

224P Lung cancer scRNA-seq analyses reveal potential mechanisms causing different efficacy of target therapy and immunotherapy between EGFR 19del and L858R lung adenocarcinoma

224P Lung cancer scRNA-seq analyses reveal potential mechanisms causing different efficacy of target therapy and immunotherapy between EGFR 19del and L858R lung adenocarcinoma

Benefits of osimertinib treat a lung adenocarcinoma patient with germline EGFR T790M, somatic EGFR 19-Del, TP53 and PIK3CA mutations

BackgroundSomatic mutations in the EGFR gene occur in about 50% of non-small cell lung cancers, with the T790M mutation significantly contributing to secondary resistance against EGFR-TKI drugs. However, EGFR T790M germline mutations rarely occur.Case presentationIn this study, we report a case of a lung adenocarcinoma family lineage linked to a germline EGFR T790M mutation. The main subject was diagnosed with stage IV lung adenocarcinoma and experienced a 19-month period without disease progression while treated with Osimertinib. We collected both clinicopathological and familial data from a patient with lung adenocarcinoma. Next-generation sequencing of 40 key genes was performed on the proband’s tumor tissue. To detect EGFR germline mutations, Sanger sequencing was conducted on peripheral blood mononuclear cells from the proband and his two daughters. Mutations such as EGFR T790M, EGFR 19-Del, TP53, and PIK3CA were identified in the proband’s lung cancer tissue. Additionally, germline EGFR T790M mutations were confirmed in the proband and his daughters through sequencing of their peripheral blood samples. CT scans revealed multiple pulmonary nodules in both daughters.ConclusionsThese observations suggest that germline mutations in EGFR T790M could be strongly linked to a familial predisposition to lung cancer.

The combined inhibition of SLC1A3 and glutaminase in osimertinib-resistant EGFR mutant cells

Background: We investigated the unknown mechanisms of osimertinib-resistant EGFR-mutant lung cancer. Methods: An osimertinib-resistant cell line (PC-9/OsmR2) was established through continuous exposure to osimertinib using an EGFR exon 19 deletion (19Del) lung adenocarcinoma cell line (PC-9). EGFR 19Del (M1), L858R/T790M/C797S (M6), and L858R/C797S (M8) expression vectors were introduced into Ba/F3 cells. A second osimertinib-resistant line (M1/OsmR) was established through continuous exposure to osimertinib using M1 cells. Results: SLC1A3 had the highest mRNA expression level in PC-9/OsmR2 compared to PC-9 cells by microarray analysis and SLC1A3 was increased by flow cytometry. In PC-9/OsmR2 cells, osimertinib sensitivity was significantly increased in combination with siSLC1A3. Because SLC1A3 functions in glutamic acid transport, osimertinib with a glutaminase inhibitor (CB-839) or an SLC1A3 inhibitor (TFB-TBOA) increased the sensitivity. Also, CB-839 plus TFB-TBOA without osimertinib resulted in greater susceptibility than did CB-839 or TFB-TBOA plus osimertinib. Comprehensive metabolome analysis showed that the M1/OsmR cells had significantly more glutamine and glutamic acid than M1 cells. CB-839 plus osimertinib exerted a synergistic effect on M6 cells and an additive effect on M8 cells. Conclusion: Targeting glutaminase and glutamic acid may overcome the osimertinib-resistant EGFR-mutant lung cancer.

Elucidating the role of RBM10 in brain metastasis of EGFR19del lung adenocarcinoma.

e20501 Background: The EGFR mutation was detected in 66.3% of Asian patients with lung adenocarcinoma. Among these mutations, EGFR 19del exhibited the highest sensitivity and best response. However, it is worth noting that patients with EGFR 19del have a high cumulative incidence of brain metastases, which contributes significantly to treatment failure. Based on previous WES analysis of primary lung cancer cases and their corresponding brain metastases, RBM10 co-mutation was observed in four out of ten cases with EGFR 19del mutation, leading to decreased expression levels of RBM10. These findings suggest a potential role for RBM10 in modulating the development of brain metastases in patients with EGFR 19del lung cancer. Methods: To investigate the role of RBM10 in brain metastasis, we performed RNA-seq on the PC9 cell line to identify metabolic pathways and genes associated with RBM10 and brain metastasis. Additionally, the brain metastasis model was established by injecting PC9 cells into the left ventricle of nude mice, and the ability of PC9 cells to form brain metastases after knocking down RBM10 was confirmed through two rounds of in vivo screening using the PC9 cell line. Lipidomics analysis further validated that RBM10 affects key metabolite production. Clip-seq and RNA-seq were employed to analyze how RBM10 regulates sphingolipid metabolism. Finally, we identified key targets affecting blood-brain barrier function within the sphingolipid metabolism pathway and verified their ability to inhibit brain metastasis using both in vitro and in vivo models. Results: RNA-seq results demonstrated the regulatory role of RBM10 in the sphingolipid metabolism pathway, specifically in GALC regulation. In vitro and in vivo models revealed an enhanced brain metastasis ability of the PC9shRBM10 group. Lipidomics analysis revealed that the knockdown of RBM10 resulted in a reduction in ceramide and an elevation in SPH. Integrated RNA-seq and Clip-seq analyses demonstrated that the splicing regulation on GALC was attenuated upon RBM10 knockdown, leading to an increase in GALC expression. Furthermore, this perturbation enhanced the downstream sphingosine-1-phosphate signalling axis (SPH-SK1/2-S1P), consequently promoting increased S1P production and elevated blood-brain barrier permeability. Finally, fingolimod, an S1P inhibitor, was employed to validate its efficacy in inhibiting brain metastasis; moreover, a combination therapy comprising osimertinib and fingolimod exhibited superior capacity for suppressing brain metastasis. Conclusions: This study aims to elucidate the regulatory mechanism underlying the impact of RBM10 on sphingolipid metabolism in brain metastasis of EGFR 19del lung adenocarcinoma, to identify novel therapeutic targets for preventing brain metastasis in patients exhibiting EGFR 19del lung adenocarcinoma with low RBM10 expression.

Genetic characteristics of cerebrospinal fluid-derived circulating tumor DNA in brain metastases of lung adenocarcinoma.

e20503 Background: Brain metastases (BM), encompassing parenchymal metastases (PM) and leptomeningeal metastases (LM), are a common and fatal complication of advanced lung adenocarcinoma (LUAD). However, the genomic disparities between PM and LM, as determined by cerebrospinal fluid (CSF)-derived circulating tumor DNA (ctDNA), and its clinical utility as a liquid biopsy medium remain unclear. Methods: We conducted a retrospective study involving 33 patients diagnosed with BM from LUAD, comprising 16 cases with PM and 17 cases with LM, at Shandong Cancer Hospital between March 2018 and June 2021. CSF and matched peripheral blood lymphocyte samples were collected from all patients, and plasma samples were collected from 25 of them. Genomic profiles of CSF and plasma in patients with PM and LM were compared. CSF-ctDNA, plasma-ctDNA, and DNA from matched peripheral blood lymphocytes underwent next-generation sequencing (NGS) based on a 769 cancer-related gene panel. Results: A total of 363 mutations were detected in CSF-ctDNA, with 90.9% (30/33) of all LUAD patients with PM or LM showing mutations. EGFR mutations were the most common, occurring in PM samples from 56.3% (9/16) of patients and in LM samples from 76.5% (13/17) of patients, followed by other frequently mutated driver genes, including TP53 in 19 (57.6%) patients, MLH1 in 9 (27.3%) patients, and KMT2C in 8 (24.2%). Notably, EGFR 19del was more prevalent as a driver mutation in patients with LM compared to those with PM in our study, particularly the p.E746_A750del mutated subtype. Furthermore, the frequency of mutations in the mismatch repair (MMR) pathway was significantly higher in patients with LM than in those with PM. Additionally, CSF exhibited a more comprehensive profile of driver genomic mutations than matched plasma in patients with any form of BM, accompanied by a higher variation burden and detection of druggable mutations. Conclusions: CSF-ctDNA sequencing revealed distinct genomic patterns in patients with BM, particularly in LM, and could potentially enhance the management of BM patients compared to plasma.

Cerebrospinal fluid ctDNA testing shows an advantage over plasma ctDNA testing in advanced non-small cell lung cancer patients with brain metastases.

Brain metastases (BM), including brain parenchyma metastases (BPM) and leptomeningeal metastases (LM), are devastating metastatic complications in advanced cancer patients. Next-generation sequencing (NGS) is emerging as a new promising tool for profiling cancer mutation, which could facilitate the diagnosis of cancer. This retrospective study aimed to investigate the molecular genetic characteristics of non-small cell lung cancer (NSCLC) patients with BPM and LM using NGS. Cerebrospinal fluid (CSF) samples and paired plasma samples were collected from 37 patients of NSCLC-BM. We profiled genetic mutation characteristics using NGS from NSCLC-BM by comparing CSF circulating tumour DNA (ctDNA) with plasma ctDNA and primary tumour tissues. Among the 37 patients with NSCLC-BM, 28 patients had LM with or without BPM, while 9 patients only had BPM. Driver and drug-resistant mutations in primary tumours with LM included: EGFR L858R (10, 35.7%), EGFR 19del (6, 21.4%), EGFR L858R+MET (1, 3.6%), EGFR L858R+S768I (1, 3.6%), ALK (2, 7.1%), ROS1 (1, 3.6%), negative (5, 17.9%), and unknown (2, 7.1%). In patients with NSCLC-LM, the detection rate and abundance of ctDNA in the CSF were significantly higher than those in paired plasma. The main driver mutations of NSCLC-LM remained highly consistent with those of the primary tumours, along with other unique mutations. Circulating tumour DNA was negative in the CSF samples of BPM patients. Patients with BMP had a higher ratio of EGFR 19del than L858R mutation (55.6% vs 11.1.%), whereas NSCLC patients with LM had a higher ratio of EGFR L858R than 19del mutation (50.0% vs 25.0%). Most patients with positive plasma ctDNA results were male (p = 0.058) and in an unstable state (p = 0.003). Our study indicated that the CSF ctDNA detected by NGS may reflect the molecular characteristics and heterogeneity of NSCLC-LM. Timely screening of patients with NSCLC for CSF ctDNA, especially for patients with positive plasma ctDNA, may facilitate the early detection of LM. Furthermore, patients with the EGFR 19del may have a higher risk of developing BPM.

Genomic heterogeneity of multiple synchronous lung cancers in Chinese population.

It is clinically challenging to infer the phylogenetic relationship between different tumor lesions of patients with multiple synchronous lung cancers (MSLC), whether these lesions are the result of independently evolved tumor or intrapulmonary metastases. We used the Illumina X10 platform to sequence 128 stage I lung cancer samples collected from 64 patients with MSLC. All samples were analyzed for mutation spectra and phylogenetic inference. We detected genetic aberrations within genes previously reported to be recurrently altered in lung adenocarcinoma including, EGFR, ERBB2, TP53, BRAF, and KRAS. Other putative driver mutations identified were enriched in RTK-RAS signaling, TP53 signaling, and cell cycle. Also, we found some interesting cases, two cases that carried EGFR L858R and T790M co-mutation in one tumor and another tumor with only EGFR 19del, and 1 case with two KRAS hotspots in the same tumor. Due to the short follow-up time and early stage, further investigation is needed to determine whether this unique mutation profile will affect their progression-free survival (PFS) and overall survival (OS). Regarding genetic evolution analysis among 64 tumor samples, 50 of them display distinct mutational profiles, suggesting these are independently evolved tumors, which is consistent with histopathological assessment. On the other hand, six patients were identified to be intrapulmonary metastasis as the mutations harbored in different lesions are clonally related. In summary, unlike intrapulmonary metastases, patients with MSLC harbor distinct genomic profiles in different tumor lesions, and we could distinguish MSLC from intrapulmonary metastases via clonality estimation.

Abstract B089: MUC1-C is a common driver of acquired osimertinb resistance in NSCLC

Abstract Background: Osimertinib is an irreversible EGFR tyrosine kinase inhibitor approved for the first-line treatment of patients with metastatic NSCLC harboring EGFR exon 19 deletions or L858R mutations. Patients treated with osimertinib invariably develop acquired resistance by mechanisms involving additional EGFR mutations, MET amplification and other pathways. There is no known involvement of the oncogenic MUC1-C protein in acquired osimertinib resistance. Methods: H1975/EGFR(L858R/T790M) and patient-derived NSCLC cells with acquired osimertinib resistance (EMT, MET amplified, C797S mutation, or PCBP2-BRAF fusion) were investigated for MUC1-C dependence in studies of EGFR pathway activation, clonogenicity and self-renewal capacity. Results: We demonstrate that MUC1-C is upregulated in H1975 osimertinib drug tolerant persister (DTP) cells and is necessary for activation of the EGFR pathway. H1975 cells selected for stable osimertinib resistance (H1975-OR) and MGH700-2D cells isolated from a patient with acquired osimertinib resistance are shown to be dependent on MUC1-C for induction of (i) p-EGFR, p-ERK and p-AKT, (ii) EMT, and (iii) the resistant phenotype. We report that MUC1-C is also required for p-EGFR, p-ERK and p-AKT activation and self-renewal capacity in acquired osimertinib-resistant (i) MET amplified MGH170-1D #2 cells, (ii) MGH121 Res#2/EGFR(T790M/C797S) cells, and (iii) MGH845-1R5/EGFR(19del)/PCBP2-BRAF fusion cells. Importantly, targeting MUC1-C in these diverse models reverses osimertinib resistance. To extend these results, we established MET amplified MGH170-1D #2 tumors in mice and found that treatment with GO-203 inhibitor, which is a cell-penetrating peptide that blocks MUC1-C homodimerization, nuclear localization, and function, results in more pronounced inhibition and that the GO-203+osimertinib combination is more effective than either agent alone. In support of these results, high MUC1 expression is associated with poor prognosis for patients with EGFR mutant NSCLCs and those treated with osimertinib. Conclusions: Our findings demonstrate that MUC1-C is a common effector of osimertinib resistance and is a potential target for the treatment of osimertinib resistant NSCLCs. Citation Format: Naoki Haratake, Hiroki Ozawa, Yoshihiro Morimoto, Nami Yamashita, Tatsuaki Daimon, Atrayee Bhattacharya, Keyi Wang, Ayako Nakashoji, Hideko Isozaki, Aaron Hata, Donald Kufe. MUC1-C is a common driver of acquired osimertinb resistance in NSCLC [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B089.

First-generation EGFR-TKI plus bevacizumab and chemotherapy for advanced EGFR-mutated non-squamous non-small-cell lung cancer: a retrospective study

Background This study aimed to compare the efficacy and safety of different treatment modalities for previously untreated advanced EGFR-mutated non-squamous non-small-cell lung cancer (NSCLC). Methods This retrospective study included 196 advanced EGFR-mutated non-squamous NSCLC. 107 received EGFR-tyrosine kinase inhibitor (EGFR-TKI) monotherapy (T), 53 received EGFR-TKI + bevacizumab (T + A), and 36 received EGFR-TKI + bevacizumab + chemotherapy (T + A + C). The endpoints included progression-free survival (PFS), overall survival (OS), objective response rate (ORR) and adverse events (AEs). Results The median PFS was 27 months in the T + A + C group, 17 months in the T + A group, and 10 months in the T group. The multivariate analysis showed lower disease progression in the T + A + C group (HR, 0.377; 95% CI, 0.224–0.634; p < .001). Subgroup analysis showed that the T + A + C group did significantly improve PFS in patients with metastatic organs ≥2, brain metastases, liver metastases, and EGFR 19del compared to T + A group. No significant improvement in OS in the T + A + C group versus the T + A group, but a significant benefit in the subgroup of patients with metastatic organs ≥2. We also performed a subgroup analysis of the T + A + C group versus the T group, which similarly showed that the T + A + C group had better PFS than the T group in most subgroups, and the T + A + C group significantly improved OS in patients with metastatic organ ≥2 and liver metastases compared with the T group. The ORR was significantly higher in the T + A + C group than A + T and T groups (83.3% vs 71.7% vs 60.7%, p = .033). In safety, the T + A + C group had a higher incidence of AEs, but the majority was grade 1–2. The most frequent AEs of grade ≥ 3 were leukopenia (8.3%) and increased aminotransferase (8.3%) in the T + A + C group. Conclusions First-generation EGFR-TKI plus bevacizumab plus chemotherapy was a promising strategy for advanced EGFR-mutated non-squamous NSCLC.

CRISPincette, and detection of low frequency cancer mutations in ctDNA.

61 Background: Liquid biopsy has emerged as a non-invasive and widely applicable approach in clinical practice for cancer detection and monitoring. Detecting low-frequency mutations in circulating tumor DNA (ctDNA) is crucial for the success of liquid biopsy; however, technical limitations have hindered the detection of low variant allele frequency (VAF) mutations. To address this issue, we developed CRISPincette, a novel method which combines next-generation sequencing with an advanced CRISPR system, GeneCker-Cas9. Methods: CRISPincette was designed to efficiently detect mutant alleles by eliminating abundant wild-type alleles from normal cell-induced cell-free DNA (cfDNA) using CRISPR/Cas9. An engineered CRISPR/Cas9 variant, GeneCker-Cas9, was developed to maintain single-base precision outside the PAM region, enabling efficient discrimination of single-base mutations at all 20 positions within a single guide RNA target sequence. This advanced fidelity significantly improved the accuracy compared to high-specificity SpCas9 variants (SpCas9-HF and eSpCas9). To validate the sensitivity and accuracy of ctDNA detection using CRISPincette, we employed NGS standard materials (Horizon HD776, 778, 779) and assessed the improvement in ctDNA detection sensitivity for EGFR gene mutations (EGFR 19del, EGFR L858R, EGFR T790M). Subsequently, we analyzed the clinical applicability of CRISPincette using plasma samples from 7 non-small cell lung cancer (NSCLC) patients (6 patients with EGFR mutations and 1 patient without EGFR mutations). Results: Our analysis showed an approximately 10 to 30-fold enhancement in the detection sensitivity of EGFR gene mutations. Concordant detection of EGFR mutations was observed in the 6 patients with EGFR mutations using real-time PCR tests in each tissue biopsy, and no EGFR mutation was detected in the patient without the EGFR mutation. This confirmed CRISPincette's high accuracy and sensitivity in detecting low-frequency mutations in ctDNA. Conclusions: The implementation of CRISPincette has significantly improved the accuracy and sensitivity of liquid biopsy, making it a reliable and non-invasive alternative for confirming molecular pathological information in cancer patients. Furthermore, the high accuracy of CRISPincette will be a powerful tool for monitoring treatment and prognosis through the timing of anticancer drug administration. Overall, CRISPincette represents a substantial advancement in liquid biopsy technology, with potential implications for cancer diagnosis, treatment allocation, and monitoring the emergence of resistance.

Efficacy observation and prognosis analysis of EGFR-TKIs alone versus EGFR-TKIs plus chemotherapy in advanced lung adenocarcinoma with EGFR Exon 19 Deletion, Exon 21 L858R mutation: A historical cohort study.

The aim of this study was to investigate the clinical efficacy and determine the prognostic value of Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKIs) alone versus EGFR-TKIs plus chemotherapy for the treatment of advanced lung adenocarcinoma with EGFR Exon 19 Deletion(19Del), Exon 21 L858R (L858R) mutation. The demographic and clinical characteristics of 110 newly diagnosed metastatic lung adenocarcinoma patients with the EGFR 19Del, L858R mutation from June 2016 to October 2018 were retrospectively analyzed. Total remission rate (ORR), disease control rate (DCR), median progression-free survival (mPFS), and patient 1-year/2-year survival between EGFR-TKIs combined with first-line platinum-containing double-drug chemotherapy (Observation) group and an EGFR-TKIs alone (Control) group were evaluated and analyzed. For lung adenocarcinoma patients with the EGFR 19Del, L858R mutation, the Observation group had a better ORR (81.4% vs 52.2%), mPFS (12.0 vs 9 months), and 2-year survival (72.1% vs 52.2%) than the Control group, and the differences were statistically significant (P < .05), but DCR (95.3% vs 88.1%) and 1-year survival (90.7% vs 83.6%) were not significantly different between the groups (P > .05). For lung adenocarcinoma with the EGFR 19Del mutation, the Observation group showed a better ORR (81.8% vs 54.3%), and mPFS (14.5 vs 11.0 months) than the Control group, and the differences were statistically significant (P < .05), but DCR (95.5% vs 91.4%), 1-year survival (90.9% vs 85.7%), and 2-year survival (72.7% vs 60.0%) were not significantly different (P > .05). For lung adenocarcinoma with the EGFR L858R mutation, the Observation group showed a better ORR (81.0% vs 50.0%), mPFS (12.0 vs 9.0 months), and 2-year survival (71.4% vs 43.8%) than the Control group (P < .05), but DCR (95.2% vs 84.4%) and 1-year survival (90.5% vs 81.3%) were not significantly different (P > .05). Compared to EGFR-TKIs alone, EGFR-TKIs combined with chemotherapy improved ORR and mPFS in cases of advanced lung adenocarcinoma with EGFR 19Del, L858R mutation. In particular, patients with the EGFR L858R mutation showed a long-term survival benefit trend. EGFR-TKIs combined chemotherapy may therefore be a viable treatment method for delaying targeted drug resistance.

CRISPR/Cas12a-drived fluorescent and electrochemical signal-off/on dual-mode biosensors for ultrasensitive detection of EGFR 19del mutation

The mutation status of epidermal growth factor receptor exon 19 (EGFR 19) is critical in predicting the susceptibility to tyrosine kinase inhibitors. Herein, we develop CRISPR/Cas12a-drived fluorescent and electrochemical dual-mode biosensors for detection of EGFR 19 deletion (EGFR 19del). By introducing a padlock probe with two endonuclease sites for target recognition, the rolling-circle strand displacement amplification (RC-SDA) is triggered to achieve preamplification and CRISPR/Cas12a reaction. When EGFR 19del is present, no amplified products activate the CRISPR/Cas12a system, resulting in the fluorescent signal remaining in the "off" state. To improve the detection accuracy and sensitivity, we have ingeniously constructed an electrochemical biosensor that converts the "signal-off" state to the "signal-on" state. In this design, the inactive Cas12a does not cleave the electrochemical probe, which contains a T-rich sequence with a 5'methylene blue modification. With the assistance of Hg2+, the electrochemical probe can form a “hairpin-like” of Thymine–Hg–Thymine complex, generating an enhanced current. Experimental results demonstrate that the limit of detection (LOD) for the fluorescent biosensor is 18.62 fM, while the electrochemical biosensor achieves an LOD of 0.13 fM. Furthermore, the biosensors can discriminate 0.5% and 0.1% mutation, respectively. They also exhibit the capability to differentiate between wild-type and mutant genes from various cells. The obtained results are identical to those obtained by qPCR method, indicating their broad application prospects in drug development and disease surveillance.

Effects of concomitant chronic obstructive pulmonary disease on immune microenvironment in non-small cell lung cancer patients.

e20522 Background: Chronic obstructive pulmonary disease (COPD) as a progressive deterioration of lung function, has caused significant morbidity and mortality, especially in developing countries. Persistent lung inflammation and potential lung stroma remodeling in COPD may be important causes of lung cancer. Previous studies have shown that non-small cell lung cancer (NSCLC) patients with COPD have a worse prognosis than those without, but the reasons have not been determined. Due to the increasing application of ICIs in the NSCLC, the characteristics of the immune microenvironment in the NSCLC patients concomitant COPD are worth exploring. Methods: Immune microenvironment and the next generation sequencing (NGS) data of twenty NSCLC patients from Sun Yat-sen Memorial Hospital were analyzed. Formalin-fixed paraffin-embedded biopsy tissue before first-line treatment to prepare tumor tissue slides. Samples were stained using an Opal automation mIF Detection Kit (Akoya) for immune cells. The immune cell infiltration were reported as percentages and density from each individual cell subpopulation in the tumor or stromal area. The landscape of gene mutantions was obtained by NGS detection of 733-gene panel, sequencing depth was 35000x. Results: There were 8 (40%) patients concomitant COPD, and the median age was 65.5-year-old. Analysis the immune cell infiltration in all patients, including T cells, B cells, macrophages and NK cells through 13 markers, showed no difference between COPD and non-COPD groups. However, comparing the differences between tumor and stromal immune microenvironment, it was found that there was a significant difference in the percentages of M1 macrophages between tumor and stromal in COPD group (P = 0.031), but no difference in non-COPD group (P = 0.47). Further analysis of the difference in cell density between tumor and stroma showed that the stromal M1 macrophages in the COPD group was significantly higher than that in the non-COPD group (P = 0.017), as well as PD-1+CD8+ T cells (P = 0.05). Additionally, a preliminary analysis of the gene mutation characteristics had done. In COPD patients with somatic mutations, the most frequently mutated gene was EGFR (60%), followed by TP53 (50%) and GLI2 (50%), which were similar as non-COPD patients. The most common variant of COPD patients are the missense mutation of EGFR L858R, but it was EGFR 19del in non-COPD. Conclusions: The results showed that the COPD was correlated with the infiltration status of M1 macrophages and PD-1+CD8+ T cell, and poor immune cell infiltration in tumor of COPD patients may be the potential influencing factors for the worse prognosis. The characteristics of immune microenvironment suggest that promoting the entry of immune cells from stroma into tumor may be a potential mechanism for the benefit of immunotherapy in NSCLC patients with COPD.

Circulating tumor DNA to guide furmonertinib monotherapy or combination therapy in advanced EGFR mutant non-small cell lung cancer (NSCLC): A randomized, open-label, multicenter study (FOCUS-C).

TPS9150 Background: Detection of EGFR ctDNA after several weeks EGFR-TKIs treatment was an effective method to identify prognosis of advanced EGFR mutant NSCLC patients. Patients with uncleared EGFR ctDNA had shorter progression-free survival (PFS) ( Mack PC et al; CCR 2022). However, whether they can benefit from EGFR-TKI combination therapy has not been reported. Furmonertinib (AST2818), a potent, orally bioavailable, highly brain penetrant, third generation EGFR-TKI with unique chemical structure designed to improve potency and specificity, showed superior efficacy compared with gefitinib as first-line therapy in EGFR mutant NSCLC along with an acceptable safety profile without new signals ( Shi, YK et al.; Lancet Respir Med 2022). We hypothesized that monitoring clearance of EGFR ctDNA in blood could rationally guide subsequent monotherapy or combination therapy with furmonertinib and will improve outcomes in patients with uncleared EGFR ctDNA. Methods: The FOCUS-C study is a multicenter, open-label, randomized study. Patients who are aged 18 years or older and have histologically confirmed, locally advanced or metastatic, stage IIIB, IIIC, or IV unresectable NSCLC with EGFR exon 19 deletions (19Del) or exon 21 Leu858Arg mutation (L858R) on tissue biopsy and plasma will be treated with furmonertinib. Eligible patients with uncleared EGFR 19Del or L858R ctDNA after 3 weeks furmonertinib treatment will be stratified according to EGFR mutation (19Del or L858R), central nervous system metastases (with or without) and detectable accompanying gene aberrances in plasma (with or without) and randomly assigned (2: 2: 1) to receive furmonertinib or furmonertinib plus chemotherapy (pemetrexed and carboplatin for 4 cycles followed by maintenance pemetrexed) or furmonertinib plus chemotherapy plus bevacizumab (pemetrexed, carboplatin and bevacizumab for 4 cycles followed by maintenance pemetrexed and bevacizumab) in 21-day cycles until disease progression, the occurrence of intolerable toxicities, withdrawal of consent, or other discontinuation reasons judged by the investigators. The primary endpoint is PFS between furmoneritnib plus chemotherapy versus furmonertinib alone. Secondary endpoints include PFS, objective response rate, duration of response, disease control rate, overall survival and safety. Several exploratory endpoints will also be evaluated based on ctDNA detection by next-generation sequencing (Genecast, Wuxi, China). The study is enrolling. 34 patients had been enrolled till 2nd Feb 2023. Clinical trial information: NCT05334277 .

The complexity of EGFR exon 19 deletion and L858R mutant cells as assessed by proteomics, transcriptomics, and metabolomics

Most lung adenocarcinoma-associated EGFR tyrosine kinase mutations are either an exon 19 deletion (19Del) or L858R point mutation in exon 21. Although patients whose tumors contain either of these mutations exhibit increased sensitivity to tyrosine kinase inhibitors, progression-free and overall survival appear to be longer in patients with 19Del than in those with L858R. In mutant-transfected Ba/F3 cells, 19Del and L858R were compared by multi-omics analyses including proteomics, transcriptomics, and metabolomics. Proteome analysis identified increased plastin-2, TKT, PDIA5, and ENO1 expression in L858R cells, and increased EEF1G expression in 19Del cells. RNA sequencing showed significant differences between 19Del and L858R cells in 112 genes. Metabolome analysis showed that amino acids, adenylate, guanylate, NADPH, lactic acid, pyruvic acid glucose 6-phosphate, and ribose 5-phosphate were significantly different between the two mutant cells. Because GSH was increased with L858R, we combined osimertinib with the GSH inhibitor buthionine sulfoximine in L858R cells and observed synergistic effects. The complexity of EGFR 19Del and L858R mutant cells was demonstrated by proteomics, transcriptomics, and metabolomics analyses. Therapeutic strategies for lung cancer with different EGFR mutations could be considered because of their different metabolic phenotypes.

A potential treatment option for transformed small-cell lung cancer on PD-L1 inhibitor-based combination therapy improved survival

ObjectivesTransformed small-cell lung cancer (T-SCLC) has an extremely poor prognosis, and no remedies based on immunotherapy have been evaluated among T-SCLC patients. We retrospectively analysed the efficacy and safety of combining atezolizumab with chemotherapy for T-SCLC. MethodsForty-seven patients harbouring EGFR mutations who developed T-SCLC were enrolled. Eleven patients who used immunotherapy were defined as the I/O group, and the remaining 36 were defined as the Non-I/O group. Clinical characteristics, pathological data, and survival outcomes were collected. RNA sequencing and whole-exome sequencing (WES) were performed for in-depth analysis. ResultsAll patients received at least one line of EGFR-TKI before rebiopsy to confirm T-SCLC. Nine patients received atezolizumab-bevacizumab-carboplatin-paclitaxel (albumin-bound) (ABCP), and the remaining 2 received atezolizumab-etoposide-carboplatin (ECT) in the I/O group. The objective response rate was 73 % (8/11). The median progression-free survival (mPFS) of T-SCLC on post-transformation therapy with I/O group and Non-I/O group was 5.1 m and 4.1 m, respectively. The median post-T-SCLC overall survival of the I/O group was significantly longer than that Non-I/O group (20.2 m vs 7.9 m, P ＜ 0.01). T-SCLC harbouring EGFR L858R tended to be longer than EGFR 19del (mPFS: not reached vs 3.7 m, P = 0.11). Positive PD-L1 status was also associated with PFS benefits (mPFS: 6.0 m vs 3.7 m, P = 0.20). Furthermore, RNA sequencing revealed that expression of SFTPA1 is significantly higher in the durable clinical benefit group. WES showed that STC2 mutation is more frequently observed at the time-point immunotherapy acquired resistance. Combination therapy based on a PD-L1 inhibitor was well tolerated, and the safety profile was consistent with previously reported studies. ConclusionOur study first demonstrated that a PD-L1 inhibitor combined with chemotherapy ± bevacizumab could be a potential safe option for specific SCLC-transformed patients. Subsequent studies with more patients are essential to verify the efficacy and potential biomarkers.

Comprehensive analyses of genomic features and mutational signatures in adenosquamous carcinoma of the lung.

Adenosquamous carcinoma (ASC) of the lung is a relatively rare tumor with strong aggressiveness and poor prognosis. The analysis of mutational signatures is becoming routine in cancer genomics and has implications for pathogenesis, classification, and prognosis. However, the distribution of mutational signatures in ASC patients has not been evaluated. In this study, we sought to reveal the landscape of genomic mutations and mutational signatures in ASC. Next-generation sequencing (NGS) technology was used to retrieve genomic information for 124 ASC patients. TP53 and EGFR were the most prevalent somatic mutations observed, and were present in 66.9% and 54.8% of patients, respectively. CDKN2A (21%), TERT (21%), and LRP1B (18.5%) mutations were also observed. An analysis of gene fusion/rearrangement characteristics revealed a total of 64 gene fusions. The highest frequency of variants was determined for ALK fusions, with six ALK-EML4 classical and two intergenic ALK fusions, followed by three CD74-ROS1 fusions and one ROS1-SYN3 fusion. EGFR 19del (45.6%), and EGFR L858R (38.2%) and its amplification (29.4%) were the top three EGFR mutations. We extracted mutational signatures from NGS data and then performed a statistical analysis in order to search for genomic and clinical features that could be linked to mutation signatures. Amongst signatures cataloged at COSMIC, the most prevalent, high-frequency base changes were for C > T; and the five most frequent signatures, from highest to lowest, were 2, 3, 1, 30, and 13. Signatures 1 and 6 were determined to be associated with age and tumor stage, respectively, and Signatures 22 and 30 were significantly related to smoking. We additionally evaluated the correlation between tumor mutational burden (TMB) and genomic variations. We found that mutations ARID2, BRCA1, and KEAP1 were associated with high TMB. The homologous recombination repair (HRR) pathway-related gene mutation displayed a slightly higher TMB than those without mutations. Our study is the first to report comprehensive genomic features and mutational signatures in Chinese ASC patients. Results obtained from our study will help the scientific community better understand signature-related mutational processes in ASC.

Lung adenocarcinoma with EGFR 19Del and an ALK rearrangement benefits from alectinib instead of an EGFR-TKI: A case report

Rationale:A remarkable concurrence of an EGFR mutation and an EML4-ALK fusion (double positive) occasionally occurs within a narrow number of patients. Previous studies using targeted therapy on EGFR/ALK co-mutated patients have commonly focused on single tyrosine kinase inhibitors (TKIs) or on the sequential use of EGFR-TKIs and ALK-TKIs. At present, no consensus exists regarding the treatment of patients with double positive mutations. The effectiveness of precision therapy also remains unknown.Patient concerns:A 53-year-old female non-smoker who described recurrent coughing and blood in her sputum over a month-long interval was examined at a local hospital.Diagnosis:Using computed tomography (CT) and positron emission tomography CT (PET-CT), the patient was diagnosed with Stage IVb lung adenocarcinoma (T4N3M1).Interventions:The patient had a novel ALK-RAB10 rearrangement identified using DNA sequencing, which, at the transcript level, was actually a canonical ALK fusion that caused a response to alectinib therapy.Outcomes:The patient has achieved partial remission (PR), with a progression free survival (PFS) of 16 months, and continues to benefit.Lessons:Our results may indicate differential sensitivities to TKIs in patients harboring an EGFR mutation and an ALK rearrangement. Our patient’s response to alectinib, instead of to EGFR-TKIs, may lead to an expanded list of alectinib beneficiaries who have rare gene co-alterations in lung adenocarcinoma.

EP16.03-038 Single-cell Analyses Reveal Tumor Microenvironment Differences between EGFR 19del and L858R mutations in Lung Adenocarcinoma

Lung cancer is the leading cause of cancer-related mortality among malignant tumors worldwide. Lung adenocarcinoma (LUAD) accounts for 40% of all cases and is the most common histological subtype of non-small cell lung cancer (NSCLC). Activating somatic mutations, mostly identified as 19del and L858R in EGFR tyrosine kinase domain, may predict response to EGFR tyrosine kinase inhibitors (TKIs) in NSCLC patients. Although EGFR 19del and L858R patients are sensitive to TKIs, they showed different clinical benefits such as prolonged PFS in 19del patients.

Driver coexistence characteristics of ALK-fusion in Chinese patients with lung cancer.

8530 Background: ALK fusions and other driver mutations are usually mutually exclusive. With the widespread application of genetic testing techniques, the coexistence of ALK fusions and other driver mutations could be detected, such as ALK fusion and EGFR driver mutations. However, there were no systematical studies about the coexistence of ALK fusions and other driver mutations. Here, we retrospectively investigated the coexistence of ALK fusions and other driver mutations. Methods: Samples with ALK fusions were extracted from a Chinese lung cancer cohort, which from OncoPanscan (Genetron Health) based sequencing of tissue. Driver mutations of EGFR, ROS1, RET, NTRK1/2/3, BRAF, MET, KRAS and ERBB2 could be detected. Results: In the cohort, 692 samples with ALK fusions contained the intact kinase domain. These samples could be classified into three forms: canonical fusions (only EML4 partner, n = 601), single non-canonical fusions (only non- EML4 partner, n = 51) and complex non-canonical fusions (two or more partners, n = 40). Among the 692 samples, only 20 samples (20/692, 2.89%) coexisted with other driver mutations, which indicated that the driver coexistence were rare. 70% (14/20) of driver coexistence were happened on canonical fusions ( EML4-ALK) samples. They were coexisting with EGFR L858R (3), EGFR L858R plus ROS1 fusion (1), EGFR L858R plus MET amplification (1), KRAS G12C/D/V (3), MET amplification (3), MET Exon14 skipping (1), ERBB2 amplification (1), and MET amplification plus ERBB2 amplification (1), respectively. 20% (4/20) of driver coexistence samples were single non-canonical ALK fusions coexisting with EGFR 19del (1) or 20ins (1) or L858R (1) or MET amplification (1). Another 10% (2/20) samples were complex non-canonical ALK fusions coexisting with EGFR G719S (1) or RET fusion (1). Most co-mutations have corresponding targeted inhibitors, maybe these patients can be treated by combined or sequential therapies. Among canonical fusions, single non-canonical fusions and complex non-canonical fusions of ALK, the frequency of the samples without coexistence of driver mutations was respectively 97.67% (587/601), 92.16% (47/51), 95.00% (38/40), without significant difference (P = 0.056). Maybe single/complex non-canonical fusions are also strong drivers as canonical fusions. Conclusions: In this cohort, very few of ALK fusion patients coexisted with other driver mutations. Among the co-existence samples, ALK fusion were mainly coexisting with the site mutations of EGFR and KRAS, amplifications of MET and ERBB2, fusions of ROS1 and RET. These samples maybe obtain more effective outcomes by combined or sequential therapies.