EGFR T790M Mutation Research Articles

Anti-EGFR aptamer exhibits direct anti-cancer effects in NSCLC cells harboring EGFR L858R mutations

Non-small cell lung cancer (NSCLC) adenocarcinoma (LUAD) is a leading cause of death worldwide. Activating mutations in the tyrosine kinase domain of the oncogene epidermal growth factor receptor (EGFR) are responsible for ~10–50% of all LUAD cases. Although tyrosine kinase inhibitors (TKIs) have been effective in prolonging patient survival and quality of life, acquired resistance and disease progression are inevitable, presenting a clear unmet need for alternative or adjuvant therapeutics. Here we show that an anti-EGFR aptamer (EGFRapt) decreases viability and tumor growth of LUAD cell lines harboring the L858R ± T790M mutation in EGFR. Additionally, we elucidate the mechanism by which EGFRapt exerts these effects by monitoring cellular processes associated with kinase-dependent and kinase-independent mechanisms. Overall, these data establish that EGFRapt has direct anti-cancer activity in mutant EGFR positive LUAD via targetable mechanisms that are independent of existing approaches, and they provide a foundation for further development of nucleic acid-based therapies that target EGFR.

The potential role of next-generation sequencing in identifying MET amplification and disclosing resistance mechanisms in NSCLC patients with osimertinib resistance.

Osimertinib, one of the third-generation EGFR-tyrosine kinase inhibitors (TKIs) designed to target EGFR T790M mutation, significantly improves the prognosis of lung cancer. However, drug resistance still happens and MET amplification is responsible for one of the main causes. Fluorescence in situ hybridization (FISH) is the gold standard for MET amplification detection, but fundamentally limited by observer subjectivity. Herein, we assessed the value of next-generation sequencing (NGS) method in MET amplification detection in non-small cell lung cancer (NSCLC), as well as revealed the mutation profiling of NSCLC patients with osimertinib resistance to provide some valuable clues to the mechanisms of resistance. A total of 317 cancer tissue samples from 317 NSCLC patients at time of progression following osimertinib were submitted to NGS and only 96 tissues were tested by FISH simultaneously. With FISH results as gold standard, enumeration algorithm was applied to establish the optimal model for identifying MET amplification using gene copy number (GCN) data. The optimal model for identifying MET amplification was constructed based on the GCN of MET, BRAF, CDK6 and CYP3A4, which achieved a 74.0% overall agreement with FISH and performed well in identifying MET amplification except polysomy with a sensitivity of 85.7% and a specificity of 93.9%. The inconsistency between NGS and FISH occurred mainly in polysomy subtype, while MET GCN ≥ 5 could be reliably recognized by NGS. Moreover, the most frequently mutated genes in NSCLC patients with osimertinib resistance were EGFR (59.94%), followed by TP53 (43.85%), NRG1 (9.46%), PIK3CA (6.31%), and ATM (5.36%). The known resistance mechanisms, including MET amplification, EGFR (C797S, L718Q/R), TP53, CDK4, CDK6, CDKN2A, BRAF, KRAS, NRAS and PIK3CA mutations were also disclosed in our cohort. NGS assay can achieve a high concordance with FISH in MET amplification detection and has advantages in portraying various genetic alterations, which is of worthy in clinical promotion.

EGFR T790M mutation detection in NSCLC patients resistant to tyrosine kinase inhibitor therapy.

The finding of mutations that activate epidermal growth factor receptor (EGFR) in people with lung adenocarcinoma resulted in the creation of a new class of biological treatments called tyrosine kinase inhibitors (TKI). These medications have changed how patients with EGFR mutations are clinically managed, nearly doubling their survival rate compared to standard chemotherapy. Though 1st and 2nd generation EGFR TKIs are initially highly effective, typically within 9-14 months all tumors with the mutation progress due to secondary resistance mutations involving alternative molecular pathways. In most cases (up to 60%), this is due to the T790M mutation emerging in the EGFR gene. The study included 85 patients with NSCLC with progression of the disease after treatment with TKI 1st and 2nd generation. The T790M mutation was determined by digital polymerase chain reaction (PCR) on the QIAcuity One 5plex digital PCR system and traditional real-time PCR. Real-time PCR analysis of the presence of the T790M mutation was performed using the Therascreen EGFR Plasma RGQ PCR Kit (Qiagen). Using a digital PCR system in QIAcuity One (Qiagen) nanoplanets, the T790M mutation was analysed by digital PCR. The age of the patients ranged from 37 to 85 years. Of 85 patients with NSCLC with disease progression after TKI treatment, T790M mutations were detected during digital PCR in 30 of 85 patients, which is 35.2% of the sample, and with traditional real-time PCR, positive mutations came out only in 3 out of 85 patients.

Repeated rebiopsy for detection of EGFR T790M mutation in patients with advanced-stage lung adenocarcinoma: Associated factors and treatment outcomes of Osimertinib.

This study was performed to investigate the detection rate of EGFR T790M mutation by repeated rebiopsy, to identify the clinical factors related to repeated rebiopsy, and to assess survival outcomes according to the methods and numbers of repeated rebiopsies in patients with lung adenocarcinoma who received sequential osimertinib after failure of previous 1st or 2nd generation EGFR-tyrosine kinase inhibitors. This retrospective study included patients with advanced-stage lung adenocarcinoma who were confirmed to have EGFR T790M mutation and to have received osimertinib from January 2020 to February 2021 at Samsung Medical Center. The presence of T790M mutation was assessed based on either plasma circulating tumor DNA (ctDNA) or tissue specimens. Results A total of 443 patients underwent rebiopsy, with 186 (42.0%) testing positive for the T790M mutation by the sixth rebiopsy. The final analysis included 143 eligible patients. Progression-free survival was not significantly different in terms of the methods (tissue: 13.3 months, 95% confidence interval [CI]: [9.4, 23.5] vs plasma: 11.1 months, 95% CI: [8.1, 19.4], p = 0.33) and numbers (one: 13.4 months, 95% CI: [9.4, 23.5] vs two or more: 11.0 months, 95% CI: [8.1, 14.8], p = 0.51) of repeated rebiopsies. Longer overall survival (OS) was found in patients in whom T790M was detected by tissue specimens rather than by plasma ctDNA (2-year OS rate: 81.7% for tissue vs 63.9% for plasma, p = 0.0038). Factors related to the lower numbers of rebiopsies included age and bone metastasis. Factor associated with T790M detection in tissue rather than in plasma was pleural metastasis, while advanced tumor stage was related to T790M confirmation in plasma rather than in tissue. Repeated rebiopsy for T790M detection in patients with NSCLC can increase the detection rate of the mutation. Detection of T790M by plasma ctDNA might be related to poor survival outcomes.

CtDNA Dynamics and Mechanisms of Acquired Resistance in Patients Treated with Osimertinib with or without Bevacizumab from the Randomized Phase II ETOP-BOOSTER Trial.

The ETOP 10-16 BOOSTER study was a randomized phase II trial of osimertinib and bevacizumab therapy versus osimertinib therapy in patients with an acquired EGFR T790M mutation. The mechanisms of acquired resistance to osimertinib and bevacizumab have not been described previously. Next-generation sequencing (Guardant360) was conducted in serial plasma samples. The association between ctDNA and efficacy outcomes was explored, and molecular alterations at progression were described. A total of 136 patients (88% of 155 randomized) had plasma samples at baseline (68 per arm), 110 (71%) at week 9, and 65 (42%) at progression. In a multivariable model for progression-free survival (PFS), the treatment effect was found to differ by smoking status (interaction P = 0.046), with the effect of smoking also differing by baseline EGFR T790M (interaction P = 0.033), whereas both TP53 at baseline and the tissue EGFR exon 21 L858R mutation were significantly associated with worse PFS outcome. Smokers (current/former) without baseline EGFR T790M showed a significant improvement in PFS under combination treatment, albeit with small numbers (P = 0.015). Week-9 EGFR T790M clearance was associated with improved PFS in the osimertinib arm (P = 0.0097). Acquired EGFR C797S mutations were detected in 22% and 13% of patients in the combination and osimertinib arms, respectively. The differential effect of treatment by smoking was not explained by TP53 mutations or other molecular alterations examined. Molecular mechanisms of acquired resistance were detected, but no novel molecular alterations were identified in the combination arm.

Investigating EGFR, BRAF, and RAS Mutations in Oral and Cutaneous Squamous Cell Neoplasms: A Preliminary Report on Romanian Patients

Background: Head and neck cancers, and particularly, oral cancers have a complex pathogenesis that includes genetic mutations and epigenetic alterations which interfere with cellular signaling and can trigger tumor development. The purpose of this study was to reveal whether low-frequency hotspot mutations may be detected in a study lot with histopathological evidence of squamous cell carcinoma (SCC) of the oral mucosa and skin of the head and neck. Methods: Tumor biopsies from treatment naïve patients were tested for BRAF V600, NRAS G12/G13, NRAS Q61, KRAS Q61 mutations, and EGFR exon 19 deletions (Ex19Del) using droplet digital PCR (ddPCR). The tumors were also analyzed for EGFR T790M mutations by RT-PCR, using a CE-IVD validated kit, with a limit of detection of 0.05%. Results: None of the examined cases exhibited NRAS G12/G13, NRAS Q61, KRAS Q61, BRAF V600, or EGFR T790M mutations, indicating that these alterations are rare events in SCC pathogenesis. Interestingly, among the 12 specimens tested by ddPCR for EGFR Ex19Del, an HPV-negative cSCC tumor occurring in the parotid region tested positive for this drug-sensitizing mutation, offering unexplored therapeutic perspectives to the patient from whom it was collected. Conclusions: Our study highlights the important clinical implications of detecting low-frequency hotspot mutations in tumor biopsies by ddPCR. We believe that the ddPCR-assisted analysis of these mutations in larger SCC cohorts may provide us with mechanistic insights regarding their role in SCC pathogenesis and guide the development of novel therapeutic strategies for this problematic disease.

Clinical utility of repeated rebiopsy for EGFR T790M mutation detection in non-small cell lung cancer.

In cases where rebiopsy fails to find the epidermal growth factor receptor (EGFR) T790M mutation, the criteria for selecting patients for repeated rebiopsy remains unclear. This study aimed to assess the impact of repeated rebiopsy on T790M mutation detection in non-small cell lung cancer (NSCLC) patients. Patients with advanced EGFR-mutated NSCLC between January 2018 and December 2021 at three-referral hospitals in South Korea underwent retrospective review. Of 682 patients who had rebiopsy after disease progression, T790M mutation status was assessed in plasma circulating tumor DNA (ctDNA) and/or tumor tissues. The overall T790M positivity rate increased from 40.8% after the first rebiopsy to 52.9% following multiple rebiopsies in the entire study population. Longer duration of initial EGFR TKI use (OR 1.792, ≥8 months vs. <8 months, p=0.004), better EGFR TKI responses (OR 1.611, complete or partial response vs. stable disease, p=0.006), presence of bone metastasis (OR 2.286, p<0.001) were correlated with higher T790M positivity. Longer EGFR TKI use and better responses increased T790M positivity in repeated tissue rebiopsy, while bone metastasis favored liquid rebiopsy. Additionally, T790M status has been shown to be positive over time through repeated rebiopsies ranging from several months to years, suggesting its dynamic nature. In this study, among patients who initially tested negative for T790M in rebiopsy, repeated rebiopsies uncovered an additional 23.5% T790M positivity. Particularly, it is suggested that repeated rebiopsies may be valuable for patients with prolonged EGFR TKI usage, better responses to treatment, and bone metastasis.

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.

Downregulation of Rad51 Expression and Activity Potentiates the Cytotoxic Effect of Osimertinib in Human Non-Small Cell Lung Cancer Cells.

Osimertinib (AZD9291) is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has shown significant clinical benefits in patients with EGFR-sensitizing mutations or the EGFR T790M mutation. The homologous recombination (HR) pathway is crucial for repairing DNA double-strand breaks (DSBs). Rad51 plays a central role in HR, facilitating the search for homology and promoting DNA strand exchange between homologous DNA molecules. Rad51 is overexpressed in numerous types of cancer cells. B02, a specific small molecule inhibitor of Rad51, inhibits the DNA strand exchange activity of Rad51. Previous studies have indicated that B02 disrupted Rad51 foci formation in response to DNA damage and inhibited DSBs repair in human cells and sensitized them to chemotherapeutic drugs in vitro and in vivo. However, the potential therapeutic effects of combining osimertinib with a Rad51 inhibitor are not well understood. The aim of this study was to elucidate whether the downregulation of Rad51 expression and activity can enhance the osimertinib-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells. We used the MTS, trypan blue dye exclusion and colony-formation ability assay to determine whether osimertinib alone or in combination with B02 had cytotoxic effects on NSCLC cell lines. Real-time polymerase chain reaction was conducted to measure the amounts of Rad51 mRNA. The protein levels of phosphorylated AKT and Rad51 were determined by Western blot analysis. We found that osimertinib reduced Rad51 expression by inactivating AKT activity. Rad51 knockdown using small interfering RNA or AKT inactivation through the phosphatidylinositol 3-kinase inhibitor LY294002 or si-AKT RNA transfection enhanced the cytotoxic and growth inhibitory effects of osimertinib. In contrast, AKT-CA (a constitutively active form of AKT) vector-enforced expression could mitigate the cytotoxic and cell growth inhibitory effects of osimertinib. Furthermore, B02 significantly enhanced the cytotoxic and cell growth inhibitory effects of osimertinib in NSCLC cells. Compared to parental cells, the activation of AKT and Rad51 expression in osimertinib-resistant cells could not be significantly inhibited by osimertinib treatment. Moreover, the increased expression of Rad51 is associated with the resistance mechanism in osimertinib-resistant H1975 and A549 cells. Collectively, the downregulation of Rad51 expression and activity enhances the cytotoxic effect of osimertinib in human NSCLC cells.

Design, Synthesis and Cytotoxic Studies of Novel 4-anilinoquinazoline Derivatives of Potential Agents for Non-small-cell Lung Cancer

Background: The pre-existing EGFR (Epidermal Growth Factor Receptors) inhibitors (Gefitinib, Afatinib and osimertinib) show significant resistance after one year of EGFR therapy in NSCLC (Non-small cell lung cancer) patients. With the aim of overcoming the resistance problem associated with a current therapeutic regimen, there is an imperative need for the development of novel 4- anilinoquinazoline derivatives that are specifically designed for resistance cases of NSCLC patients. Objective: We designed and synthesized eighteen 4-anilinoquinazolines derivatives as a novel scaffold and evaluated their anti-cancer potential against different NSCLC cell lines. Methods: Molecular docking study of designed compounds were performed on Glide v5.8 (Schrodinger, LLC, New York, NY). Synthesis of 4-anilinoquinazoline derivatives were performed, based on the docking score and was characterized by various spectroscopic methods. Further, in vitro anti-cancer activity was performed using MTT assay on different cancer cell lines. Results: Molecular docking analysis [EGFRT790M mutant (4I22)] indicated that most of these analogs (6g, 6j, 6l, 6m and 6o) were found to be higher docking scores than gefitinib. Furthermore, spectral analysis revealed that the designed compounds were synthesized successfully. The compounds 6a, 6d, 6g, 6i, 6j and 6m were identified as the potent inhibitors against (A431, H1975, A549) cell lines as compared to reference standard gefitinib. Excitingly, compound 6j (with IC50 values of 4.88 ± 0.13, 4.38 ± 0.08 &amp; 11.97 ± 0.14 μM) was identified as the most potent inhibitor for (A431, H1975, A549) cell lines. Conclusion: The study suggested that the six derivatives showed significant therapeutic potential against different NSCLC cell lines as compared to reference standard gefitinib.

Dacomitinib overcomes acquired resistance to osimertinib in advanced NSCLC patients with EGFR L718Q mutation: A two-case report.

Acquired resistance still inevitably occurs in patients treated with third-generation TKI osimertinib. Although the EGFR L718Q mutation has been reported as a scarce mechanism of osimertinib resistance, advanced therapeutic strategies are still in development. In this report, we included 2 cases of patients who acquired EGFR L858R/L718Q mutation after osimertinib and were overcome by dacomitinib. Case 1: A 77-year-old woman was diagnosed with stage IV lung adenocarcinoma. Case 2: A 64-year-old woman was diagnosed with stage IV lung adenocarcinoma. Case 1: The patient was diagnosed with adenocarcinoma with EGFR L858R mutation. Since then, treatment with gefitinib was administrated, leading to a progression-free survival of 18 months. The treatment was switched to osimertinib based on the detection of EGFR T790M mutation, resulting in a progression-free survival of 24 months. Subsequently, EGFR L718Q mutation was detected. Case 2: The patient was diagnosed with adenocarcinoma with EGFR L858R mutation. Icotinib was used as the first-line treatment for 7 months. Osimertinib was applied as the second-line treatment for 13 months based on the EGFR T790M mutation. Subsequently, EGFR L718Q mutation was detected. Case 1: Dacomitinib was administered. Case 2: Dacomitinib was administered. Case 1:The progression-free survival was 8 months. Case 2: The progression-free survival was 3 months. Dacomitinib is a potential treatment option for NSCLC patients with EGFR L718Q mutation after resistance to Osimertinib. Further research is needed to validate the efficacy of Dacomitinib in this context.

Antitumor activity of afatinib in EGFR T790M-negative human oral cancer therapeutically targets mTOR/Mcl-1 signaling axis.

This study investigates the role and effectiveness of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in oral cancer, focusing on the clinical relevance of EGFR and myeloid cell leukemia-1 (Mcl-1) in head and neck cancers (HNCs). It aims to explore the molecular mechanism of afatinib, a TKI, in treating human oral cancer. We conducted an in silico analysis using databases like The Cancer Genome Atlas, Gene Expression Omnibus, and Clinical Proteomic Tumor Analysis Consortium, along with immunohistochemistry staining, to study EGFR and Mcl-1 expression in HNCs. For investigating afatinib's anticancer properties, we performed various in vitro and in vivo analyses, including trypan blue exclusion assay, Western blotting, 4'-6-diamidino-2-phenylindole staining, flow cytometry, quantitative real-time PCR, Mitochondrial membrane potential assay, overexpression vector construction, transient transfection, and a tumor xenograft model. Higher expression levels of EGFR and Mcl-1 were observed in HNC patient tissues compared to normal tissues, with their co-expression significantly linked to poor prognosis. There was a strong correlation between EGFR and Mcl-1 expressions in oral cancer patients. Afatinib treatment induced apoptosis and suppressed Mcl-1 in oral cancer cell lines without the EGFR T790M mutation. The mechanism of afatinib-induced apoptosis involved the EGFR/mTOR/Mcl-1 axis, as shown by the effects of mTOR activator MHY1485 and inhibitor rapamycin. Afatinib also increased Bim expression, mitochondrial membrane permeabilization, and cytochrome c release. It significantly lowered tumor volume without affecting body, liver, and kidney weights. Afatinib, targeting the EGFR/mTOR/Mcl-1 axis, shows promise as a therapeutic strategy for oral cancer, especially in patients with high EGFR and Mcl-1 expressions.

Lazertinib versus Platinum-Based Chemotherapy with Epidermal Growth Factor Receptor (EGFR)-Positive Non-Small-Cell Lung Cancer after Failing EGFR-Tyrosine Kinase Inhibitor: A Real-World External Comparator Study.

Lazertinib is a third-generation tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR-TKI) that selectively inhibit common EGFR mutation and T790M mutation in non-small-cell lung cancer (NSCLC) patients. No previous studies have compared lazertinib to platinum-based chemotherapy. We have compared lazertinib with platinum-based chemotherapy in EGFR-mutated NSCLC patients after previous EGFR-TKI therapy. We retrospectively compared 200 patients from LASER201, LASER301, and LASER-PMS studies to 334 patients who were treated with platinum-based chemotherapy after previous EGFR-TKI from the Samsung Medical Center. After propensity score matching (PSM), we selected 156 patients from each group. The primary outcome was progression-free survival (PFS), with overall survival (OS), objective response rate (ORR), and time to treatment discontinuation (TTD) as secondary outcomes. The median follow-up of PFS was 15.61 months in the lazertinib group and 21.67 months in the external control group. The PFS was significantly longer in patients who were treated with lazertinib than those treated with platinum-based chemotherapy (10.97 months vs. 5.10 months; adjusted hazard ratio (HR) 0.40; 95% confidence interval (CI), 0.29-0.55; p < 0.01) after PSM. Lazertinib showed superior OS (32.23 months vs. 18.73 months; adjusted HR 0.45; 95% CI, 0.29-0.69; p < 0.001), ORR (64.1% vs. 47.4%), and TTD (11.66 months vs. 6.73 months; adjusted HR 0.54; 95% CI, 0.39-0.75; p < 0.001) compared to platinum-based chemotherapy. Based on this retrospective, external control study, lazertinib has demonstrated significantly better efficacy compared with platinum-based chemotherapy. The external controls provide important context to evaluate efficacy in single-arm studies.

Mutational Characteristics and Clinical Outcomes for Lung Adenocarcinoma With EGFR Germline Mutations

IntroductionGermline mutations driving lung cancer have been infrequently reported in the literature, with EGFR T790M being a known germline mutation identified in 1% of NSCLCs. Typically, a somatic EGFR mutation is acquired to develop lung adenocarcinoma. Osimertinib has become a standard-of-care treatment for EGFR T790M-positive lung cancer. MethodsWe perform a retrospective analysis through the Lung Cancer Moon Shot GEMINI database at the University of Texas MD Anderson Cancer Center. Of the patients that underwent cell-free DNA analysis, germline mutations were identified by those with high variant allelic fraction approximating 50%, followed by further confirmation on genetic testing. ResultsWe identified 22 patients with germline EGFR mutations, with the majority harboring an EGFR T790M mutation (95.5%) and an EGFR L858R somatic mutation (50%). Notably, most patients were female (86.4%), non-smokers (81.8%), white (86.4%), had a family history of lung cancer (59.1%), and stage IV at diagnosis (72.7%). A distinct radiographic pattern of small multifocal ground-glass pulmonary nodules was observed in the majority of our cohort (72.7%).Among the 18 with advanced-stage NSCLC, 12 patients (66.7%) were treated with first-line osimertinib, demonstrating a median progression-free survival (PFS) of 16.9 months (95% confidence interval [CI]: 6.3–not reached [NR]). Others were treated with first-line afatinib (11.1%) or chemotherapy (22.2%). Among the 17 patients treated with osimertinib (in first or second-line), median PFS was 20.4 months (95% CI: 6.3–NR) and median overall survival was 82.0 months (95% CI: 28.4–NR). ConclusionsBased on our institutional cohort, NSCLC driven by EGFR germline mutations occurs more frequently in non-smoking, white females with multi-focal pulmonary nodules radiographically. Osimertinib for advanced germline EGFR-mutated NSCLC renders similar PFS compared to somatic T790M EGFR-mutated NSCLC.

Real-world study of lazertinib as second-line or greater treatment in advanced non-small cell lung cancer.

Lazertinib is an oral, third-generation EGFR-TKI, which specifically targets the EGFR T790M mutation along with activating mutations Ex19del and L858R. More real-world data are needed to evaluate its efficacy and safety in treating locally advanced and metastatic non-small cell lung cancer (NSCLC) following prior EGFR TKI treatment. This multicenter retrospective study was conducted at seven university hospitals affiliated to the Catholic Medical Center (CMC) in Korea. A clinical data warehouse (CDW) platform was used to access and extract information. A total of 48 patients were assessed. The majority were female (75%) and diagnosed with adenocarcinoma (95.8%). All patients had the EGFR mutation at diagnosis, 27 (56.3%) had the exon 19 deletion, 20 (41.7%) had the L858R mutation, and one (2.0%) had the exon 18 mutation. The median progression-free survival (PFS) was 15.4 months. At 6, 12, and 18 months, PFS rates were 79.1%, 53.6%, and 27.3%, respectively. When PFS was analyzed by prior TKI duration (<18 months vs. >18 months), significant differences were noted at the 6 and 9-month mark (p = 0.013 and p = 0.010, respectively). In multivariate analysis for PFS, only prior TKI duration and ECOG score showed statistical significance (p = 0.026 and p = 0.049, respectively). In the multivariate analysis for OS, ECOG score showed statistical significance (p = 0.006). Among 48 patients, 34 (70.8%) experienced adverse events (AEs) related to lazertinib. The most frequent AEs were skin reaction (29.8%), diarrhea (21.3%), and peripheral neuropathy (20.8%). The results suggest that lazertinib is effective in second or more line settings, with tolerable safety profile. More patient data are necessary to find possible prognostic markers associated with patient outcome.

The clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in patients with lung adenocarcinoma

BackgroundThe treatment of non-small cell lung cancer (NSCLC) patients can be complicated by the presence of the EGFR-T790M mutation. Although primary or secondary EGFR-T790M mutations have been extensively studied worldwide, there are few reports on the clinicopathological characteristics and physiological mechanisms of lung adenocarcinoma (LUAD) with only the EGFR-T790M primary mutation. MethodsThe clinical data of all LUAD patients with only the EGFR-T790M primary mutation were collected. Immunohistochemical staining was performed on cell cycle-related proteins, targeted therapy indicators, and prognosis-related proteins in the specimens obtained from puncture biopsies or surgeries. ObjectivesThe aim of this study is to analyze the clinicopathological features and possible physiological mechanisms of only the EGFR-T790M primary mutation in LUAD, and to offer recommendations for clinical management. ResultsTwo patients who have only the T790M de novo mutation were both female (2/12,928, 0.02%). β-catenin and Cyclin D1 were both highly expressed. In case 1, IHC results showed a positive Ki67 and mutant P53 and there was a significant increase in serum CYFRA 21–1. Third-generation of EGFR TKIs resulted in a partial response (PR) time of less than 8 months in case 1. In case 2, the patient underwent surgical resection and adjuvant chemotherapy, resulting in a progression-free survival (PFS) time of 25 months. ConclusionThe results suggest that abnormal activation of the Wnt signaling pathway may be specifically associated with the EGFR-T790M primary mutation in LUAD. Furthermore, it has been observed that patients with significant Ki67, mutant P53, and CYFRA 21–1 expression tend to have a poor prognosis.

Repeat biopsy versus initial biopsy in terms of complication risk factors and clinical outcomes for patients with non-small cell lung cancer: a comparative study of 113 CT-guided needle biopsy of lung lesions.

The safety and feasibility of repeat biopsy after systemic treatment for non-small cell lung cancer have received extensive attention in recent years. The purpose of this research was to compare complication rates between initial biopsy and rebiopsy in non-small cell lung cancer patients with progressive disease and to assess complication risk factors and clinical results after rebiopsy. The study included 113 patients initially diagnosed with non-small cell lung cancer who underwent lung biopsy at initial biopsy and rebiopsy after progression while on epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and/or chemotherapy from January 2018 to December 2021. We compared the incidence of complications between the initial biopsy and rebiopsy and analyzed the predictors factors that influenced complications in patients who underwent rebiopsy. The successful rate of rebiopsy was 88.5% (100/113). With the exception of two cases where lung adenocarcinoma changed into small cell lung cancer with gefitinib treatment, 98 individuals retained their initial pathological type. The secondary EGFR T790M mutation accounts for 55.6% of acquired resistance. The total number of patients with complications in initial biopsy was 25 (22.1%) and 37 (32.7%) in the rebiopsy. The incidence of pulmonary hemorrhage increased from 7.1% at the initial biopsy to 10.6% at rebiopsy, while the incidence of pneumothorax increased from 14.2% to 20.4%. Compared with the initial biopsy, the incidence of overall complications, parenchymal hemorrhage, and pneumothorax increased by 10.6%, 3.5%, and 6.2%, respectively. In all four evaluations (pneumorrhagia, pneumothorax, pleural reaction, and overall complication), there were no significant differences between the rebiopsy and initial biopsy (all p > 0.05). The multivariate logistic regression analysis suggested that male sex (odds ratio [OR] = 5.064, p = 0.001), tumor size ≤ 2cm (OR = 3.367, p = 0.013), EGFR-TKIs with chemotherapy (OR = 3.633, p =0.023), and transfissural approach (OR = 7.583, p = 0.026) were independent risk factors for overall complication after rebiopsy. Compared with the initial biopsy, the complication rates displayed a slight, but not significant, elevation in rebiopsy. Male sex, tumor size ≤ 2cm, transfissural approach, and EGFR-TKIs combined with chemotherapy were independent risk factors for rebiopsy complications.

T790M mutation sensitizes non-small cell lung cancer cells to radiation via suppressing SPOCK1

BackgroundApproximately 50% of patients harbor the T790M mutation after developing first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance. Evidence has showed the major treatment failure is local relapses and limited metastases. Several studies have demonstrated the value of radiotherapy in metastatic non-small cell lung cancer (NSCLC) with the EGFR T790M mutation after the development of TKI resistance. The aim of this study was to explore the role of radiation in T790M-mutant NSCLC and the value of early radiotherapy for NSCLC with T790M-mediated EGFR-TKI resistance. MethodsGefitinib-resistant NSCLC cell lines were established via stepwise exposure to increasing concentrations of gefitinib (PC-9-GR). Droplet digital PCR was used to determine the relative T790M subclone abundance. In vitro and in vivo models were established using different mixtures of PC-9-GR and PC-9 cells. Differentially expressed genes were identified using RNA sequencing. Two research models were constructed (salvage and prophylactic radiotherapy) to determine the effects of early radiotherapy on gefitinib-resistant cells. ResultsPC-9-GR cells exhibited higher radiosensitivity than PC-9 cells (sensitivity enhancement ratio = 1.5). Salvage radiation reduced the number of T790M-mutant subclones, and the relative T790M abundance was significantly lower than that without radiation at 90 days (10.94% vs. 21.54%). Prophylactic radiation prevented the development of T790M subclones. These results were also confirmed in vivo. qRT-PCR revealed threefold elevation of miR-1243 in PC-9-GR cells, and the increased radiosensitivity of PC-9-GR cells was inhibited when miR-1243 was knocked down. RNA sequencing revealed that SPOCK1 was downregulated in PC-9-GR cells. Interestingly, bioinformatic analysis showed that SPOCK1 was a target gene of miR-1243. SPOCK1 knockdown markedly increased the radiosensitivity of PC-9 cells. ConclusionGefitinib-resistant NSCLC with the T790M mutation had higher radiosensitivity than that without the mutation, possibly mediated by SPOCK1. Early radiotherapy can eliminate T790M subclones, providing evidence for the benefit of early local treatment in patients with TKI-resistant NSCLC.

Targeting pyruvate dehydrogenase kinase 1 overcomes EGFR C797S mutation-driven osimertinib resistance in non-small cell lung cancer

Osimertinib, a selective third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), effectively targets the EGFR T790M mutant in non-small cell lung cancer (NSCLC). However, the newly identified EGFR C797S mutation confers resistance to osimertinib. In this study, we explored the role of pyruvate dehydrogenase kinase 1 (PDK1) in osimertinib resistance. Patients exhibiting osimertinib resistance initially displayed elevated PDK1 expression. Osimertinib-resistant cell lines with the EGFR C797S mutation were established using A549, NCI-H292, PC-9, and NCI-H1975 NSCLC cells for both in vitro and in vivo investigations. These EGFR C797S mutant cells exhibited heightened phosphorylation of EGFR, leading to the activation of downstream oncogenic pathways. The EGFR C797S mutation appeared to increase PDK1-driven glycolysis through the EGFR/AKT/HIF-1α axis. Combining osimertinib with the PDK1 inhibitor leelamine helped successfully overcome osimertinib resistance in allograft models. CRISPR-mediated PDK1 knockout effectively inhibited tumor formation in xenograft models. Our study established a clear link between the EGFR C797S mutation and elevated PDK1 expression, opening new avenues for the discovery of targeted therapies and improving our understanding of the roles of EGFR mutations in cancer progression.

Design, synthesis, and evaluation of antitumor activity of Mobocertinib derivatives, a third-generation EGFR inhibitor

Mobocertinib, as a structural analog of the third generation TKI Osimertinib, can selectively act on the EGFRex20 mutation. We have structurally modified Mobocertinib to obtain new EGFR inhibitors. In this paper, we chose Mobocertinib as a lead compound for structural modification to investigate the effect of Mobocertinib derivatives on EGFRT790M mutation. We designed and synthesized 63 Mobocertinib derivatives by structural modification using the structural similarity strategy and the bioelectronic isoarrangement principle. Then, we evaluated the in vitro antitumor activity of the 63 Mobocertinib derivatives and found that the IC50 of compound H-13 against EGFRL858R/T790M mutated H1975 cells was 3.91 μM, and in further kinase activity evaluation, the IC50 of H-13 against EGFRL858R/T790M kinase was 395.2 nM. In addition, the preferred compound H-13 was able to promote apoptosis of H1975 tumor cells and block the proliferation of H1975 cells in the G0/G1 phase; meanwhile, it was able to significantly inhibit the migratory ability of H1975 tumor cells and inhibit the growth of H1975 cells in a time-concentration-dependent manner. In the in vivo anti-tumor activity study, the preferred compound H-13 had no obvious toxicity to normal mice, and the tumor inhibition effect on H1975 cell-loaded nude mice was close to that of Mobocertinib. Finally, molecular dynamics simulations showed that the binding energy between compound H-13 and 3IKA protein was calculated to be −162.417 ± 14.559 kJ/mol. In summary, the preferred compound H-13 can be a potential third-generation EGFR inhibitor.