BACKGROUND: EGFR tyrosine kinase inhibitors (TKIs) are the standard therapy for non-small-cell lung cancer (NSCLC) patients with EGFR-activating mutations in the first-line setting. Despite initial efficacy, resistance to EGFR-TKIs often develops, and platinum-based chemotherapy is the predominant subsequent treatment. For this study, we aimed to identify prognostic factors for overall survival (OS) and progression-free survival (PFS) among advanced EGFR-mutant NSCLC patients receiving platinum-pemetrexed after progression on EGFR-TKIs. Our analysis specifically focuses on 1st-line treatments limited to 1st- or 2nd-generation EGFR-TKIs, while not restricting later-line treatments involving osimertinib prior to chemotherapy.
METHODS: From 2012 to 2017, 363 patients who received first-line treatment with first- or second-generation EGFR-TKIs, including gefitinib, erlotinib, and afatinib were enrolled. Some patients received different EGFR-TKIs, including osimertinib, as later-line treatment before platinum-pemetrexed.
RESULTS: Median OS from the initiation of platinum-pemetrexed was 22.0 months and median PFS with platinum-pemetrexed was 6.2 months. In the multivariate Cox model, we identified three independent prognostic factors for better OS: postoperative recurrence (HR: 0.34, p = 0.004), first-line EGFR-TKI PFS ≥12 months (HR: 0.54, p = 0.002), and osimertinib treatment after platinum-pemetrexed (HR: 0.56, p = 0.005) while BMI <18.5 indicated poor prognosis (HR:1.76, p = 0.049). No statistically significant independent prognostic factors for PFS were found. Receiving osimertinib before platinum-pemetrexed treatment did not impact PFS with platinum-pemetrexed treatment (HR: 1.11, p = 0.64).
CONCLUSIONS: Postoperative recurrence, first-line EGFR-TKI PFS ≥12 months and osimertinib treatment after platinum-pemetrexed predicted better OS, while BMI <18.5 predicted worse OS. Osimertinib treatment before platinum-pemetrexed treatment did not affect the efficacy of platinum-pemetrexed.

Protein-based therapeutics, including antibodies and antibody-like-proteins, have increasingly attracted attention due to their high specificity compared to small-molecular drugs. The Gγ recruitment system, one of the in vivo yeast two-hybrid systems for detecting protein-protein interactions, has been previously developed using yeast signal transduction machinery. In this study, we modified the Gγ recruitment system to screen the protein mutants that efficiently bind to the intracellular domain of the epidermal growth factor receptor L858R mutant (cytoEGFRL858R). Using the modified platform, we performed in vivo directed evolution for growth factor receptor-bound protein 2 (Grb2) and its truncated variant containing only the Src-homology 2 (SH2) domain, successfully identifying several mutants that more strongly bound to cytoEGFRL858R than their parental proteins. Some of them contained novel beneficial mutations (F108Y and Q144H) and specifically bound to the recombinant cytosolic phosphorylated EGFR in vitro, highlighting the utility of the evolutionary platform.

BACKGROUND: Several patients treated with osimertinib experience progressive disease. The aim was to clarify the mechanisms underlying resistance to osimertinib.
METHODS: ELUCIDATOR: A multi-centre, prospective, observational study involved chemotherapy-naive patients with advanced non-small cell lung cancer receiving osimertinib. Mutations in cancer-associated genes, detected via ultrasensitive next-generation sequencing of circulating tumour deoxyribonucleic acid samples, were collected at baseline and after progressive disease detection. These paired plasma samples were compared.
RESULTS: Of 188 patients enrolled (May 2019-January 2021), 178 (119 females [67 %]) median age 74 years, were included. Patients, n = 95 (53 %) had epidermal growth factor receptor exon 19 deletion mutations. Among 115 patients with progressive disease, circulating tumour deoxyribonucleic acid levels of 85 patients were analysed. MET amplification (n = 4), TP53 mutations (n = 4), PIK3CA mutations (n = 3), BRINP3 mutation (n = 2), BRAF mutation (n = 2), APC mutation (n = 1), RET mutation (n = 1) and epidermal growth factor receptor (EGFR) resistance mutation, and C797S (n = 1) were detected. Patients with baseline TP53 mutations, with MET or EGFR amplification had shorter progression-free (PFS) and overall survival. Patients with PIK3CA mutations tended to shorter PFS.
CONCLUSIONS: MET amplification and PIK3CA mutation mechanisms underly resistance to osimertinib in patients. Patients with coexisting mutations or amplifications at baseline had shorter PFS and overall survival.

Patients with EGFR-mutated non-small cell lung cancer (NSCLC) respond poorly to immune checkpoint inhibitors (ICIs). It has been reported that the number of CD8+T cells is reduced in EGFR-mutated NSCLC. However, the extent of heterogeneity and effector function of distinct populations of CD8+T cells has not been investigated intensively. In addition, studies investigating whether a combination of radiotherapy and ICIs can improve the efficacy of ICIs in EGFR-mutated lung cancer are lacking. Single-cell RNA sequencing (scRNA-seq) was used to investigate the heterogeneity of CD8+T cell populations in EGFR-mutated NSCLC. The STING pathway was explored after hypofractionated radiation of EGFR-mutated and wild-type cells. Mice bearing LLC-19del and LLC-EGFR tumors were treated with radiotherapy plus anti-PD-L1. The scRNA-seq data showed the percentage of progenitor exhausted CD8+T cells was lower in EGFR-mutated NSCLC. In addition, CD8+T cells in EGFR-mutated NSCLC were enriched in oxidative phosphorylation. In EGFR-mutated and wild-type cells, 8 Gy × 3 increased the expression of chemokines that recruit T cells and activate the cGAS-STING pathway. In the LLC-19del and LLC-EGFR mouse model, the combination of radiation and anti-PD-L1 significantly inhibited the growth of abscopal tumors. The enhanced abscopal effect was associated with systemic CD8+T cell infiltration. This study provided an intensive understanding of the heterogeneity and effector functions of CD8+T cells in EGFR-mutated NSCLC. We showed that the combination of hypofractionated radiation and anti-PD-L1 significantly enhanced the abscopal responses in both EGFR-mutated and wild-type lung cancer by activating CD8+T cells in mice.

OBJECTIVE: To evaluate the value of computed tomography (CT)-based radiomics combined with clinical-genetic features in predicting brain metastasis in patients with stage III/IV epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC).
METHODS: The study included 147 eligible patients treated at our institution between January 2018 and May 2021. Patients were randomly divided into two cohorts for model training (n = 102) and validation (n = 45). Radiomics features were extracted from the chest CT images before treatment, and a radiomics signature was constructed using the Least Absolute Shrinkage and Selection Operator regression. Kaplan-Meier survival analysis was used to describe the differences in brain metastasis-free survival (BM-FS) risk. A clinical-genetic model was developed using Cox regression analysis. Radiomics, genetic, and combined prediction models were constructed, and their predictive performances were evaluated by the concordance index (C-index).
RESULTS: Patients with a low radiomics score had significantly longer BM-FS than those with a high radiomics score in both the training (p < 0.0001) and the validation (p = 0.0016) cohorts. The C-indices of the nomogram, which combined the radiomics signature and N stage, overall stage, third-generation tyrosine kinase inhibitor treatment, and EGFR mutation status, were 0.886 (95% confidence interval [CI] 0.823-0.949) and 0.811 (95% CI 0.719-0.903) in the training and validation cohorts, respectively. The combined model achieved a higher discrimination and clinical utility than the single prediction models.
CONCLUSIONS: The combined radiomics-genetic model could be used to predict BM-FS in stage III/IV NSCLC patients with EGFR mutations.

Plexiform neurofibromas (PNFs) are a prevalent and severe phenotype associated with NF1, characterized by a high teratogenic rate and potential for malignant transformation. The growth and recurrence of PNFs are attributed to aberrant proliferation and migration of Nf1-deficient Schwann cells. Protein tyrosine phosphatase receptor S (PTPRS) is believed to modulate cell migration and invasion by inhibiting the EMT process in NF1-derived malignant peripheral nerve sheath tumors. Nevertheless, the specific role of PTPRS in NF1-derived PNFs remains to be elucidated. The study utilized the GEO database and tissue microarray to illustrate a decrease in PTPRS expression in PNF tissues, linked to tumor recurrence. Furthermore, the down- and over-expression of PTPRS in Nf1-deficient Schwann cell lines resulted in the changes of cell migration and EMT processes. Additionally, RTK assay and WB showed that PTPRS knockdown can promote EGFR expression and phosphorylation. The restoration of EMT processes disrupted by alterations in PTPRS levels in Schwann cells can be achieved through EGFR knockdown and EGFR inhibitor. Moreover, high EGFR expression has been significantly correlated with poor prognosis. These findings underscore the potential role of PTPRS as a tumor suppressor in the recurrence of PNF via the regulation of EGFR-mediated EMT processes, suggesting potential targets for future clinical interventions.

Lung cancer is the leading cause of cancer-related deaths, in part due to its late diagnosis. Increased epidermal growth factor receptor (EGFR) expression in cancer cells is associated with a poor prognosis, and EGFR tyrosine kinase inhibitors are widely used in cancer treatment. This study aimed to clarify the relationship between EGFR expression on T cells and cancer prognosis in patients with non-small cell lung cancer (NSCLC). Forty patients with NSCLC and 40 healthy volunteers were included in this study. Peripheral CD4+T helper (Th1, Th2, Th9, Th17, Th1Th17, follicular and peripheral Th) and cytotoxic T lymphocyte (CD8+follicular and peripheral T) subsets were identified with flow cytometry according to their chemokine receptors. EGFR expression on T lymphocytes in relation to overall survival (OS) was investigated in patients with NSCLC. The patients [mean age (min-max) = 64.03 (45-83); 20 stage I-III and 20 stage IV] had increased EGFR expression on CD3+T, CD4+Th, Th1, Th2, and Th17 cells compared to the controls (p < 0.05). High EGFR expression on CD3+T, CD4+Th, Th1, and Th2 cells was associated with poor OS. Also, PD-1 expression on lymphocytes, CD3+T, and Th cells was increased in patients with NSCLC compared to controls. The high expression of EGFR and PD-1 on Th cells and the reduced percentage of lymphocytes and Th cells, especially in stage IV patients with NSCLC, revealed that increased EGFR activity may trigger apoptosis of Th cells and promote the development of metastases, while high EGFR expression on CD3+T, CD4+Th, Th1, and Th2 cells may be an independent poor prognostic marker in NSCLC.

BACKGROUND: Epidermal growth factor receptor (EGFR) mutation and c-ros oncogene 1 (ROS1) rearrangement are key genetic alterations and predictive tumor markers for non-small cell lung cancer (NSCLC) and are typically considered to be mutually exclusive. EGFR/ROS1 co-mutation is a rare event, and the standard treatment approach for such cases is still equivocal.
METHODS: Herein, we report the case of a 64-year-old woman diagnosed with lung adenocarcinoma, with concomitant EGFR L858R mutation and ROS1 rearrangement. The patient received two cycles of chemotherapy after surgery, but the disease progressed. Following 1-month treatment with gefitinib, the disease progressed again. However, after switching to crizotinib, the lesion became stable. Currently, crizotinib has been administered for over 53 months with a remarkable treatment effect.
CONCLUSIONS: The efficacy of EGFR tyrosine kinase inhibitors and crizotinib was vastly different in this NSCLC patient with EGFR/ROS1 co-mutation. This report will aid future treatment of such patients.

Epidermal growth factor receptor (EGFR) is a transmembrane tyrosine kinase that is frequently modified by glycosylation post-translationally. In cancer, EGFR amplifications and hotspot mutations such as L858R that promote proliferation have been detected in a significant fraction of non-small cell lung carcinomas and breast adenocarcinomas. Molecular dynamic simulations suggested that glycosylation at asparagine residue 361 (N361) promotes dimerization and ligand binding. We stably expressed glycosylation-deficient mutant EGFR N361A, with or without the oncogenic mutation L858R. Immunofluorescence and flow cytometry demonstrated that the mutants were each well expressed at the cell membrane. N361A decreased proliferation relative to wild-type EGFR as well as decreased sensitivity to ligands. Proximity ligation assays measuring co-localization of EGFR with its binding partner HER2 in cells revealed that N361A mutations increased co-localization. N361A, located near the binding interface for the EGFR inhibitor necitumumab, desensitized cells expressing the oncogenic EGFR L858R to antibody-based inhibition. These findings underline the critical relevance of post-translational modifications on oncogene function.

The emergence of targeted therapies in non-small-cell lung cancer (NSCLC), including inhibitors of epidermal growth factor receptor (EGFR) tyrosine kinase, has increased the need for robust companion diagnostic tests. Nowadays, detection of actionable variants in exons 18-21 of the EGFR gene by qPCR and direct DNA sequencing is often replaced by next-generation sequencing (NGS). In this study, we evaluated the diagnostic usefulness of targeted NGS for druggable EGFR variants testing in clinical NSCLC material previously analyzed by the IVD-certified qPCR test with respect to DNA reference material. We tested 59 NSCLC tissue and cytology specimens for EGFR variants using the NGS \'TruSight Tumor 15\' assay (Illumina) and the qPCR \'cobas EGFR mutation test v2\' (Roche Diagnostics). The sensitivity and specificity of targeted NGS assay were evaluated using the biosynthetic and biological DNA reference material with known allelic frequencies (VAF) of EGFR variants. NGS demonstrated a sufficient lower detection limit for diagnostic applications (VAF < 5%) in DNA reference material; all EGFR variants were correctly identified. NGS showed high repeatability of VAF assessment between runs (CV% from 0.02 to 3.98). In clinical material, the overall concordance between NGS and qPCR was 76.14% (Cohen\'s Kappa = 0.5933). The majority of discordant results concerned false-positive detection of EGFR exon 20 insertions by qPCR. A total of 9 out of 59 (15%) clinical samples showed discordant results for one or more EGFR variants in both assays. Additionally, we observed TP53 to be a frequently co-mutated gene in EGFR-positive NSCLC patients. In conclusion, targeted NGS showed a number of superior features over qPCR in EGFR variant detection (exact identification of variants, calculation of allelic frequency, high analytical sensitivity), which might enhance the basic diagnostic report.