An engineered DNA aptamer-based PROTAC for precise therapy of p53-R175H hotspot mutant-driven cancer.

Targeting oncogenic mutant p53 represents an attractive strategy for cancer treatment due to the high frequency of gain-of-function mutations and ectopic expression in various cancer types. Despite extensive efforts, the absence of a druggable active site for small molecules has rendered these mutants therapeutically non-actionable. Here we develop a selective and effective proteolysis-targeting chimera (PROTAC) for p53-R175H, a common hotspot mutant with dominant-negative and oncogenic activity. Using a novel iterative molecular docking-guided post-SELEX (systematic evolution of ligands by exponential enrichment) approach, we rationally engineer a high-performance DNA aptamer with improved affinity and specificity for p53-R175H. Leveraging this resulting aptamer as a binder for PROTACs, we successfully developed a selective p53-R175H degrader, named dp53m. dp53m induces the ubiquitin-proteasome-dependent degradation of p53-R175H while sparing wildtype p53. Importantly, dp53m demonstrates significant antitumor efficacy in p53-R175H-driven cancer cells both in vitro and in vivo, without toxicity. Moreover, dp53m significantly and synergistically improves the sensitivity of these cells to cisplatin, a commonly used chemotherapy drug. These findings provide evidence of the potential therapeutic value of dp53m in p53-R175H-driven cancers.

Ionizable Polymeric Micelles with Phenylalanine Moieties Enhance Intracellular Delivery of Self-Replicating RNA for Long-Lasting Protein Expression In Vivo.

mRNA-based therapeutics are revolutionizing the landscape of medical interventions. However, the short half-life of mRNA and transient protein expression often limits its therapeutic potential, demanding high treatment doses or repeated administrations. Self-replicating RNA (RepRNA)-based treatments could offer enhanced protein production and reduce the required dosage. Here, we developed polymeric micelles based on flexible poly(ethylene glycol)-poly(glycerol) (PEG-PG) block copolymers modified with phenylalanine (Phe) moieties via biodegradable ester bonds for the efficient delivery of RepRNA. These polymers successfully encapsulated RepRNA into sub-100 nm micelles assisted by the hydrophobicity of the Phe moieties and their ability to π-π stack with the bases in RepRNA. The micelles made from Phe-modified PEG-PG (PEG-PG(Phe)) effectively maintained the integrity of the loaded RepRNA in RNase-rich serum conditions. Once taken up by cells, the micelles triggered a pH-responsive membrane disruption, promoted by the strong protonation of the amino groups at endosomal pH, thereby delivering the RepRNA to the cytosol. The system induced strong protein expression in vitro and outperformed commercial transfecting reagents in vivo, where it resulted in enhanced and long-lasting protein expression.

Prolonged usage of fosaprepitant for prevention of delayed chemotherapy-induced nausea and vomiting(CINV) in patients receiving highly emetogenic chemotherapy.

BACKGROUND: Even though chemotherapy-induced nausea and vomiting (CINV) can be well controlled in the acute phase, the incidence of delayed CINV remains high. In this study, we intend to investigate whether prolonged use of NK-1 receptor antagonist (RA) in addition to 5-HT3 RA and dexamethasone (DEX) was more effective in preventing delayed CINV. METHODS: This randomised, open-label, controlled study was designed to compare the efficacy and safety of fosaprepitant 150 mg given on days 1,3 (prolonged group) versus on day 1 (regular group) in patients receiving highly emetogenic chemotherapy (HEC). All patients also treated with palonosetron on day 1 and DEX on days 1-3. The primary endpoint was the incidence of delayed nausea and vomiting. The second endpoint was AEs. All the above endpoints were defined according to CTCAE 5.0. RESULTS: Seventy-seven patients were randomly assigned to prolonged group and seventy-nine to regular group. Prolonged group demonstrated superiority in controlling delayed CINV to regular group, with statistically significant lower incidence of nausea (6.17% vs 12.66%, P = 0.0056), and slightly lower incidence of grade 1 vomiting (1.62% vs 3.80%, P = 0.0953) in the delayed phase. In addition, prolonged use of fosaprepitant was safe. No significant difference was found between the two groups regarding constipation, diarrhea, hiccough, fatigue, palpitation and headache in delayed phase. CONCLUSIONS: Prolonged use of fosaprepitant can effectively and safely prevent delayed CINV in patients receiving HEC.

EGFR p.V774M/p.L833V compound mutations in lung adenocarcinoma responded well to almonertinib: a case report.

Background: There are about 10-15% of uncommon EGFR mutations found in NSCLC patients, and their sensitivity to EGFR TKIs still lack sufficient clinical evidence, especially for rare compound mutations. Almonertinib is the third generation of EGFR-TKI that has demonstrated excellent efficacy in classical mutations, however, effects in rare mutations have also been rarely reported. Case presentation: In this case report, we present a patient with advanced lung adenocarcinoma with a rare EGFR p.V774M/p.L833V compound mutations, who achieved long-lasting and stable disease control after first-line Almonertinib targeted therapy. This case report could provide more information for therapeutic strategy selecting of NSCLC patients harboring rare EGFR mutations. Conclusion: We report for the first time the long-lasting and stable disease control with Almonertinib for EGFR p.V774M/p.L833V compound mutations treatment, hoping to provide more clinical case references for the treatment of rare compound mutations.

[Initial Treatment of Aumolertinib in Combination with Bevacizumab for Advanced NSCLC with Primary EGFR T790M Mutation: A Report of Three Cases and Literature Review].

With the development of sequencing technology, the detection rate of non-small cell lung cancer (NSCLC) with primary epidermal growth factor receptor (EGFR) T790M mutation is increasing. However, the first-line treatment for primary EGFR T790M-mutated NSCLC still lacks standard recommendations. Here, we reported three advanced NSCLC cases with EGFR-activating mutation and primary T790M mutation. The patients were initially treated with Aumolertinib combination with Bevacizumab; among which, one case was discontinued Bevacizumab due to bleeding risk after treatment for three months. Treatment was switched to Osimertinib after ten months of treatment. Another case switched to Osimertinib and discontinued Bevacizumab after thirteen months of treatment. The best effect response in all three cases was partial response (PR) after initial treatment. Two cases progressed after first-line treatment and progression-free survival (PFS) was eleven months and seven months respectively. The other one patient had persistent response after treatment, and the treatment duration has reached nineteen months. Two cases had multiple brain metastases before administration and the best response to intracranial lesions was PR. The intracranial PFS was fourteen months and not reached (16+ months), respectively. There were no new adverse events (AEs), and no AEs of grade three or above were reported. In addition, we summarized the research progress of Osimertinib in the treatment of NSCLC with primary EGFR T790M mutation. In conclusion, Aumolertinib combined with Bevacizumab in the treatment of advanced NSCLC with primary EGFR T790M mutation has a high objective response rate (ORR) and control ability of intracranial lesions, which can be used as one of the initial options for first-line advanced NSCLC with primary EGFR T790M mutation.
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DNASE1L3 regulation by transcription factor FOXP2 affects the proliferation, migration, invasion and tube formation of lung adenocarcinoma.

Lung adenocarcinoma (LUAD) is prone to bone metastasis, resulting in poor prognosis. The present study aimed to detect the expression of deoxyribonuclease 1-like 3 (DNASE1L3) and forkhead-box P2 (FOXP2) in LUAD cells to investigate the role of DNASE1L3 in the regulation of proliferation, migration, invasion and tube formation of LUAD cells and how FOXP2 affects DNASE1L3 expression. The expression of DNASE1L3 and FOXP2 in LUAD cells was analyzed by reverse transcription-quantitative PCR (RT-qPCR) and western blotting. The transfection efficiency of DNASE1L3 overexpression plasmids, FOXP2 overexpression or interference plasmids into A549 cells was also confirmed by RT-qPCR and western blotting. The viability, proliferation, migration and invasion and tube formation of LUAD cells following transfection was in turn detected by MTT, EdU staining, wound healing, Transwell and tube formation assay. The expression of proteins associated with epithelial-mesenchymal transformation and tube formation was detected by western blotting. Binding between DNASE1L3 and FOXP2 was confirmed by dual-luciferase reporter assay and chromatin immunoprecipitation. Gene Expression Profiling Interactive Analysis database predicted that underexpression of DNASE1L3 in LUAD was associated with poor prognosis. DNASE1L3 expression was decreased in LUAD cells and overexpression of DNASE1L3 inhibited the proliferation, migration, invasion and tube formation of LUAD cells. Transcription factor FOXP2 positively regulated DNASE1L3 transcription in LUAD cells. FOXP2 was also underexpressed in LUAD cells and downregulation of FOXP2 promoted proliferation, migration, invasion and tube formation of LUAD cells, which was reversed by overexpression of DNASE1L3. In conclusion, DNASE1L3 was positively regulated by transcription factor FOXP2 and overexpression inhibited proliferation, migration, invasion and tube formation of LUAD cells.

STRN-ALK Fusion in Lung Adenocarcinoma with Brain Metastasis Responded Well to Ensartinib: A Case Report.

STRN-ALK fusion is a rare ALK rearrangement identified in non-small cell lung cancer (NSCLC) patients. Here, we reported a case of lung adenocarcinomas with brain metastasis, harboring STRN-ALK fusion, responded well to ensartinib. This case report could provide more information for the therapeutic strategy selecting of NSCLC patients harboring STRN-ALK fusion.

[DNA Damage Repair System and Antineoplastic Agents in Lung Cancer].

DNA damage repair (DDR) system plays an important role in maintaining of genomic stability. Accumulation of DNA lesions or deficiency of DDR system could drive tumorigenesis as well as promote tumor progression; meanwhile, they could also provide therapeutic opportunities and targets. Of all the antineoplastic agents of lung cancers, many of them targeted or were associated with DNA damage and repair pathways, such as chemotherapies and antibody-drug conjugates which were designed directly causing DNA damages, targeted drugs inhibiting DNA repair pathways, and immune-checkpoint inhibitors. In this review, we described the role of DNA damage and repair pathways in antitumor activity of the above agents, as well as summarized the application and clinical investigations of these antineoplastic agents in lung cancers, in order to provide more information for exploring precision and effective strategies for the treatment of lung cancer based on the mechanism of DNA damage and repair.
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[Two Case Reports of Type 2 Diabetes Induced by Immune Checkpoint Inhibitors 
Combined with Chemotherapy].

Immune checkpoint inhibitors (ICIs) have become an important means of cancer treatment, and their application in the clinic is becoming more and more widespread. The adverse reactions caused by ICIs are gradually recognized. Among them, immunotherapy-related diabetes is a rare adverse reaction and type 1 diabetes mellitusis common. With the wide application of ICIs combined with chemotherapy in lung cancer patients, patients with type 2 diabetes mellitus have gradually been discovered during the treatment. However, the effect of continued use of ICIs maintenance therapy on blood glucose and ICIs treatment process in these patients is still unclear. This article reports two cases of type 2 diabetes mellitus induced by immune checkpoint inhibitor combined with chemotherapy, one of whom converted to type 1 diabetes mellitus, in order to increase the understanding of immunotherapy-related diabetes.
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Transepithelial delivery of insulin conjugated with phospholipid-mimicking polymers via biomembrane fusion-mediated transcellular pathways.

Epithelial barriers that seal cell gaps by forming tight junctions to prevent the free permeation of nutrients, electrolytes, and drugs, are essential for maintaining homeostasis in multicellular organisms. The development of nanocarriers that can permeate epithelial tissues without compromising barrier function is key for establishing a safe and efficient drug delivery system (DDS). Previously, we have demonstrated that a water-soluble phospholipid-mimicking random copolymer, poly(2-methacryloyloxyethyl phosphorylcholine30-random-n­butyl methacrylate70) (PMB30W), enters the cytoplasm of live cells by passive diffusion manners, without damaging the cell membranes. The internalization mechanism was confirmed to be amphiphilicity-induced membrane fusion. In the present study, we demonstrated energy-independent permeation of PMB30W through the model epithelial barriers of Madin-Darby canine kidney (MDCK) cell monolayers in vitro. The polymer penetrated epithelial MDCK monolayers via transcellular pathways without breaching the barrier functions. This was confirmed by our unique assay that can monitor the leakage of the proton as the smallest indicator across the epithelial barriers. Moreover, energy-independent transepithelial permeation was achieved when insulin was chemically conjugated with the phospholipid-mimicking nanocarrier. The bioactivity of insulin as a growth factor was found to be maintained even after translocation. These fundamental findings may aid the establishment of transepithelial DDS with advanced drug efficiency and safety. STATEMENT OF SIGNIFICANCE: A nanocarrier that can freely permeate epithelial tissues without compromising barrier function is key for successful DDS. Existing strategies mainly rely on paracellular transport associated with tight junction breakdown or transcellular transport via transporter recognition-mediated active uptake. These approaches raise concerns about efficiency and safety. In this study, we performed non-endocytic permeation of phospholipid-mimicking polymers through the model epithelial barriers in vitro. The polymer penetrated via transcytotic pathways without breaching the barriers of biomembrane and tight junction. Moreover, transepithelial permeation occurred when insulin was covalently attached to the nanocarrier. The bioactivity of insulin was maintained even after translocation. The biomimetic design of nanocarrier may realize safe and efficient transepithelial DDS.

Next-generation sequencing of homologous recombination genes could predict efficacy of platinum-based chemotherapy in non-small cell lung cancer.

Background: With the widespread use of next-generation sequencing (NGS) in clinical practice, an increasing number of biomarkers that predict a response to anti-tumor therapy in non-small cell lung cancer (NSCLC) has been identified. However, validated biomarkers that can be used to detect a response to platinum-based chemotherapy remain unavailable. Several studies have suggested that homologous recombination deficiency (HRD) may occur in response to platinum-based chemotherapy in ovarian cancer and breast cancer. However, currently there is a lack of proven and reliable HRD markers that can be used to screen for patients who may benefit from platinum-based chemotherapy, especially in NSCLC. Methods: NGS was used to screen for gene mutations, including homologous recombination (HR) genes and common driver gene mutations in NSCLC. Cox regression analysis was performed to identify potential clinicopathological or gene mutation factors associated with survival in patients receiving platinum-based chemotherapy, while Kaplan-Meier analysis with the log-rank test was performed to assess the effect of HR gene mutations on progression-free survival (PFS). Results: In a retrospective cohort of 129 patients with advanced NSCLC, 54 who received platinum-based chemotherapy with or without anti-angiogenic therapy were included in the analysis. Univariate and multivariate Cox proportional hazard regression analyses showed that HR gene mutations were associated with platinum-based chemotherapy sensitivity. Efficacy results indicated that the objective response rates (ORR) for patients with BRCA1/2 mutations and BRCA1/2 wild type were 75% and 30.4% (p=0.041), while the median PFS was 7.5 and 5.5 months (hazard ratio [HR], 0.52; 95% CI, 0.27-1.00; p=0.084), respectively. The ORRs of patients with HR gene mutations and HR gene wild type were 60% and 23.6% (p=0.01), and the median PFS was 7.5 and 5.2 months (HR, 0.56; 95% CI, 0.32-0.97; p=0.033), respectively. Conclusions: HR gene mutations show potential as promising biomarkers that may predict sensitivity to platinum-based chemotherapy in advanced and metastatic NSCLC.

Safety and efficacy of administering reduced doses of pegylated recombinant human granulocyte-colony stimulating factors in patients treated with cisplatin and etoposide for small cell carcinoma: A retrospective study.

BACKGROUND: The aim of this study was to discuss the safety and efficacy of administering reduced doses (3 mg) of pegylated recombinant human granulocyte-colony stimulating factor (PEG-rhG-CSF) at approximately 24 h or up to three days following treatment with etoposide and cisplatin (EP). METHODS: A total of 104 cycles from 31 patients were divided into a PEG-rhG-CSF prophylaxis group (PP-Group) and a control group (No-PP-Group). The PP-Group received a reduced dose of 3 mg of PEG-rhG-CSF within a minimum of 15 h and a maximum of 72 h following EP chemotherapy, while the rest did not receive any G-CSF prophylaxis (No-PP-Group). For both groups, complete blood counts, incidence of febrile neutropenia (FN), grade III or IV neutropenia, and the use of antibiotics to treat neutropenia were recorded. RESULTS: There was statistically no significant difference in the incidence of FN (0% vs. 1.4%, p = 1), antibiotic use due to neutropenia (0% vs. 2.7%, p = 0.881), estimated lowest mean marginal (EM) platelet (106.56 × 109 /L vs. 127.70 × 109 /L, p = 0.056) and hemoglobin (110.48 g/L vs. 110.14 g/L, p = 0.906) levels between the two groups. However, when compared with the No-PP-group, the white blood cell count in the PP-group was significantly higher (EM means: 4.95 × 109 /L vs. 2.80 × 109 /L, p < 0.01), while the incidence of grade III or IV neutropenia was significantly lower (9.1% vs. 68.1%, p < 0.01). CONCLUSIONS: The administration of a low dose (3 mg) of PEG-rhG-CSF within approximately 24 h or up to three days following EP treatment is safe and effective at reducing the risk of neutropenia. These findings bring a more flexible administration interval between PEG-rhG-CSF and EP treatment.

Nbnrp1 mediates Verticillium dahliae effector PevD1-triggered defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway in Nicotiana benthamiana.

PevD1, a fungal effector secreted by Verticillium dahliae, could induce hypersensitive responses-like necrosis and systemic acquired resistance (SAR) in cotton and tobacco plants. PevD1 could drastically induce the expression of Nbnrp1, which is an asparagine-rich protein (NRP) of Nicotiana benthamiana. Our previous research indicated that Nbnrp1 positively regulated PevD1-induced cell necrosis and disease resistance. In this study, we further investigated PevD1-induced immune responses in both wild-type (WT) and Nbnrp1-RNAi lines through RNA-seq, in order to reveal the underlying mechanism of Nbnrp1-modulated PevD1-induced disease resistance in N. benthamiana. Results showed that Nbnrp1-RNAi lines exhibited reduced PevD1-induced immune responses, like inhibiting H2O2 accumulation and MAPK phosphorylation. To silence Nbnrp1 inhibited the expression of PevD1-induced differential expression genes (DEGs) involved in pathways associated with sesquiterpenoid and triterpenoid biosynthesis, flavone and flavonol biosynthesis, plant-pathogen interaction and phenylpropanoid biosynthesis, etc. It is worth noting that sesquiterpene phytoalexin capsidiol accumulation were obviously decreased in Nbnrp1-RNAi plants after PevD1 treatment, accompanied with the down-expression of EAS and EAH, which were two key genes related to capsidiol biosynthesis. These results suggested that Nbnrp1 mediates PevD1-induced defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway.

Transcriptome analysis reveals key signature genes involved in the oncogenesis of lung cancer.

Previous studies have suggested potential signature genes for lung cancer, however, due to factors such as sequencing platform, control, data selection and filtration conditions, the results of lung cancer-related gene expression analysis are quite different. Here, we performed a meta-analysis on existing lung cancer gene expression results to identify Meta-signature genes without noise. In this study, functional enrichment, protein-protein interaction network, the DAVID, String, TfactS, and transcription factor binding were performed based on the gene expression profiles of lung adenocarcinoma and non-small cell lung cancer deposited in the GEO database. As a result, a total of 574 differentially expressed genes (DEGs) affecting the pathogenesis of lung cancer were identified (207 up-regulated expression and 367 down-regulated expression in lung cancer tissues). A total of 5,093 interactions existed among the 507 (88.3%) proteins, and 10 Meta-signatures were identified: AURKA, CCNB1, KIF11, CCNA2, TOP2A, CENPF, KIF2C, TPX2, HMMR, and MAD2L1. The potential biological functions of Meta-signature DEGs were revealed. In summary, this study identified key genes involved in the process of lung cancer. Our results would help the developing of novel biomarkers for lung cancer.

Molecular profiling of Chinese R-CHOP treated DLBCL patients: Identifying a high-risk subgroup.

Diffuse large B-cell lymphoma (DLBCL) is a clinically aggressive and heterogenous disease. Although most patients can be cured by immunochemotherapy, 30% to 40% patient will ultimately develop relapsed or refractory disease. Here, we investigated the molecular landscapes of patients with diverse responses to R-CHOP. We performed capture-based targeted sequencing on baseline samples of 105 DLBCL patients using a panel consisting of 112 lymphoma-related genes. Subsequently, 81 treatment-naïve patients with measurable disease and followed for over 1 year were included for survival analysis. Collectively, the most commonly seen mutations included IGH fusion (69%), PIM1(33%), MYD88 (29%), BCL2 (29%), TP53 (29%), CD79B (25%) and KMT2D (24%). Patients with TP53 mutations were more likely to have primary refractory disease (87.0% vs 50.0%, P = .009). For those with TP53 disruptive mutations, 91.7% patients were in the primary refractory group. Interestingly, BCL-2 somatic hypermutation was only seen in patients without primary refractory disease (P = .014). In multivariate analysis, BCL-2 amplification (hazard ratio [HR] = 2.94, P = .022), B2M mutation (HR = 2.99, P = .017) and TP53 mutation (HR = 3.19, P < .001) were independently associated with shorter time to progression (TTP). Furthermore, TP53 mutations was correlated with worse overall survival (P = .049). Next, we investigated mutation landscape in patients with wild-type (WT) TP53 (n = 58) and found that patients harboring MYD88 L265P had significantly inferior TTP than those with WT or non-265P (P = .046). Our study reveals the mutation spectrum of treatment-naive Chinese DLBCL patients. It also confirms the clinical significance of TP53 mutations and indicates the prognostic value of MYD88 L265P in TP53 WT patients.

Pathological Mechanistic Studies of Osimertinib Resistance in Non-Small-Cell Lung Cancer Cells Using an Integrative Metabolomics-Proteomics Analysis.

BACKGROUND: Osimertinib is the first-line therapeutic option for the T790M-mutant non-small-cell lung cancer and the acquired resistance obstructs its application. It is an urgent challenge to identify the potential mechanisms of osimertinib resistance for uncovering some novel therapeutic approaches. METHODS: In the current study, the cell metabolomics based on ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry and the qualitative and tandem mass tags quantitative proteomics were performed. RESULTS: 54 differential metabolites and 195 differentially expressed proteins were, respectively, identified. The amino acids metabolisms were significantly altered. HIF-1 signaling pathway modulating P-glycoproteins expression, PI3K-Akt pathway regulating survivin expression, and oxidative phosphorylation were upregulated, while arginine and proline metabolism regulating NO production and glycolysis/gluconeogenesis were downregulated during osimertinib resistance. CONCLUSION: The regulation of HIF-1 and PI3K-Akt signaling pathway, energy supply process, and amino acids metabolism are the promising therapeutic tactics for osimertinib resistance.

EGFR exon 19-deletion aberrantly regulate ERCC1 expression that may partly impaired DNA damage repair ability in non-small cell lung cancer.

BACKGROUND: Epidermal growth factor receptor (EGFR) activating mutations are usually associated with DNA damage repair (DDR) deficiency. However, the precise mechanism has remained elusive. In this study, we aimed to investigate whether EGFR exon 19 deletion mutation downstream signals contributed to DDR deficiency by downregulation of excision repair cross-complementation group-1 (ERCC1), a key factor in DDR, expression and function. METHODS: We first measured cell survival, DNA damage (γ-H2AX foci formation) and damage repair (ERCC1 and RAD51 foci formation) ability in response to DNA cross-linking drug in EGFR exon 19 deletion and EGFR wild-type cells separately. We then investigated the involvement of EGFR downstream signals in regulating ERCC1 expression and function in EGFR exon 19 deletion cells as compared with EGFR wild-type ones. RESULTS: We observed increased γ-H2AX, but impaired ERCC1 and RAD51 nuclear foci formation in EGFR exon 19 deletion cells as compared with EGFR wild-type ones treated with DNA cross-linker. In addition, we identified that inhibition of EGFR exon 19 deletion signals increased ERCC1 expression, whereas blocked wild-type EGFR signals decreased ERCC1 expression, on both mRNA and protein levels. Furthermore, EGFR exon 19 deletion downstream signals not only inhibited ERCC1 expression but also influenced ERCC1 foci formation in response to DNA cross-linker. CONCLUSION: Our findings indicated that the aberrant EGFR exon 19 deletion signals were not only associated with decreased expression of ERCC1 but were also involved in impaired ERCC1 recruitment in response to DNA cross-link damage, thereby providing us with more evidence for exploring the mechanism of DDR deficiency in EGFR mutant NSCLC.

[Molecular Mechanism and Progression of Primary Resistance to EGFR-TKI
- Analysis of 2 Cases].

Tyrosine kinase inhibitor (TKI) have been proved to be effective in the treatment of advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) sensitive mutation, which is superior to chemotherapy. However, there are still some patients with sensitive mutations have primary drug resistance. It may be related to the coexistence of susceptible and resistant mutations of EGFR gene, downstream mutations of EGFR pathway, MET amplification and BIM deletion polymorphism. We present 2 cases of primary drug resistance and analyze the reasons.
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