Clinical trials of tyrosine kinase inhibitors for lung cancer in China: a review

PURPL Promotes M2 Macrophage Polarization in Lung Cancer by Regulating RBM4/xCT Signaling

Lung cancer is the most common malignancy worldwide. Long non-coding RNA (lncRNA) p53 upregulated regulator of P53 levels (PURPL) is abnormally in various cancers. However, the reports on its roles in lung cancer are limited. The purpose of present study is to investigate the potentials of lncRNA PURPL in lung cancer. PURPL and mRNA expression was determined using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR). The location of PURPL was detected using RNA fluorescence in situ hybridization (FISH) assay. Protein expression was detected using western blot. Cellular functions were determined using flow cytometry. The interaction between PURPL and RNA-binding motif 4 (RBM4) was confirmed using RNA immunoprecipitation (RIP) assay. PURPL was overexpressed in lung cancer cells and patients. Overexpressed PURPL promoted M2 macrophage polarization and suppressed ferroptosis. Additionally, PURPL maintained the mRNA stability of cystine glutamate reverse transporter (xCT) via regulating RBM4. xCT knockdown antagonized the effects of overexpressed PURPL and inhibited M2 macrophage polarization via inducing macrophage ferroptosis. PURPL/RBM4/xCT axis promoted M2 macrophage polarization in lung cancer. Therefore, PURPL may be a potential target of lung cancer.

Identification of a Six-Gene SLC Family Signature With Prognostic Value in Patients With Lung Adenocarcinoma

Given the importance of solute carrier (SLC) proteins in maintaining cellular metabolic homeostasis and that their dysregulation contributes to cancer progression, here we constructed a robust SLC family signature for lung adenocarcinoma (LUAD) patient stratification. Transcriptomic profiles and relevant clinical information of LUAD patients were downloaded from the TCGA and GEO databases. SLC family genes differentially expressed between LUAD tissues and adjacent normal tissues were identified using limma in R. Of these, prognosis-related SLC family genes were further screened out and used to construct a novel SLC family-based signature in the training cohort. The accuracy of the prognostic signature was assessed in the testing cohort, the entire cohort, and the external GSE72094 cohort. Correlations between the prognostic signature and the tumor immune microenvironment and immune cell infiltrates were further explored. We found that seventy percent of SLC family genes (279/397) were differentially expressed between LUAC tissues and adjacent normal. Twenty-six genes with p-values < 0.05 in univariate Cox regression analysis and Kaplan-Meier survival analysis were regarded as prognosis-related SLC family genes, six of which were used to construct a prognostic signature for patient classification into high- and low-risk groups. Kaplan-Meier survival analysis in all internal and external cohorts revealed a better overall survival for patients in the low-risk group than those in the high-risk group. Univariate and multivariate Cox regression analyses indicated that the derived risk score was an independent prognostic factor for LUAD patients. Moreover, a nomogram based on the six-gene signature and clinicopathological factors was developed for clinical application. High-risk patients had lower stromal, immune, and ESTIMATE scores and higher tumor purities than those in the low-risk group. The proportions of infiltrating naive CD4 T cells, activated memory CD4 T cells, M0 macrophages, resting dendritic cells, resting mast cells, activated mast cells, and eosinophils were significantly different between the high- and low-risk prognostic groups. In all, the six-gene SLC family signature is of satisfactory accuracy and generalizability for predicting overall survival in patients with LUAD. Furthermore, this prognostics signature is related to tumor immune status and distinct immune cell infiltrates in the tumor microenvironment.

Guidelines for clinical practice of ALK fusion detection in non-small-cell lung cancer: a proposal from the Chinese RATICAL study group

The presence of anaplastic lymphoma kinase (ALK) rearrangement defines a molecular subtype of non-small cell lung cancer (NSCLC). ALK inhibitors (ALKIs) confer significant clinical benefits in patients with ALK-positive advanced NSCLC; therefore, it is of great clinical significance to select accurate, rapid, and appropriate ALK testing methods to screen for patients who are suitable for anti-ALK treatment. In recent years, great progress has been made in the development and clinical application of ALKIs, as well as in our understanding of acquired drug resistance mechanisms. Meanwhile, new ALK companion diagnostic platforms have been developed and applied in clinical practice. Although many studies have shown that there is a high rate of concordance among these platforms, new problems continue to appear during testing. To maximize the benefit for patients, accurate testing results can be obtained by first selecting the appropriate testing method and then formulating, optimizing, and complying with the standardized testing process in accordance with the testing population and specimen types. With the ongoing accumulation of clinical practice data, experience from quality control of ALK testing, and results from multicenter research, an updated expert consensus is necessary. The experts who participated in the discussion and development of this guideline have a rich background in theoretical and clinical testing experience, which ensures the practical value of the information presented in this guideline.

MET amplification identified by next-generation sequencing and its clinical relevance for MET inhibitors

Background

MET amplification plays an important role in the development of non-small-cell lung cancer (NSCLC) either de novo or in resistance to epidermal growth factor receptor tyrosine–kinase inhibitor (EGFR-TKI) settings. Fluorescence in situ hybridization (FISH) is the standard method for MET amplification. With more and more discoveries of oncogenic driver genes, next-generation sequencing (NGS) plays a significant role in precision oncology. Meanwhile, the role of NGS in MET amplification remains uncertain.

Methods

Forty patients diagnosed with advanced NSCLC were included. FISH and NGS were conducted prior to MET inhibitors treatment. MET amplification by FISH was defined as a MET/CEP7 ratio of  >  2.0 and/or copy number (CN)  >  5. MET amplification by NGS was defined as gene copy number (GCN)  ≥  5.

Results

The concordance rate among FISH and NGS was 62.5% (25/40). MET amplification identified by FISH showed the optimal predictive value. The partial response (PR) rate was 68.0% (17/25 with MET amplification) vs. 6.7% (1/15 without MET amplification); the median progression-free survival (PFS) was 5.4 months versus 1.0 months (P  < 0.001). MET amplification identified by NGS failed to distinguish significant clinical outcomes. The PR rate was 60.0% (6/10, with MET GCN  ≥ 5) vs. 40.0% (12/30, with MET GCN  < 5); the median PFS was 4.8 months vs. 2.2 months (P  = 0.357). The PR rate was 68.8% (11/16) and the median PFS was 4.8 months in patients with focal amplification by NGS.

Conclusions

MET amplification identified by FISH remains the optimal biomarker to identify suitable candidates for MET-TKI therapy. In comparison, amplification identified by NGS seems not as robust to be effective predictive biomarker. Further exploration is needed regarding the focal amplification by NGS in predicting the efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-021-00245-y.

Cancer biomarkers for targeted therapy

Tumor-associated antigens (TAA) or cancer biomarkers are major targets for cancer therapies. Antibody- based agents targeting the cancer biomarkers include monoclonal antibodies (MoAbs), radiolabeled MoAbs, bispecific T cell engagers, and antibody-drug conjugates. Antibodies targeting CD19, CD20, CD22, CD30, CD33, CD38, CD79B and SLAMF7 are in clinical applications for hematological malignancies. CD123, CLL-1, B cell maturation antigen, and CD138 are targets for cancer immunotherapeutic agents, including the chimeric antigen receptor - engineered T cells. Immune checkpoint inhibitors (ICIs) against PD-1, PD-L1, and CTLA-4 have led to the revolution of cancer immunotherapy. More ICIs targeting IDO, LAG3, TIM-3, TIGIT, SIGLECs, VISTA and CD47 are being explored. Small molecule inhibitors (SMIs) against tyrosine kinase oncoproteins such as BCR-ABL, JAK2, Bruton tyrosine kinase, FLT3, EGFR, ALK, HER2, VEGFR, FGFR, MEK, and MET have fundamentally changed the landscape of cancer therapy. SMIs against BCL-2, IDHs, BRAF, PI3 kinase, mTOR, PARP, and CDKs have become the mainstay in the treatment of a variety of cancer types. To reduce and avoid off-tumor toxicities, cancer-specific TAAs such as CD33 are being manufactured through systems biology approach. Search for novel biomarkers and new designs as well as delivery methods of targeted agents are fueling the next wave of advances in cancer therapy.

Chinese perspectives on clinical efficacy and safety of alectinib in patients with ALK-positive advanced non-small cell lung cancer

The incidence of lung cancer is increasing in China, in contrast to trends in Western countries, due to the increasing numbers of smokers and high levels of air pollution. Non-small-cell lung cancer (NSCLC) is the most common form of lung cancer, accounting for approximately 85% of lung cancers. Better understanding of the pathogenesis of NSCLC has led to the identification of multiple genetic mutations and chromosomal translocations such as those in the anaplastic lymphoma kinase (ALK) gene. To facilitate the identification of treatment targets, multiple guidelines (European Society for Medical Oncology, National Comprehensive Cancer Network, and American Society of Clinical Oncology) now recommend screening for genetic factors to help guide treatment decisions. In recent years, multiple ALK inhibitors have been developed to treat NSCLC, including the first-generation tyrosine kinase inhibitor (TKI) crizotinib; second-generation TKIs such as ceritinib, ensartinib, brigatinib, and alectinib; the third-generation TKI lorlatinib; and the fourth-generation TKI repotrectinib. These agents differ in structure, potency, and activity, both systemically and their effects on central nervous system (CNS) metastases. Recently, alectinib was approved in China to treat patients with locally advanced or metastatic NSCLC that were ALK+. Alectinib has demonstrated activity against NSCLC, including metastases within the CNS, with better tolerability than crizotinib. These ALK inhibitors represent significant advances in the treatment of NSCLC and yet patients will likely still exhibit disease progression. Alectinib offers greater potency with greater specificity as well as a better toxicity profile than many other TKIs that are currently available. Here, we review the role of ALK as a therapeutic target in NSCLC, the testing methods for identifying ALK-rearranged NSCLC, and the various TKIs currently being used or explored for treatment in this setting, with a focus on alectinib from a Chinese perspective.

MET inhibitors for targeted therapy of EGFR TKI-resistant lung cancer

Treatment of non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutation with EGFR-TKIs has achieved great success, yet faces the development of acquired resistance as the major obstacle to long-term disease remission in the clinic. MET (or c-MET) gene amplification has long been known as an important resistance mechanism to first- or second-generation EGFR-TKIs in addition to the appearance of T790 M mutation. Recent preclinical and clinical studies have suggested that MET amplification and/or protein hyperactivation is likely to be a key mechanism underlying acquired resistance to third-generation EGFR-TKIs such as osimertinib as well, particularly when used as a first-line therapy. EGFR-mutant NSCLCs that have relapsed from first-generation EGFR-TKI treatment and have MET amplification and/or protein hyperactivation should be insensitive to osimertinib monotherapy. Therefore, combinatorial therapy with osimertinib and a MET or even a MEK inhibitor should be considered for these patients with resistant NSCLC carrying MET amplification and/or protein hyperactivation.

Ocular and orbital side effects of ALK inhibitors: a review article

ALK inhibitors are a new group of tyrosine kinase inhibitors, highly efficient in the treatment of non-small-cell lung carcinoma. However, these targeted therapies can induce various adverse effects, including ocular toxicity. To date, few articles reporting ophthalmological side effects of ALK inhibitors have been published. In this review, we aim to describe the different side effects and to collect information regarding the causes behind the discrepancy between the reported rates of visual disorders. Frequent ocular side effects of ALK inhibitors included flashes, post-flashbulb effect, stripes, photopsia, accommodation disorder, presbyopia, reduced visual acuity and blurred vision. Optic neuropathy, vitreous floaters, diplopia, cataract and macular edema were also reported.

Recent advances on anti-angiogenesis receptor tyrosine kinase inhibitors in cancer therapy

Angiogenesis has always been the topic of major scientific interest in the field of malignant tumors. Nowadays, targeting angiogenesis has achieved success in various carcinomas by several mechanisms, including the use of anti-angiogenic small molecule receptor tyrosine kinase inhibitors (TKIs). The development of TKIs targeting pro-angiogenic receptors, mainly vascular endothelial growth factor receptor (VEGFR) family, have significantly improved the outcome of certain types of cancers, like renal cell carcinoma, hepatocellular carcinoma, and colorectal carcinoma. However, the general response rate is not very satisfactory. The particular toxicity profile and resistance to anti-angiogenic targeted agents are unavoidable, and no specific marker is available to screen responsive patients to TKIs for precision therapy. To date, about 11 anti-angiogenic TKIs with different binding capacities to angiogenic receptor tyrosine kinase have been approved for the treatment of patients with advanced cancers. This review presents all approved anti-angiogenic small molecule receptor TKIs so far with an emphasis on their indications and clinical efficacy. We also discuss the combination between TKIs and immune checkpoint blockade inhibitors based on the most recent exciting outcome in immunotherapy.

Transporter and Lysosomal Mediated (Multi)drug Resistance to Tyrosine Kinase Inhibitors and Potential Strategies to Overcome Resistance

Tyrosine kinase inhibitors are a class of chemotherapeutic drugs that target specific protein kinases. These tyrosine kinase inhibitors constitute a relatively new class of drugs which target for instance Bcr-Abl, Epidermal Growth Factor Receptor (EGFR) and Vascular Endothelial Growth Factor Receptor (VEGFR). Despite some initial successes, the overall therapeutic benefit of tyrosine kinase inhibitors in the clinic has been mixed. Next to mutations in the target, multidrug resistance is a major obstacle for which still no clinically effective strategies have been developed. Major mechanisms of multidrug resistance are mediated by drug efflux transporter proteins. Moreover, there is accumulating evidence that multidrug resistance can also be caused by lysosomal sequestration of drugs, effectively trapping tyrosine kinase inhibitors and preventing them from reaching their target. Lysosomal drug sequestration seems to work together with ATP-binding cassette transporters, increasing the capacity of lysosomes to mediate sequestration. Both membrane efflux transporter proteins and lysosomes present potential therapeutic targets that could reverse multidrug resistance and increase drug efficacy in combination therapy. This review describes both mechanisms and discusses a number of proposed strategies to circumvent or reverse tyrosine kinase inhibitor-related multidrug resistance.

Influence of different drug delivery methods for Endostar combined with a gemcitabine/cisplatin regimen in locally advanced or metastatic lung squamous cell carcinoma: A retrospective observational study

Continuous endovenous administration of Endostar (CE) gradually replaced drip intravenous administration of Endostar (DE) in lung squamous cell carcinoma (SCC) treatment presently, but the efficacy and safety of CE and DE which is better in advanced lung SCC are yet unclear. To evaluate the feasibility of CE as an alternative to DE with gemcitabine/cisplatin (GP) chemotherapy. Data were collected from patients admitted with locally advanced or metastatic lung SCC from January 2011 to April 2015, including the patients' characteristics, the therapeutic regimen, the treatment effectiveness, and toxicity. There are 71 patients with pathologically confirmed lung SCC retrospectively assigned to a treatment (CE) group of 48 patients and a control (DE) group of 23 patients. The response of each tumor to the therapy was assessed every 2 cycles by a chest and upper abdomen computed tomography for the comparison of curative effects and adverse reactions. Compared with the DE group, the response rate and disease control rate were noninferior in the CE group. The median progression-free survival and overall survival in the CE and DE groups were no significantly difference (5.5 vs 5.5 months, P = .141; 22.9 vs 14.3 months, P = .053). Increased progression-free survival (PFS) for patients in CE group was observed across 3 subgroups analyzed. There was a 35.7% reduction in the total dose of Endostar per cycle in the CE group compared with that in the DE group. Thus, in combination with GP chemotherapy, CE could be a suitable alternative to DE in locally advanced or metastatic SCC patients, resulting in less hemoptysis, less treatment time, and lower costs.

Strong Programmed Death Ligand 1 Expression Predicts Poor Response and De Novo Resistance to EGFR Tyrosine Kinase Inhibitors Among NSCLC Patients With EGFR Mutation

INTRODUCTION

This study evaluated whether tumor expression of programmed death ligand 1 (PD-L1) could predict the response of EGFR-mutated NSCLC to EGFR tyrosine kinase inhibitor (TKI) therapy.

METHODS

We retrospectively evaluated patients who received EGFR-TKIs for advanced NSCLC at the Guangdong Lung Cancer Institute between April 2016 and September 2017 and were not enrolled in clinical studies. The patients' EGFR and PD-L1 statuses were simultaneously evaluated.

RESULTS

Among the 101 eligible patients, strong PD-L1 expression significantly decreased objective response rate, compared with weak or negative PD-L1 expression (35.7% versus 63.2% versus 67.3%, p = 0.002), and shortened progression-free survival (3.8 versus 6.0 versus 9.5 months, p < 0.001), regardless of EGFR mutation type (19del or L858R). Furthermore, positive PD-L1 expression was predominantly observed among patients with de novo resistance rather than acquired resistance to EGFR-TKIs (66.7% versus 30.2%, p = 0.009). Notably, we found a high proportion of PD-L1 and cluster of differentiation 8 (CD8) dual-positive cases among patients with de novo resistance (46.7%, 7 of 15). Finally, one patient with de novo resistance to EGFR-TKIs and PD-L1 and CD8 dual positivity experienced a favorable response to anti-programmed death 1 therapy.

CONCLUSIONS

This study revealed the adverse effects of PD-L1 expression on EGFR-TKI efficacy, especially in NSCLC patients with de novo resistance. The findings indicate the reshaping of an inflamed immune phenotype characterized by PD-L1 and CD8 dual positivity and suggest potential therapeutic sensitivity to programmed death 1 blockade.

Overexpression of PEAK1 contributes to epithelial-mesenchymal transition and tumor metastasis in lung cancer through modulating ERK1/2 and JAK2 signaling

Pseudopodium-enriched atypical kinase 1 (PEAK1), a novel non-receptor tyrosine kinase, has been demonstrated to act as an oncogenic regulator in breast and pancreatic cancers. However, the role of PEAK1 in the progression and metastasis of lung cancer is still unknown. Here, we observed that ectopic PEAK1 expression promoted lung cancer cell migration and invasion, while PEAK1 knockout resulted in suppressed cell migration and invasion. Interestingly, cell proliferation did not significantly increase or decrease in either the PEAK1 overexpression or knockout groups compared with the corresponding control cells. In addition, PEAK1 overexpression could induce epithelial-to-mesenchymal transition (EMT) and the expression of matrix metalloproteinase-2 (MMP2) and MMP9 both in vitro and in vivo, whereas PEAK1 knockout had the opposite effects. Then, we had confirmed that PEAK1 was significantly upregulated in lung cancer tissues, and correlated with a higher tumor node metastasis stage. Moreover, PEAK1 upregulation markedly enhanced the activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and Janus kinase-2 (JAK2) signaling in lung cancer cells. Further work demonstrated that the combination of PD98059 with AZD1480 could reverse the effects of PEAK1-induced EMT, cell migration and invasion. Our findings highlight a newer mechanism for PEAK1 in regulating EMT and metastasis in lung cancer, which might serve as a therapeutic target for lung cancer patients.

Insight into resistance mechanism of anaplastic lymphoma kinase to alectinib and JH-VIII-157-02 caused by G1202R solvent front mutation

BACKGROUND

Mutated anaplastic lymphoma kinase (ALK) drives the development of advanced non-small cell lung cancer (NSCLC). Most reported small-molecule inhibitors targeting the ALK domain do not display good inhibition of the G1202R solvent front mutation. The solvent front mutation was assumed to hinder drug binding. However, a different fact could be uncovered by the simulations reported in this study through a structural analog of alectinib (JH-VIII-157-02), which demonstrated potent effects against the G1202R mutation.

METHODS

Molecular docking, conventional molecular dynamics (MD) simulations, free energy calculations, and umbrella sampling (US) simulations were carried out to make clear the principles of the binding preferences of alectinib and JH-VIII-157-02 toward ALKWT and the ALK G1202R (ALKG1202R) mutation.

RESULTS

JH-VIII-157-02 has similar binding affinities to both ALKWT and ALKG1202R whereas it has has a much lower binding affinity for alectinib to ALKG1202R. Analysis of individual energy terms indicate the major variation involves the van der Waals and entropy terms. Structural analysis reveals that the conformational change of the ATP-binding glycine-rich loop was primarily responsible for the alectinib resistance, not JH-VIII-157-02. In addition, US simulations prove JH-VIII-157-02 has similar dissociative processes from both ALKWT and ALKG1202R, while alectinib is more easily dissociated from ALKG1202R than from ALKWT, thus indicating lesser residence time.

CONCLUSION

Both the binding affinity and the drug residence time should be emphasized in rational drug design to overcome the G1202R solvent front mutation in ALK resistance.

Multiple treatment modalities for brain metastasis in patients with EGFR-mutant non-small-cell lung cancer

Background

There are many controversies concerning the best management of epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC) patients with brain metastases (BMs). The use of upfront EGFR tyrosine kinase inhibitors (TKIs) and the withholding of local therapies or upfront radiation therapies (RTs) remain controversial. Available treatment options include local therapies such as whole-brain radiation therapy (WBRT), stereotactic radiosurgery (SRS) and surgery, EGFR-TKIs, and chemotherapy. However, the optimal management of combination therapies is still under consideration.

Patients and methods

A total of 45 EGFR-mutated NSCLC patients with BMs were included. All patients successively received EGFR-TKIs, RT (WBRT or SRS), and chemotherapy between 2010 and 2015 at Zhejiang Cancer Hospital. Patient follow-up was conducted by telephone until February 2017. The treatment response was evaluated, and survival data were collected and analyzed by Kaplan–Meier analysis and the Cox regression method.

Results

The median overall survival (OS) was 28 months. Patients with the exon 19 deletion showed the strongest trend toward a longer median OS compared to patients with the exon 21 L858R mutation (not reached vs 26.5 months, P=0.0969). There was no difference in OS between the upfront RT group and the deferral group (26.5 vs 28 months, P=0.57), and similar results were found between the first-line chemotherapy group and the EGFR-TKI group (28 vs 23.2 months, P=0.499). In multivariate analysis, the prognosis correlated with EGFR mutation type (P=0.017).

Conclusion

EGFR-mutant NSCLC patients with BM benefited from the combination and sequential therapies of EGFR-TKIs, chemotherapy, and RTs. Patients with the EGFR exon 19 deletion may have a better OS. However, the optimal timing of RT interval remains to be explored.

A real-world study of treatment patterns and survival outcome in advanced anaplastic lymphoma kinase-positive non-small-cell lung cancer

Crizotinib is an anti-cancer drug with a substantial beneficial effect in advanced non-small-cell lung cancer (NSCLC) patients harboring anaplastic lymphoma kinase (ALK) rearrangement. However, the real-world data currently available on this drug are limited. Thus, the present study aimed to retrospectively examine the treatment patterns and survival outcome of 83 advanced NSCLC patients with ALK rearrangement in a single center in China. Of the 83 patients enrolled, 33 (39.8%) patients received crizotinib and the remaining 50 (60.2%) patients received chemotherapy as the initial therapy. The first-line use of crizotinib prolonged the PFS1 (progression-free survival to the first detection of subsequent disease progression) compared with chemotherapy (median, 18.5 vs. 4.9 months; P<0.001), however, it did not prolong the overall survival (OS; P=0.802). At the last follow up, 71 (85.5%) patients had received crizotinib and 12 (14.5%) patients were crizotinib-naive. Patients who had received crizotinib exhibited a significantly longer OS as compared with those who were crizotinib-naive [hazard ratio (HR) for mortality, 0.279; 95% confidence interval, 0.107-0.727; P<0.05). Among the 71 patients who had received crizotinib, this was administered as a first-line therapy in 33 (46.5%) cases, as a second-line therapy in 22 (31.0%) cases and after the second-line therapy in 16 (22.5%) cases. No significant difference in the OS among the three groups was observed (P=0.577). The Cox multivariate analysis identified the following independent negative prognostic factors for OS: Smoking history (HR=4.565), liver invasion at diagnosis (HR=4.294) and bone invasion at diagnosis (HR=2.587). In addition, the use of crizotinib (HR=0.319) was identified as a positive prognostic factor for OS. In conclusion, the present real-world study revealed that the use of crizotinib improved the long-term survival of patients with ALK-positive advanced NSCLC. There was no difference in survival outcome between patients with initial use of crizotinib and those with subsequent use of crizotinib after first-line therapy.

Effective assessment of low times MET amplification in pleural effusion after epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) acquired resistance: Cases report

RATIONALE

The mechanism of the first-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) acquired resistance included T790M mutation, cellular-mesenchymal to epithelial transition factor (MET) or EGFR amplification, PIK3CA mutation, and transformation to small cell lung cancer. MET amplification accounted for only about 5% of the resistance cases.

PATIENTS CONCERNS

Few report detected MET amplification in pleural effusion. Here, we reported 2 lung adenocarcinoma cases with MET amplification in pleural effusion rapidly responded to crizotinib after EGFR-TKIs acquired resistance.

DIAGNOSES

Biopsy via bronchoscopy, next-generation sequencing (NGS) in pleural effusion.

INTERVENTIONS

EGFR-TKIs (Icotinib), MET inhibitor crizotinib.

OUTCOMES

After a progression-free survival of 9 months and 23months, respectively, both cases progressed accompanying with pleural effusion. Results of NGS in pleural effusion showed MET amplification (2-3 times) in both cases. The 2 patients were treated with a MET inhibitor crizotinib and rapidly responded.

CONCLUSION

MET amplification in pleural effusion could predict a perfect response to crizotinib after EGFR-TKIs acquired resistance, even only a low times gene amplification.