Clinical outcomes in ALK-rearranged lung adenocarcinomas according to ALK fusion variants

ALK F1174S mutation impairs ALK kinase activity in EML4-ALK variant 1 and sensitizes EML4-ALK variant 3 to crizotinib

Objective

To assess the influence of F1174S mutation on kinase activity and drug sensitivity of the echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) fusion (EML4-ALK) variants 1 and 3.

Methods

We constructed mammalian expression plasmids of both wildtype and F1174 mutant EML4-ALK variants 1 and 3, and then characterized them with cell models by performing immunoblotting, neurite outgrowth assay, focus formation assay as well as protein stability assay. Drug sensitivity to ALK tyrosine kinase inhibitors was also compared between wildtype and F1174 mutant EML4-ALK fusions. In addition, we characterized the effect of different F1174 kinase domain mutations in the context of EML4-ALK fusions.

Results

In contrast to the oncogenic ALK-F1174S mutation that has been reported to be activating in the context of full-length ALK in neuroblastoma, EML4-ALK (F1174S) variant 1 exhibits impaired kinase activity leading to loss of oncogenicity. Furthermore, unlike the previously reported F1174C/L/V mutations, mutation of F1174 to S sensitizes EML4-ALK variants 3a and 3b to crizotinib.

Conclusion

These findings highlight the complexity of drug selection when treating patients harboring resistance mutations and suggest that the F1174S mutation in EML4-ALK variant 1 is likely not a potent oncogenic driver. Additional oncogenic driver or other resistance mechanisms should be considered in the case of EML4-ALK variant 1 with F1174S mutation.

Efficacy of alectinib in lung adenocarcinoma patients with different anaplastic lymphoma kinase (ALK) rearrangements and co-existing alterations-a retrospective cohort study

Background

Alectinib significantly improves survival of non-small cell lung cancer (NSCLC) patients with anaplastic lymphoma kinase (ALK)-rearrangement. In this study, we analyzed the effects of different ALK rearrangements and co-mutations on the efficacy of alectinib.

Methods

Using the electronic medical record system, we reviewed in terms of clinical and pathological features patients with advanced (IIIB/IV stage) ALK-rearranged NSCLC at Shanghai Chest Hospital between January 2018 and December 2021 who were treated with alectinib in first or second line and were assessed for objective response rate (ORR), disease control rate (DCR), and progression-free survival (PFS).

Results

A total of 66 patients were enrolled in the study, and 17 types of ALK rearrangements were detected, of which five types of ALK rearrangements responded well to alectinib. We classified ALK-rearrangements into four main types, namely echinoderm microtubule-associated protein-like 4 (EML4)-ALK (E6:A20), EML4-ALK (E13:A20), EML4-ALK (E20:A20), and others. There was no significant difference in ORR and DCR of these types (ORR: 31.3% vs. 13.0% vs. 18.2% vs. 17.6%, P=0.575; DCR: 93.8% vs. 95.6% vs. 100.0% vs. 88.2%, P=0.627). The 3-year PFS rates were 25.0% (4/16) vs. 13.0% (3/23) vs. 27.3% (3/11) vs. 18.8% (3/16) for EML4-ALK (E6:A20), EML4-ALK (E13:A20), EML4-ALK (E20:A20), and others, respectively (P=0.725). The results of co-mutation analysis showed that the median PFS (mPFS) for patients with tumors harboring TP53 mutations was 30.4 months, significantly shorter than that of patients with tumors without co-mutations and whose mPFS was not mature (P=0.026). TSC1 co-mutation was also identified as a detrimental factor in outcome, with a DCR of 60% vs. 100% (P=0.031), mPFS of 30.4 months vs. not applicable (P=0.160) in patients with vs. those without this co-mutation, respectively. The efficacy of alectinib in patients with brain metastases is comparable to that in patients without distant organ metastases. There were two cases with specific fusion types that also responded to alectinib; namely, double ALK-rearrangements: EML4-ALK (E13:A20) and MSH2-ALK (M7:A20), and with a rare fusion partner, SPECC1L-ALK (S8:A20). Their PFS were 8.7 and 38.0 months, respectively.

Conclusions

In this study, the efficacy of alectinib in different types of ALK-rearrangements varied slightly. TP53 and TSC1 co-mutations were identified as detrimental factors affecting efficacy. This study provides references for the response to alectinib in patients with different types of ALK rearrangements and co-mutation.

Comprehensive NGS profiling to enable detection of ALK gene rearrangements and MET amplifications in non-small cell lung cancer

Introduction

Next-generation sequencing (NGS) is currently widely used for biomarker studies and molecular profiling to identify concurrent alterations that can lead to the better characterization of a tumor's molecular landscape. However, further evaluation of technical aspects related to the detection of gene rearrangements and copy number alterations is warranted.

Methods

There were 12 ALK rearrangement-positive tumor specimens from patients with non-small cell lung cancer (NSCLC) previously detected via fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and an RNA-based NGS assay, and 26 MET high gene copy number (GCN) cases detected by FISH, selected for this retrospective study. All 38 pre-characterized cases were reassessed utilizing the PGDx™ elio™ tissue complete assay, a 505 gene targeted NGS panel, to evaluate concordance with these conventional diagnostic techniques.

Results

The detection of ALK rearrangements using the DNA-based NGS assay demonstrated excellent sensitivity with the added benefit of characterizing gene fusion partners and genomic breakpoints. MET copy number alterations were also detected; however, some discordances were observed likely attributed to differences in algorithm, reporting thresholds and gene copy number state. TMB was also assessed by the assay and correlated to the presence of NSCLC driver alterations and was found to be significantly lower in cases with NGS-confirmed canonical driver mutations compared with those without (p=0.0019).

Discussion

Overall, this study validates NGS as an accurate approach for detecting structural variants while also highlighting the need for further optimization to enable harmonization across methodologies for amplifications.

EML4‑ALK fusion gene in non‑small cell lung cancer (Review)

Non-small cell lung cancer (NSCLC) is a malignant tumor with a high morbidity and mortality rate that is a threat to human health. With the development of molecular targeted research, breakthroughs have been made on the molecular mechanism of lung cancer. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene is one of the most important pathogenic driver genes of NSCLC discovered thus far. Four generations of targeted drugs for EML4-ALK have been developed, with patients benefiting significantly from these drugs. Therefore, EML4-ALK has become a research hotspot in NSCLC. The aim of the present study is to introduce the current research progress of EML4-ALK and its association with NSCLC.

Crizotinib Versus Conventional Chemotherapy in First-Line Treatment for ALK-Positive Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

INTRODUCTION

Lung cancer is the most frequently diagnosed type of cancer and the main cause of death from malignant neoplasms worldwide. One of the most recent discoveries in the context of non-small cell lung cancer (NSCLC) was the mutation of the anaplastic lymphoma kinase receptor (ALK). This genetic alteration is found in approximately 2-5% of NSCLC patients, and crizotinib was the first targeted therapy discovered for its first-line treatment.

OBJECTIVE

To conduct a systematic review and meta-analysis to estimate the magnitude of the overall survival (OS) and progression-free survival (PFS) from using crizotinib as treatment compared to traditional chemotherapy to guide future decision making.

METHODS

PRISMA and Cochrane recommendations were followed using the findings based on studies published in the main international electronic databases. Selection criteria included the following: randomized clinical trials (RCT) or cohort studies that had assessed the efficacy and effectiveness of crizotinib as monotherapy in patients with NSCLC with ALK fusions.

RESULTS

From 2504 publications identified in the literature, only eight publications referring to seven studies met the selection criteria, with high heterogeneity identified between the studies. Overall, there was a significant gain in PFS (HR 0.38; 95% CI 0.30-0.49; p < 0.00001); however, there was no significant gain in OS (HR 0.68; 95% CI 0.43-1.08; p = 0.10).

CONCLUSION

The study highlighted and confirmed that treatment with crizotinib led to clinical improvement in PFS among patients with advanced NSCLC with ALK fusion, as previously reported. However, there was no increase in overall survival in patients with NSCLC with genetic alterations of ALK. This must be considered when reviewing and funding treatments for NSCLC patients with this mutation.

The impact of the ALK fusion variant on clinical outcomes in EML4-ALK patients with NSCLC: a systematic review and meta-analysis

Background: Recent studies showed that ALK-fusion variants are associated with heterogeneous clinical outcomes. However, contradictory conclusions have been drawn in other studies showing no correlation between ALK variants and prognoses. Methods: A systematic review and meta-analysis was performed to evaluate the prognostic value of EML4-ALK fusion variants for patient outcomes. Results: 28 studies were included in the analysis. According to the pooled results, patients harboring variant 1 showed equivalent progression-free survival (PFS) and overall survival (OS) with non-v1 patients (hazard ratio [HR] for PFS: 0.91 [0.68-1.21]; p = 0.499; OS: 1.12 [0.73-1.72]; p = 0.610). Similarly, patients with v3 showed the same disease progress as non-v3 patients (pooled HR for PFS = 1.07 [0.72-1.58]; p = 0.741). However, pooled results for OS suggested that patients with v3 had worse survival than non-v3 patients (HR = 3.44 [1.42-8.35]; p = 0.006). Conclusion: Results suggest that patients with v1 exhibited no significant difference from non-v1 in terms of OS and PFS, while v3 was associated with shorter OS in ALK-positive patients with non-small cell lung cancer.

A novel GHR-ALK fusion gene in a patient with metastatic lung adenocarcinoma and its response to crizotinib: a case report

Anaplastic lymphoma kinase (ALK) rearrangement occurs in approximately 5% of non-small cell lung cancers (NSCLCS), and EML4-ALK is the most commonly observed ALK fusion variant in NSCLC. However, growth hormone receptor (GHR) as the fusion partner for ALK and the clinical response to ALK tyrosine kinase inhibitors in patients with metastatic lung adenocarcinoma (LUAD) who carry the GHR-ALK variant have not been documented. This case describes a 63-year-old woman diagnosed with metastatic LUAD. Immunohistochemistry revealed positive ALK expression, and the patient was treated with crizotinib. After 3 weeks of treatment, the patient had a partial response. Because of treatment-related adverse events, the dose of crizotinib was reduced. After 3.7 months, computed tomography uncovered disease progression. Next-generation sequencing identified a novel GHR-ALK fusion in the plasma of the patient. The patient was treated again with crizotinib, but the disease progressed again 2 months later. Then, the patient received chemotherapy. She succumbed to her disease 11 months after the initial diagnosis. Our work provides evidence supporting the use of crizotinib in patients with metastatic LUAD harboring GHR-ALK.

Association of anaplastic lymphoma kinase variants and alterations with ensartinib response duration in non-small cell lung cancer

Background

Here, we aimed to assess the association of ALK variants and alterations with ensartinib response duration in NSCLC, and explore the potential value of computed tomography (CT) radiomic features in predicting progression‐free survival (PFS).

Methods

We enrolled 88 patients with identified ALK variant NSCLC in a multicenter phase 2 trial, and assessed the impact of ALK variants and secondary ALK alterations on the clinical outcome (response duration) of patients receiving ensartinib. We also established a multifactorial model of clinicopathological and quantitative CT radiomic features to predict PFS and risk stratification. Kaplan–Meier analysis was conducted to identify risk factors for tumor progression.

Results

Univariate analysis indicated a statistical difference (p = 0.035) in PFS among ALK variants in three classifications (V1, V3, and other variants). Secondary ALK alterations were adversely associated with PFS both in univariate (p = 0.008) and multivariate (p = 0.04) analyses and could identify patients at high risk for early progression in the Kaplan–Meier analysis (p = 0.002). Additionally, response duration to crizotinib <1 year and liver metastasis were adversely associated with PFS. The combined model, composed of clinicopathological signature and CT radiomic signature, showed good prediction ability with the area under the receiver operating characteristic curve being 0.85, and 0.89 in the training and validation dataset respectively.

Conclusions

Our study showed that secondary ALK alterations were adversely associated with ensartinib efficacy, and that ALK variants might not correlate with PFS. The quantitative radiomic signature provided added prognostic prediction value to the clinicopathological features.

Targeting EML4-ALK gene fusion variant 3 in thyroid cancer

Finding targetable gene fusions can expand the limited treatment options in radioactive iodine-refractory (RAI-r) thyroid cancer. To that end, we established a novel cell line 'JVE404' derived from an advanced RAI-r papillary thyroid cancer (PTC) patient, harboring an EML4-ALK gene fusion variant 3 (v3). Different EML4-ALK gene fusions can have different clinical repercussions. JVE404 cells were evaluated for cell viability and cell signaling in response to ALK inhibitors crizotinib, ceritinib and lorlatinib, in parallel to the patient's treatment. He received, after first-line lenvatinib, crizotinib (Drug Rediscovery Protocol (DRUP) trial), and lorlatinib (compassionate use). In vitro treatment with crizotinib or ceritinib decreased viability in JVE404, but most potently and significantly only with lorlatinib. Western blot analysis showed a near total decrease of 99% and 89%, respectively, in pALK and pERK expression levels in JVE404 cells with lorlatinib, in contrast to remaining signal intensities of a half and a third of control, respectively, with crizotinib. The patient had a 6-month lasting stable disease on crizotinib, but progressive disease occurred, including the finding of cerebral metastases, at 8 months. With lorlatinib, partial response, including clinical cerebral activity, was already achieved at 11 weeks' use and ongoing partial response at 7 months. To our best knowledge, this is the first reported case describing a patient-specific targeted treatment with lorlatinib based on an EML4-ALK gene fusion v3 in a thyroid cancer patient, and own cancer cell line. Tumor-agnostic targeted therapy may provide valuable treatment options in personalized medicine.

Concomitant mutation status of ALK-rearranged non-small cell lung cancers and its prognostic impact on patients treated with crizotinib

Background

In non-small cell lung cancer (NSCLC), anaplastic lymphoma kinase (ALK) rearrangement characterizes a subgroup of patients who show sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, the prognoses of these patients are heterogeneous. A better understanding of the genomic alterations occurring in these tumors could explain the prognostic heterogeneity observed in these patients.

Methods

We retrospectively analyzed 96 patients with NSCLC with ALK detected by immunohistochemical staining (VENTANA anti-ALK(D5F3) Rabbit Monoclonal Primary Antibody). Cancer tissues were subjected to next-generation sequencing using a panel of 520 cancer-related genes. The genomic landscape, distribution of ALK fusion variants, and clinicopathological characteristics of the patients were evaluated. The correlations of genomic alterations with clinical outcomes were also assessed.

Results

Among the 96 patients with immunohistochemically identified ALK fusions, 80 (83%) were confirmed by next-generation sequencing. TP53 mutation was the most commonly co-occurring mutation with ALK rearrangement. Concomitant driver mutations [2 Kirsten rat sarcoma viral oncogene homolog (KRAS) G12, 1 epidermal growth factor receptor (EGFR) 19del, and 1 MET exon 14 skipping] were also observed in 4 adenocarcinomas. Echinoderm microtubule associated protein-like 4 (EML4)-ALK fusions were identified in 95% of ALK-rearranged patients, with 16.2% of them also harboring additional non-EML4-ALK fusions. Nineteen non-EML4 translocation partners were also discovered, including 10 novel ones. Survival analyses revealed that patients concurrently harboring PIK3R2 alterations showed a trend toward shorter progression-free survival (6 vs. 13 months, P=0.064) and significantly shorter overall survival (11 vs. 32 months, P=0.004) than did PIK3R2-wild-type patients. Patients with concomitant alterations in PI3K the signaling pathway also had a shorter median overall survival than those without such alterations (23 vs. 32 months, P=0.014), whereas progression-free survival did not differ significantly.

Conclusions

The spectrum of ALK-fusion variants and the landscape of concomitant genomic alterations were delineated in 96 NSCLC patients. Our study also demonstrated the prognostic value of concomitant alterations in crizotinib-treated patients, which could facilitate improved stratification of ALK-rearranged NSCLC patients in the selection of candidates who could optimally benefit from therapy.

ALK variants, PD-L1 expression, and their association with outcomes in ALK-positive NSCLC patients

It remains unclear how programmed death-ligand 1 (PD-L1) expression interacts with anaplastic lymphoma kinase (ALK) mutation, its variants, and the outcome of treatment. One hundred and twenty four out of 1255 patients (9.9%) were deemed ALK-positive by the Ventana IHC assay. PD-L1 status and ALK variants were available in 100 and 59 patients, respectively. PD-L1 positive (TPS ≥ 1%) and strong positive (TPS ≥ 50%) rate was 50% and 16%, respectively. A total of 64 variant types were detected in 59 patients. V1 (32.8%) and V3a/b (28.1%) were the most common variants. There was no significant association between ALK variants and the PD-L1 expression. The presence of V3a/b subtype independently predicted a worse overall survival in patients receiving ALK inhibitor(s) (aHR 5.10 [95% CI 1.22–21.25], P = 0.025) and platinum plus pemetrexed (aHR 9.62 [95% CI 1.90–48.80], P = 0.006). While incorporating ALK variants and PD-L1 expression together, patients with non-V3a/b/positive PD-L1 showed a trend towards longer OS. In conclusion, ALK-positive NSCLC patients possess a high PD-L1 expression rate. Although there was no significant association between PD-L1 expression and ALK variants, the outcome of ALK-positive patients could be sorted by these two biomarkers.

Diffusion tensor and postcontrast T1-weighted imaging radiomics to differentiate the epidermal growth factor receptor mutation status of brain metastases from non-small cell lung cancer

PURPOSE

To assess whether the radiomic features of diffusion tensor imaging (DTI) and conventional postcontrast T1-weighted (T1C) images can differentiate the epidermal growth factor receptor (EGFR) mutation status in brain metastases from non-small cell lung cancer (NSCLC).

METHODS

A total of 99 brain metastases in 51 patients who underwent surgery or biopsy with underlying NSCLC and known EGFR mutation statuses (57 from EGFR wild type, 42 from EGFR mutant) were allocated to the training (57 lesions in 31 patients) and test (42 lesions in 20 patients) sets. Radiomic features (n = 526) were extracted from preoperative MR images including T1C and DTI. Radiomics classifiers were constructed by combinations of five feature selectors and four machine learning algorithms. The trained classifiers were validated on the test set, and the classifier performance was assessed by determining the area under the curve (AUC).

RESULTS

EGFR mutation status showed an overall discordance rate of 12% between the primary tumors and corresponding brain metastases. The best performing classifier was a combination of the tree-based feature selection and linear discriminant algorithm and 5 features were selected (1 from ADC, 2 from fractional anisotropy, and 2 from T1C images), resulting in an AUC, accuracy, sensitivity, and specificity of 0.73, 78.6%, 81.3%, and 76.9% in the test set, respectively.

CONCLUSIONS

Radiomics classifiers integrating multiparametric MRI parameters may have potential in differentiating the EGFR mutation status in brain metastases from NSCLC.

Impact of ALK variants on brain metastasis and treatment response in advanced NSCLC patients with oncogenic ALK fusion

Background

To investigate the impact of ALK variants on the features of brain metastases (BM), the outcome of chemotherapy and targeted therapy using crizotinib, as well as the progression pattern in patients with ALK fusion.

Methods

Patients with ALK fusion were retrospectively collected from January 2013 to July 2017 in Shanghai Pulmonary Hospital. ALK rearrangements were identified via ARMS-PCR. ALK variants were identified via Sanger Sequencing.

Results

A total of 135 patients and 41 with brain metastasis were identified. Radiological features showed that the patients with ALK variant 1 had a larger BM size compared with patients with ALK non-variant 1 (median tumor size: 16.89 vs. 11.01 mm, P=0.031). Similar time to treatment failure (TTF) was observed in patients with ALK variant 1 and non-variant 1 who received first-line crizotinib (median TTF: 15.7 vs. 13.8 months, HR =0.75, P=0.34). Patients with ALK variant 1 who had baseline BM had significantly shorter TTF than non-variant 1 with baseline BM when treated with first-line crizotinib (median TTF: 9.1 vs. 14.9 months, HR =2.68, P=0.037). In patients treated with chemotherapy, ALK variant 1 was associated with inferior TTF (median TTF: 5.6 vs. 8.1 months, HR =1.66, P=0.039). Progression pattern was similar between ALK variant 1 and non-variant 1.

Conclusions

Patients with ALK variant 1 and baseline BM had inferior TTF on first-line crizotinib treatment and presented with more aggressive radiological features. Patients with ALK non-variant 1 had better clinical outcome on first-line chemotherapy.

Inhibition of Mitogen-Activated Protein Kinase Kinase Alone and in Combination with Anaplastic Lymphoma Kinase (ALK) Inhibition Suppresses Tumor Growth in a Mouse Model of ALK-Positive Lung Cancer

Anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer most commonly arises through EML4 (Echinoderm Microtuble Like 4)-ALK chromosomal fusion. We have previously demonstrated that combination of the ALK inhibitor crizotinib with the MEK inhibitor selumetinib was highly effective at reducing cell viability of ALK-positive non-small-cell lung cancer (H3122) cells. In this study, we further investigated the efficacy of crizotinib and selumetinib combination therapy in an in vivo xenograft model of ALK-positive lung cancer. Crizotinib decreased tumor volume by 52% compared with control, and the drug combination reduced tumor growth compared with crizotinib. In addition, MEK inhibition alone reduced tumor growth by 59% compared with control. Crizotinib and selumetinib alone and in combination were nontoxic at the dose of 25 mg/kg, with values for ALT (<80 U/l) and creatinine (<2 mg/dl) within the normal range. Our results support the combined use of crizotinib with selumetinib in ALK-positive lung cancer but raise the possibility that a sufficient dose of an MEK inhibitor alone may be as effective as adding an MEK inhibitor to an ALK inhibitor. SIGNIFICANCE STATEMENT: This study contains in vivo evidence supporting the use of combination MEK inhibitors in ALK+ lung cancer research, both singularly and in combination with ALK inhibitors. Contrary to previously published reports, our results suggest that it is possible to gain much of the benefit from combination treatment with an MEK inhibitor alone, at a tolerable dose.

Rapid detection and genotyping of ALK fusion variants by adapter multiplex PCR and high-resolution melting analysis

Anaplastic lymphoma kinase (ALK) fusion is a promising predictive biomarker of ALK-tyrosine kinase inhibitor (ALK-TKI) treatment. Furthermore, different fusion variants correlate to different ALK-TKIs responses. Although variant identification assists in treatment direction, most ALK detection assays do not genotype different fusion variants. We developed a high-resolution melting (HRM) assay to rapidly detect ALK fusions and automatically distinguish at least 20 fusion variants in one tube. Adapter multiplex PCR was designed to amplify ALK fusion variants and the reference gene GAPDH. After HRM, negative derivative curves showed a low temperature GAPDH peak, and if an ALK fusion was present, a high temperature peak from the ALK segment and variably a middle temperature part associated with the fusion partner. Selected regions of the second derivative curves were analyzed to extract features (∆T_m, PTS/ITS, H₁/H₂) that define two curve types (monotonic and non-monotonic). Synthetic samples of 20 ALK fusion variants were used to train a quadratic discriminate analysis model, and the accuracy was 97.06% (66/68) and 85.71% (144/162) for monotonic and non-monotonic variants, respectively. The limit of detection of the assay was 1%. The analytical sensitivity of genotyping was 1 and 5% for monotonic and non-monotonic variants, respectively. In a blinded study, we detected ALK fusion from formalin-fixed paraffin-embedded lung cancer samples with a 100% 47) and genotyping /47) and genotyping (7/7). Multiplex adapter HRM is a simple, fast, and sensitive way of ALK fusion detection and genotyping. Automatic genotyping with parameters extracted from second derivative curves is a promising method that may be applicable to other types of gene variants detected by HRM.

Anaplastic Lymphoma Kinase (ALK)-positive Tumors: Clinical, Radiographic and Molecular Profiles, and Uncommon Sites of Metastases in Patients With Lung Adenocarcinoma

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene rearrangements are observed in about 4% to 8% non-small cell lung cancer (NSCLC). ALK+ tumors have been associated with increased pleural and pericardial disease. Our primary objective was to determine the uncommon sites of metastasis of ALK+ NSCLC. Secondary objectives included study of coexisting mutations and factors impacting survival of ALK+ NSCLC.

METHODS

All patients with metastatic ALK+ NSCLC at the City of Hope Cancer Center in Duarte, California from 2010 to 2017 were selected for retrospective chart review. The demographic variables were collected. The molecular statuses of patients were evaluated through commercially available platforms for next-generation sequencing. Three-dimensional volumetric images were generated for the primary lesion and different sites of metastasis.

RESULTS

Sixty two patients with ALK+ NSCLC were identified from 2010 to 2017. The median age was 59 with 36 (58%) female individuals and only 20 (32%) smokers. Twenty four patients had uncommon sites of metastasis which were thyroid, soft tissue, chest and abdominal wall, spleen, peritoneum, omentum, kidney, and ovary. Common characteristics of the primary lesions were right upper lobe location (N=23 [37%]), oval shape (N=22 [35%]), irregular margins (N=26 [42%]), solid lesions (N=27 [44%]), presence of pleural contact or effusion (N=22 [35%]). Twenty four patients had next-generation sequencing testing which showed coexisting mutations such as TP53 (N=8), EGFR (N=5), KRAS (N=3). Patients with uncommon sites of metastasis had a decreased median survival compared with common sites (39 vs. 82 m, P=0.046).

CONCLUSION

In NSCLC, ALK rearrangements may not be mutually exclusive mutations and can present with unique radiographic patterns. Patients with uncommon sites of metastasis may have worse outcomes.

Mechanisms of suppression of cell growth by dual inhibition of ALK and MEK in ALK-positive non-small cell lung cancer

Anaplastic lymphoma kinase (ALK) rearrangement, a key oncogenic driver in a small subset of non-small cell lung cancers, confers sensitivity to ALK tyrosine kinase inhibitors (TKIs). Crizotinib, a first generation ALK-TKI, has superiority to standard chemotherapy with longer progression-free survival and higher objective response rate. However, clinical benefit is limited by development of resistance, typically within a year of therapy. In this study the combined effect of crizotinib and the MEK inhibitor selumetinib was investigated in both crizotinib naïve (H3122) and crizotinib resistant (CR-H3122) ALK-positive lung cancer cells. Results showed that combination treatment potently inhibited the growth of both H3122 and CR-H3122 cells, resulting from increased apoptosis and decreased cell proliferation as a consequence of suppressed downstream RAS/MAPK signalling. The drug combination also elicited a greater than 3-fold increase in Bim, a mediator of apoptosis, and p27, a cyclin dependent kinase inhibitor compared to crizotinib alone. The results support the hypothesis that combining MEK inhibitors with ALK inhibitor can overcome ALK inhibitor resistance, and identifies Bim, PARP and CDK1 as druggable targets for possible triple drug therapy.

Molecular findings reveal possible resistance mechanisms in a patient with ALK-rearranged lung cancer: a case report and literature review

Background: Non-small-cell lung cancer (NSCLC) is recognised as a particularly heterogeneous disease, encompassing a wide spectrum of distinct molecular subtypes. With increased understanding of disease biology and mechanisms of progression, treatment of NSCLC has made remarkable progress in the past two decades. Molecular testing is considered the hallmark for the diagnosis and treatment of NSCLC, with liquid biopsies being more and more often applied in the clinical setting during the recent years. Rearrangement of the ALK gene which results in the generation of fusion oncogenes is a common molecular event in NSCLCs. Among ALK fusion transcripts, EML4-ALK fusion is frequently observed and can be targeted with ALK tyrosine kinase inhibitors (TKI). However, acquired resistance and disease progression in many cases are inevitable.

Method: Here, we present the case of a patient with NSCLC treated with TKIs, in which molecular profiling of the tumour was performed with different methods of tissue and plasma testing at each disease progression. A review of the literature was further conducted to offer insights into the resistance mechanisms of ALK-rearranged NSCLC.

Conclusions: Based on the results, the EML4-ALK fusion initially detected in tumour tissue was preserved throughout the course of the disease. Two additional ALK mutations were later detected in the tissue and plasma and are likely to have caused resistance to the administered TKIs. Continued research into the mechanisms of acquired resistance is required in order to increase the benefit of the patients treated with targeted ALK TKIs.

The Impact of Clinical Factors, ALK Fusion Variants, and BIM Polymorphism on Crizotinib-Treated Advanced EML4-ALK Rearranged Non-small Cell Lung Cancer

Patients' clinical factors and genetics factors such as anaplastic lymphoma kinase (ALK) fusion variants and BIM (Bcl-2-like 11) polymorphism were reported to be associated with clinical outcome in crizotinib-treated advanced non-small cell lung cancer (NSCLC). However, the results were still controversial. We analyzed outcome of 54 patients with known ALK fusion variants who received crizotinib for advanced NSCLC. Thirty of them had successful BIM polymorphism analysis and 6 (20%) had a BIM deletion. Multivariate Cox regression analysis found that previous anticancer therapy [adjusted hazard ratio (aHR) 1.35, 95% confidence interval (CI), 1.04–1.76 for each additional line of therapy, p = 0.025] and Eastern Cooperative Oncology Group (ECOG) performance status ≥2 (aHR 8.35, 95% CI, 1.52–45.94, p = 0.015) were independent factors for progression-free survival (PFS). Only ECOG performance status ≥2 (aHR 7.20, 95% CI, 1.27–40.79, p = 0.026) was an independent factor for overall survival (OS). Neither ALK fusion variants nor the presence of a BIM deletion was associated with crizotinib PFS or OS. After adjusting with clinical factors, different ALK variants and BIM polymorphism might not be independent factors for crizotinib PFS or OS in advanced NSCLC with ALK rearrangement.

The prevalence of EML4-ALK variants in patients with non-small-cell lung cancer: a systematic review and meta-analysis

To investigate the prevalence of EML4-ALK variants in non-small-cell lung cancer (NSCLC) patients. Materials & methods: Database of Pubmed, Embase, Medline and Cochrane Library were searched systematically to April 2018. Results: A total of 39 articles including 1903 NSCLC patients with ALK positive were recruited. The overall pooled prevalence for EML4-ALK variant 1 to 3 was 81.84% (95% CI: 76.68-86.99%), ranging from 86.64% tested by RT-PCR to 70.85% tested by other methods (p = 0.00). Subgroup analysis showed that the pooled prevalences of variant 1, 2 and 3 were 40.38% (95% CI: 34.83-45.93%), 6.59% (95% CI: 4.27-8.91%) and 26.54% (95% CI: 20.89-32.2%), respectively. Conclusion: This present study provides the exact prevalence of EML4-ALK rearrangement in different variants for NSCLC patients with ALK positive.

Long-term complete response in a patient with postoperative recurrent ALK-rearranged lung adenocarcinoma treated with crizotinib: A case report

Anaplastic lymphoma kinase (ALK) gene rearrangements are identified in approximately 5% of patients with non-small cell lung cancer (NSCLC). Despite initial dramatic responses to ALK inhibitors, the majority of patients relapse within 1 year, owing to the development of resistance. Herein we present a case of variant type 2 ALK-rearranged lung adenocarcinoma recurrence with multiple lung metastasis that maintained complete response over 5 years with crizotinib, which is the first approved ALK inhibitor. The efficacy of crizotinib may vary among ALK fusion variants and thus, variant type may represent an important factor in guiding the treatment strategy for ALK-rearranged lung adenocarcinoma.

Variability in lung cancer response to ALK inhibitors cannot be explained by the diversity of ALK fusion variants

Multiple laboratory evidences indicate that distinct variants of ALK translocations differ in their biochemical properties and responsiveness to ALK tyrosine kinase inhibitors (TKIs). These data are supported by some clinical studies, which showed improved responses to crizotinib in non-small cell lung cancer (NSCLC) patients carrying particular variants of ALK translocation. We retrospectively considered 64 Russian patients with ALK-rearranged NSCLC, who were treated by crizotinib (n = 23), ceritinib (n = 39) or alectinib (n = 2). ALK fusion variants were genotyped by PCR. Median progression-free survival (PFS) approached to 18 and 21 months in subjects with "short" (v.3a/b, v.5a/b) vs. "long" (TAPE-domain containing) fusion variants (p = 0.783), respectively; similar data were obtained while comparing EML4/ALK variant 1 vs. other ALK translocations (19 and 21 months, respectively; p = 0.604). Objective response rates were also strikingly similar in the above groups ("short": 88%, "long": 77%, p = 0.479; variant 1: 76%, other translocations: 81%, p = 0.753). Furthermore, ALK variants did not influence the disease outcomes when patients treated by crizotinib and ceritinib were analyzed separately. Overall, PFS on ALK TKI did not depend on whether the drug was administered upfront or after chemotherapy. Ceritinib produced significantly longer PFS than crizotinib (p = 0.022). In conclusion, this study revealed that distinct ALK translocation variants render similar clinical responsiveness to ALK inhibitors.

Challenges in ALK inhibition of ALK-positive non-small-cell lung cancer: from ALK positivity detection to treatment strategies after relapse

ALK positivity, despite representing only in a small proportion of patients with non-small-cell lung cancer, is worth researching at diagnosis given the possibility to treat these patients with some targeted ALK inhibitors, which are more potent than chemotherapy. Thanks to understanding the resistance mechanisms, newer and more selective inhibitors are now available in clinical practice. Hence, this disease represents, after EGFR inhibition, a largely effective precision medicine approach. However, there are still some clinical situations in which the targeted drug seems to be ineffective. This review discusses some uncertainty about such a 'precision medicine application', focusing on some weaknesses and giving perspectives and suggestions to improve the management of this specific population.

The correlation between crizotinib efficacy and molecular heterogeneity by next-generation sequencing in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) patients with EML4-ALK fusion exhibited various durations of response to crizotinib. Molecular heterogeneity is also one of the factors associated with resistance to crizotinib. This study investigated the relevance of molecular heterogeneity to the clinical efficacy of crizotinib using next-generation sequencing (NGS).

Methods

A total of 52 ALK-positive advanced NSCLC patients were enrolled. The genetic variation was revealed by NGS. We identified different ALK fusion types, allelic fraction (AF) and additional coexisting mutations (ACMs) and evaluated the correlation between the above three factors and clinical response to crizotinib.

Results

Among the group that was detected with ALK+ fusion by immunohistochemistry (IHC), patients detected as ALK- fusion by the NGS method were associated with a shorter progression-free survival (PFS) compared with ALK+ patients by NGS. Moreover, for different ALK fusion types, the median PFS of variant 1/2/3 and other uncommon variants were 305, 557, 242 and 370 days, respectively. Although there was no statistically significant difference (P=0.201), patients with ALK variant 2 appeared to display a longer PFS than other types of variants in this study. There was no significant difference in the relationship between ALK fusion AF and PFS (P=0.639). Additionally, there was no correlation between ACMs and PFS in the three groups (IHC+, IHC+/NGS-, and IHC+/NGS+, P=0.738, 0.801 and 0.550). We analysed the relationship between TP53/FAT3 and PFS in the IHC+/NGS+ group, and there was no statistically significant difference (P=0.712/0.631).

Conclusions

It is necessary to use multiple methods together to detect ALK fusion, and we can continue to carry out the study of the correlation between the different contents of heterogeneity of gene mutations and TKI effects using the NGS method.

Impact of EML4-ALK Variant on Resistance Mechanisms and Clinical Outcomes in ALK-Positive Lung Cancer

Purpose Advanced anaplastic lymphoma kinase ( ALK) fusion-positive non-small-cell lung cancers (NSCLCs) are effectively treated with ALK tyrosine kinase inhibitors (TKIs). However, clinical outcomes in these patients vary, and the benefit of TKIs is limited as a result of acquired resistance. Emerging data suggest that the ALK fusion variant may affect clinical outcome, but the molecular basis for this association is unknown. Patients and Methods We identified 129 patients with ALK-positive NSCLC with known ALK variants. ALK resistance mutations and clinical outcomes on ALK TKIs were retrospectively evaluated according to ALK variant. A Foundation Medicine data set of 577 patients with ALK-positive NSCLC was also examined. Results The most frequent ALK variants were EML4-ALK variant 1 in 55 patients (43%) and variant 3 in 51 patients (40%). We analyzed 77 tumor biopsy specimens from patients with variants 1 and 3 who had progressed on an ALK TKI. ALK resistance mutations were significantly more common in variant 3 than in variant 1 (57% v 30%; P = .023). In particular, ALK G1202R was more common in variant 3 than in variant 1 (32% v 0%; P < .001). Analysis of the Foundation Medicine database revealed similar associations of variant 3 with ALK resistance mutation and with G1202R ( P = .010 and .015, respectively). Among patients treated with the third-generation ALK TKI lorlatinib, variant 3 was associated with a significantly longer progression-free survival than variant 1 (hazard ratio, 0.31; 95% CI, 0.12 to 0.79; P = .011). Conclusion Specific ALK variants may be associated with the development of ALK resistance mutations, particularly G1202R, and provide a molecular link between variant and clinical outcome. ALK variant thus represents a potentially important factor in the selection of next-generation ALK inhibitors.

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.

Response to crizotinib in advanced ALK-rearranged non-small cell lung cancers with different ALK-fusion variants

INTRODUCTION

Anaplastic lymphoma kinase (ALK) rearrangements are present in approximately 5% of non-small-cell lung cancers (NSCLCs). NSCLCs with ALK-rearrangement can be effectively treated with crizotinib. However, magnitude and duration of responses are found to be heterogeneous. This study explored the clinical efficacy of crizotinib in different ALK variants.

METHODS

Among 96 ALK-rearrangement patients treated with crizotinib, 60 patients were identified with tumor specimens that could be evaluated by next-generation sequencing (NGS). We retrospectively evaluated the efficacy of crizotinib in different ALK variants.

RESULTS

The median Progression-free survival (PFS) of the 96 ALK-rearrangement patients was 14.17 months. Among the 60 patients with NGS results, the most frequent variants were variant 3a/b (33.33%), variant 1 (23.33%) and variant 2 (15.00%). The percentage of rare EML4-ALK variants and non EML4-ALK variants were 10.00% and 18.33%. Survival analysis showed that patients with variant 2 appeared to have longer PFS than others (P = .021); also, patients with TP53 mutation seemed to have an unfavorable PFS than those with TP53 wild-type with a borderline p value (P = .068). After adjusting for other baseline characteristics, EML4-ALK variant 2 was identified as an important factor for a better PFS of crizotinib. We also found that patients with variant 3a/b had shorter duration of response to crizotinib; however, no significant difference of PFS was observed between the PFS of variant3a/b and non-v3 EML4-ALK variants.

CONCLUSIONS

Our results indicate prolonged PFS in patients with EML4-ALK variant 2.

EML4-ALK fusion variant V3 is a high-risk feature conferring accelerated metastatic spread, early treatment failure and worse overall survival in ALK+ non-small cell lung cancer

In order to identify anaplastic lymphoma kinase-driven non-small cell lung cancer (ALK⁺ NSCLC) patients with a worse outcome, who might require alternative therapeutic approaches, we retrospectively analyzed all stage IV cases treated at our institutions with one of the main echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion variants V1, V2 and V3 as detected by next-generation sequencing or reverse transcription-polymerase chain reaction (n = 67). Progression under tyrosine kinase inhibitor (TKI) treatment was evaluated both according to Response Evaluation Criteria in Solid Tumors (RECIST) and by the need to change systemic therapy. EML4-ALK fusion variants V1, V2 and V3 were found in 39%, 10% and 51% of cases, respectively. Patients with V3-driven tumors had more metastatic sites at diagnosis than cases with the V1 and V2 variants (mean 3.3 vs. 1.9 and 1.6, p = 0.005), which suggests increased disease aggressiveness. Furthermore, V3-positive status was associated with earlier failure after treatment with first and second-generation ALK TKI (median progression-free survival [PFS] by RECIST in the first line 7.3 vs. 39.3 months, p = 0.01), platinum-based combination chemotherapy (median PFS 5.4 vs. 15.2 months for the first line, p = 0.008) and cerebral radiotherapy (median brain PFS 6.1 months vs. not reached for cerebral radiotherapy during first-line treatment, p = 0.028), and with inferior overall survival (39.8 vs. 59.6 months in median, p = 0.017). Thus, EML4-ALK fusion variant V3 is a high-risk feature for ALK⁺ NSCLC. Determination of V3 status should be considered as part of the initial workup for this entity in order to select patients for more aggressive surveillance and treatment strategies.

ALK fusion variants detection by targeted RNA-next generation sequencing and clinical responses to crizotinib in ALK-positive non-small cell lung cancer

OBJECTIVES

The aim of the present study was firstly to assess in a clinical setting the yields of an amplicon-based parallel RNA sequencing (RNA-seq) assay for ALK fusion transcript variants detection in comparison with immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH) in a selected population of ALK-positive and ALK-negative non-small cell lung cancer (NSCLC) cases, and secondly to evaluate the impact of the ALK variant on crizotinib efficacy.

MATERIALS AND METHODS

The cohort used for the assessment of the RNA-seq assay comprised 53 samples initially diagnosed as being ALK-positive based on the results obtained by IHC and/or FISH, and 23 ALK-negative samples. A distinction was made between 'truly' IHC/FISH positive or 'truly' IHC/FISH negative samples, and those for which the IHC and/or FISH were equivocal (IHC) or borderline-positive (FISH).

RESULTS

On the overall population, RNA-seq sensitivity (Se) and specificity (Spe) were of 80% and 100%, respectively when IHC and FISH were combined. For the 31 'truly positive' samples, Se and Spe of 100% were reached. An ALK status could be assigned by RNA-seq in 10/10 of the equivocal and/or borderline-positive IHC/FISH cases, 2/7 IHC/FISH discordant cases. When crizotinib efficacy was evaluated according to the type of ALK variant, better clinical outcomes were observed in crizotinib-treated patients with EML4-ALK v1/v2/others variants compared to v3a/b variants.

CONCLUSION

RNA-seq detects ALK rearrangements with a high sensitivity and specificity using only 10 ng of RNA. It appears to be a promising rescue technique for non-clear-cut IHC/FISH cases and also offers a unique opportunity to identify ALK fusion variants and evaluate their predictive value for ALK inhibitors efficacy.

EML4-ALK Variants: Biological and Molecular Properties, and the Implications for Patients

Since the discovery of the fusion between EML4 (echinoderm microtubule associated protein-like 4) and ALK (anaplastic lymphoma kinase), EML4-ALK, in lung adenocarcinomas in 2007, and the subsequent identification of at least 15 different variants in lung cancers, there has been a revolution in molecular-targeted therapy that has transformed the outlook for these patients. Our recent focus has been on understanding how and why the expression of particular variants can affect biological and molecular properties of cancer cells, as well as identifying the key signalling pathways triggered, as a result. In the clinical setting, this understanding led to the discovery that the type of variant influences the response of patients to ALK therapy. Here, we discuss what we know so far about the EML4-ALK variants in molecular signalling pathways and what questions remain to be answered. In the longer term, this analysis may uncover ways to specifically treat patients for a better outcome.

An update on biomarkers for kinase inhibitor response in non-small-cell lung cancer

INTRODUCTION

The discovery of activating genetic and their use as predictive biomarkers for targeted therapy, such as tyrosine kinase inhibitors (TKIs), has changed the treatment paradigm of non-small cell lung cancer (NSCLC). As a result, epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) TKIs have become the standard first-line treatment. Since then, other kinds of targetable oncogenic alterations have been identified in NSCLC. Several novel, molecularly-targeted TKIs have now achieved regulatory approval, while many others are currently in early- or late-phase clinical trial testing. These TKIs have significantly impacted and changed clinical outcomes for advanced NSCLC. Areas covered: In this review, the authors discuss recent evidence and progress in targeted therapies, especially small molecular tyrosine kinase inhibitors, matched with their biomarkers for the treatment of advanced NSCLC. Expert commentary: Although targeted therapies dramatically improve the outcome of patients with NSCLC harboring specific oncogenic alterations, molecular and clinical resistance almost invariably develops. New TKIs specifically active in molecular subgroups of NSCLC or the resistance setting have now been developed. The development of additional TKIs and rational combinations may further improve outcomes of NSCLC.

CRISPR/Cas9 Technology-Based Xenograft Tumors as Candidate Reference Materials for Multiple EML4-ALK Rearrangements Testing

The echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (ALK) receptor tyrosine kinase (EML4-ALK) rearrangement is an important biomarker that plays a pivotal role in therapeutic decision making for non-small-cell lung cancer (NSCLC) patients. Ensuring accuracy and reproducibility of EML4-ALK testing by fluorescence in situ hybridization, immunohistochemistry, RT-PCR, and next-generation sequencing requires reliable reference materials for monitoring assay sensitivity and specificity. Herein, we developed novel reference materials for various kinds of EML4-ALK testing. CRISPR/Cas9 was used to edit various NSCLC cell lines containing EML4-ALK rearrangement variants 1, 2, and 3a/b. After s.c. inoculation, the formalin-fixed, paraffin-embedded (FFPE) samples from xenografts were prepared and tested for suitability as candidate reference materials by fluorescence in situ hybridization, immunohistochemistry, RT-PCR, and next-generation sequencing. Sample validation and commutability assessments showed that all types of FFPE samples derived from xenograft tumors have typical histological structures, and EML4-ALK testing results were similar to the clinical ALK-positive NSCLC specimens. Among the four methods for EML4-ALK detection, the validation test showed 100% concordance. Furthermore, these novel FFPE reference materials showed good stability and homogeneity. Without limitations on variant types and production, our novel FFPE samples based on CRISPR/Cas9 editing and xenografts are suitable as candidate reference materials for the validation, verification, internal quality control, and proficiency testing of EML4-ALK detection.

A large, single-center, real-world study of clinicopathological characteristics and treatment in advanced ALK-positive non-small-cell lung cancer

Crizotinib has achieved astonishing success in advanced non-small-cell lung cancer (NSCLC) patients harboring anaplastic lymphoma kinase (ALK) rearrangement. However, no real-world studies described the clinicopathological characteristics and treatment of such patients in China. Patients were consecutively collected from Sun Yat-sen University Cancer Center. Chi-square test was applied to explore the relationship between ALK fusion status and metastasis sites. Kaplan-Meier methods and multivariable analyses were used to estimate progression-free survival (PFS). A total of 291 advanced NSCLC patients (ALK (+), N = 97; both ALK & epidermal growth factor receptor (EGFR) (-), N = 194) were enrolled. The occurrence of brain metastasis in ALK-positive patients was significantly higher than double-negative ones both at baseline (26.5% vs. 16.5%, P = 0.038) and during treatment (25.8% vs. 11.9%, P = 0.003), but opposite for pleural effusion (6.2% vs. 26.9%, P < 0.001 at baseline; 3.1% vs. 10.3%, P = 0.031 during treatment). ALK-positive patients of 53.6% used crizotinib, whereas others only received chemotherapy (37.1%) or supportive care (9.3%). Usage of crizotinib prolonged PFS compared with chemotherapy in ALK-positive patients (median PFS 17.6 m vs. 4.8 m, P < 0.001). ALK-positive NSCLC had more brain metastasis and less pleural effusion than double-negative ones. Crizotinib showed better PFS than chemotherapy in advanced ALK-positive NSCLC at any line. However, half advanced ALK-positive patients never received crizotinib, which was grim and need improving.