Echinoderm Microtubule-associated Protein-like 4-anaplastic Lymphoma Kinase Fusion Research Articles

Gastric mesenchymal tumor with smooth muscle differentiation and echinoderm microtubule‐associated protein‐like 4‐anaplastic lymphoma kinase (EML4‐ALK) fusion

Gastric mesenchymal tumors are relatively rare, and their molecular pathogeneses are poorly understood, except for gastrointestinal stromal tumor, desmoid, and inflammatory myofibroblastic tumors. We report a case of a gastric mesenchymal tumor with prominent smooth muscle cell differentiation and an echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion. On gross section, the tumor was 26 mm at the largest diameter, well-circumscribed, and located in the submucosal and muscular layers of the stomach wall. Histologically, the tumor comprised intersecting fascicles of spindle cells, non-atypical nuclei, and highly eosinophilic cytoplasm. Myxoid changes were observed focally, but inflammatory infiltrates were only evident in limited areas. Immunochemical staining revealed that the tumor was positive for α-smooth muscle actin and desmin. Diffuse positive staining for h-caldesmon was observed throughout the tumor, which suggested smooth muscle cell differentiation. Intracytoplasmic staining for ALK protein was also observed, and fluorescence in situ hybridization using ALK break-apart probes showed split chromosomal signals. RNA-sequencing analysis identified EML4-ALK fusion transcripts. We concluded that the tumor was a gastric mesenchymal tumor with smooth muscle differentiation based on its distinct differential smooth muscle properties, such as highly eosinophilic cytoplasm and diffuse expression of h-caldesmon. Furthermore, activated ALK may underly the tumor's pathogenesis.

Distribution of EML4-ALK fusion variants and clinical outcomes in patients with resected non-small cell lung cancer

ObjectivesThe molecular profiles and prognosis of anaplastic lymphoma kinase (ALK) fusion and resectable non-small cell lung cancer (NSCLC) remain unclear. This study aimed to explore the distribution of ALK fusion variants and prognostic factors in patients with surgically resected NSCLC. Material and methodsAmong the 93 ALK positive surgical patients screened by immunohistochemistry (IHC) or real-time polymerase chain reaction (RT-PCR), 63 patients were confirmed as ALK rearrangement by next-generation sequencing (NGS), including 55 cases of stage I-III and 8 cases of stage IV. Medical records were retrospectively reviewed, the distribution of ALK fusion variants and prognostic factors were analyzed. ResultsAll of the 55 early stage patients were histological adenocarcinoma. No other fusion types were found except for echinoderm microtubule-associated protein-like 4- anaplastic lymphoma kinase (EML4-ALK). EML4-ALK variant 1 (E13:A20; 25/55, 45.5 %) was the predominant variant type, followed by EML4-ALK variant 3 (E6:A20; 19/55, 34.5 %) and variant 2 (E20:A20; 8/55, 14.5 %). Concomitant mutations occurred in 22 patients (22/55, 40.0 %), which involved in 32 co-mutations from 12 kinds of mutated genes. TP53 mutations were most common in coexisting mutations (13/32, 40.6 %). TP53 mutations were less frequently occurred in variant 1 group (3/25, 12.0 %) than in non-variant 1 group (10/30, 33.3 %, P = 0.064). The median disease-free survival (DFS) of the 55 patients was 22.1 months, and the median overall survival (OS) was not mature at the time of analysis. Multivariable analysis showed that stage T3 and EML4-ALK variant 3 were independent prognostic factors for shorter DFS. Neither TP53 mutations nor any coexisting mutations were related to prognosis. ConclusionsThis study illustrated the patterns of EML4-ALK fusion variants and gene profiles in patients with resected NSCLC. Advanced T stage and EML4-ALK variant 3 were associated with worse prognosis. The role of TP53 mutations in prognosis is worthy of further study.

Screening of significant oncogenic changes in air pollution-related lung cancer in Chinese population.

BackgroundAir pollution-related lung cancer has been considered as a deteriorating public health problem worldwide, particularly in developing countries. The highly air polluted regions in China particularly Xuanwei and Fuyuan counties have markedly high lung cancer rates and are considered as good models to study air pollution-related lung cancer. The present study investigated the clinically significant oncogenes in air pollution-related lung cancers.MethodsA combination of reverse transcriptase PCR (RT-PCR) and DNA sequencing was applied to examine the expression, mutations, or fusions of target genes, including human epidermal growth factor receptor 2 (HER2), echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK), and cluster of differentiation 74-ROS proto-oncogene 1 (CD74-ROS1).ResultsOf the 82 patients with lung cancer, 20.7% (17/82) exhibited HER2 up-regulation, and 1.2% (1/82) harbored HER2 insertion at exon 20. HER2 overexpression was not associated with air pollution levels and smoking status. A total of 6.1% (5/82) samples exhibited ALK gene rearrangements; two belonged to EML4-E2 + ALK-E20 and three were EML4-E13 + ALK-E20; all the five cases occurred either in smokers or in patients from the most air-polluted region. A total of 3.6% (3/82) carried the CD74-ROS1 fusion gene (CD74-E6 + ROS1-E34); the fusion event was not statistically associated with air pollution levels.ConclusionsThe high rates of prevalence indicated in the present study suggest that the screening of HER2 overexpression and EML4-ALK fusion events may assist in guiding treatment in air pollution-related lung cancer; the RT-PCR-based test proposed in this study may be a useful tool in clinical applications to screen these genetic changes.

Clinicopathological and Prognostic Significance of EML4-ALK Rearrangement in Patients with Surgically Resected Lung Adenocarcinoma: A Propensity Score Matching Study.

ObjectiveThe echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene is a key oncogenic driver in non-small cell lung cancer (NSCLC). This study analyzed the clinicopathological characteristics and prognostic significance of EML4-ALK fusion gene in patients with surgically resected adenocarcinoma.MethodsThe clinicopathological characteristics of 1056 consecutive patients with surgically resected stage I–IIIA adenocarcinoma were collected from February 2014 to October 2014, and EML4-ALK rearrangement was detected using real-time polymerase chain reaction (RT-PCR) technology. To compare the imaging and pathological features, a propensity score matching (PSM) method was performed. The follow-up information was collected to evaluate the long-term outcomes of patients with EML4-ALK rearrangement.ResultsThe prevalence of EML4-ALK rearrangement was 6.6% in 1056 consecutive patients. A total of 70 EML4-ALK-positive and 210 EML4-ALK-negative patients were identified after PSM. Imaging and pathological analyses showed that EML4-ALK rearrangement was significantly associated with less ground-glass opacity (GGO) (adjusted OR=1.38, 95% CI=1.03–1.85, Ptrend=0.029) and higher prevalence of non-invasive mucinous adenocarcinoma mucin-laden adenocarcinomas (non-IMA MLA, adjusted OR=6.79, 95% CI=2.69–17.17, P<0.001). EML4-ALK rearrangement was found to be an unfavorable prognostic factor for disease-free survival (DFS) in female patients (HR=2.26, 95% CI=1.13–4.53, P=0.021).ConclusionOur results suggest that adenocarcinomas harboring EML4-ALK fusion gene exhibit specific radiological and pathological characteristics compared with EML4-ALK-negative adenocarcinomas. In female patients, EML4-ALK rearrangement was associated with shorter DFS.

Apatinib reverses alectinib resistance by targeting vascular endothelial growth factor receptor 2 and attenuating the oncogenic signaling pathway in echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene-positive lung cancer cell lines.

Overexpression of insulin growth factor 1 receptor (IGF-1R) and its ligand, insulin growth factor 1 (IGF-1), is related to treatment resistance and worse prognosis in many types of tumors. We reported recently that IGF-1R activation by IGF induces resistance to alectinib and stimulates the production of vascular endothelial growth factor, which indicates that IGF induces alectinib resistance and angiogenesis. This study aimed to determine the effect of bigeminal inhibition of anaplastic lymphoma kinase (ALK) and angiogenesis on human insulin growth factor 1 receptor (hIGF-1)-triggered drug resistance in echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-positive lung cancer. Human lung adenocarcinoma H3122 and H2228 cells were exposed to a combination of insulin growth factor 1 receptor (IGF-1), alectinib, or apatinib. The effects of the combination therapy were examined using cell the Cell Counting Kit-8 assay, the colony-forming assay, the scratch test, and flow cytometry analysis, and the molecular mechanism was assessed by western blot. At nontoxic concentrations, apatinib restored alectinib sensitivity by increasing drug-induced apoptosis and inhibiting viability, migration, and invasion in IGF-triggered drug resistant cells. Moreover, we found that apatinib restored sensitivity to alectinib mainly through suppression of the ALK downstream signaling pathway and antiangiogenesis signaling. Taken together, our results indicate that simultaneous inhibition of ALK and vascular endothelial growth factor R2 by the combination of alectinib with apatinib may be useful for controlling progression of EML4-ALK fusion gene lung cancer by reversing ALK-TKI resistance and inhibiting angiogenesis.

Clinical outcome study of crizotinib in immunohistochemistry-proven echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion gene among Indian patients with adenocarcinoma lung.

Aims:The anaplastic lymphoma kinase (ALK) Break Apart FISH Probe Kit and Ventana anti-ALK (D5F3) CDx immunohistochemistry (IHC) assay are the Food and Drug Administration-approved companion diagnostic for targeted therapy with the ALK inhibitor crizotinib in lung cancers. The aim of this study was to assess the efficacy and safety of twice daily crizotinib tablet (250 mg) in IHC-proven echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene among Indian patients with adenocarcinoma lung in the routine clinical practice.Subjects and Methods:Patients with nonsmall cell lung cancer (NSCLC), adenocarcinoma histology, whose tumors were found to be positive for EML4-ALK fusion gene using IHC, were considered for this study. IHC analysis was performed using a Ventana automated immunostainer (Benchmark XT). Detection was performed using Optiview DAB detection and amplification kit.Results:A total of 25 NSCLC adenocarcinoma patients were included in the study. There were 14 (56%) women and 10 (44%) men with a median age of 53 years. All patients had Stage IV disease at the time of initiation of crizotinib therapy. One patient achieved complete response and 20 achieved response rate (PR) for an overall PR of 84%. The median progression-free survival (PFS) was 11.8 months and median overall survival (OS) was 20.6 months. Two (8%) patients experienced severe hepatotoxicity requiring permanent discontinuation of crizotinib therapy.Conclusions:A very high PR, PFS, and OS achieved in our study population indicates that IHC can accurately identify EML4 ALK fusion gene mutations in lung adenocarcinoma patients who are responsive to ALK inhibitors such as crizotinib. IHC should be considered as a cost-effective alternative to FISH, especially in low-resource countries.

Clinicopathological and molecular epidemiological study of lung cancer patients seen at a tertiary care hospital in Northern India.

Aims:The primary objective of this study was to estimate the clinicopathological and molecular profile of lung cancer patients along with the evaluation of their clinical characteristics at a tertiary care hospital in Northern India.Subjects and Methods:A total of 421 patients with lung cancer histology who were treated at Max Super Speciality Hospitals were included in the study. The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki and permission was obtained from the Ethics Committee before the start of the study. Clinical characteristics and molecular profiling data were collected from the patient's medical records.Results:There were 330 (78.4%) men and 91 (21.6%) women with a median age of 62 years (range: 30–93 years). Of the 421 patients, 388 (92.2%) patients had the nonsmall cell lung cancer (NSCLC) histology whereas 33 (7.8%) patients were of SCLC histology. Histology and gender had a significant association with NSCLC and SCLC (P < 0.05). Epidermal growth factor receptor (EGFR) and echinoderm microtubule-associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene testing was done in 120 and 93 patients, respectively. Of the 120 patients, 24 (20%) cases were positive for EGFR mutations whereas EML4-ALK fusion gene was present in 8 (8.6%) out of 93 patients.Conclusions:Our study confirms the importance of molecular testing in the NSCLC patient subgroup with an aim to identify the exact molecular targets that can benefit from the newer generation of targeted therapies.

Gene Expression and Clinical Characteristics of Molecular Targeted Therapy in Non-small Cell Lung Cancer Patients in Shandong

背景与目的分子生物学靶向治疗已逐渐成为非小细胞肺癌（non-small cell lung cancer, NSCLC）的一个重要治疗手段，本研究通过分析山东地区NSCLC多种驱动基因表达情况及临床病理特征，为筛选分子靶向治疗目标人群提供理论依据。方法采用荧光探针PCR法检测表皮生长因子受体（epidermal growth factor receptor, EGFR）、棘皮动物微管相关蛋白4-间变性淋巴瘤激酶（echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase, EML4-ALK）、肉瘤致癌因子-受体酪氨酸激酶（ROS proto-oncogene 1, receptor tyrosine kinase, ROS1）、鼠类肉瘤病毒癌基因（Kirsten rat sarcoma viral oncgene, KRAS）基因表达情况，回顾性分析阳性病例的临床病理特征。结果EGFR基因突变阳性率为36.70%，主要为19、21外显子突变，突变人群主要为女性、腺癌、不吸烟患者，组间差异有统计学意义。EML4-ALK融合基因重排阳性率为9.37%。人群特征主要为60岁以下不吸烟人群，组间差异有统计学意义，基因突变与病理类型和性别间无明显差异。ROS1融合基因重排阳性率为3.67%，均为60岁以下患者，组间差异有统计学意义。23份病例标本开展KRAS基因检测，阳性标本数2例，阳性率为8.70%。2份阳性标本均为60岁以上病例，男女各占1例，病理类型均为腺癌，均无吸烟史。此外，未发现有两种基因同时突变的病例。结论EGFR、EML4-ALK、ROS1、KARS基因在NSCLC患者中存在较高的突变率，且具有不同的人群特征，在选择靶向治疗人群中具有重要意义。

Detection of Echinoderm Microtubule Associated Protein Like 4-Anaplastic Lymphoma Kinase Fusion Genes in Non-small Cell Lung Cancer Clinical Samples by a Real-time Quantitative Reverse Transcription Polymerase Chain Reaction Method.

Objective To establish a real-time quantitative reverse transcription polymerase chain reaction assay (qRT-PCR) for the rapid, sensitive, and specific detection of echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion genes in non-small cell lung cancer. Methods The specific primers for the four variants of EML4-ALK fusion genes (V1, V2, V3a, and V3b) and Taqman fluorescence probes for the detection of the target sequences were carefully designed by the Primer Premier 5.0 software. Then, using pseudovirus containing EML4-ALK fusion genes variants (V1, V2, V3a, and V3b) as the study objects, we further analyzed the lower limit, sensitivity, and specificity of this method. Finally, 50 clinical samples, including 3 ALK-fluorescence in situ hybridization (FISH) positive specimens, were collected and used to detect EML4-ALK fusion genes using this method. Results The lower limit of this method for the detection of EML4-ALK fusion genes was 10 copies/μl if no interference of background RNA existed. Regarding the method's sensitivity, the detection resolution was as high as 1% and 0.5% in the background of 500 and 5000 copies/μl wild-type ALK gene, respectively. Regarding the method's specificity, no non-specific amplification was found when it was used to detect EML4-ALK fusion genes in leukocyte and plasma RNA samples from healthy volunteers. Among the 50 clinical samples, 47 ALK-FISH negative samples were also negative. Among 3 ALK-FISH positive samples, 2 cases were detected positive using this method, but another was not detected because of the failure of RNA extraction. Conclusion The proposed qRT-PCR assay for the detection of EML4-ALK fusion genes is rapid, simple, sensitive, and specific, which is deserved to be validated and widely used in clinical settings.

Driven Gene in Patients with Lung Squamous Cell Carcinoma: Analysis of Clinicopathologic Characteristics and Prognosis

背景与目的表皮生长因子受体（epidermal growth factor receptor, EGFR）、间变淋巴瘤激酶（anaplastic lymphoma kinase, ALK）以及KRAS基因是非小细胞肺癌（non-small cell lung cancer, NSCLC）常见的驱动基因。多项临床研究已证实，EGFR敏感突变及棘皮动物微管相关类蛋白4-间变淋巴瘤激酶（echinoderm microtubule-associated protein like 4-anaplastic lymphoma kinase, EML4-ALK）基因重排的晚期肺腺癌患者，一线治疗选择靶向药物优于化疗，其在总缓解率（overall response rate, ORR）、无进展生存期（progression-free survival, PFS）及生活质量方面均有明显优势。然而，在肺鳞癌患者中，目前尚无明确的基因检测位点及靶向药物来指导临床治疗。本研究旨在分析肺鳞癌患者EGFR、ALK以及KRAS基因的突变状态，以及相关的临床病理特征，从而为今后的治疗提供相应指导。方法回顾性分析已行相关驱动基因检测的肺鳞癌患者90例，利用突变扩增阻滞系统（amplification refractory mutation system, ARMS）的方法进行EGFR及KRAS基因检测，荧光原位杂交（fluorescence in situ hybridization, FISH）技术进行ALK基因融合检测。结果90例患者均进行了EGFR及KRAS基因检测，8例患者为EGFR基因突变（8.8%）；2例患者为KRAS基因突变（2.2%）；18例患者通过FISH方法进行了ALK基因融合检测，1例患者存在EML4-ALK基因融合（5.6%）。女性患者的EGFR基因突变率高于男性（P=0.022）。EGFR突变及野生型患者在病理分期（P=0.042）及分化程度（P=0.003）上均有差异。以胸膜为首发转移部位的EGFR突变患者比率高于EGFR野生型患者（P=0.013）。靶向治疗与化疗对EGFR突变患者的PFS无影响（P=0.607）。结论ALK基因融合患者应用靶向治疗后可获得理想疗效。

Detection of EML4-ALK fusion gene and features associated with EGFR mutations in Chinese patients with non-small-cell lung cancer.

PurposeEchinoderm microtubule-associated protein-like 4–anaplastic lymphoma kinase (EML4-ALK) and epidermal growth factor receptor (EGFR) define specific molecular subsets of lung cancer with distinct clinical features. We aimed at revealing the clinical features of EML4-ALK fusion gene and EGFR mutation in non-small-cell lung cancer (NSCLC).MethodsWe enrolled 694 Chinese patients with NSCLC for analysis. EML4-ALK fusion gene was analyzed by real-time polymerase chain reaction, and EGFR mutations were analyzed by amplified refractory mutation system.ResultsAmong the 694 patients, 60 (8.65%) patients had EML4-ALK fusions. In continuity correction χ2 test analysis, EML4-ALK fusion gene was correlated with sex, age, smoking status, and histology, but no significant association was observed between EML4-ALK fusion gene and clinical stage. A total of 147 (21.18%) patients had EGFR mutations. In concordance with previous reports, EGFR mutation was correlated with age, smoking status, histology, and clinical stage, whereas patient age was not significantly associated with EGFR mutation. Meanwhile, to our surprise, six (0.86%) patients had coexisting EML4-ALK fusions and EGFR mutations.ConclusionEML4-ALK fusion gene defines a new molecular subset in patients with NSCLC. Six patients who harbored both EML4-ALK fusion genes and EGFR mutations were identified in our study. The EGFR mutations and the EML4-ALK fusion genes are coexistent.

Distinct epithelial growth factor receptor mutation profile in non-small-cell lung cancer patients from the Xuanwei area of China

The Xuanwei county in China has a high incidence of lung cancer and related mortality. Previous studies have suggested that these cases may be associated with a distinctive pattern of mutations in the epithelial growth factor receptor (EGFR) gene. In this retrospective study, we investigated the mutation profile of EGFR in non-small-cell lung cancer (NSCLC) tissues from patients in Xuanwei, and the associated clinicopathological characteristics. Specimens from 258 consecutive patients with lung cancer (90 from Xuanwei and 168 from other areas of Yunnan province) were subjected to amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) to detect EGFR mutations. In 67 specimens from Xuanwei, the results were confirmed by direct DNA sequencing for EGFR mutations. Immunohistochemistry (IHC) for the echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion protein was performed on all specimens from Xuanwei. We observed that Xuanwei patients presented with distinctive clinicopathological characteristics, including female gender predominance, younger age, higher rate of lymph node metastasis, higher rate of adenocarcinoma histological classification and lower disease stage, and a low rate of the ‘classical’ mutations on EGFR exons 19 and 21 compared with non-Xuanwei patients (7.8 and 21.6% vs. 49.3 and 39.7%, respectively; P<0.05 for combined data). However, a significantly higher percentage of Xuanwei patients harbored co-mutation of EGFR exons 18 and 20 compared with non-Xuanwei patients (45.1 vs. 4.1%, respectively; P<0.0001). Specimens from 2 Xuanwei patients (2.2%) were positive for the EML4-ALK fusion protein; by IHC, neither harbored EGFR mutations. There was no obvious association between EGFR mutations and disease stage or lymph node involvement. Thus, NSCLC patients in Xuanwei presented with a unique EGFR profile of high rates of co-mutation of exons 18 and 20, and low rates of exon 19 or 21 mutations when compared with patients from other areas in the same province, whereas only few of the tumors from Xuanwei patients expressed the EML4-ALK oncogene.

Constitution of ALK fusion variants in East Asian lung adenocarcinoma

The purpose of the study is to investigate the constitution of anaplastic lymphoma kinase (ALK) fusion variants in East Asian lung adenocarcinoma (LUAC) patients and to provide instructional data for the variants that should be included in the companion diagnostic assay to screen for ALK positive patients. From June 2014 to August 2015, 158 ALK fusion positive formalin-fixed, paraffin-embedded (FFPE) samples were identified, including 3 patient-derived xenograft (PDX) tissues and 155 resected or fine needle aspiration (FNA) tissues, all derived from Korean or Chinese patients. Either purified RNA or crude tissue lysate from the 158 FFPE samples were analyzed by NanoString nCounter Elements assay with a multiplexed probe mix in a single tube targeting ALK fusion transcripts including 29 known variants. Of the total 158 ALK fusion positive samples, 133 samples harbored echinoderm microtubule-associated protein-like 4 ALK (EML4-ALK) fusion, 4 samples harbored Kinesin Family Member 5B ALK (KIF5B-ALK) fusion, 4 samples harbored huntingtin interacting protein 1 ALK (HIP1-ALK) fusion, 1 sample harbored kinesin light chain 1 ALK (KLC1-ALK) fusion, and the remaining 16 samples harbored novel fusion variants. Of the 133 EML4-ALK positive samples, 55 samples harbored E13:A20 variants (Variant 1), 55 samples harbored E6:A20 (Variant 3), 16 samples harbored E20:A20 (Variant 2), 4 samples harbored E18:A20 and 3 samples harbored E2:A20. This is the largest molecular epidemiological study to describe ALK fusion variants in East Asian LUAC patients. EML4 is the most common fusion partner of ALK gene. About 84% of ALK fusion positive patients harbor EML4-ALK, and 5.7% harbor non-EML4-ALK fusions. The remaining 10% harbor fusions with unknown partners. For EML4-ALK, E13:A20 and E6:A20 are the most common variants, comprising more than 80% of EML4-ALK fusion. E20:A20, E18:A20 and E2:A20 are also identified in East Asian patients. The constitution of EML4-ALK fusion variants is similar to the previous reports of patient cohorts in western countries. All the ALK fusion variants mentioned should be included in the LUAC fusion screening assays.

EML4-ALK translocation is associated with early onset of disease and other clinicopathological features in Chinese female never-smokers with non-small-cell lung cancer.

Non-small-cell lung cancer (NSCLC) with echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) translocation is resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), including gefitinib and erlotinib, but responds to the ALK-TKI crizotinib. Characterization of EML4-ALK translocation may provide invaluable information to facilitate disease diagnosis and improve the outcome of customized treatment. Although the occurrence of EML4-ALK translocation is likely to be affected by the smoking habits and gender of patients, the translocation has not been characterized extensively in female never-smokers with NSCLC. Therefore, 280 female never-smokers that were diagnosed with NSCLC were enrolled in the present study, and characteristics of EML4-ALK translocation, including the frequency, were determined in these NSCLC patients. EML4-ALK fusion variants were detected using Multiplex one-step reverse transcription-polymerase chain reaction and subsequently confirmed by DNA sequencing and Vysis ALK Break Apart fluorescence in situ hybridization analysis. The EML4-ALK fusion variants were detected in 21 carcinoma tissue specimens, accounting for 7.5% of the enrolled patients. Out of these patients with EML4-ALK fusion variants, EML4-ALK fusion variant 1 was identified in 12 patients, indicating that variant 1 is the most common type of EML4-ALK fusion gene in the present cohort of patients. ALK mRNA was aberrantly expressed in all the tissues with EML4-ALK translocation, but not in the carcinoma tissues without EML4-ALK translocation. In addition, the EML4-ALK translocation was more frequently found in younger patients. The median age of patients with EML4-ALK translocation was 50.95±2.29 years, which was significantly younger (P<0.01) than the median age of the patients without EML4-ALK translocation (57.15±0.56). The EML4-ALK translocation was detected exclusively in undifferentiated tumors that were graded as poorly- or moderately-differentiated carcinomas and suspected to be more malignant compared with well-differentiated tumors. In summary, the present study found that 7.5% of patients with NSCLC that are female never-smokers harbor EML4-ALK translocations, which are associated with the aberrant expression of ALK mRNA, early onset of disease and undifferentiated carcinomas.

Abstract 545: Plasma-based diagnostics for detection of EML4-ALK fusion transcripts in NSCLC patients

Abstract Introduction: The EML4-ALK (echinoderm microtubule-associated protein-like 4/anaplastic lymphoma kinase) translocation represents a predictive driver mutation in non-small cell lung cancer (NSCLC). As EML4-ALK is both associated with resistance to EGFR inhibitors and druggability with FDA approved ALK kinase inhibitors, molecular profiling of the respective fusion transcripts is an important prerequisite for therapy. Ongoing clinical trials and development of new ALK inhibitors for personalized treatment also emphasize the need for development of accompanying diagnostics. Today's determination of EML4-ALK fusions is based on biopsies and fine-needle aspirates. These techniques are constrained by surgical complications, availability of tissue and sample heterogeneity. To overcome these challenges, the mutational analysis of fusion transcripts in plasma is expected to be a valuable benefit for non-surgical and longitudinal monitoring of EML4-ALK positive NSCLC patients. Experimental procedures: Using our proprietary column-based method to isolate vesicle-derived RNA from a few ml of patient plasma from NSCLC patients, we were able to consistently and reproducibly isolate sufficient amounts of high quality exoRNA. The purified exoRNA was subjected to RT-qPCR screening for EML4-ALK fusion transcripts, with assays designed to independently detect fusion transcripts of EML4-ALK variants v1, v2 and v3. During development of the qPCR, assay performance was characterized on synthetic nucleic acid oligos spiked into plasma of healthy human donors. The diagnostic assay was finally validated on time-matched tissue and plasma samples derived from NSCLC patients. Summary: Our data demonstrates the ability to detect rare predictive mutations in exosomal and other vesicular-derived RNA transcripts isolated from patient plasma. Here, NSCLC samples were characterized by monitoring their expression profile of EML4-ALK variants. The qPCR assays specifically detected the three major fusion transcript variants representing more than 70% of all EML4-ALK positive cases. The assay displayed high selectivity over wild type background and data showed correlation with tissue analysis. Iterative modeling of the assay significantly improved specificity and sensitivity towards its application as a diagnostic test. Conclusions: Liquid biopsies represent a low-risk and comprehensive method to screen for predictive cancer markers in plasma of NSCLC patients during longitudinal monitoring. The efficient isolation of exosomal/vesicle-derived RNA via spin column enables subsequent analysis of rare fusion transcripts for diagnostic development. As a proof of concept, we implemented a qPCR-based assay to determine EML4-ALK translocations in plasma from NSCLC patients, indicating the feasibility of developing a diagnostic test, which could facilitate effective personalized treatment. Citation Format: Kay Brinkmann, Daniel Enderle, Tina Koestler, Stefan Bentink, Jennifer Emenegger, Alexandra Spiel, Romy Mueller, Vincent O'Neill, Johan Skog, Mikkel Noerholm. Plasma-based diagnostics for detection of EML4-ALK fusion transcripts in NSCLC patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 545. doi:10.1158/1538-7445.AM2015-545

Frequency of EGFR Mutation and EML4-ALK fusion gene in Arab Patients with Adenocarcinoma of the Lung

Abstract Introduction: Improvement in the clinical outcome of lung cancer is likely to be achieved by identification of the molecular events that underlie its pathogenesis. The frequency of epidermal growth factor receptor (EGFR) mutations is ethnicity-dependent, with a higher proportion in Asian populations than in whites, while the incidence of EML4-ALK (echinoderm microtubule-associated-protein like 4-anaplastic lymphoma kinase) fusion gene ranged from 1.6% to 16.4% in patients with NSCLC and these individuals were distinct from those harbouring mutations in the epidermal growth factor receptor gene. This study was conducted to determine the frequency of EGFR mutation and EML4-ALK fusion gene in our population and to determine the effect of different clinicopathological features on the expression of those mutations in patients with lung adenocarcinoma. Results: EGFR mutations were detected in approximately 33% of our patients in this series; the most frequently detected mutation was exon 19 deletion. EML4-ALK fusion gene was detected in 7.3% of patients. Conclusion: Our population exhibited the incidence of EGFR mutation approximately similar to that reported in East Asia and Japanese patients, higher than that recorded in USA, and Australia. However, more studies with larger patients’ numbers are needed to verify this finding.

The role of immunohistochemical analysis in the evaluation of EML4-ALK gene rearrangement in lung cancer.

Among the mutations described in non-small cell lung carcinoma is a rearrangement resulting from an inversion within chromosome 2p leading to the formation of a fusion gene, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK). Fluorescence in situ hybridization (FISH) is the gold standard for the detection of ALK gene rearrangements. However, molecular methods are not readily available in all pathology laboratories. Immunohistochemistry (IHC) using an antibody directed against the EML4-ALK fusion protein provides a widely available alternative method of detection. We assessed whether IHC is a comparable and cost-effective alternative to FISH analysis for the detection of ALK gene rearrangements. A total of 110 non-small cell lung carcinoma cases (63 surgical/biopsy and 47 cytology specimens), previously tested for ALK gene rearrangements by FISH [7 (6.4%) positive for the rearrangement], were probed for the EML4-ALK fusion protein using a monoclonal EML4-ALK antibody, clone 5A4. Cells were considered to stain positive for ALK if >5% of cells showed cytoplasmic staining of at least grade 1 intensity (scale: 0 to 3). A cost analysis was performed using ALK IHC as a screening test. The sensitivity and specificity of the EML4-ALK IHC stain compared with ALK FISH analysis were 100% and 96%, respectively. All 7 FISH-positive cases stained positive by IHC, whereas 4 FISH-negative cases demonstrated positive staining. One of the 4 FISH-negative, IHC-positive cases harbored an EML4-ALK rearrangement by RT-PCR yielding 3 false-positive results overall. The κ agreement between IHC and FISH methods is 0.76 (substantial/excellent). The potential savings of implementing the ALK IHC as a screening method would be $10,418.21. Sensitivity of the EML4-ALK IHC stain is excellent (100%) but due to its suboptimal specificity, IHC cannot reliably supplant FISH analysis for the detection of ALK gene rearrangements. IHC shows promise as a screening tool to prevent unnecessary costly FISH analysis.

Anaplastic lymphoma kinase translocation is correlated with anaplastic lymphoma kinase expression and mutually exclusive with epidermal growth factor receptor mutation in Taiwanese non-small cell lung cancer.

The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene is an important biomarker for target therapy. The aim of this study is to better understand the clinical and molecular features of the EML4-ALK fusion gene in lung cancer patients in Taiwan and therefore to generate an efficient algorithm for the detection of ALK translocation. In the first cohort, ALK translocation was identified in 1 adenocarcinoma from 100 lung cancer patients by using break apart fluorescent in situ hybridization (FISH). Next, we detected 6 ALK translocations in another 40 EGFR wild type adenocarcinomas but not in 40 cases with EGFR mutation. Histological analysis revealed that solid growth with signet-ring cells or cribriform glands with extracellular mucin were noted in all the 7 ALK translocated cases. One ALK positive cancer with mucinous cribriform pattern had no ALK expression. ALK expression was correlated with ALK translocation (p < 0.001), but not with ALK gene copy number gain (CNG) (P = 0.838). ALK translocation was also mutually exclusive with EGFR mutation in Taiwanese non-small cell lung cancer (P = 0.033). These results indicate that screening tests for EGFR mutation status and/or ALK expression could help efficiently select ALK translocated patients for target therapy.

Response to erlotinib in a patient with lung adenocarcinoma harbouring the EML4-ALK translocation: A case report.

Lung cancer is the leading cause of cancer-associated mortality worldwide, and the mainstay of treatment remains to be personalised therapy. Tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKIs) have been reported to exert a significant impact in the treatment of non-small cell lung cancer (NSCLC), particularly in patients harbouring mutations in the EGFR gene. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) gene translocation has been described in a subset of patients with NSCLC and possesses potent oncogenic activity. This translocation represents one of the most novel molecular targets in the treatment of NSCLC. Patients who harbour the EML4-ALK rearrangement possess lung tumours that lack EGFR or K-ras mutations. The present study reports the case of a patient possessing the EML4-ALK rearrangement that was initially treated with erlotinib and achieved a lasting clinical response. To the best of our knowledge, the current study is the first report of a clinical response to EGFR-TKI in a patient with lung adenocarcinoma harbouring the EML4-ALK fusion gene, but no EGFR mutations. However, as the disease progressed, the ALK gene status of the tumour was investigated, and based upon a positive result, the patient was treated with crizotinib and achieved a complete response. In conclusion, the present study suggests that the EML4-ALK rearrangement is not always associated with resistance to EGFR-TKIs. Further studies are required to clarify the biological features of these tumours and to investigate the mechanisms underlying the primary resistance to EGFR-TKIs when the EML4-ALK rearrangement is present.

Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase rearrangement and epidermal growth factor receptor mutation coexisting in Chinese patients with lung adenocarcinoma.

The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) rearrangement is almost in mutual exclusion to epidermal growth factor receptor (EGFR) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations, with rare exceptions. This study aimed to search for the coexisting gene alterations in Chinese patients with lung adenocarcinoma (LAC). We detected mutations in the EGFR, KRAS, and ALK gene rearrangements in samples from 131 Chinese patients with LAC. ALK rearrangements were identified by fluorescent in situ hybridization. Mutations in EGFR (exons 19 to 21) and KRAS (codons 12 and 13) were determined by real time polymerase chain reaction. All patients were classified into four distinct genotype groups: EGFR mutations (n = 63; 48.1%), ALK rearrangements (n = 9; 6.9%), KRAS mutations (n = 8; 6.1%), and the wild-type (unmutated) genotype of all three genes (WT/WT/WT) (n = 53; 40.5%). Interestingly, two never-smoking women (2/131, 1.5%) harbored coexisting ALK rearrangement and EGFR mutation. ALK rearrangement occurred more frequently in young patients (8/9) (P = 0.687), non-smokers (8/9) (P = 0.077), and those who had no family history of LAC (8/9) (P = 1.000); all KRAS mutations occurred in the EGFR wild type (P = 0.007). KRAS mutations were generally detected in young patients (6/8) (P = 0.658) and in those who had no family history (7/8) (P = 1.000); EGFR mutations correlated with gender (P = 0.001), and smoking status (P < 0.001). Two patients harboring both EGFR mutation and EML4-ALK rearrangement were detected in this study. Our data was apparently inconsistent with the traditional view that the EML4-ALK fusion gene in patients is resistant to EGFR-TKIs.