The prevalence of EGFR mutations in non‐small cell lung cancer in an unselected Caucasian population

EGFR mutation frequencies in unselected Caucasian populations are unknown. This study assesses the prevalence of EGFR mutations in an unselected population‐based cohort, and the correlation between mutation and gender, age, ethnicity, smoking habits, and pathological data. NSCLC patients diagnosed in a well‐defined Danish population were included. The type of the diagnostic material, and data on smoking were registered. The mutation analyses were investigated by Therascreen EGFR RGQ‐PCR Kit or Sanger sequencing. A total of 658 men and 598 women were included. 6.2% were never smokers, 38.9% were ex‐smokers, and 54.9% were current smokers. One thousand one hundred and sixty‐one (92.4%) patients had sufficient material for mutation analysis. Cytological material was used for 38% of the mutation analyses. 5.4% had mutation in the EGFR gene (4.3% men/6.7% women). 87% were activating mutations. 8.0% of adenocarcinomas, and 1.9% of squamous cell carcinomas were mutated. 29.4%, 4.4% and 2.9% of never, ex‐ and current smokers were mutated (p < 0.001). No difference in mutation rate was observed between patients with cytology only, histology only or both cytology and histology available. 5.4% of the patients had EGFR mutation. Adenocarcinomas were mutated more often (8.0%) than squamous cell carcinomas (1.9%). Mutations were found in never smokers as well as in former and current smokers. No difference in gender and age regarding mutation status was observed. EGFR mutations analysis was possible in almost all patients with no difference between cytology and histology specimens.     

Screening for ALK abnormalities in central nervous system metastases of non‐small‐cell lung cancer

Anaplastic lymphoma kinase (ALK) gene rearrangement was reported in 3%–7% of primary non‐small‐cell lung cancer (NSCLC) and its presence is commonly associated with adenocarcinoma (AD) type and non‐smoking history. ALK tyrosine kinase inhibitors (TKIs) such as crizotinib, alectinib and ceritinib showed efficiency in patients with primary NSCLC harboring ALK gene rearrangement. Moreover, response to ALK TKIs was observed in central nervous system (CNS) metastatic lesions of NSCLC. However, there are no reports concerning the frequency of ALK rearrangement in CNS metastases. We assessed the frequency of ALK abnormalities in 145 formalin fixed paraffin embedded (FFPE) tissue samples from CNS metastases of NSCLC using immunohistochemical (IHC) automated staining (BenchMark GX, Ventana, USA) and fluorescence in situ hybridization (FISH) technique (Abbot Molecular, USA). The studied group was heterogeneous in terms of histopathology and smoking status. ALK abnormalities were detected in 4.8% (7/145) of CNS metastases. ALK abnormalities were observed in six AD (7.5%; 6/80) and in single patients with adenosuqamous lung carcinoma. Analysis of clinical and demographic factors indicated that expression of abnormal ALK was significantly more frequently observed (P = 0.0002; χ² = 16.783) in former‐smokers. Comparison of IHC and FISH results showed some discrepancies, which were caused by unspecific staining of macrophages and glial/nerve cells, which constitute the background of CNS tissues. Their results indicate high frequency of ALK gene rearrangement in CNS metastatic sites of NSCLC that are in line with prior studies concerning evaluation of the presence of ALK abnormalities in such patients. However, they showed that assessment of ALK by IHC and FISH methods in CNS tissues require additional standardizations.     

Molecular breakdown: a comprehensive view of anaplastic lymphoma kinase (ALK)‐rearranged non‐small cell lung cancer

Most anaplastic lymphoma kinase (ALK)‐rearranged non‐small cell lung cancers (NSCLCs) show good clinical response to ALK inhibitors. However, some ALK‐rearranged NSCLC patients show various primary responses with unknown reasons. Previous studies focused on the clinical aspects of ALK fusions in small cohorts, or were conducted in vitro and/or in vivo to investigate the function of ALK. One of the suggested theories describes how echinoderm microtubule‐associated protein‐like 4 (EML4)–ALK variants play a role towards different sensitivities in ALK inhibitors. Until now, there has been no integrated comprehensive study that dissects ALK at the molecular level in a large scale. Here, we report the largest extensive molecular analysis of 158 ALK‐rearranged NSCLCs and have investigated these findings in a cell line construct experiment. We discovered that NSCLCs with EML4–ALK short forms (variant 3/others) had more advanced stage and frequent metastases than cases with the long forms (variant 1/others) (p = 0.057, p < 0.05). In vitro experiments revealed that EML4–ALK short forms show lower sensitivity to ALK inhibitors than do long forms. Clinical analysis also showed a trend for the short forms showing worse PFS. Interestingly, we found that breakpoints of ALK are evenly distributed mainly in intron 19 and almost all of them undergo a non‐homologous end‐joining repair to generate ALK fusions. We also discovered four novel somatic ALK mutations in NSCLC (T1151R, R1192P, A1280V, and L1535Q) that confer primary resistance; all of them showed strong resistance to ALK inhibitors, as G1202R does. Through targeted deep sequencing, we discovered three novel ALK fusion partners (GCC2, LMO7, and PHACTR1), and different ALK fusion partners showed different intracellular localization. With our findings that the EML4–ALK variants, new ALK somatic mutations, and novel ALK‐fusion partners may affect sensitivity to ALK inhibitors, we stress the importance of targeted therapy to take the ALK molecular profiling into consideration. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Prognostic significance of urokinase plasminogen activator receptor and its cleaved forms in blood from patients with non‐small cell lung cancer

Urokinase plasminogen activator (uPA) cleaves its three‐domain cell surface receptor, uPAR, liberating domain I [uPAR(I)] and leaving the cleaved uPAR(II‐III) on the cell surface. Both intact and cleaved uPAR can be shed from the cell surface. uPAR(I) was previously shown to be a prognostic factor in lung tumour extracts. Here we analyse uPAR forms in blood from patients with non‐small cell lung cancer (NSCLC). Preoperatively sampled plasma/serum from 32 patients with NSCLC was analysed. Three time‐resolved fluoroimmunoassays (TR‐FIAs) measuring intact uPAR(I‐III) (TR‐FIA 1), uPAR(I‐III) + uPAR(II‐III) (TR‐FIA 2) and uPAR(I) (TR‐FIA 3) were applied. The Spearman rank correlations between plasma and serum levels of uPAR(I‐III), uPAR(I‐III) + uPAR(II‐III), and uPAR(I) were 0.89, 0.94 and 0.68 respectively. Survival analysis demonstrated that high levels of all uPAR forms were associated with shorter survival. Adjusted for histological subtype high plasma uPAR(I‐III) and uPAR(I) levels as well as serum uPAR(I) levels were significantly associated with shorter OS (hazards ratios = 4.3, 2.8 and 3.8 respectively). High blood levels of intact uPAR and its cleaved forms are associated with poor prognosis in NSCLC.     

Cytomorphology of non‐small cell lung carcinoma with anaplastic lymphoma kinase gene rearrangement

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase demonstrating activating mutations in several malignancies including a subset (1–5%) of non‐small cell lung carcinomas (NSCLC). Prior work examining, the histologic features of these tumors found a spectrum of findings, notably a solid/acinar pattern, as well as a mucinous cribriform pattern. We present the first study to date describing the cytomorphology of NSCLC harboring ALK rearrangements. A retrospective database search was conducted to identify cytologic specimens of NSCLC demonstrating ALK rearrangement. Cytogenetic analysis was performed with fluorescence in situ hybridization. A total of 12 patients were identified, 10 with available material. Cellular morphology and smear background was evaluated in the study group, as well as control cases lacking ALK rearrangement. A total of 25 specimens from 10 patients were obtained. Five patients never smoked, and four patients had a remote smoking history. ALK rearrangements were identified in cells with unique cytologic characteristics. All cases demonstrated moderate to poor differentiation with a predominance of single cells showing anisonucleosis and frequent intracytoplasmic neutrophils. The control cases showed cells with smaller, less pleomorphic nuclei, and smaller nucleoli with more clusters/tissue fragments. Several unique cytomorphologic features were consistently identified in the study population relative to the control population and include a prominence of single, markedly enlarged tumor cells with plasmacytoid features and anisonucleosis, as well as intracytoplasmic neutrophils. Larger studies are warranted to confirm our preliminary findings, as these features may help establish a more cost‐effective means to select patients being tested for ALK mutational analysis. Diagn. Cytopathol. 2015;43:8–15. © 2014 Wiley Periodicals, Inc.     

Heparin co‐factor II enhances cell motility and promotes metastasis in non‐small cell lung cancer

Using the Serial Analysis of Gene Expression (SAGE) database from the Cancer Genome Anatomy Project, we identified heparin co‐factor II (HCII), which is over‐expressed in non‐small cell lung cancer (NSCLC). Here, we investigated the clinical significance of HCII and provided molecular evidence to support the suggestion that HCII could enhance cancer metastasis in NSCLC. We found that high HCII expression in tumour tissue was associated with increased cancer recurrence and shorter overall survival times in 75 clinically operable NSCLC patients. High pretreatment plasma concentration of HCII was associated with reduced overall survival in 57 consecutive NSCLC patients. We over‐expressed and knocked down HCII expression in lung cancer cell lines and confirmed that HCII could promote cell motility, invasion ability and filopodium dynamics in NSCLC cells in vitro and increased metastatic colonization in an in vivo mouse model. Exogenous treatment of HCII promoted cancer cell migration, and this promigratory effect of HCII was independent of thrombin. We further showed that HCII could up‐regulate cancer cell migration through the activation of PI3K, which acts upstream of Rac1 and Cdc42, and this effect could be blocked by heparin. We suggest that HCII is a novel metastasis enhancer and may be used as a prognostic predictor for heparin treatment in NSCLC. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd     

Interleukin 17A genetic variations and susceptibility to non‐small cell lung cancer

Lung cancer is the leading cause of cancer‐related death, in which non‐small cell lung cancer (NSCLC) is the most common type. Evidence have shown that interleukin 17 (IL‐17) greatly involves in human immune responses. In this study, we investigated the effect of IL‐17 on NSCLC by examining the association between IL‐17A genetic polymorphisms and the susceptibility to NSCLC. IL‐17A ‐420A/G and IL‐17A ‐73G/A polymorphisms were detected in 330 NSCLC patients and 382 healthy controls. We found that subjects carrying ?73GA genotype or AA genotype had 2.09‐fold or 2.52‐fold increased risk of NSCLC than those with ?73GG genotype [odds ratio (OR) = 2.09, 95% confidence interval (CI), 1.46 – 2.98, p < 0.001; OR = 2.52, 95% CI, 1.30–4.88, p = 0.005, respectively). However, the IL‐17A ‐420A/G did not reveal any correlation with the cancer. Further investigation showed that prevalence of IL‐17A ?73GA genotype and A allele were significantly increased in adenocarcinoma patients (OR = 1.75, 95% CI, 1.08–2.86, p = 0.024, OR = 1.57, 95% CI, 1.09–2.28, p = 0.016, respectively). We also evaluated the effect of the polymorphisms on gene expression, and identified that peripheral blood mononuclear cells with IL‐17A ‐73GA and AA genotypes produced significantly higher level of IL‐17 than the cells with IL‐17A ‐73GG genotype. Our results suggest that IL‐17A ‐73G/A genetic variations may upregulate IL‐17 expression and are associated with increased susceptibility to NSCLC.     

Immunohistochemical analysis of the expression of E‐cadherin and ZEB1 in non‐small cell lung cancer

We performed an immunohistochemical analysis of the expression of zinc‐finger E‐box binding homeobox 1 (ZEB1), a master regulator of epithelial‐mesenchymal transition (EMT), and determined its relationship with E‐cadherin in 157 non‐small cell lung carcinomas (93 adenocarcinomas, 36 squamous cell carcinomas, 18 large cell carcinomas, and 10 pleomorphic carcinomas). Although the expression of E‐cadherin was low in the subset of adenocarcinomas (10%) and squamous cell carcinomas (11%), ZEB1 expression was only observed in one case of squamous cell carcinoma and none of the adenocarcinomas. In contrast, the low expression of E‐cadherin (50% and 90%, respectively) and the positive expression of ZEB1 (11% and 50%, respectively) were more frequently observed in poorly differentiated carcinomas (large cell carcinomas and pleomorphic carcinomas). Overall, the expression of ZEB1 was inversely correlated with that of E‐cadherin. Furthermore, the distribution of ZEB1‐positive cancer cells was more restricted than in the area in which the expression of E‐cadherin was lost, and the former was detected within the latter. We concluded that the expression of ZEB1 was not necessarily associated with the low expression of E‐cadherin in lung adenocarcinomas and squamous cell carcinomas. The expression of ZEB1 correlated with an undifferentiated and/or sarcomatoid morphology that may occur in the late stage of EMT.     

Frequent overexpression of ErbB – receptor family members in brain metastases of non‐small cell lung cancer patients

The ErbB receptor family has been implicated in brain metastases (BM) formation in various cancer types and specific targeted therapies are available. We investigated the overexpression of EGFR, HER2 and HER3 in BM of non‐small cell lung cancer (NSCLC) patients to get a better insight on pathobiology of BM and potential drugable targets. We performed immunohistochemical analysis of EGFR, HER2 and HER3 on tissue microarrays of 131 NSCLC‐BM. Fifty‐one of 131 (38.9%) specimens were considered as positive for EGFR overexpression, 12/131 (9.2%) for HER2 and 27/131 (20.6%) for HER3 respectively. Sixty‐nine of 131 (52.7%) of the cases showed overexpression of at least one marker. Four of 131 (3.1%) were positive for all three markers. Strong correlation was observed between HER2 and HER3 overexpression (p = 0.009; Chi‐square test after Bonferroni‐Holmes correction). No statistically significant correlation of EGFR, HER2 or HER3 overexpression with clinico‐pathological parameters including overall survival times was observed. We observed overexpression of ErbB receptor family members, which represent established therapeutic targets in various primary tumours, in approximately half of NSCLC‐BM. Further studies should investigate the role of the ErbB pathway in development of and as a therapeutic target in BM of NSCLC patients.