Immunohistochemistry to identify EGFR mutations or ALK rearrangements in patients with lung adenocarcinoma

Comprehensive molecular analysis of driver mutations in non-small cell lung carcinomas and its correlation with PD-L1 expression, An Indian perspective

BACKGROUND

The understanding of molecular mechanisms involved in non-small cell lung carcinoma (NSCLC) has revolutionized significantly in the recent years. These have helped to develop personalized management strategies by identifying specific molecular alterations such as mutations in EGFR, ROS1, BRAF, ERBB2, MET, ALK, and KRAS genes. These mutations are targetable ensuring a better clinical outcome. Next-generation sequencing (NGS) methodology is the recommended technique for the identification of driver mutations in the five hot-spot genes (EGFR, ALK, ROS1, MET, and BRAF) involved in the NSCLC. NGS has numerous advantages including multiplexing, tissue conservation, identification of rare and novel variants, and reduced cost over the sequential single gene testing. Herein, we sought to demonstrate the mutational profile in NSCLC and their clinicopathologic correlation in a contemporary cohort of Indian NSCLC patients. Additionally, we studied the correlation of oncogenic driver mutations with PD-L1 status in these patients.

MATERIALS AND METHODS

Five fifty-two stage IV NSCLC patients (adenocarcinoma=490; squamous cell carcinoma=51; adenosquamous carcinoma=5; large cell carcinoma=2; sarcomatoid carcinoma=3; spindle cell carcinoma=1) underwent broad molecular profiling by a custom-made, targeted DNA- and RNA-based five hot-spot genes lung cancer panel (EGFR, ALK, ROS1, BRAF, and MET), compatible with the NGS Ion S5 system. The mutations were correlated with the clinicopathologic characteristics. Additionally, PD-L1 expression status, available on 252 tumors, was correlated with the oncogenic drivers.

RESULTS

Validation of the 5 gene panel yielded the following results: a) specificity of 99.74%; b) sensitivity of 100% for single nucleotide variants (SNVs) (>5% variant allele frequency, VAF), indels (>10% VAF) and fusions; c) 100% intra- and inter-run reproducibility; d) 88% inter-laboratory agreement. Validated panel was then used to analyze clinical samples. Sixty percentage tumors harbored either one (54.71%) or multiple (3.26%) mutations. EGFR and BRAF V600E mutations, ALK and ROS1 rearrangements, and MET exon 14 skipping mutation were observed in 38.41% (n = 212) and 2.72% (n = 15) patients, 12.14% (n = 67) and 3.62% (n = 20) patients, and 1.09% (n = 6) patients, respectively. EGFR exon 19 deletion accounted for 52.83% of all mutations, followed by L858R (35.85%), T790M (5.19%), exon 20 insertions (6.6%), and other rare mutations (G719X, L861Q, S768I) (9.91%). Concurrent EGFR with ALK, EGFR with ROS1, EGFR with MET, and EGFR with BRAF were observed in 10, 4, 1, and 3 patients, respectively. PD-L1 was expressed in 134 patients (53.2%). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors.

CONCLUSIONS

This is one of the largest cohorts of NSCLC for comprehensive targeted mutational profiling and correlation with the PD-L1 expression. The mutations are more prevalent in non-smoker females for all genes, except ALK (non-smoker males). MET and BRAF mutations are more common in elderly population whereas EGFR mutations, and ALK and ROS1 genes rearrangements are more prevalent in younger population. The most common histopathologic subtype/feature associated with various mutations was as follows: acinar with EGFR, solid with ALK, macronucleoli with ROS1, signet ring with MET, and micropapillary with BRAF.

Development of an immuno-wall device for the rapid and sensitive detection of EGFR mutations in tumor tissues resected from lung cancer patients

Detecting molecular targets in specimens from patients with lung cancer is essential for targeted therapy. Recently, we developed a highly sensitive, rapid-detection device (an immuno-wall device) that utilizes photoreactive polyvinyl alcohol immobilized with antibodies against a target protein via a streptavidin–biotin interaction. To evaluate its performance, we assayed epidermal growth factor receptor (EGFR) mutations, such as E746_A750 deletion in exon 19 or L858R substitution in exon 21, both of which are common in non-small cell lung cancer and important predictors of the treatment efficacy of EGFR tyrosine kinase inhibitors. The results showed that in 20-min assays, the devices detected as few as 1% (E746_A750 deletion) and 0.1% (L858R substitution) of mutant cells. Subsequent evaluation of detection of the mutations in surgically resected lung cancer specimens from patients with or without EGFR mutations and previously diagnosed using commercially available, clinically approved genotyping assays revealed diagnostic sensitivities of the immuno-wall device for E746_A750 deletion and L858R substitution of 85.7% and 87.5%, respectively, with specificities of 100% for both mutations. These results suggest that the immuno-wall device represents a good candidate next-generation diagnostic tool, especially for screening of EGFR mutations.

Anaplastic lymphoma kinase fusions: Roles in cancer and therapeutic perspectives

Receptor tyrosine kinase (RTK) anaplastic lymphoma kinase (ALK) serves a crucial role in brain development. ALK is located on the short arm of chromosome 2 (2p23) and exchange of chromosomal segments with other genes, including nucleophosmin (NPM), echinoderm microtubule-associated protein-like 4 (EML4) and Trk-fused gene (TFG), readily occurs. Such chromosomal translocation results in the formation of chimeric X-ALK fusion oncoproteins, which possess potential oncogenic functions due to constitutive activation of ALK kinase. These proteins contribute to the pathogenesis of various hematological malignancies and solid tumors, including lymphoma, lung cancer, inflammatory myofibroblastic tumors (IMTs), Spitz tumors, renal carcinoma, thyroid cancer, digestive tract cancer, breast cancer, leukemia and ovarian carcinoma. Targeting of ALK fusion oncoproteins exclusively, or in combination with ALK kinase inhibitors including crizotinib, is the most common therapeutic strategy. As is often the case for small-molecule tyrosine kinase inhibitors (TKIs), drug resistance eventually develops via an adaptive secondary mutation in the ALK fusion oncogene, or through engagement of alternative signaling mechanisms. The updated mechanisms of a variety of ALK fusions in tumorigenesis, proliferation and metastasis, in addition to targeted therapies are discussed below.

Establishing a Dedicated Lung Cancer Biobank at the University Center Hospital of Nice (France). Why and How?

Lung cancer is the major cause of death from cancer in the world and its incidence is increasing in women. Despite the progress made in developing immunotherapies and therapies targeting genomic alterations, improvement in the survival rate of advanced stages or metastatic patients remains low. Thus, urgent development of effective therapeutic molecules is needed. The discovery of novel therapeutic targets and their validation requires high quality biological material and associated clinical data. With this aim, we established a biobank dedicated to lung cancers. We describe here our strategy and the indicators used and, through an overall assessment, present the strengths, weaknesses, opportunities and associated risks of this biobank.

Any Place for Immunohistochemistry within the Predictive Biomarkers of Treatment in Lung Cancer Patients?

The identification of certain genomic alterations (EGFR, ALK, ROS1, BRAF) or immunological markers (PD-L1) in tissues or cells has led to targeted treatment for patients presenting with late stage or metastatic lung cancer. These biomarkers can be detected by immunohistochemistry (IHC) and/or by molecular biology (MB) techniques. These approaches are often complementary but depending on, the quantity and quality of the biological material, the urgency to get the results, the access to technological platforms, the financial resources and the expertise of the team, the choice of the approach can be questioned. The possibility of detecting simultaneously several molecular targets, and of analyzing the degree of tumor mutation burden and of the micro-satellite instability, as well as the recent requirement to quantify the expression of PD-L1 in tumor cells, has led to case by case development of algorithms and international recommendations, which depend on the quality and quantity of biological samples. This review will highlight the different predictive biomarkers detected by IHC for treatment of lung cancer as well as the present advantages and limitations of this approach. A number of perspectives will be considered.

Efficacy of D5F3 IHC for detecting ALK gene rearrangement in NSCLC patients: a systematic review and meta-analysis

We conducted a pooled analysis comparing the efficacy of an immunohistochemistry (IHC) assay using the D5F3 antibody with that of fluorescence in situ hybridization (FISH) for detecting ALK gene rearrangement in NSCLC patients. A total of 32 studies involving 5805 samples were included in this review. Pooled sensitivity for D5F3 IHC was 0.97 (95%CI: 0.93-0.98), specificity was 0.99 (95%CI: 0.98-1.00), PLR was 119.20 (95%CI: 57.79-245.89), NLR was 0.03 (95%CI: 0.02-0.07), DOR was 3526.66 (95%CI: 1344.71-9249.03), and AUROC was 1.00 (95%CI: 0.99-1.00). Meta-regression revealed that specimen type was a source of heterogeneity for specificity, and specimen type and FISH signal distance were sources of heterogeneity in the joint model. Subgroup analysis revealed that sensitivity and specificity were higher when the FISH signal distance standard was ≥ 2 than when it was ≥ 1. Sensitivity was higher for tumor specimens than for cell specimens; specificity was higher for cell specimens than for tumor specimens. In conclusion, the D5F3 IHC assay was nearly as effective as FISH for detection of ALK gene rearrangement in NSCLC patients.

Immunohistochemistry for predictive biomarkers in non-small cell lung cancer

In the era of targeted therapy, predictive biomarker testing has become increasingly important for non-small cell lung cancer. Of multiple predictive biomarker testing methods, immunohistochemistry (IHC) is widely available and technically less challenging, can provide clinically meaningful results with a rapid turn-around-time and is more cost efficient than molecular platforms. In fact, several IHC assays for predictive biomarkers have already been implemented in routine pathology practice. In this review, we will discuss: (I) the details of anaplastic lymphoma kinase (ALK) and proto-oncogene tyrosine-protein kinase ROS (ROS1) IHC assays including the performance of multiple antibody clones, pros and cons of IHC platforms and various scoring systems to design an optimal algorithm for predictive biomarker testing; (II) issues associated with programmed death-ligand 1 (PD-L1) IHC assays; (III) appropriate pre-analytical tissue handling and selection of optimal tissue samples for predictive biomarker IHC.

ALK in Non-Small Cell Lung Cancer (NSCLC) Pathobiology, Epidemiology, Detection from Tumor Tissue and Algorithm Diagnosis in a Daily Practice

Patients with advanced-stage non-small cell lung carcinoma (NSCLC) harboring an ALK rearrangement, detected from a tissue sample, can benefit from targeted ALK inhibitor treatment. Several increasingly effective ALK inhibitors are now available for treatment of patients. However, despite an initial favorable response to treatment, in most cases relapse or progression occurs due to resistance mechanisms mainly caused by mutations in the tyrosine kinase domain of ALK. The detection of an ALK rearrangement is pivotal and can be done using different methods, which have variable sensitivity and specificity depending, in particular, on the quality and quantity of the patient’s sample. This review will first highlight briefly some information regarding the pathobiology of an ALK rearrangement and the epidemiology of patients harboring this genomic alteration. The different methods used to detect an ALK rearrangement as well as their advantages and disadvantages will then be examined and algorithms proposed for detection in daily routine practice.

Diagnostic accuracy of PCR for detecting ALK gene rearrangement in NSCLC patients: A systematic review and meta-analysis

Background

Anaplastic lymphoma kinase (ALK) gene fusion has been reported in 3∼5% non-small cell lung carcinoma (NSCLC) patients, and polymerase chain reaction (PCR) is commonly used to detecting the gene status, but the diagnostic capacity of it is still controversial. A systematic review and meta-analysis was conducted to clarify the diagnostic accuracy of PCR for detecting ALK gene rearrangement in NSCLC patients.

Results

18 articles were enrolled, which included 21 studies, involving 2800 samples from NSCLC patients. The overall pooled parameters were calculated: sensitivity was 92.4% [95% confidence interval (CI): 82.2%–97.0%], specificity was 97.8% [95% CI: 95.1%–99.0%], PLR was 41.51 [95% CI: 18.10–95.22], NLR was 0.08 [95% CI: 0.03–0.19], DOR was 535.72 [95% CI: 128.48–2233.79], AUROC was 0.99 [95% CI: 0.98–1.00].

Materials and Methods

Relevant articles were searched from PubMed, EMBASE, Web of Science, Cochrane library, American Society of Clinical Oncology (ASCO), European Society for Medical Oncology (ESMO), China National Knowledge Infrastructure (CNKI), China Wan Fang databases and Chinese biomedical literature database (CBM). Diagnostic capacity of PCR test was assessed by the pooled sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the summary receiver operating characteristic (AUROC).

Conclusions

Based on the results from this review, PCR has good diagnostic performance for detecting the ALK gene fusion in NSCLC patients. Moreover, due to the poor methodology quality of the enrolled trials, more well-designed multi-center trials should be performed.

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

Background

Clinical outcomes of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer according to ALK fusion variants are not clear. We aimed to investigate the prevalence of ALK fusion variants and to compare clinical outcomes according to ALK fusion variants.

Methods

A retrospective analysis was conducted on patients with advanced ALK-rearranged adenocarcinoma treated with chemotherapy and ALK inhibitors. ALK rearrangement was identified by fluorescence in situ hybridization and confirmed by immunohistochemistry. Peptide nucleic acid-mediated quantitative polymerase chain reaction assays, designed to detect 28 types of echinoderm microtubule-associated protein-like 4 (EML)-ALK rearrangements, were performed. Clinicopathological analysis and treatment outcomes with platinum-based chemotherapy, pemetrexed therapy, and ALK inhibitors—including crizotinib and ceritinib—were evaluated.

Results

A total of 52 patients with ALK-rearranged lung adenocarcinoma were enrolled. EML4-ALK variant 1 (v1) was the most common variant (38.5 %) followed by the non-EML4 variant (36.5 %), EML4-ALK variant 3a/b (19.2 %), and EML4-ALK variant 2 (5.8 %). No clinicopathological distinction was found between the different ALK fusion variants. Treatment response rates for each therapeutic agent did not differ according to ALK fusion variant. However, EML4 variants, especially v1, showed significantly longer progression-free survival (PFS) on pemetrexed treatment than did non-EML4 variants (median 31.1 months versus 5.7 months, P = 0.003). PFS with platinum-based chemotherapy and ALK inhibitors did not differ according to ALK fusion variant. Multivariate survival analysis using Cox’s regression model revealed v1 as the only predictive factor for prolonged PFS on pemetrexed.

Conclusions

Among ALK fusion variants, v1 is the most common subtype. It showed superior progression-free survival on pemetrexed than did non-EML4 variants. No survival difference was demonstrated between variants treated with crizotinib or ceritinib.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1061-z) contains supplementary material, which is available to authorized users.

[Influence of Immunohistochemistry Scoring Criteria in Detecting EGFR Mutations]

背景与目的

恰当的免疫组化染色评分可确保突变检测结果的可靠性，目前大多数研究认为“四分法”是所有评分系统中最佳的方法。本研究旨在探讨不同四分法染色评分对检测结果的影响。

方法

用三种不同的四分法免疫组化染色评分标准评价83例非小细胞肺癌标本表皮生长因子受体（epidermal growth factor receptor, EGFR）突变情况，并以液相芯片法作为金标准进行比较，计算每种方法的灵敏度、特异度、阳性预测值（positive predictive value, PPV）、阴性预测值（negative predictive value, NPV）、与金标准间一致度及三种标准间是否存在统计学差异。

结果

三种标准在检测EGFR突变方面不存在统计学差异，每种标准检测结果的特异度均明显优于灵敏度。染色为“3+”的标本，PPV均可高达100%。

结论

不同的四分法评分没有绝对的最佳标准，但无论用何种标准，免疫组化法（immunohistochemistry, IHC）检测EGFR突变的特异度均明显优于灵敏度。评分为“3+”的标本，可认为实际确实存在突变，直接接受EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）治疗。

Epidermal growth factor receptor mutation in adenocarcinoma lung in a North Indian population: Prevalence and relation with different clinical variables

Introduction:

Lung cancer is one of the most common causes of cancer deaths worldwide. Adenocarcinoma is taking over squamous cell lung cancer as the predominant histological subtype. Several cytotoxic drugs are available for the treatment of lung cancer, but side effects limit their use. Recently, targeted therapies for cancers have come into clinical practice.

Aims and Objectives:

To determine the prevalence of epidermal growth factor receptor (EGFR) mutation in adenocarcinoma lung in a North Indian population and its relation with different clinical variables.

Materials and Methods:

A total of 57 patients who met inclusion criteria were recruited into the study. Relevant history, clinical examination and investigations were done. EGFR mutation was done in all patients.

Results:

A total of twenty patients tested positive for EGFR mutation. EGFR was more frequently detected in female patients (53.8%), while as only 19.4% of the male patients expressed EGFR mutation, which was statistically very significant (P = 0.007). EGFR mutation was more frequently detected in nonsmokers (52%) as compared to smokers (21.9%) which also was statistically significant (P value of 0.018). EGFR mutation was more common in Stage III and IV adenocarcinomas (48%) as compared to Stage I and II (21.4%) which was statistically significant (P value 0.034).

Conclusion:

EGFR mutation should be routinely done in all patients of adenocarcinoma lung particularly non-smoker females with Stage III and IV disease.

Diagnostic algorithm for detection of targetable driver mutations in lung adenocarcinomas: Comprehensive analyses of 205 cases with immunohistochemistry, real-time PCR and fluorescence in situ hybridization methods

OBJECTIVES

Analysis of the targetable driver mutations is now recommended in all patients with advanced lung adenocarcinoma. Molecular-based methods are usually adopted, however, along with the implementation of highly sensitive and/or mutation-specific antibodies, immunohistochemistry (IHC) has been considered an alternative method for identifying driver mutations in lung adenocarcinomas.

MATERIALS AND METHODS

A total of 205 lung adenocarcinomas were examined for EGFR mutations and ALK and ROS1 rearrangements using real-time PCR, fluorescence in situ hybridization (FISH) and IHC in parallel. The performance of different commercially available IHC antibody clones toward targetable driver mutations was evaluated. The association between these driver mutations and clinicopathological characteristics was also analyzed.

RESULTS

In 205 cases we studied, 58.5% were found to harbor EGFR mutations, 6.3% ALK rearrangements and 1.0% ROS1 rearrangements. Compared to molecular-based methods, IHC of EGFR mutations showed an excellent specificity but the sensitivity is suboptimal, while IHC of ALK and ROS1 rearrangements demonstrated high sensitivity and specificity. No significant difference regarding the performance of different antibody clones toward these driver mutations was observed, except that clone SP125 showed a higher sensitivity than 43B2 in the detection of p.L858R of EGFR.

CONCLUSION

In circumstances such as poor quality of nucleic acids or low content of tumor cells, IHC of EGFR mutation-specific antibodies could be used as an alternative method. Patients negative for EGFR mutations are subjected to further analysis on ALK and ROS1 rearrangements using IHC methods. Herein, we proposed a lung adenocarcinoma testing algorithm for the application of IHC in therapeutic diagnosis.

ALK ambiguous-positive non-small cell lung cancers are tumors challenged by diagnostic and therapeutic issues

Searching for ALK rearrangements using the approved fluorescent in situ hybridization (FISH) test and complementary immunohistochemistry (IHC) has become the rule to treat patients with advanced non‑small cell lung cancer (NSCLC) with anti‑ALK targeted therapy. The concordance between the two techniques is reported to be strong but imperfect. We report our experience with cases of ALK‑rearranged lung adenocarcinomas pointing out particularly ambiguous cases. FISH and IHC data on ALK but also c‑MET IHC as well as EGFR and KRAS mutation screening are considered, together with response to crizotinib treatment. We classified the 55 FISH ALK‑rearranged tumors into two groups according to the FISH and IHC results: a concordant FISH+IHC+ group (31 tumors) and an ambiguous group (24 tumors). These tumors were considered as 'ambiguous' ALK‑positive due to negative (21 tumors) or non‑contributive (3 tumors) IHC. In addition, the percentage of FISH-positive nuclei was between 15 and 20% in 17 tumors belonging to one or the other group (now called borderline tumors). We discuss the accuracy of the different tests with intent to determine whether ambiguous and borderline tumors are real positive ALK‑rearranged tumors. To conclude, ambiguous ALK‑positive lung cancers are challenging tumors with diagnosis and therapeutic issues that can justify parallel FISH, IHC and molecular screening strategy.

Circulating Biomarkers in Non-Small-Cell Lung Cancer: Current Status and Future Challenges

Despite recent advances, non-small-cell lung cancer remains a devastating disease and carries a grim prognosis. Major contributing factors include difficulties in diagnosing the disease early in its course during the asymptomatic stage and the poor understanding of the biology underlying disease progression. Liquid biopsies, noninvasive blood tests that detect circulating biomarkers such as circulating tumor cells and tumor-derived nucleic acid fragments, are in a rapidly evolving field of research that could provide answers to both of these unmet needs. Herein, we review the relevant data concerning the diagnostic, predictive, and prognostic significance of 3 distinct but potentially complementary circulating biomarkers in non-small-cell lung cancer: circulating tumor cells, cell-free DNA, and microRNAs.

Diamond: immunohistochemistry versus sequencing in EGFR analysis of lung adenocarcinomas

AIMS

Identification of epidermal growth factor receptor (EGFR) mutations in lung adenocarcinomas is the single most important predictor of clinical response and outcome using EGFR tyrosine kinase inhibitors (TKIs). EGFR E746-A750del and L858R mutations are the most common gene alterations, also predicting the best clinical response to TKIs. We evaluated the accuracy of EGFR mutation-specific antibodies in a large cohort of lung adenocarcinomas, with different molecular settings and types of tissue samples.

METHODS

300 lung adenocarcinomas diagnosed on cytology (48 cell blocks), biopsy (157 cases) and surgical resections (95 cases) were selected. All cases were investigated for EGFR by sequencing and two mutation-specific antibodies (clone 6B6 for E746-A750del; clone 43B2 for L858R) were tested using an automated immunostainer. Discordant results were investigated by next-generation sequencing (NGS).

RESULTS

Overall sensitivity and specificity of mutant-specific antibodies were 58.6% and 98.0%, respectively, and they increased up to 84% and 100% if only tumours harbouring E746-A750del were considered. In 13 discordant cases, NGS confirmed immunohistochemistry results in eight samples.

CONCLUSIONS

The EGFR mutation-specific antibodies have a fair/good sensitivity and good/high specificity in identifying classic mutations, but they cannot replace molecular tests. The antibodies work equally well on biopsies and cell blocks, possibly permitting a rapid screening in cases with poor material.

[Immunohistochemical detections of EGFR status in NSCLC]

背景与目的

存在表皮生长因子受体（epidermal growth factor receptor, EGFR）突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）患者对EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）治疗有良好反应。与检测EGFR突变的分子水平手段相比，免疫组织化学法（immunohistochemistry, IHC）价格低廉，操作简便、迅速，易开展。本研究旨在探索免疫组化法检测EGFR突变的准确性。

方法

选取97例NSCLC患者的手术或组织活检标本行EGFR特异性抗体的免疫组化染色，分析染色阳性标本的临床病理特征，并继续接受液相芯片检测验证是否存在突变；新收集40例被证实为EGFR突变的手术标本接受免疫组化染色，计算免疫组化法检出突变灵敏度。

结果

97例NSCLC标本，17例染色阳性，染色阳性标本好发于女性、腺癌、不吸烟患者中，其染色阳性标本中，76.9%实际存在突变。40例EGFR突变标本中，免疫组化法检出突变的灵敏度为40%。

结论

免疫组化法染色评分为强阳性的标本结果准确，但该方法灵敏度不甚理想，不同研究者所得结果差异较大，临床推广是否可行仍有待进一步探讨。

Efficacy of bronchoscopic biopsy for the detection of epidermal growth factor receptor mutations and anaplastic lymphoma kinase gene rearrangement in lung adenocarcinoma

Background

To explore the efficacy of bronchoscopic biopsy for the detection of epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) gene rearrangement in lung adenocarcinoma.

Methods

All patients with bronchoscopic biopsy-proven lung adenocarcinoma at the Peking Union Medical College Hospital from January 2009 to November 2011 were enrolled. Scorpion amplification refractory mutation system (ARMS) was used to detect EGFR gene mutations and fluorescence in situ hybridization (FISH) to detect ALK rearrangement. The correlation of immunohistochemistry (IHC) results with standard methods for EGFR mutation status and ALK rearrangement were checked.

Results

Bronchoscopic specimens were successfully used to detect EGFR mutation and ALK rearrangement with success rates of 85.2% and 71.3%, respectively, in non-small cell lung cancer patients. EGFR analysis by ARMS yielded a positive result in 35.8% (33/92) and positive ALK rearrangement was detected by FISH in 7.8% (6/77) of cases. It was more likely to be unsuccessful in patients with tumor cells less than 100/high power field and the ratio tumor numbers in 0–10%. In EGFR-IHC, the sensitivity and specificity of E746-A750 deletions were 73.3% (11/15) and 93.3% (70/75), respectively, and those of L858R were 93.3% (14/15) and 93.2% (69/74), respectively. In ALK-IHC, the sensitivity and specificity were 50% (3/6) and 100% (71/71), respectively.

Conclusions

Small bronchoscopic specimens could achieve higher successful detection rates via EGFR mutation and ALK gene rearrangement.

Identification of EGFR Mutations by Immunohistochemistry with EGFR Mutation-Specific Antibodies in Biopsy and Resection Specimens from Pulmonary Adenocarcinoma

Purpose

Mutation-specific antibodies have recently been developed for identification of epidermal growth factor receptor (EGFR) mutations by immunohistochemistry (IHC). This study was designed to investigate whether the type of specimen (biopsy vs. resection) would make a difference in determining mutation status by IHC, and to evaluate whether biopsies are suitable for detection of mutant EGFR protein.

Materials and Methods

IHC was performed using mutation-specific antibodies for E746-A750 deletion (DEL) and L858R point mutation (L858R) in biopsies and tissue microarrays of resected tumors from 154 patients with pulmonary adenocarcinoma. Results were then compared with DNA sequencing data.

Results

Molecular-based assays detected EGFR mutations in 62 patients (40.3%), including 14 (9.1%) with DEL, and 31 (20.1%) with L858R. IHC with two mutation-specific antibodies showed a homogeneous staining pattern, and correctly identified EGFR mutation status in 89% (137/154). Overall (biopsy/resection) sensitivity, specificity, positive predictive value, and negative predictive value were 75.6% (78.3%/72.7%), 94.5% (90.9%/96.3%), 85% (78.3%/88.9%), and 90.4% (90.9%/89.7%), respectively.

Conclusion

Our data showed that IHC using EGFR mutation–specific antibodies is useful for detection of EGFR mutations with high specificity and good sensitivity not only for resection specimens but also for biopsy materials. Therefore, IHC using EGFR mutation–specific antibodies may preclude a second biopsy procedure to obtain additional tissues for identification of EGFR mutations by molecular assays in biopsies from advanced cancer, particularly when tumor cells in the samples are limited.

Discrepancies between FISH and immunohistochemistry for assessment of the ALK status are associated with ALK 'borderline'-positive rearrangements or a high copy number: a potential major issue for anti-ALK therapeutic strategies

BACKGROUND

Patients with advanced lung adenocarcinomas expressing ALK rearrangements are highly responsive to crizotinib, a dual ALK/c-MET inhibitor. Immunohistochemistry (IHC) is an easy clinically and routinely applicable cost-effective assay for ALK, c-MET and ROS1 protein expression for potential treatment with crizotinib. The purpose of this study was to evaluate the percentage and the pattern of ALK-rearranged cells, the variation in the native ALK copy number, as well as ALK, c-MET and ROS1 protein expression, and their significance on outcome of crizotinib-treated lung adenocarcinoma patients.

PATIENTS AND METHODS

Consecutive lung adenocarcinoma specimens (n = 176) 'double-negative' (wild-type EGFR and KRAS) were tested for ALK rearrangements/copy number alterations and for ALK, c-MET and ROS1 protein expression using automated standardized protocols. Preliminary data on the outcome of crizotinib-treated patients were recorded.

RESULTS

FISH analysis identified 26/176 (15%) cases with ALK rearrangements. Seven cases had discordant results between the ALK FISH and IHC. Five cases with discordant FISH-positive/IHC-negative revealed FISH 'borderline' positivity (15%-20%). Three cases overexpressed c-MET and responded to crizotinib, and two cases with ALK-'borderline' rearranged cells only, not associated with c-MET expression, progressed under crizotinib. Two cases with discordant FISH-negative/IHC-positive revealed ALK gene amplification without associated c-MET or ROS1 protein expression.

CONCLUSIONS

The discrepancies observed between the IHC and FISH data revealed unexpected biological events, rather than technical issues, which potentially can have a strong impact on the therapeutic strategy with crizotinib.

Current challenges for detection of circulating tumor cells and cell-free circulating nucleic acids, and their characterization in non-small cell lung carcinoma patients. What is the best blood substrate for personalized medicine?

The practice of "liquid biopsy" as a diagnostic, prognostic and theranostic tool in non-small cell lung cancer (NSCLC) patients is an appealing approach, at least in theory, since it is noninvasive and easily repeated. In particular, this approach allows patient monitoring during treatment, as well as the detection of different genomic alterations that are potentially accessible to targeted therapy or are associated with treatment resistance. However, clinical routine practice is slow to adopt the liquid biopsy. Several reasons may explain this: (I) the vast number of methods described for potential detection of circulating biomarkers, without a consensus on the ideal technical approach; (II) the multiplicity of potential biomarkers for evaluation, in particular, circulating tumor cells (CTCs) vs. circulating tumor DNA (ctDNA); (III) the difficulty in controlling the pre-analytical phase to obtain robust and reproducible results; (IV) the present cost of the currently available techniques, which limits accessibility to patients; (V) the turnaround time required to obtain results that are incompatible with the urgent need for delivery of treatment. The purpose of this review is to describe the main advances in the field of CTC and ctDNA detection in NSCLC patients and to compare the main advantages and disadvantages of these two approaches.

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

Context

Immunohistochemistry has become an indispensable ancillary tool for the accurate classification of pleuropulmonary and mediastinal neoplasms necessary for therapeutic decisions and predicting prognostic outcome in the era of personalized medicine. Diagnostic accuracy has significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

Objective

To increase the accuracy of diagnosis and classify pleuropulmonary neoplasms through immunohistochemistry.

Data Sources

Literature review, authors' research data, and personal practice experience.

Conclusions

This review article has shown that appropriately selecting immunohistochemical panels enables pathologists to effectively diagnose most primary pleuropulmonary neoplasms and differentiate primary lung tumors from a variety of metastatic tumors to the lung. The discovery of new mutation-specific antibodies identifying a subset of specific gene-arranged lung tumors provides a promising alternative and cost-effective approach to molecular testing. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoiding potential diagnostic errors.

Prevalence and natural history of ALK positive non-small-cell lung cancer and the clinical impact of targeted therapy with ALK inhibitors

Improved understanding of molecular drivers of carcinogenesis has led to significant progress in the management of lung cancer. Patients with non-small-cell lung cancer (NSCLC) with anaplastic lymphoma kinase (ALK) gene rearrangements constitute about 4%-5% of all NSCLC patients. ALK+ NSCLC cells respond well to small molecule ALK inhibitors such as crizotinib; however, resistance invariably develops after several months of treatment. There are now several newer ALK inhibitors, with the next generation of agents targeting resistance mutations. In this review, we will discuss the prevalence and clinical characteristics of ALK+ lung cancer, current treatment options, and future directions in the management of this subset of NSCLC patients.

[Immunohistochemical detections of EGFR mutations in NSCLC]

近些年来，人们越来越认识到，存在表皮生长因子受体（epidermal growth factor receptor, EGFR）突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）患者对靶向药物EGFR酪氨酸激酶抑制剂（EGFR-tyrosine kinase inhibitor, EGFR-TKI）的治疗有良好反应。目前，检测EGFR突变应用最多且较为可靠的是以DNA分子为基础的检测（如DNA测序）方法，但此法操作繁琐，耗时长，花费高，对样本要求严格。相比之下，免疫组织化学法（immunohistochemistry, IHC）则充分弥补了上述缺陷，可作为EGFR突变筛查的辅助手段。但影响其结果的因素较多，如不同的免疫组化染色方法、不同抗原修复液的选择及不同的结果评判标准等，因此此法尚未广泛应用于临床，仅处于研究阶段。本文通过检索不同研究者应用免疫组化法对NSCLC患者进行EGFR突变检测的相关文献，进一步讨论如何合理应用免疫组化法检测EGFR突变可发挥其临床应用的最大价值。

Diagnostic value of mutation-specific antibodies for immunohistochemical detection of epidermal growth factor receptor mutations in non-small cell lung cancer: a meta-analysis

Background

Various studies have assessed the diagnostic accuracy of EGFR mutation-specific antibodies in non-small cell lung cancer (NSCLC). We performed a meta-analysis of existing data to investigate the diagnostic value of mutation-specific antibodies for detection of EGFR mutations in NSCLC.

Methods

We systematically retrieved relevant studies from PubMed, Web of Knowledge, and Google Scholar. Data from studies that met the inclusion criteria were extracted for further exploration of heterogeneity, including calculation of the average sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and analysis of SROC(summary receiver operating characteristic) curves.

Results

Fifteen studies met our inclusion criteria. A summary of the meta-analysis of the efficacy of the anti-E746-A750 antibody was as follows: sensitivity, 0.60 (95% CI, 0.55–0.64); specificity, 0.98 (95% CI, 0.97–0.98); PLR, 33.50 (95% CI, 13.96–80.39); NLR, 0.39 (95% CI, 0.30–0.51) and DOR, 111.17 (95% CI, 62.22–198.63). A similar meta-analysis was performed for the anti-L858R antibody with results as follows: sensitivity, 0.76 (95% CI, 0.71–0.79); specificity, 0.96 (95% CI, 0.95–0.97); PLR, 24.42 (95% CI, 11.66–51.17); NLR, 0.22 (95% CI, 0.12–0.39) and DOR, 126.66 (95% CI, 54.60–293.82).

Conclusion

Immunohistochemistry alone is sufficient for the detection of EGFR mutations if the result is positive. Molecular-based analyses are necessary only if the anti-E746-A750 antibody results are negative. Immunohistochemistry seems more suitable for clinical screening for EGFR mutations prior to molecular-based analysis.

[Value of immunohistochemical staining with mutation-specific antibodies in detecting EGFR mutations: a meta-analysis]

BACKGROUND

It has been proven that epidermal growth factor receptor (EGFR) mutation is the most important predictive factor for determining the effect of EGFR tyrosine kinase inhibitors (TKIs) applied to non-small cell lung cancer (NSCLC) patients. The patients with EGFR mutations response better to TKIs. To detect EGFR mutation has been particularly essential to select first-line treatment for lung cancer patients. To research and analyze the sensitivity and specificity of immunohistochemistry (IHC) using mutation specific antibodies in detecting EGFR mutations compared with DNA sequencing, and further evaluate the accuracy and clinical application value of IHC.

METHODS

All required articles in Pubmed database were searched. The deadline of retrieval was March 26, 2013. Then further screening the articles based on the inclusion and exclusion criteria. Meta analysis of diagnostic test was applied to analyze the sensitivity and specificity of IHC compared with DNA sequencing for the detection of EGFR mutations.

RESULTS

Ten articles were included in the meta analysis, there were 1,679 samples in L858R group and 1,041 samples in E746-A750del group. The DOR were 225.17 (95%CI: 55.67-910.69) and 267.16 (95%CI: 132.45-538.88) respectively; the AUC of SROC were 0.948,4 (SEAUC=0.014,4) and 0.981,3 (SEAUC=0.009,9) respectively; the Q values were 0.888,3 (SEQ*=0.019,2) and 0.939,7 (SEQ*=0.019,1) respectively.

CONCLUSIONS

The specificity and sensitivity of IHC method using these two mutation-specific antibodies were relatively high. As a screening method for EGFR mutations, the IHC with mutation specific antibodies is of clinical value.

Accurate and economical detection of ALK positive lung adenocarcinoma with semiquantitative immunohistochemical screening

Right detection of anaplastic lymphoma kinase (ALK) gene rearrangement is pivotal to selection of patients with lung adenocarcinoma for ALK-targeted therapy. We explored the potential of combination of immunohistochemistry (IHC) screening and fluorescence in situ hybridization (FISH) as an affordable practice. We analyzed 410 unselected lung adenocarcinomas by ALK IHC (D5F3 clone) and FISH. Some equivocal cases were further analyzed by RT-PCR. The EGFR mutation was detected by pyrosequencing assay. In total 368 cases which got all IHC, FISH, EGFR mutation results were eligible for analysis. Cases were evaluated as IHC score 3+ (n = 26), score 2+ (n = 9), score 1+ (n = 51), and score 0 (n = 282), respectively. 23 of 26 IHC 3+ and 5 of 9 IHC 2+ cases were FISH positive, whereas 3 of 26 IHC 3+, 4 of 9 IHC 2+ and all 333 IHC 1+/0 cases were FISH negative. If considering FISH as the standard, the sensitivity and specificity of ALK IHC 3+/2+ as ALK positive were 100% and 97.9%, respectively. Three IHC 3+ cases reported as FISH “negative” were actually ALK positive confirmed by ALK RT-PCR or re-detected. Based on the final classify, ALK IHC 3+/2+ was 100% sensitive and 98.8% specific. However, FISH was 90.3% sensitive and 100% specific. IHC 2+ was regarded as equivocal and need to be confirmed by FISH or RT-PCR. In the 368 cases, 8.4% cases had ALK positive, 52.2% cases had EGFR mutation, and only one case had a coexisting. Manually semiquantitative ALK IHC (primary antibody D5F3 coupled with secondary DAKO Envision system) used as the initial screening combined with auxiliary FISH confirmation is a reliable, economical approach to identify ALK positive lung adenocarcinoma. The IHC can find some ALK positive cases which would be missed by FISH only.

Molecular analysis of circulating tumour cells-biology and biomarkers

Growing evidence for intratumour heterogeneity informs us that single-site biopsies fall short of revealing the complete genomic landscape of a tumour. With an expanding repertoire of targeted agents entering the clinic, screening tumours for genomic aberrations is increasingly important, as is interrogating the tumours for resistance mechanisms upon disease progression. Multiple biopsies separated spatially and temporally are impractical, uncomfortable for the patient and not without risk. Here, we describe how circulating tumour cells (CTCs), captured from a minimally invasive blood test-and readily amenable to serial sampling-have the potential to inform intratumour heterogeneity and tumour evolution, although it remains to be determined how useful this will be in the clinic. Technologies for detecting and isolating CTCs include the validated CellSearch(®) system, but other technologies are gaining prominence. We also discuss how recent CTC discoveries map to mechanisms of haematological spread, previously described in preclinical models, including evidence for epithelial-mesenchymal transition, collective cell migration and cells with tumour-initiating capacity within the circulation. Advances in single-cell molecular analysis are enhancing our ability to explore mechanisms of metastasis, and the combination of CTC and cell-free DNA assays are anticipated to provide invaluable blood-borne biomarkers for real-time patient monitoring and treatment stratification.

Guideline Recommendations for Testing of ALK Gene Rearrangement in Lung Cancer: A Proposal of the Korean Cardiopulmonary Pathology Study Group

Rearrangement of anaplastic lymphoma kinase (ALK) gene is the best predictor of response to crizotinib, an ALK tyrosine kinase inhibitor. However, the prevalence of the ALK fusion is low, so accurate patient identification is crucial for successful treatment using ALK inhibitors. Furthermore, most patients with lung cancer present with advanced-stage disease at the time of diagnosis, so it is important for pathologists to detect ALK-rearranged patients while effectively maximizing small biopsy or cytology specimens. In this review, we propose a guideline recommendation for ALK testing approved by the Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists.

ALK testing for the right patients: integration into practice and impact on clinics

SUMMARY Patients with non-small-cell lung cancer who harbor ALK gene rearrangements can derive significant clinical benefit from ALK tyrosine kinase inhibitor. However, the prevalence of the ALK fusion is low, therefore, accurate patient identification is crucial for successful treatment using the ALK inhibitor. There are several methods used to detect the ALK gene rearrangement: fluorescence/chromogenic in situ hybridization, immunohistochemistry, reverse transcriptase-PCR and next-generation sequencing. This review is focused on practical issues of each testing methodology for ALK rearrangement and how they may impact on clinical decision-making.

[Role of the surgical pathologist for tissue management in oncology]

Currently, the increasing number of ancillary methods to be performed from tumoral tissues in a pathology laboratory determines the necessity to have an optimal strategy for tissue management. The size of tissue samples dedicated for a pathological examination becomes smaller and smaller, as the diagnosis can be made with non or less invasive methods. However, the samples should also allow to provide the prognosis as well as to realise biological molecular testing in order to found a genomic alteration. Thus, it is critical to think about how to share and to pool the different expertises and abilities in a pathology laboratory in order to optimize the achievement of the different ancillary methods. Thus, following the morphological study made in hematoxylin-eosin staining, it is necessary to preempt the number of immunohistochemical and in situ hybridization studies, which will be potentially done from the tissue samples. Moreover, since the genomic alteration detection in tumours is mainly performed from DNA extracted from tissues, it is necessary to take in account some numerous parameters, in particular the nature and the time of fixation, the percentage of tumour cells, the presence of necrotic area, the percentage of inflammatory cells and the sample size. The strategy for an optimal tissue management in an oncology-pathology laboratory is critical and takes part of the different steps allowing to get an accreditation according the ISO15189 norm.

Comparison of IHC, FISH and RT-PCR methods for detection of ALK rearrangements in 312 non-small cell lung cancer patients in Taiwan

Background

Recently Echinoderm microtubule-associated protein-like 4- anaplastic lymphoma kinase (EML4-ALK) fusion gene has become an important biomarker for ALK tyrosine kinase inhibitor (crizotinib) treatment in NSCLC. However, the best detection method and the significance of EML4-ALK variant types remain uncertain.

Methods

Reverse transcriptase-polymerase chain reaction (RT-PCR), fluorescence in Situ hybridization (FISH) and Immunohistochemical (IHC) stain were performed on tumor tissues of 312 NSCLC patients for detection of ALK rearrangements. Mutation analyses for EGFR and KRAS genes were also performed.

Results

Thirteen of the 312 patients (4.17%) had ALK rearrangements detected by RT-PCR. If RT-PCR data was used as the gold standard, FISH tests had a low sensitivity (58.33%), but very good specificity (99.32%). IHC stain had better sensitivity (91.67%) than FISH, but lower specificity (79.52%), when the cut off was IHC2+. All of the 8 patients with high abundance of EML4-ALK positive cells in tumor tissues (assessed by the signal intensities of the RT-PCR product), were also have high expression of ALK protein (IHC3+), and positive for FISH, except one failed in FISH. Variants 3a+3b (4/5, 80%) of EML4-ALK fusion gene were more common to have high abundance of EML4-ALK positive cells in tumor tissues than variant 1 (1/3, 33.3%). Meta-analysis of the published data of 2273 NSCLC patients revealed that variant 3 (23/44, 52.3%) was the most common type in Chinese population, while variant 1 (28/37, 75.7%) was most common in Caucasian.

Conclusions

Among the three detection methods, RT-PCR could detect not only the presence of EML4-ALK fusion gene and their variant types, but also the abundance of EML4-ALK positive cells in NSCLC tumor tissues. The latter two factors might affect the treatment response to anti-ALK inhibitor. Including RT-PCR as a diagnostic test for ALK inhibitor treatment in the prospective clinical trials is recommended.

Rare ALK expression but no ALK rearrangement in pancreatic ductal adenocarcinoma and neuroendocrine tumors

OBJECTIVES

Anaplastic lymphoma kinase (ALK) gene rearrangements were first identified in anaplastic large cell lymphomas. Subsequently, they have been observed in other tumor types with ALK-rearranged tumors demonstrating responsiveness to ALK inhibitors. The aggressiveness of pancreatic ductal adenocarcinoma warrants the examination of ALK rearrangements in pancreatic cancer as a potential therapeutic target. Immunohistochemical expression of ALK1 correlates with ALK rearrangements in other tumors. We performed ALK immunohistochemistry on samples of pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumors using 2 tissue microarrays.

METHODS

ALK1 expression was scored for each case as 0, 1+, 2+, or 3+ using established criteria. Fluorescence in situ hybridization using a break-apart assay with probes for ALK was performed to detect ALK rearrangement in ALK1-positive cases.

RESULTS

All 46 neuroendocrine tumors were negative for ALK1. Of 140 ductal adenocarcinoma cases, 5 showed immunoreactivity for ALK1: 1 was 3+, 2 were 2+, and 2 were 1+. However, fluorescence in situ hybridization for ALK rearrangement was negative in all 5 cases.

CONCLUSIONS

The results demonstrate that ALK1 expression is uncommon in both pancreatic ductal adenocarcinoma and neuroendocrine tumors. Rare ALK1 expression is not induced by ALK translocation, and ALK is unlikely to be a therapeutic target in pancreatic tumors.

Diagnostic value of a novel fully automated immunochemistry assay for detection of ALK rearrangement in primary lung adenocarcinoma

BACKGROUND

To evaluate the diagnostic value of a novel fully automated immunohistochemistry (IHC) assay for detection of anaplastic lymphoma kinase (ALK) fusion in a large number of ALK-positive lung adenocarcinoma (ADC) patients.

PATIENTS AND METHODS

We tested 196 lung ADCs for ALK rearrangement by two IHC assays (Ventana pre-diluted ALK D5F3 antibody with the Optiview DAB IHC detection kit and Optiview Amplification kit, D5F3 by Cell Signaling Technology (CST) with Ultraview DAB detection kit by Ventana), fluorescence in situ hybridization (FISH) and real-time reverse transcription-PCR (RT-PCR). CST ALK IHC was scored using the scoring scheme of 0, no staining; 1+, faint; 2+, moderate; and 3+, strong cytoplasmic reactivity in ≥ 10% of tumor cells. As for Ventana IHC, a binary scoring system (positive or negative for ALK status) was adopted for evaluating the staining results.

RESULTS

Among 196 cases tested, 63 (32%), 65 (33%), 70 (36%), and 69 (35%) cases were ALK positive by FISH, Ventana IHC, CST IHC, and RT-PCR, respectively. The sensitivity and specificity of Ventana IHC were 100% and 98%, respectively. Two Ventana IHC-positive cases, which were also CST IHC score of 3+, showed FISH negative, but their ALK rearrangement was confirmed by RT-PCR and direct sequencing. The sensitivity and specificity of CST IHC with staining intensity score of 1+ or more were 100% and 95%, respectively. Five (25%, of 20) patients with CST IHC score of 1+ were both FISH and RT-PCR negative. The sensitivity and specificity of RT-PCR for detection of ALK fusion were 98% and 95%, respectively. The total accordance rate between ALK RT-PCR and Ventana IHC was 97%.

CONCLUSIONS

The novel fully automated IHC assay is a reliable screening tool in routine pathologic laboratories for identification of patients with ALK rearrangement for targeted therapy in lung ADC.

Immunohistochemical detection of mutations in the epidermal growth factor receptor gene in lung adenocarcinomas using mutation-specific antibodies

BACKGROUND

The recent development of antibodies specific for the major hotspot mutations in the epidermal growth factor receptor (EGFR), L858R and E746_A750del, may provide an opportunity to use immunohistochemistry (IHC) as a screening test for EGFR gene mutations. This study was designed to optimize the IHC protocol and the criteria for interpretation of the results using DNA sequencing as the gold-standard.

METHODS

Tumor sections from fifty lung adenocarcinoma specimens from Chinese patients were immunostained using L858R and E746_A750del-specific antibodies using three different antigen retrieval solutions, and the results were evaluated using three different sets of criteria. The same specimens were used for DNA purification and analysis of EGFR gene mutations.

RESULTS

In this study the optimal buffer for antigen retrieval was EDTA (pH 8.0), and the optimal scoring method was to call positive results when there was moderate to strong staining of membrane and/or cytoplasm in >10% of the tumor cells. Using the optimized protocol, L858R-specific IHC showed a sensitivity of 81% and a specificity of 97%, and E746_A750del-specific IHC showed a sensitivity of 59% and a specificity of 100%, both compared with direct DNA analysis. Additionally, the mutant proteins as assessed by IHC showed a more homogeneous than heterogeneous pattern of expression.

CONCLUSIONS

Our data demonstrate that mutation-specific IHC, using optimized procedures, is a reliable prescreening test for detecting EGFR mutations in lung adenocarcinoma.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2059012601872392.

ALK-gene rearrangement: a comparative analysis on circulating tumour cells and tumour tissue from patients with lung adenocarcinoma

BACKGROUND

A subgroup of anaplastic lymphoma kinase (ALK)-rearranged lung tumours can respond to ALK inhibitors. Until now, the ALK status in circulating tumour cells (CTCs) isolated from patients with lung cancer has not been characterised. We assessed the ALK status in CTCs detected in patients with lung cancer and correlated the results to the ALK status defined in the corresponding tumour tissue.

PATIENTS AND METHODS

A total of 87 patients with lung adenocarcinoma showing CTCs isolated using the isolation by size of epithelial tumour cell method were screened for their ALK status both in tumour samples and in CTCs. ALK break-apart fluorescence in situ hybridisation (FISH) and immunoreactivity analyses using an anti-ALK antibody (5A4 clone) were carried out on CTCs and compared with the results obtained in the corresponding tissue specimens.

RESULTS

A total of five patients showed ALK-gene rearrangement and strong ALK protein expression in CTCs and in the corresponding tumour samples. Both ALK-FISH and ALK immunoreactivity analyses show negative results in CTCs and corresponding tumour samples for 82 patients. Conclusions We demonstrated that the ALK status can be determined in CTCs isolated from patients with lung cancer by immunocytochemistry and FISH analyses. These results favour non-invasive, ALK-gene status pre-screening on a routine basis on CTCs isolated from patients with lung cancer and open new avenues for real-time monitoring for adapted targeted therapy.

EML4-ALK testing in non-small cell carcinomas of the lung: a review with recommendations

In non-small cell lung cancer, epidermal growth factor receptor gene mutations and anaplastic lymphoma kinase (ALK) gene rearrangements have a major impact upon the level of response to treatment with specific tyrosine kinase inhibitors. This review describes the molecular basis of ALK inhibition, summarizes current data on the effectiveness and safety of ALK inhibition therapy, describes the different testing methodologies with their advantages and disadvantages, provides a suggested testing algorithm and puts forward a proposal for an external quality assessment program in ALK testing.

EML4-ALK testing in non-small cell carcinomas of the lung: a review with recommendations

In non-small cell lung cancer, epidermal growth factor receptor gene mutations and anaplastic lymphoma kinase (ALK) gene rearrangements have a major impact upon the level of response to treatment with specific tyrosine kinase inhibitors. This review describes the molecular basis of ALK inhibition, summarizes current data on the effectiveness and safety of ALK inhibition therapy, describes the different testing methodologies with their advantages and disadvantages, provides a suggested testing algorithm and puts forward a proposal for an external quality assessment program in ALK testing.