Testing for ALK rearrangement in lung adenocarcinoma: a multicenter comparison of immunohistochemistry and fluorescent in situ hybridization

Navigating resistance to ALK inhibitors in the lorlatinib era: a comprehensive perspective on NSCLC

INTRODUCTION

The emergence of anaplastic lymphoma kinase (ALK) rearrangements in non-small cell lung cancer (NSCLC) has revolutionized targeted therapy. This dynamic landscape, featuring novel ALK inhibitors and combination therapies, necessitates a profound understanding of resistance mechanisms for effective treatment strategies. Recognizing two primary categories - on-target and off-target resistance - underscores the need for comprehensive assessment.

AREAS COVERED

This review delves into the intricacies of resistance to ALK inhibitors, exploring complexities in identification and management. Molecular testing, pivotal for early detection and accurate diagnosis, forms the foundation for patient stratification and resistance management. The literature search methodology involved comprehensive exploration of Pubmed and Embase. The multifaceted perspective encompasses new therapeutic horizons, ongoing clinical trials, and their clinical implications post the recent approval of lorlatinib.

EXPERT OPINION

Our expert opinion encapsulates the critical importance of understanding resistance mechanisms in the context of ALK inhibitors for shaping successful treatment approaches. With a focus on molecular testing and comprehensive assessment, this review contributes valuable insights to the evolving landscape of NSCLC therapy.

Prognostic and predictive biomarkers in non-small cell lung carcinoma

Lung cancer is the most common cause of cancer-related deaths globally, with the highest mortality rates among both men and women. Most lung cancers are diagnosed at late stages, necessitating systemic therapy. Modern clinical management of lung cancer relies heavily upon application of biomarkers, which guide the selection of systemic treatment. Here, we provide an overview of currently approved and emerging biomarkers of non-small cell lung cancer (NSCLC), including EGFR, ALK, ROS1, RET, NTRK1-3, KRAS, BRAF, MET, ERBB2/HER2, NRG1, PD-L1, TROP2, and CEACAM5. For practical purposes, we divide these biomarkers into genomic and protein markers, based on the tested substrate. We review the biology and epidemiology of the genomic and proteomic biomarkers, discuss optimal diagnostic assays for their detection, and highlight their contribution to the contemporary clinical management of NSCLC.

Identification of a novel RSRC1-ALK (R6: A20) fusion using next-generation sequencing technique

Non-small-cell lung cancer (NSCLC) patients with anaplastic lymphoma kinase (ALK) fusion showed promising responses to ALK tyrosine kinase inhibitors (TKIs). In this study, fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), next generation sequencing (NGS) and Sanger sequencing were performed to identify the presence of ALK fusion, to investigate whether the patient may benefit from TKI therapy. Postoperative pathological analysis indicated invasive adenocarcinoma with mainly mucinous type and partial micropapillary type in left lower lung. Minimally invasive adenocarcinoma was seen in left upper lung, with mainly acinar type. NGS detected a novel RSRC1-ALK (R6: A20) fusion in left lower lobe sample, which was presented as the fusion of exon 6 of RSRC1 and exon 20 of ALK gene. Sanger sequencing validated the fusion. Break rearrangement signal of ALK gene was detected in 80% of tumor cells. Immunohistochemistry showed ALK positive expression in lung. For the treatment, the patient received ensartinib hydrochloride with a dose of 225 mg per day. He was in a state of progression-free survival for at least 24 months in follow-up with no complications. NGS can be used for exploring treatment options for NSCLC patients with ALK fusion.

PD-L1-negative non-small cell lung cancer harbouring a rare BRAF mutation with successful treatment of first-line pembrolizumab plus chemotherapy: A case report and review the literature

BRAF mutations are uncommon in non-small cell lung cancer (NSCLC), accounting for less than 5% of all NSCLC cases. The utilization of targeted therapies in non-V600E BRAF mutant NSCLC is considered controversial, although non-V600E genotype is reported in ~50% of all BRAF mutant patients. We document the case of a 63-year-old patient with NSCLC harbouring a rare BRAF E501Q mutation, who had prolonged response to immunotherapy combined with chemotherapy in Vietnam. The patient was diagnosed with metastatic PD-L1-negative lung adenocarcinoma and received pembrolizumab plus chemotherapy as first-line treatment. After completing 35 cycles of pembrolizumab and pemetrexed, his disease has remained stable during the treatment-free follow-up period, and he is alive 38 months after treatment initiation at the latest follow-up. Immune-based therapy is an appropriate option for lung adenocarcinoma with rare non-V600E BRAF mutation. Further clinical studies are necessary to determine the effectiveness of using immune-based therapy in this specific population.

Updated Views in Targeted Therapy in the Patient with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most frequent form of lung cancer and represents a set of histological entities that have an ominous long-term prognosis, for example, adenocarcinoma, squamous carcinoma and large cell carcinoma. Both small cell and non-small cell lung cancer are the main causes of oncological death and the oncological diseases with the highest incidence worldwide. With regard to clinical approaches for NSCLC, several advances have been achieved in diagnosis and treatment; the analysis of different molecular markers has led to the development of new targeted therapies that have improved the prognosis for selected patients. Despite this, most patients are diagnosed in an advanced stage, presenting a limited life expectancy with an ominous short-term prognosis. Numerous molecular alterations have been described in recent years, allowing for the development of therapies directed against specific therapeutic targets. The correct identification of the expression of different molecular markers has allowed for the individualization of treatment throughout the disease course, expanding the available therapeutic arsenal. The purpose of this article is to summarize the main characteristics of NSCLC and the advances that have occurred in the use of targeted therapies, thus explaining the limitations that have been observed in the management of this disease.

Real-World Treatment and Outcomes of ALK-Positive Metastatic Non-Small Cell Lung Cancer in a Southeast Asian Country

Purpose

Anaplastic lymphoma kinase (ALK) inhibitors are associated with good overall survival (OS) for ALK-positive metastatic non-small cell lung cancer (NSCLC). However, these treatments can be unavailable or limited by financial constraints in developing countries. Using data from a nationwide lung cancer registry, the present study aimed to identify treatment patterns and clinical outcomes of ALK-positive NSCLC in Malaysia.

Methods

This retrospective study examined data of patients with ALK-positive NSCLC from 18 major hospitals (public, private, or university teaching hospitals) throughout Malaysia between January 1, 2015 and December 31, 2020 from the National Cardiovascular and Thoracic Surgical Database (NCTSD). Data on baseline characteristics, treatments, radiological findings, and pathological findings were collected. Overall survival (OS) and time on treatment (TOT) were calculated using the Kaplan-Meier method.

Results

There were 1581 NSCLC patients in the NCTSD. Based on ALK gene-rearrangement test results, only 65 patients (4.1%) had ALK-positive advanced NSCLC. Of these 65 patients, 59 received standard-of-care treatment and were included in the analysis. Crizotinib was the most commonly prescribed ALK inhibitor, followed by alectinib and ceritinib. Patients on ALK inhibitors had better median OS (62 months for first-generation inhibitors, not reached at time of analysis for second-generation inhibitors) compared to chemotherapy (27 months), but this was not statistically significant (P=0.835) due to sample-size limitations. Patients who received ALK inhibitors as first-line therapy had significantly longer TOT (median of 11 months for first-generation inhibitors, not reached for second-generation inhibitors at the time of analysis) compared to chemotherapy (median of 2 months; P<0.01).

Conclusion

Patients on ALK inhibitors had longer median OS and significantly longer TOT compared to chemotherapy, suggesting long-term benefit.

Quantitative Multiplexed Proteomics Could Assist Therapeutic Decision Making in Non-Small Cell Lung Cancer Patients with Ambiguous ALK Test Results

Therapeutic guidance in non-small cell lung cancer (NSCLC) tumors that are positive for anaplastic lymphoma kinase (ALK) fluorescent in situ hybridization (FISH), but negative for ALK immunohistochemistry, is still challenging. Parallel routine screening of 4588 NSCLC cases identified 22 discordant cases. We rechecked these samples using ALK antibodies and selected reaction monitoring (SRM) quantitative multiplexed proteomics screening multiple protein targets, including ALK and MET for the ALK tyrosine kinase inhibitor (TKI), and FR-alpha, hENT1, RRM1, TUBB3, ERCC1, and XRCC1 for chemotherapy. The presence of ALK (31.8%), MET (36.4%), FR-alpha (72.7%), hENT1 (18.2%), RRM1 (31.8%), TUBB3 (72.9%), ERCC1 (4.5%), and a low level of XRCC1 (54.4%) correlated with clinical outcomes. SRM was more sensitive than the ALK D5F3 assay. Among the eight cases receiving ALK TKI, four cases with ALK or MET detected by SRM had complete or partial responses, whereas four cases without ALK or MET showed progression. Twenty-seven treatment outcomes from 20 cases were assessed and cases expressing more than half of the specific predictive proteins were sensitive to matching therapeutic agents and showed longer progression-free survival than the other cases (p < 0.001). SRM showed a potential role in therapeutic decision making in NSCLC patients with ambiguous ALK test results.

Copy Number Variation and Rearrangements Assessment in Cancer: Comparison of Droplet Digital PCR with the Current Approaches

The cytogenetic and molecular assessment of deletions, amplifications and rearrangements are key aspects in the diagnosis and therapy of cancer. Not only the initial evaluation and classification of the disease, but also the follow-up of the tumor rely on these laboratory approaches. The therapeutic choice can be guided by the results of the laboratory testing. Genetic deletions and/or amplifications directly affect the susceptibility or the resistance to specific therapies. In an era of personalized medicine, the correct and reliable molecular characterization of the disease, also during the therapeutic path, acquires a pivotal role. Molecular assays like multiplex ligation-dependent probe amplification and droplet digital PCR represent exceptional tools for a sensitive and reliable detection of genetic alterations and deserve a role in molecular oncology. In this manuscript we provide a technical comparison of these two approaches with the golden standard represented by fluorescence in situ hybridization. We also describe some relevant targets currently evaluated with these techniques in solid and hematologic tumors.

Onco-Receptors Targeting in Lung Cancer via Application of Surface-Modified and Hybrid Nanoparticles: A Cross-Disciplinary Review

Lung cancer is among the most prevalent and leading causes of death worldwide. The major reason for high mortality is the late diagnosis of the disease, and in most cases, lung cancer is diagnosed at fourth stage in which the cancer has metastasized to almost all vital organs. The other reason for higher mortality is the uptake of the chemotherapeutic agents by the healthy cells, which in turn increases the chances of cytotoxicity to the healthy body cells. The complex pathophysiology of lung cancer provides various pathways to target the cancerous cells. In this regard, upregulated onco-receptors on the cell surface of tumor including epidermal growth factor receptor (EGFR), integrins, transferrin receptor (TFR), folate receptor (FR), cluster of differentiation 44 (CD44) receptor, etc. could be exploited for the inhibition of pathways and tumor-specific drug targeting. Further, cancer borne immunological targets like T-lymphocytes, myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and dendritic cells could serve as a target site to modulate tumor activity through targeting various surface-expressed receptors or interfering with immune cell-specific pathways. Hence, novel approaches are required for both the diagnosis and treatment of lung cancers. In this context, several researchers have employed various targeted delivery approaches to overcome the problems allied with the conventional diagnosis of and therapy methods used against lung cancer. Nanoparticles are cell nonspecific in biological systems, and may cause unwanted deleterious effects in the body. Therefore, nanodrug delivery systems (NDDSs) need further advancement to overcome the problem of toxicity in the treatment of lung cancer. Moreover, the route of nanomedicines’ delivery to lungs plays a vital role in localizing the drug concentration to target the lung cancer. Surface-modified nanoparticles and hybrid nanoparticles have a wide range of applications in the field of theranostics. This cross-disciplinary review summarizes the current knowledge of the pathways implicated in the different classes of lung cancer with an emphasis on the clinical implications of the increasing number of actionable molecular targets. Furthermore, it focuses specifically on the significance and emerging role of surface functionalized and hybrid nanomaterials as drug delivery systems through citing recent examples targeted at lung cancer treatment.

BCL2 and BCL6 atypical/unbalanced gene rearrangements in diffuse large B-cell lymphoma are indicators of an aggressive clinical course

AIMS

Diffuse large B-cell lymphoma (DLBCL) is the most common type of aggressive non-Hodgkin's lymphoma that represents a heterogeneous group of disease that is differentially characterised by clinical, molecular and cytogenetic features. MYC, BCL2 and BCL6 gene rearrangements have been identified as prognostic factors in DLBCL, especially for MYC. Nevertheless the frequency and effect of atypical/unbalanced BCL6, BCL2 and MYC translocations in DLBCL is not fully documented. Here, we aimed to analyse those atypical/unbalanced rearrangements in DLBCL and to assess their prognostic impact.

METHODS

We collected tumour tissue and clinical data from 97 DLBCL and used interphase fluorescence in situ hybridisation (FISH) with break-apart probe to characterise BCL6, BCL2 and MYC gene pattern.

RESULTS

19 of 97 (19,6%) cases of DLBCL had atypical/ unbalanced gene rearrangements (14 involving BCL6 gene, 5 involving BCL2 gene and none involving MYC gene). Compared with patients with simple gene rearrangement and patients without cytogenetic abnormality, patients with atypical/unbalanced gene rearrangement were in an unfavourable risk group by the International Prognostic Index (p=0039), died of disease (p=0012), harboured relapse or progression (p=0011) and had shorter overall (p=0,04), relapse free (p=0029) and event free (p=0026) survival.

CONCLUSIONS

We showed that patients with DLBCL with BCL2 or BCL6 atypical/unbalanced rearrangements constituted a group of patients with poor outcome. We also underlined the importance of FISH analyses, easily feasible in routine practise, at diagnosis of DLBCL to detect the rather frequent and clinically significant atypical/unbalanced aberrations of these genes.

Treatment of advanced non-small-cell lung cancer: The 2019 AIOM (Italian Association of Medical Oncology) clinical practice guidelines

The Italian Association of Medical Oncology (AIOM) has developed clinical practice guidelines for the treatment of patients with advanced non-small cell lung cancer (NSCLC). In the current paper a panel of AIOM experts in the field of thoracic malignancies discussed the available scientific evidences, with the final aim of providing a summary of clinical recommendations, which may guide physicians in their current practice.

Elucidation of the relationships of MET protein expression and gene copy number status with PD-L1 expression and the immune microenvironment in non-small cell lung cancer

OBJECTIVES

Alterations in the MET gene, such as mutations and high-level amplification, are important drivers of non-small cell lung cancer (NSCLC). The efficacy of immune checkpoint inhibitors (ICIs) in lung cancer with MET abnormalities is unclear. We evaluate the potential relationship between MET alterations and the tumor immune microenvironment and PD-1/PD-L1 axis.

MATERIAL AND METHODS

MET and phospho-MET protein expression were assessed in 622 resected NSCLC specimens. MET amplification was assessed by fluorescence in-situ hybridization in 272 tumors. PD-L1 expression was evaluated by immunohistochemistry. CD8+, Foxp3+, CD45RO, and PD-1+ tumor-infiltrating lymphocytes (TILs) in the tumor nest and surrounding stroma were profiled. Associations with MET alterations were explored.

RESULTS

The cohort comprised 425 male patients (68.3 %), 184 never-smokers (29.6 %), and 408 adenocarcinoma (ADC) patients (65.6 %). Median age was 68 years. MET alteration was observed mainly in ADCs (18.9 % MET-positive, 3.9 % phospho-MET-positive, and 15.1 % with MET amplification). PD-L1 expression was significantly increased in MET-altered ADCs (P < 0.001 for MET; P = 0.002 for phospho-MET; P = 0.019 for MET amplification). Most TIL subset numbers in the tumor nest were significantly increased in MET-altered tumors. Only MET amplification was independently associated with tumoral CD8 + TILs. Three of the six patients responded to ICI treatment; two of them showed MET overexpression and an increase in MET copy number.

CONCLUSION

MET-altered tumors showed significantly stronger PD-L1 expression and more abundant tumoral TILs than non-MET-altered tumors. Among the MET alterations assessed, MET amplification was particularly implicated in the inflamed microenvironment, suggesting that MET-amplified tumors might respond to ICIs.

Correlation between RICTOR overexpression and amplification in advanced solid tumors

Rapamycin-insensitive companion of mTOR (RICTOR) is a key component of mammalian target of rapamycin (mTOR) complex 2 (mTORC2), and promotes cellular proliferation and survival through the activation of downstream AGC kinase family members. The amplification of RICTOR has been proposed as a therapeutically relevant genomic alteration. However, other than next-generation sequencing, precise diagnostic methods to detect RICTOR amplification in advanced solid cancers have not been fully explored. We performed immunohistochemistry (IHC) analysis on solid tumor tissues from 435 cancer patients. Overexpression of RICTOR was found in 213 cases (49.0 %: 1+, 29.4 %; 2+, 15.2 %; 3+, 4.4 %) consisting of 111 colorectal cancers, 42 gastric cancers, 16 renal cell carcinomas, 8 soft tissue sarcomas, 6 hepatocellular carcinomas, 6 cholangiocarcinomas, 4 lung cancers, and 37 other tumors. RICTOR overexpression was heterogeneous (stained < 50 % of the tumor volume) in 32.4 % (12/37) of IHC-positive cases. We performed fluorescence in situ hybridization (FISH) in 37 RICTOR-overexpressed IHC-positive cases (1+, 12; 2+, 11; 3+, 14) and 13 IHC-negative solid tumors. FISH enabled us to detect RICTOR amplification in 7/12 (58.3 %) IHC 1+, 10/11 (90.9 %) IHC 2+, and 11/14 (78.6 %) IHC 3+ cases. In total, there was amplification in 75.7 % (n = 28) of the RICTOR-overexpressed cases, according to FISH. There was RICTOR amplification in only 7.7 % of the RICTOR IHC-negative cases. RICTOR amplification was significantly more common in IHC-positive cases than in IHC-negative cases (p < 0.0001). The IHC results correlated well with those of FISH (r = 0.60). RICTOR overexpression is more common in solid tumors than previously reported in cases detected by next-generation sequencing. This discrepancy may be caused by intratumoral heterogeneity. In conclusion, heterogeneous RICTOR overexpression is common in solid tumors and RICTOR IHC can be used as a screening tool to detect RICTOR amplification.

Fluorescence in Situ Hybridization (FISH) for Detecting Anaplastic Lymphoma Kinase (ALK) Rearrangement in Lung Cancer: Clinically Relevant Technical Aspects

In 2011, the Vysis Break Apart ALK fluorescence in situ hybridization (FISH) assay was approved by the United States Food and Drug Administration as a companion diagnostic for detecting ALK rearrangement in lung cancer patients who may benefit from treatment of tyrosine kinase inhibitor therapy. This assay is the current “gold standard”. According to updated ALK testing guidelines from the College of American Pathologists, the International Association for the Study of Lung Cancer and the Association for Molecular Pathology published in 2018, ALK immunohistochemistry is formally an alternative to ALK FISH, and simultaneous detection of multiple hot spots, including, at least, ALK, ROS1, RET, MET, ERBB2, BRAF and KRAS genes is also recommended while performing next generation sequencing (NGS)-based testing. Therefore, ALK status in a specimen can be tested by different methods and platforms, even in the same institution or laboratory. In this review, we discuss several clinically relevant technical aspects of ALK FISH, including pros and cons of the unique two-step (50- to 100-cell) analysis approach employed in the Vysis Break Apart ALK FISH assay, including: the preset cutoff value of ≥15% for a positive result; technical aspects and biology of discordant results obtained by different methods; and incidental findings, such as ALK copy number gain or amplification and co-existent driver mutations. These issues have practical implications for ALK testing in the clinical laboratory following the updated guidelines.

The Role of Ancillary Techniques in Pulmonary Cytopathology

Ancillary techniques play an essential role in pulmonary cytopathology. Immunoperoxidase and special stains are by far the most common ancillary techniques used in cytopathology; however, the role of molecular diagnosis is growing, especially in the fields of pulmonary oncology and infectious disease. In this article, we review the uses of ancillary techniques in lung tumor diagnosis, lung tumor classification, predictive marker determination, primary versus metastasis differential diagnosis, and infectious organism detection.

RNA-based analysis of ALK fusions in non-small cell lung cancer cases showing IHC/FISH discordance

Background

Rearrangements of the anaplastic lymphoma kinase (ALK) belong to the promising targets in the therapy of advanced non-small cell lung cancer (NSCLC) and are predominantly detected by immunohistochemistry (IHC) and/or fluorescence in-situ hybridization (FISH). However, both methods occasionally produce discordant results, especially in so-called borderline (BL) cases, showing ALK FISH-positive signals in 10–20% of the tumor nuclei around the cutoff (15%). This leads to a diagnostic and thus to a therapeutic dilemma.

Methods

We selected 18 unequivocal (12 ALK IHC/FISH-negative; 6 ALK IHC/FISH-positive) and 15 equivocal samples with discordant results between FISH (Abbott, Vysis LSI ALK Dual Color) and IHC (Ventana, D5F3), including cases with FISH-BL results, for further RNA based-analysis. To detect ALK rearrangement at the transcriptional level, RNA was analyzed using a targeted multiplex-PCR panel followed by IonTorrent sequencing and by direct transcript counting using a digital probe-based assay (NanoString). Sensitivity of both methods was defined using RNA obtained from an ALK-positive cell line dilution series.

Results

Cases with unequivocal IHC/FISH results showed concordant data with both RNA-based methods, whereas the three IHC-negative/FISH-positive samples were negative. The four IHC-negative/FISH-BL-negative cases, as well as the five IHC-negative/FISH-BL-positive samples showed negative results by massive parallel sequencing (MPS) and digital probe-based assay. The two IHC-positive/FISH-BL-positive cases were both positive on the RNA-level, whereas a tumor with questionable IHC and FISH-BL-positive status displayed no ALK fusion transcript.

Conclusions

The comparison of methods for the confirmation of ALK rearrangements revealed that the detection of ALK protein by IHC and ALK fusion transcripts on transcriptional level by MPS and the probe-based assay leads to concordant results. Only a small proportion of clearly ALK FISH-positive cases are unable to express the ALK protein and ALK fusion transcript which might explain a non-responding to ALK inhibitors. Therefore, our findings led us to conclude that ALK testing should initially be based on IHC and/or RNA-based methods.

[Current Status for Anaplastic Lymphoma Kinase in Non-small Cell Lung Cancer]

The incidence of ALK gene rearrangement in non-small cell lung cancer (NSCLC) was about 3% to 5%. ALK gene inhibitors have made great breakthrough in recent years, significantly extending the survival period of patients with ALK(+) advanced NSCLC. But the majority of patients will be acquired drug resistance after treatment. This article has been explained separately from the ALK genetic background, the detection method, the treatment of the three generations of ALK inhibitors and the strategy after drug resistance. It is desire to have reference value and reference meaning for clinical work.
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ALK (D5F3) CDx: an immunohistochemistry assay to identify ALK-positive NSCLC patients

Screening for anaplastic lymphoma kinase (ALK) rearrangements is a very important process in treatment decision making for advanced non-small-cell lung cancer (NSCLC). Although fluorescent in situ hybridization (FISH) is considered the universally accepted reference standard, it is associated with technical difficulties and high costs that have made global implementation of this assay challenging. Conversely, ALK immunohistochemistry has shown high sensitivity and specificity compared to FISH and other molecular assays and is more cost-effective. In fact, the ALK (D5F3) CDx immunohistochemistry assay was approved by the US Food and Drug Administration as a standalone test for ALK rearrangements in lung cancer in 2015. In this review, we will discuss the overview of ALK rearrangements in NSCLC, various testing methods for ALK rearrangements, and the details of immunohistochemistry for ALK, in particular one with the ALK antibody clone D5F3.

Fluorescent In Situ Hybridization in Surgical Pathology Practice

There have been rapid and significant advances in diagnostic and predictive molecular techniques in recent years with profound impact on patient care. In situ hybridization (ISH) studies have become well entrenched in surgical pathology practice and their role in the evaluation of HER2 in breast carcinoma and their diagnostic utility in soft tissue pathology are well known. Fluorescent ISH is being increasingly used in other sites such as the head and neck and the gynecologic tract. Like most tests in surgical pathology, ISH studies require good quality tissue, correlation with clinical and histopathologic findings, and adherence to guidelines for optimal assay performance and interpretation. Although ISH studies are largely performed in tertiary centers, the tissue is often processed by a variety of laboratories and the referring pathologists are required to discuss the need, relevance, and significance of these tests and the results with their clinical colleagues. Here we review the predictive and diagnostic utility of fluorescent ISH studies in a variety of organ systems, the preanalytical factors that may affect the results, and the pitfalls in the interpretation that all practicing surgical pathologists should be aware of.

An Update on Predictive Biomarkers for Treatment Selection in Non-Small Cell Lung Cancer

It is now widely established that management of lung cancer is much more complex and cannot be centered on the binary classification of small-cell versus non-small cell lung cancer (NSCLC). Lung cancer is now recognized as a highly heterogeneous disease that develops from genetic mutations and gene expression patterns, which initiate uncontrolled cellular growth, proliferation and progression, as well as immune evasion. Accurate biomarker assessment to determine the mutational status of driver mutations such as EGFR, ALK and ROS1, which can be targeted by specific tyrosine kinase inhibitors, is now essential for treatment decision making in advanced stage NSCLC and has shifted the treatment paradigm of NSCLC to more individualized therapy. Rapid advancements in immunotherapeutic approaches to NSCLC treatment have been paralleled by development of a range of potential predictive biomarkers that can enrich for patient response, including PD-L1 expression and tumor mutational burden. Here, we review the key biomarkers that help predict response to treatment options in NSCLC patients.

Biomarkers for ALK and ROS1 in Lung Cancer: Immunohistochemistry and Fluorescent In Situ Hybridization

CONTEXT

- A small proportion of non-small cell lung cancers harbor rearrangements of ALK or ROS1 genes, and these tumors are sensitive to targeted tyrosine kinase inhibitors. It is crucial for pathologists to accurately identify tumors with these genetic alterations to enable patients to access optimal treatments and avoid unnecessary side effects of less effective agents. Although a number of different techniques can be used to identify ALK- and ROS1-rearranged lung cancers, immunohistochemistry and fluorescence in situ hybridization are the mainstays.

OBJECTIVE

- To review the role of immunohistochemistry in assessment of ALK and ROS1 rearrangements in lung cancer, focusing on practical issues in comparison with other modalities such as fluorescence in situ hybridization.

DATA SOURCES

- This manuscript reviews the current literature on ALK and ROS1 detection using immunohistochemistry and fluorescence in situ hybridization as well as current recommendations.

CONCLUSIONS

- Although fluorescence in situ hybridization remains the gold standard for detecting ALK and ROS1 rearrangement in non-small cell lung cancer, immunohistochemistry plays an important role and can be an effective screening method for detection of these genetic alterations, or a diagnostic test in the setting of ALK.

Epithelioid cell histiocytoma with SQSTM1-ALK fusion: a case report

Background

Epithelioid cell histiocytoma (ECH), which is also known as epithelioid benign fibrous histiocytoma, has been classified as a rare variant of fibrous histiocytoma (FH). However, the recent detection of ALK protein expression and/or ALK gene rearrangement in ECH suggests that it might be biologically different from conventional FH.

Case presentation

A 27-year-old male presented with nodule on his left foot, which had been present for 5 years. A macroscopic examination revealed an exophytic, hyperkeratotic nodule on the dorsum of the left foot. Tumorectomy was performed, and a microscopic examination showed a subepidermal lesion composed of sheets of tumor cells with oval to round nuclei and ill-defined eosinophilic cytoplasm. The tumor cells were diffusely positive for factor XIIIa and ALK, but were negative for AE1/AE3 keratin, alpha-smooth muscle actin, CD30, CD34, CD68, PU.1, melan A, MITF, and S-100 protein. ALK immunostaining showed a diffuse cytoplasmic staining pattern. ALK fluorescence in situ hybridization demonstrated break-apart signals, which was suggestive of ALK rearrangement. A 5′-rapid amplification of cDNA ends assay detected SQSTM1-ALK fusion, in which exon 5 of the SQSTM1 gene was fused to exon 20 of the ALK gene. The patient was free from recurrence and distant metastasis at the 1-year of follow-up.

Conclusion

We were able to demonstrate the SQSTM1-ALK fusion gene in ECH. Practically, detecting immunopositivity for ALK and appropriate cell-lineage markers are the key to diagnosing ECH.

Pattern of care and survival of anaplastic lymphoma kinase rearranged non-small cell lung cancer (ALK+ NSCLC) in an Australian Metropolitan Tertiary Referral Centre: A retrospective cohort analysis

AIM

To report on the pattern of care and survival of anaplastic lymphoma kinase rearranged non-small cell lung cancer (ALK+NSCLC) in a real-world retrospective cohort from an Australian tertiary referral center.

METHODS

Individuals with a pathological diagnosis of ALK+NSCLC via immunohistochemistry and fluorescence in situ hybridization and a radiological diagnosis of stage IV disease were eligible. Patients were identified via the Pathology Department specimen database and electronic patient chart review. Data were collected and analyzed for baseline demographics, radiological pattern of disease and response to treatment, treatment sequencing, toxicity and survival.

RESULTS

Thirty-five patients were identified over a 7-year period from 2010 to 2016 and followed for a median of 23 months. Median overall survival (OS) in the entire cohort was immature at data cut, 46.0 months (95% confidence interval [CI], 22.53-69.47 months), with the longest surviving patient was alive 62.1 months since diagnosis. Objective radiological response rate overall across six potential treatments and six treatment lines (range 1-6) was 58.2%. Almost 50% received at-least two lines of ALK inhibitor therapy with median OS in this group estimated to be 53.4 months (95% CI, 35.1 months-not reached). Toxicity was manageable with a low rate of ≥ grade 3 toxicity (n = 7). Forty-eight percent relapsed within the CNS and 43% overall died due to CNS progression. In those with CNS diagnosis at baseline and/or progression within the CNS (n = 32), median OS was also 46.0 months (95% CI, 24.22-66.78 months).

CONCLUSION

This retrospective cohort analysis of a single tertiary institution experience in treating ALK+NSCLC demonstrates impressive OS and the importance and impact of careful management of CNS disease in this patient population.

Anaplastic lymphoma kinase (ALK)-expressing Lung Adenocarcinoma with Combined Neuroendocrine Component or Neuroendocrine Transformation: Implications for Neuroendocrine Transformation and Response to ALK-tyrosine Kinase Inhibitors

BACKGROUND

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) are usually effective in lung adenocarcinoma patients with anaplastic lymphoma kinase (ALK) rearrangement. However, even after a good response to ALK-TKI therapy, most patients acquire resistance to these agents. Histological transformation is one of several suggested mechanisms of acquired resistance to ALK-TKIs. The clinicopathologic features of four patients with ALK-expressing adenocarcinoma and neuroendocrine features were analyzed.

METHODS

We selected combined neuroendocrine differentiation in pulmonary adenocarcinoma cases with positive ALK immunostaining. Neuroendocrine differentiation was confirmed by CD56 immunohistochemical stain. Additional ALK fluorescence in situ hybridization (FISH) study and epidermal growth factor receptor (EGFR) mutation tests were also performed.

RESULTS

All four cases were positive for ALK immunohistochemistry and no EGFR mutations were detected. Interestingly, the results of ALK FISH assays showed rearrangement in only two cases. Three cases showed combined adenocarcinoma and neuroendocrine component without history of ALK-TKI administration; one of them was treated with crizotinib and experienced partial tumor regression. The remaining case had an adenocarcinoma at initial biopsy and she showed a partial response to crizotinib, and neuroendocrine changes were visible on second biopsy. Then she was treated with ceritinib and achieved a partial response.

CONCLUSION

We suggest that ALK-rearranged adenocarcinoma with combined neuroendocrine component is responsive to ALK-TKIs. Moreover, even after neuroendocrine transformation as a result of resistance to ALK-TKIs, the tumor may have partial response to second generation ALK-TKIs.

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.

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.

Comparison of Four PD-L1 Immunohistochemical Assays in Lung Cancer

INTRODUCTION

Four different programmed death ligand 1 immunohistochemical assays are approved or in development as companion or complementary diagnostics to different immunotherapeutic agents in lung carcinoma. We sought to determine whether these assays are technically equivalent and whether one antibody can be used on an alternate staining platform.

METHODS

Serial sections of tissue microarrays constructed from 368 cases of resected lung cancer were stained for 22C3 and 28-8 on the Dako Link 48 platform (Dako, Carpinteria, Ca) and for SP142 and SP263 on the Ventana Benchmark Ultra platform (Ventana Medical Systems, Tucson, AZ) strictly as per product insert. A protocol was developed to use the 22C3 antibody on the Ventana Benchmark Ultra platform.

RESULTS

Differences in mean tumor cell and immune cell staining were observed between the four assays (p < 0.001). Differences between 22C3 and 28-8 were not statistically significant. Concordance of tumor cell scores was good (intraclass correlation coefficient [ICC] = 0.674), particularly when SP142 was excluded as an outlier (ICC = 0.755). The highest concordance was seen between 22C3 and 28-8 (ICC = 0.812). Concordance was poor for immune cell staining (ICC = 0.212). When dichotomized according to clinically relevant cutoffs, pairwise comparisons showed poor to moderate concordance (κ = 0.196-0.578), with positive percent agreement ranging from 15.1% to 90.0%. The 22C3 antibody performed comparably on the Dako Link 48 platform and the alternate Ventana Benchmark Ultra platform (ICC = 0.921, κ = 0.897).

CONCLUSIONS

Concordance between the four programmed death ligand 1 immunohistochemical assays when performed and scored as intended show that apart from 28-8 and 22C3, they cannot be used interchangeably in clinical practice. A protocol was successfully developed to use 22C3 on an alternate platform, which may help to overcome some barriers to implementation.

The Presence of ALK Alterations and Clinical Relevance of Crizotinib Treatment in Pediatric Solid Tumors

Soft tissue sarcomas (STS) and neuroblastomas (NBL), are childhood malignancies still associated with poor prognoses despite the overall improvement in childhood tumor survival of the past decades. Anaplastic lymphoma kinase (ALK) inhibition is promising new strategy to improve the outcome of these pediatric tumors. Eighteen histologic samples of pediatric STS and 19 NBL patients were analyzed for ALK abnormalities using fluorescent in situ hybridization (FISH) with break-apart probes and immunohistochemistry (IHC). ALK alterations were presented in 20 of the 37 sections. The presence of ALK alteration in NBL samples were detected using IHC in 84,2% of all cases compared to 21,1% FISH positivity. In STS cases the results were less different (IHC 16,7% vs FISH 22,2%). The difference can be explained by the different type of molecular alterations. FISH method detected translocation and amplification, but not the point mutation of ALK gene. IHC confirmed the diagnosis by detecting the expression of ALK protein.After ALK positivity was proven, the effectiveness and safety of the crizotinib therapy was examined in 4 patients (1 alveolar rhabdomyosarcoma (RMA), 1 embryonal rhabdomyosarcoma (RME), 1 inflammatory myofibroblastic tumor (IMT), 1 NBL). We observed continuous remission of the IMT patient, all other cases the inhibitor treatment was not curative.Our findings underline the importance of screening the ALK status parallel with both IHC and FISH. Crizotinib treatment had a long-term effect in ALK positive IMT patients, however itwas only temporary efficient in relapsed, progressive STS and NBL.

Inflammatory Myofibroblastic Tumors of the Female Genital Tract Are Under-recognized: A Low Threshold for ALK Immunohistochemistry Is Required

Inflammatory myofibroblastic tumor (IMT) of the female genital tract is under-recognized. We investigated the prevalence of ALK-positive IMT in lesions previously diagnosed as gynecologic smooth muscle tumors. Immunohistochemistry (IHC) for ALK was performed on tissue microarrays of unselected tumors resected from 2009 to 2013. Three of 1176 (0.26%) “leiomyomas” and 1 of 44 (2.3%) “leiomyosarcomas” were ALK IHC positive, confirmed translocated by fluorescence in situ hybridization (FISH) and therefore more appropriately classified as IMT. On review significant areas of all 4 tumors closely mimicked smooth muscle tumors morphologically, but all showed at least subtle/focal features suggesting IMT. Recognizing that the distinction between IMT and leiomyoma/leiomyosarcoma can be subtle, we then reviewed 1 hematoxylin and eosin slide from each patient undergoing surgery for “leiomyoma” from 2014 to 2017 and selected cases for ALK IHC with a low threshold. Of these, 30 of 571 (5.3%) underwent IHC. Two were confirmed to be IHC positive and FISH rearranged. Of the 6 IMTs, only 1 tumor with a previous diagnosis of leiomyosarcoma, an infiltrative margin and equivocal necrosis, metastasized. Of note it demonstrated a less aggressive clinical course compared with most metastatic leiomyosarcomas (alive with disease at 6 y). The patient was subsequently offered crizotinib to which she responded rapidly. In conclusion, IMTs may closely mimic gynecologic smooth muscle tumors. IMTs account for at least 5 of 1747 (0.3%) tumors previously diagnosed as leiomyoma and 1 of 44 (2.3%) as leiomyosarcoma. These tumors may be recognized prospectively with awareness of subtle/focal histologic clues, coupled with a low threshold for ALK IHC.

Epitope mapping of spontaneous autoantibodies to anaplastic lymphoma kinase (ALK) in non-small cell lung cancer

The anaplastic lymphoma kinase (ALK) is recognized by the immune system as a tumor antigen, and preclinical evidence suggests that ALK-rearranged NSCLCs can also be successfully targeted immunologically using vaccine-based approaches. In contrast to ALK-rearranged lymphomas, the frequency and clinical significance of spontaneous ALK immune responses in patients with ALK-rearranged NSCLCs are largely unknown. We developed an enzyme-linked immunosorbent assay (ELISA) to measure anti-ALK antibody levels and mapped specific peptide epitope sequences within the ALK cytoplasmic domain in patients with non-small cell lung cancer. The ELISA method showed good correlation with ALK antibody titers measured with a standard immunocytochemical approach. Strong anti-ALK antibody responses were detected in 9 of 53 (17.0%) ALK-positive NSCLC patients and in 0 of 38 (0%) ALK-negative NSCLC patients (P<0.01), and the mean antibody levels were significantly higher in ALK-positive than in ALK-negative NSCLC patients (P=0.02). Across individual patients, autoantibodies recognized different epitopes in the ALK cytoplasmic domain, most of which clustered outside the tyrosine kinase domain. Whether the presence of high ALK autoantibody levels confers a more favorable prognosis in this patient population warrants further investigation.

Worse disease-free, tumor-specific, and overall survival in surgically-resected lung adenocarcinoma patients with ALK rearrangement

Introduction

This study determined the prevalence of anaplastic lymphoma kinase (ALK) rearrangement, and identified the associations of ALK rearrangement with clinicopathologic characteristics and treatment outcomes in patients with surgically-resected stage I-III lung adenocarcinoma.

Methods

A total of 534 surgically-resected lung adenocarcinoma patients were studied. The prevalence of ALK protein over-expression was determined by a fully-automated immunochemistry assay (with mouse monoclonal Ventana D5F3 antibody), and the associations of ALK rearrangement with clinicopathologic characteristics and treatment outcomes were analyzed.

Results

Forty-two (7.9%) of the 534 lung adenocarcinoma patients were ALK IHC-positive. ALK rearrangement was significantly associated with younger age (P = 0.011), high T-stage (P = 0.025), high pathologic stage (P = 0.002), solid predominant adenocarcinoma with mucin production (P = 0.006), invasive mucinous adenocarcinoma (P = 0.009), and receipt of adjuvant therapy after surgery (P = 0.036), but no significant associations were found between the ALK rearrangement and sex or smoking status. ALK IHC-positivity was significantly associated with a shorter disease-free survival, tumor-specific survival, and overall survival (P = 0.001, 0.026, and 0.007, respectively). Multivariate analysis showed that ALK IHC-positivity was an adverse prognostic factor for disease-free survival (HR, 1.80; 95% CI 1.18-2.77; P = 0.007), tumor-specific survival (HR, 2.59; 95% CI 1.35-4.97; P = 0.004), and overall survival (HR, 1.92; 95% CI 1.07-3.44; P = 0.030).

Conclusion

The clinical characteristics of patients with ALK-positive lung adenocarcinoma were similar to those of EGFR-mutated patients. ALK rearrangement was an adverse prognostic factor in surgically-resected lung adenocarcinoma patients.

Correlation between molecular analysis, diagnosis according to the 2015 WHO classification of unresected lung tumours and TTF1 expression in small biopsies and cytology specimens from 344 non-small cell lung carcinoma patients

We investigated correlations between diagnosis according to the 2015 World Health Organization (WHO) classification of unresected lung tumours, molecular analysis and TTF1 expression in small biopsy and cytology specimens from 344 non-small cell lung carcinoma (NSCLC) patients. One case failed testing for EGFR, KRAS and ALK abnormalities and six had insufficient tumour for ALK testing. Overall mutation rate in 343 cases was 48% for the genes tested, with 19% EGFR, 33% KRAS and 4% BRAF mutations, and 5% ALK rearrangements detected. More EGFR-mutant (78%) and ALK-rearranged (75%) tumours had morphologic adenocarcinoma than KRAS-mutant (56%) tumours. Despite no significant difference in the overall rate of any molecular abnormality between morphologic adenocarcinoma (52%) and NSCLC, favour adenocarcinoma (47%) (p = 0.18), KRAS mutations were detected more frequently in the latter group. No significant difference in the overall rate of any molecular abnormality between TTF1 positive (49%) and TTF1 negative tumours (44%) (p = 0.92) was detected, but more EGFR-mutant (97%) and ALK-rearranged tumours (92%) were TTF1 positive than KRAS-mutant tumours (68%). Rates of EGFR, KRAS and BRAF mutations and ALK rearrangements in this Australian NSCLC patient population are consistent with the published international literature. Our findings suggest that 2015 WHO classification of unresected tumours may assist in identifying molecular subsets of advanced NSCLC.

A nCounter CNV Assay to Detect HER2 Amplification: A Correlation Study with Immunohistochemistry and In Situ Hybridization in Advanced Gastric Cancer

AIM

Screening amplified genes for targeted therapy with high-throughput technology is very important. The NanoString nCounter system allows multiplexed digital quantification of target molecules through the use of color-coded barcodes with the great advantage that formalin-fixed, paraffin-embedded (FFPE) tissue can be utilized.

METHODS

We tested nCounter custom copy number variation (CNV) panels in 220 gastric cancer samples and evaluated the utility of this method as a screening tool for the detection of CNV using HER2. For the validation of results, we compared the nCounter results with immunohistochemistry (IHC), and we further performed in situ hybridization (ISH) in discrepant cases.

RESULTS

The average HER2 gene copy numbers (CNs) by nCounter were 17.25, 2.0 and 2.61 for the HER2 IHC positive (3+), equivocal (2+), and negative cases, respectively. Out of the 16 IHC 3+ cases, 13 (81.3 %) were reported as HER2 CN gain (≥4). Gastric cancers with homogeneous HER2 overexpression or high tumor purity showed HER2 CN ≥10. Among the 192 cases with HER2 IHC negative and without HER2 gene amplification, 29 showed a HER2 CN ≥4 with the nCounter assay. The nCounter assay had a concordance rate of 83.4 % (kappa value, 0.35), a sensitivity of 66.7 %, a specificity of 85.2 %, a negative predictive value of 96 %, and a positive predictive value of 32.6 % compared with HER2 IHC/ISH results. Fresh frozen (FF) samples revealed a higher concordance rate (91.5 %, kappa value, 0.59) than FFPE samples (78.5 %, kappa value 0.27) and showed a high specificity (97.2 %).

CONCLUSION

The nCounter CNV assay is a reliable and practical method to detect high CN variations. Given the intra-tumoral HER2 heterogeneity and normal cell contamination, additional IHC and/or FISH is necessary and needs caution in interpretation, especially in FFPE tissue samples.

Anaplastic lymphoma kinase (ALK) mutations in patients with adenocarcinoma of the lung

BACKGROUND

Non-small cell lung cancer (NSCLC) is a major cause of cancer-related death. Approximately 2-16% of NSCLC patients with wild-type epidermal growth factor receptor (EGFR) harbour anaplastic lymphoma kinase (ALK) mutations. Both EGFR and ALK mutations occur most commonly in Asian patients with NSCLC. As targeted therapy is available for NSCLC patients with these mutations, it is important to establish reliable assays and testing strategies to identify those most likely to benefit from this therapy.

MATERIALS AND METHODS

Patients diagnosed with adenocarcinoma of the lung between 2010 and 2014 were tested for EGFR mutations. Of these, 92 cases were identified as EGFR wild type and suitable candidates for ALK testing utilising immunohistochemistry and the rabbit monoclonal antibody D5F3. The reliability of the IHC was confirmed by validating the results against those achieved by fluorescence in situ hybridisation (FISH) to detect ALK gene rearrangements.

RESULTS

Twelve (13%) cases were positive for ALK expression using immunohistochemistry. Of the 18 evaluable cases tested by FISH, there was 100% agreement with respect to ALK rearrangement/ALK expression between the assays, with 11 cases ALK negative and 7 cases ALK positive by both assays. ALK tumour expression was significantly more common in female compared to male patients (29.6% vs. 6.2%, P < 0.001), detected exclusively in patients that had never smoked (P < 0.001) and more frequently in metastases (22.7%) than in primary tumours (10%) (P = 0.047).

CONCLUSIONS

Detection of ALK expression by IHC is reliable and the most practical way of identifying NSCLC patients likely to benefit from crizotinib treatment.

Immunohistochemistry of Pulmonary Biomarkers: A Perspective From Members of the Pulmonary Pathology Society

The use of immunohistochemistry for the determination of pulmonary carcinoma biomarkers is a well-established and powerful technique. Immunohistochemisty is readily available in pathology laboratories, is relatively easy to perform and assess, can provide clinically meaningful results very quickly, and is relatively inexpensive. Pulmonary predictive biomarkers provide results essential for timely and accurate therapeutic decision making; for patients with metastatic non-small cell lung cancer, predictive immunohistochemistry includes ALK and programmed death ligand-1 (PD-L1) (ROS1, EGFR in Europe) testing. Handling along proper methodologic lines is needed to ensure patients receive the most accurate and representative test outcomes.

An Immunohistochemical Study of Anaplastic Lymphoma Kinase and Epidermal Growth Factor Receptor Mutation in Non-Small Cell Lung Carcinoma

INTRODUCTION

Lung cancer is one of the leading causes of cancer related death. Targeted treatment for specific markers may help in reducing the cancer related morbidity and mortality.

AIM

To study expression of Anaplastic Lymphoma Kinase (ALK)and Epidermal Growth Factor Receptor (EGFR) mutations in patients of Non-Small Cell Lung Cancer NSCLC, that are the targets for specific ALK inhibitors and EGFR tyrosine kinase inhibitors.

MATERIALS AND METHODS

Total 69 cases of histologically diagnosed NSCLC were examined retrospectively for immunohistochemical expression of EGFR and ALK, along with positive control of normal placental tissue and anaplastic large cell lymphoma respectively.

RESULTS

Of the NSCLC, Squamous Cell Carcinoma (SCC) accounted for 71.0% and adenocarcinoma was 26.1%. ALK expression was seen in single case of 60-year-old female, non-smoker with adenocarcinoma histology. EGFR expression was seen in both SCC (59.18%) and adenocarcinoma in (77.78%) accounting for 63.77% of all cases. Both ALK and EGFR mutation were mutually exclusive.

CONCLUSION

EGFR expression was seen in 63.77% of cases, highlighting the importance of its use in routine analysis, for targeted therapy and better treatment results. Although, ALK expression was seen in 1.45% of all cases, it is an important biomarker in targeted cancer therapy. Also, the mutually exclusive expression of these two markers need further studies to develop a diagnostic algorithm for NSCLC patients.

Application of Immunohistochemistry in the Diagnosis of Pulmonary and Pleural Neoplasms

CONTEXT

- A vast majority of neoplasms arising from lung or pleura are initially diagnosed based on the histologic evaluation of small transbronchial, endobronchial, or needle core biopsies. Although most diagnoses can be determined by morphology alone, immunohistochemistry can be a valuable diagnostic tool in the workup of problematic cases.

OBJECTIVE

- To provide a practical approach in the interpretation and immunohistochemical selection of lung/pleura-based neoplasms obtained from small biopsy samples.

DATA SOURCES

- A literature review of previously published articles and the personal experience of the authors were used in this review article.

CONCLUSION

- Immunohistochemistry is a useful diagnostic tool in the workup of small biopsies from the lung and pleura sampled by small biopsy techniques.

Optimized immunohistochemistry using the D5F3 antibody provides a reliable test for identification of ALK-positive lung adenocarcinomas

We used optimized immunohistochemistry (IHC) with the D5F3 antibody for detection of tumours in a prospective study of 307 pulmonary adenocarcinomas. Cases positive by IHC (1+, 2+, 3+) were further investigated by fluorescent in situ hybridization (FISH). Of 307 cases, 22 (7.2%) were moderately intensely positive (2+/3+); 18 of these (82%) were also positive by FISH. Of the four IHC-positive/FISH-negative cases, one was unsuitable for FISH and three had abnormalities of the ALK gene. All cases with weak reactivity with D5F3 (1+) were FISH-negative. The FISH positive/IHC-positive cases with moderately intense reactivity had the typical clinicopathologic features of ALK-positive patients (younger age, p < 0.01; higher frequency in metastatic sites, p < 0.01; cribriform/mucinous/signet histology, p < 0.01; stage IV disease, p < 0.01). In conclusion, our findings indicate that optimized IHC using the D5F3 antibody provides a reliable and inexpensive test for identification of ALK-positive adenocarcinomas. Inclusion of this information in the pathology report at the time of the histological diagnosis might significantly shorten time to treatment.

[Clinical Advanced in Early-stage ALK-positive Non-small Cell Lung Cancer Patients]

肺癌是我国癌症死亡最主要的原因。其中非小细胞肺癌（non-small cell lung cancer, NSCLC）占肺癌患者的85%，且大部分患者初诊时即为晚期。针对晚期NSCLC患者，分子靶向治疗成为人们关注的热点。棘皮动物微管相关蛋白-间变淋巴瘤激酶（echinoderm microtubule-associated protein-like 4 gene and the anaplastic lymphoma kinase gene, EML4-ALK）是NSCLC最常见的分子靶点之一，其特异性的小分子酪氨酸激酶抑制剂（tyrosine kinase inhibitors, TKIs）已被批准应用于ALK阳性晚期NSCLC患者的治疗。然而，ALK融合基因对早期NSCLC患者预后的影响，以及ALK阳性的早期NSCLC患者应用TKIs的必要性等问题尚不明确。本文主要围绕ALK阳性NSCLC患者的检测进展，早期ALK阳性NSCLC患者的临床病理特征、预后、ALK-TKIs应用必要性等情况做一简要综述。

ALK Immunohistochemistry for ALK Gene Rearrangement Screening in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Introduction

The aim of this study was to investigate the diagnostic accuracy of anaplastic lymphoma kinase (ALK) immunohistochemistry (IHC) for ALK gene rearrangement in non-small cell lung cancer (NSCLC) through systematic review, meta-analysis and diagnostic test accuracy review.

Methods

The current study included 11,806 NSCLC cases in 42 eligible studies. We performed concordance analyses between ALK IHC and fluorescence in situ hybridization (FISH). The diagnostic accuracy of ALK IHC was analyzed based on ALK IHC criteria and antibodies.

Results

The overall ALK IHC results were positive in 13.2%. The overall concordance rate between ALK IHC and FISH was 0.950 (95% confidence interval [CI], 0.927-0.966). In the ALK IHC-positive and negative groups, the concordance rates were 0.805 (95% CI 0.733-0.861) and 0.985 (95% CI 0.978-0.990), respectively. The ALK FISH-positive rates were 0.009 (95% CI 0.004-0.023), 0.378 (95% CI 0.217-0.572), 0.628 (95% CI 0.420-0.796) and 0.900 (95% CI 0.840-0.939) in the ALK IHC 0, 1+, 2+ and 3+ groups, respectively. In diagnostic test accuracy review for ALK IHC, the pooled sensitivity and specificity were 0.92 (95% CI 0.89-0.94) and 0.91 (95% CI 0.90-0.91), respectively. The diagnostic odds ratio and the area under the curve on the summary receiver operating characteristic curve were 266.56 (95% CI 110.83-641.14) and 0.983, respectively.

Conclusions

Our results suggested that ALK IHC equivocal (score 1+ and 2+) cases should not be considered as IHC-negative in screening for ALK gene rearrangement. Additional detailed criteria for ALK IHC equivocal cases are necessary to determine how to best apply this approach in daily practice.

Screening for ROS1 gene rearrangements in non-small-cell lung cancers using immunohistochemistry with FISH confirmation is an effective method to identify this rare target

AIMS

To assess the prevalence of ROS1 rearrangements in a retrospective and prospective diagnostic Australian cohort and evaluate the effectiveness of immunohistochemical screening.

METHODS AND RESULTS

A retrospective cohort of 278 early stage lung adenocarcinomas and an additional 104 prospective non-small-cell lung cancer (NSCLC) cases referred for routine molecular testing were evaluated. ROS1 immunohistochemistry (IHC) was performed (D4D6 clone, Cell Signaling Technology) on all cases as well as fluorescence in-situ hybridization (FISH) using the ZytoVision and Abbott Molecular ROS1 FISH probes, with ≥15% of cells with split signals considered positive for rearrangement. Eighty-eight cases (32%) from the retrospective cohort showed staining by ROS1 IHC, and one case (0.4%) showed ROS1 rearrangement by FISH. Nineteen of the prospective diagnostic cases showed ROS1 IHC staining, 12 (12%) cases of which were confirmed as ROS1 rearranged by FISH. There were no ROS1 rearranged cases that showed no expression of ROS1 with IHC. The ROS1 rearranged cases in the prospective cohort were all EGFR wild-type and anaplastic lymphoma kinase (ALK) rearrangement-negative. The sensitivity of ROS1 IHC in the retrospective cohort was 100% and specificity was 76%.

CONCLUSIONS

ROS1 rearrangements are rare events in lung adenocarcinomas. Selection of cases for ROS1 FISH testing, by excluding EGFR/ALK-positive cases and use of IHC to screen for potentially positive cases, can be used to enrich for the likelihood of identifying a ROS1 rearranged lung cancer and prevent the need to undertake expensive and time-consuming FISH testing in all cases.

Alectinib for treatment of ALK-positive non-small-cell lung cancer

Alectinib is a highly selective second-generation ALK inhibitor that is active against most crizotinib ALK resistance mutations, with a good penetration in CNS and a good safety profile. Thanks to the positive results of Phase II trials, alectinib was approved in Japan and by the US FDA for ALK-positive non-small-cell lung cancer (NSCLC) patients pretreated with crizotinib. Recently, the Phase III J-ALEX study demonstrated superiority of alectinib over crizotinib in crizotinib naive ALK-positive NSCLC, with an impressive improvement of progression-free survival. From the results and those expected of Phase III ALEX study, alectinib might become the frontline treatment of ALK-positive NSCLC. This article summarizes the therapeutic options in ALK-positive advanced NSCLC, and the chemical, pharmacodynamics, pharmacokinetics, metabolism and clinical efficacy of alectinib.