Anaplastic Lymphoma Kinase Gene Rearrangement Research Articles

Molecular Testing for EGFR Mutations and ALK Rearrangements in the Cytological Specimens From the Patients With Non-Small Cell Lung Cancer.

The aim of this study was to investigate epidermal growth factor receptor (EGFR) gene mutations and anaplastic lymphoma kinase (ALK) gene rearrangements using cytological specimens from the patients with a diagnosis of primary or metastatic lung non-small cell carcinoma. A total 307 cases were submitted for EGFR mutational analysis and 265 cases for ALK analysis. The cytological specimen sources included lung, lymph node, liver, bone, adrenal gland, mesentery mass, and body fluids/bronchial brushing. EGFR mutations in the exons 18 to 21 were analyzed with Qiagen EGFR Pyro Kits. Fluorescence in situ hybridization (FISH) studies for ALK rearrangement inv(2)(p21; p23) were performed on the paraffin-embedded cell block sections utilizing dual-color Vysis LSI ALK Break Apart Probe Kit. Among 307 fine needle aspirate cases for EGFR analysis, 302 cases (269 from cell blocks, 33 from direct smears) had sufficient material for EGFR test. Five cases failed due to inadequate cellularity. Twenty six of 302 (8.6%) cases were positive for EGFR mutations. A total of 265 cases submitted for ALK analysis included 240 cases of fine needle aspirate, 25 cases of pleural fluid/pericardial fluid/bronchial washings. Eight cases failed because of low cellularity, whereas 257 of 265 cases had sufficient material for ALK FISH study. Nine of 257 cases (3.5%) revealed ALK rearrangement by FISH. The current study demonstrates that cytological specimens can yield sufficient material for EGFR mutations and ALK rearrangement test. Our study reveals that 8.6% of EGFR mutation rate and 3.5% of ALK rearrangement rate in the cytology specimens from the patients with primary or metastatic lung non-small cell carcinoma.

Spitzoid melanoma with ALK copy number gain

Spitzoid melanoma is an uncommon melanoma (type of skin cancer) that can occur at any age, and can resemble a harmless mole called a ‘Spitz nevus’. This similarity can make it difficult to diagnose. Spitzoid tumours (Spitz nevi) have recently begun to be categorized according to their genetic profile, meaning the genes found in them, and certain molecular alterations were found to link to changes to the structure of the nevus as could be seen when examined under a microscope. For example, Spitz tumours can have what is called an anaplastic lymphoma kinase (ALK) gene rearrangement. ALK is a gene that tells your body how to make proteins that help cells talk to each other. ALK rearrangement means that part of this gene is broken and attached to another gene. Spitz tumours with ALK rearrangement have been shown to have a distinctive “plexiform pattern”. Humans have two copies of most genes, but occasionally alterations can lead to the gain or a loss of one copy. When it is a gain of one copy this is called copy gain. In this report, authors from the US discuss a case of an 87‐year‐old man with a 3cm tumour on his back, and conclude that ALK copy gain represents an additional mechanism of ALK activation among Spitzoid tumours and shows the same plexiform pattern seen among ALK‐rearranged Spitz tumours.

Neuron-Specific Enolase Is an Independent Prognostic Factor in Resected Lung Adenocarcinoma Patients with Anaplastic Lymphoma Kinase Gene Rearrangements.

BackgroundAn extensive body of research reveals the clinical value of serum tumor markers in lung cancer patients, including carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCCA), cytokeratin-19 fragments (Cyfra21-1), and neuron-specific enolase (NSE), but little is known about the clinical properties of these serum tumor markers in anaplastic lymphoma kinase (ALK)-positive lung cancer patients.Matreial/MethodsWe retrospectively analyzed 54 patients harboring ALK rearrangements and 520 patients without ALK rearrangements, and all these patients were treated exclusively by surgery between 2011 and 2016.ResultsNSE level (P=0.007 for OS) was identified as an independent prognostic factor among patients with resected ALK-positive adenocarcinoma of the lung.ConclusionsA high level of NSE is associated with worse outcome among resected lung adenocarcinoma patients harboring ALK rearrangements.

Cytomorphological Features of Lung Adenocarcinoma with Anaplastic Lymphoma Kinase Gene Rearrangement.

Background:The anaplastic lymphoma kinase (ALK) gene rearrangement is a predictive and prognostic marker in pulmonary adenocarcinoma. A series of clinical and pathological features have been documented in patients who harbor this translocation.Aims:The objectives of this study were to analyze the specific cytomorphological features of lung adenocarcinoma that harbored the ALK gene rearrangement and to compare the morphological features with the mutation-negative cases.Materials and Methods:The study sample of 40 cases included 15 ALK-positive cases and 25 ALK-negative cases. After the diagnosis was established, testing for ALK rearrangement was on the histopathology sample. The corresponding fine-needle aspiration cytology slides were retrieved from the records and cytomorphological features were analyzed.Results:A comparison of pattern between the ALK-positive and ALK-negative group revealed that the sheet-like pattern and singly scattered cells were more common in the ALK-positive group. Moderate-to-severe nuclear pleomorphism was identified in 80% of ALK-positive cases and 72% of ALK-negative cases. The presence of mucinous features and/or signet ring morphology was the most striking feature of ALK-positive cases with P value of 0.002. The presence of necrosis in the background was identified in 80% of ALK-positive cases and was statistically significant (P = 0.001).Conclusion:This is among the few studies from India, where a detailed analysis of the cytomorphological features of cases with ALK phenotype versus the mutation negative cases has been performed.

Detection of anaplastic lymphoma kinase gene rearrangement in a patient with right colon cancer

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity worldwide. Recent genome-scale molecular analyses have uncovered several potential therapeutic targets for this disease, including BRAF mutation, ERBB2 amplification, and neurotropic tropomyosin receptor kinase fusion gene. Gene rearrangements involving anaplastic lymphoma kinase (ALK) gene have been identified as oncogenic drivers in lung adenocarcinomas, and to be highly sensitive to selective kinase inhibitors. To the best of our knowledge, CRC harboring the ALK fusion gene has rarely been reported. Herein, we report a patient with right colon cancer harboring an ALK gene rearrangement and review the clinicopathologic features as well as potential therapeutic targeting of ALK-rearranged CRC in the literature.

ALK Expression in Angiomatoid Fibrous Histiocytoma: A Potential Diagnostic Pitfall.

We recently encountered a case of primary pulmonary angiomatoid fibrous histiocytoma (AFH), which was initially misdiagnosed as inflammatory myofibroblastic tumor (IMT) based in part on anaplastic lymphoma kinase (ALK) expression by immunohistochemistry (IHC). Prompted by this experience, we evaluated ALK expression in 11 AFH, 15 IMT, and 11 follicular dendritic cell sarcomas using 3 different antibody clones: D5F3, 5A4, and ALK1. ALK IHC positive cases were analyzed with fluorescence in situ hybridization (FISH) using dual color ALK break-apart probe kit. The majority of AFH cases studied were positive for ALK IHC with at least 1 antibody (9/11 D5F3, 6/9 5A4, 1/9 ALK1), most demonstrating moderate to strong cytoplasmic staining. AFH with positive ALK IHC showed no ALK gene rearrangement by FISH (0/8) with ALK copy number ranging from 1.6 to 2.1. Sixty-seven percent of IMT were ALK positive by IHC (10/15 D5F3, 8/15 5A4, 7/15 ALK1), and 9 of the 10 cases were positive for ALK gene rearrangement by FISH. All follicular dendritic cell sarcomas were negative for ALK by IHC (D5F3 and 5A4). Our results indicate that ALK expression in AFH is common, particularly with the highly sensitive D5F3 and 5A4 antibodies and enhanced detection systems, and may be a potential source of diagnostic confusion with IMT. The underlying mechanism of ALK expression in AFH is unclear, although it does not appear to be from ALK rearrangement or amplification.

Management of leptomeningeal metastases in non-small cell lung cancer.

In leptomeningeal metastasis (LM), malignant lung cancer cells reach the sanctuary site of the leptomeningeal space through haematogenous or lymphatic route and thrive in the leptomeninges because of restricted access of chemotherapeutic agents across the blood brain barrier. The incidence of LM is 3%-5% in non-small cell lung cancer (NSCLC) patients; the incidence is higher in patients with anaplastic lymphoma kinase (ALK) gene rearrangement or epidermal growth factor receptor (EGFR) mutations. However, the real-world burden of undiagnosed cases may be higher. LM diagnosis is based on clinical, radiological, and cytological testing. Disease management remains a challenge because of low central nervous system penetration of drugs. The prognosis of NSCLC patients with LM is poor with an overall survival (OS) of 3 months with contemporary treatment and <11 months with novel therapies. Therapy goals in this patient population are to improve or stabilize neurologic status, improve quality of life, and prolong survival while limiting the toxicity of chemotherapeutic regimens. We reviewed therapeutic options for management of LM in NSCLC patients with or without genetic mutations. Radiotherapy, systemic, or intrathecal chemotherapy, and personalized molecularly targeted therapy prolong the OS in patients with LM. Newer third generation EGFR-tyrosine kinase inhibitors have considerable brain penetration property and have been vital in increasing the OS especially in patients with EGFR mutations. Sequential or combination therapy third generation EGFR agents with radiotherapy or chemotherapy might be effective in increasing the quality of life and overall survival.

Alectinib in the treatment of ALK-positive metastatic non-small cell lung cancer: clinical trial evidence and experience with a focus on brain metastases.

Molecular profiling of metastatic nonsquamous non-small cell lung cancer (NSCLC) is required to guide the treatment strategy. Anaplastic lymphoma kinase (ALK) gene rearrangements are found in approximately 5% of lung adenocarcinomas and are associated with specific clinical features including a high risk of brain metastases. Crizotinib was the first ALK inhibitor developed and it demonstrated improved outcomes in patients with ALK-positive advanced NSCLC in comparison with chemotherapy. However, despite an initial response, all ALK-positive NSCLC patients develop acquired resistance to crizotinib. Because the most frequent mechanism of resistance is the development of a secondary ALK mutation, second (ceritinib, alectinib, brigatinib) and third-generation (lorlatinib) ALK inhibitors were developed. Alectinib is a second-generation ALK inhibitor and was shown to be effective for a broad spectrum of ALK rearrangements and ALK mutations. It was also shown to have high intracranial efficacy. In this article, we review clinical trial evidence of alectinib efficacy as well as publications reporting the experience of alectinib in daily practice, with a focus on brain metastases.

Natural History and Factors Associated with Overall Survival in Stage IV ALK-Rearranged Non–Small Cell Lung Cancer

IntroductionClinical variables describing the natural history and longitudinal therapy outcomes of stage IV anaplastic lymphoma kinase gene rearrangement positive (ALK-positive) NSCLC and their relationship with long-term overall survival (OS) have not previously been described in detail. MethodsPatients with stage IV NSCLC treated with an ALK inhibitor at the University of Colorado Cancer Center from 2009 through November 2017 were identified retrospectively. OS curves were constructed by using Kaplan-Meier methods. Multivariate Cox proportional hazard analysis was used to determine the relationship of variables with OS. ResultsOf the 110 patients with ALK-positive NSCLC who were identified, 105 received crizotinib as their initial ALK inhibitor. With a median follow-up time of 47 months, the median OS time from diagnosis of stage IV disease was 81 months (6.8 years). Brain metastases at diagnosis of stage IV disease (hazard ratio = 1.01, p = 0.971) and year of stage IV presentation (p = 0.887) did not influence OS. More organs with tumor at diagnosis of stage IV disease was associated with worse OS (HR = 1.49 for each additional organ with disease, including the CNS [p = 0.002]). Each additional month of pemetrexed-based therapy was associated with a 7% relative decrease in risk of death. ConclusionPatients with stage IV ALK-positive NSCLC can have prolonged OS. Brain metastases at diagnosis of stage IV disease does not influence OS. Having more organs involved with tumor at stage IV presentation is associated with worse outcomes. Prolonged benefit from pemetrexed is associated with better outcomes.

Expanding the Molecular Characterization of Thoracic Inflammatory Myofibroblastic Tumors beyond ALK Gene Rearrangements

IntroductionHalf of inflammatory myofibroblastic tumors (IMTs) regardless of anatomic location harbor anaplastic lymphoma kinase gene (ALK) rearrangements and overexpress anaplastic lymphoma kinase protein. The wide application of next-generation sequencing and the clinical benefit to tyrosine kinase inhibitors have opened new opportunities for investigation of ALK-negative IMTs. MethodsIn this study, we have investigated a series of pediatric and adult thoracic IMTs for abnormalities in a wide spectrum of actionable kinases by applying a variety of molecular and next-generation sequencing techniques, including fluorescence in situ hybridization (FISH), targeted RNA sequencing, and NanoString assay. ResultsThere were 33 patients with thoracic IMTs, including five children; their mean age was 37. The tumors showed a monomorphic spindle cell phenotype, except for one with an epithelioid morphologic pattern and moderate to severe atypia. By immunohistochemistry, 24 tumors were ALK positive, and 19 of the 24 showed ALK rearrangements and one ret proto-oncogene gene (RET) rearrangement by FISH. RNA sequencing was performed in the remaining four cases lacking ALK abnormalities by FISH, revealing ALK fusions involving tropomyosin 4 gene (TMP4) and echinoderm microtubule associated protein like 4 gene (EML4) as partner in three cases. NanoString assay was performed in the remaining case, revealing ALK alternative transcription initiation (ALKATI). Nine cases lacking ALK abnormalities were further tested by FISH or targeted RNA sequencing, revealing ROS1 rearrangement in six cases and ETS variant 6 gene (ETV6)–neurotrophic receptor tyrosine kinase 3 gene (NTRK3) fusion in three cases, respectively. ConclusionsBy using a battery of complementary molecular techniques, we have shown that all the thoracic IMTs harbored a tyrosine kinase abnormality, with 30% involving a kinase gene other than ALK, including ROS1, NTRK3, and RET gene fusions. We have also described for the first time ALKATI-induced ALK oncogenic activation in IMTs.

Application of Ventana immunocytochemical analysis on ThinPrep cytology slides for detection of ALK rearrangement in patients with advanced non\u2013small-cell lung cancer

BackgroundVentana ALK (D5F3) screening of anaplastic lymphoma kinase (ALK) gene rearrangement in tissue specimens has been approved by US FDA (Food and Drug Administration) to select treatment for non–small-cell lung carcinoma (NSCLC). However, tumor tissues are often not readily obtainable, and cytology specimens and may be the only tumor material available for diagnosis and molecular marker analysis. In this study, we evaluated the feasibility of ALK immunocytochemistry (ICC) on ThinPrep slides and determined a suitable scoring system for interpretation of the results.MethodsOne hundred twenty-one fine-needle aspirate (FNA) specimens from metastatic lesions of NSCLC were analyzed. ALK rearrangement was detected on ThinPrep cytology slides using the Ventana immunocytochemistry ALK-D5F3 system, which adopts two scoring systems for interpretation of the ICC results. The results were subsequently confirmed by reverse transcription polymerase chain reaction (RT-PCR) analysis and fluorescence in situ hybridization (FISH).ResultsAmong the 121 ICC specimens, 16 that were considered ALK-positive by either scoring system were referred for PCR analysis. Among the ALK ICC-negative cases, 33 had correlated FISH ALK results. A total of 49 specimens that exhibited either a positive or negative ICC result with a correlated ALK status were analyzed statistically. ICC results showed a high concordance rate with the results of PCR/FISH analysis. The sensitivity and specificity of ALK ICC by the binary scoring algorithm were 68.75 and 96.97%, respectively. These values increased to 93.75 and 96.97%, respectively, when interpreted by the semiquantified interpretation system.ConclusionsALK ICC analysis on ThinPrep slides is a reliable ALK testing method, and the semiquantified interpretation system on cytology specimens is recommended rather than the binary scoring algorithm on tissue specimens.

P1.09-22 Detection of ALK Gene Rearrangement in FFPE Tissues of Non-Small Cell Lung Cancer Using in Situ RNA Hybridization

Approximately 4-7% of non-small cell lung cancer (NSCLC) harbor anaplastic lymphoma kinase (ALK) gene rearrangements which lead to overexpression of ALK fusion protein and constitutive activation of the kinase. The tumor with ALK gene rearrangements is sensitive to its inhibitor, so identification of this molecular feature from the patients accurately is important. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are conventional methods for testing ALK gene rearrangement and protein overexpression respectively; however it is challenge for distinguishing some rare variations by FISH, or determining the equivocal stain by IHC. A morphology related method under bright field about rearranged mRNA expression (RNAscope) of ALK gene fusion was developed, which is helpful to realize the biological behavior of ALK gene, together with FISH (break apart FISH probe kit, Abbott) and IHC (D5F3 clone, Ventana). We explored 7 cases of formalin-fixed paraffin-embedded (FFPE) samples from NSCLC patients by RNAscope® 2.5 Red assay Three of seven samples were found with ALK positive by RNAscope, which matched with FISH and IHC results. In these 3 ALK positive samples, exon 19-29 of ALK gene transcribed RNA signals were revealed by probe-Hs-ALK E1-E18 (score 1 to 2 in >50% cells), whereas exon 1-18 transcribed RNA signals were not shown by probe-Hs-ALK E19-E29, which confirmed by FISH results (with break apart signals). In 2 of 4 ALK RNAscope negative cases, ALK RNA signals were detected by both probe-Hs-ALK E1-E18 (score 2) and probe-Hs-ALK E19-E29 (score 2) in small regions (showed a small number of signals), which may indicate that ALK gene amplification and also confirmed by FISH results (with more than 2 fusion signals). And these 2 typical ALK RNAscope negative samples were considered close to be disomy by FISH. Our results demonstrate that RNAscope® 2.5 Red assay is a reliable and precise method to detect ALK mRNA expression caused by ALK gene fusion and also a one to discover the ALK gene amplification as well in FFPE samples of NSCLC, even though latter’s clinical significant is not clear. RNAscope® 2.5 Red assay is a both sensitive and specific method to provide information on the spatial distribution of ALK gene status and morphologic characteristic of tumors simultaneously under the bright field microscope.

Targeted Therapy With Anaplastic Lymphoma Kinase Inhibitor (Alectinib) in Adolescent Metastatic Non–Small Cell Lung Carcinoma

Primary lung adenocarcinoma is extremely rare in the pediatric age group. We report an 18-year-old man with non-small cell lung carcinoma stage IV with brain and bone metastatic. Lung biopsy showed expression of PDL1 along with rearrangement of ALK gene at chromosome 2p23. However, neither mutation of ROS1 nor epidermal growth factor receptor overexpression was seen. Second-generation anaplastic lymphoma kinase (ALK) inhibitor (alectinib) is initiated as first line of treatment. After 8 months of treatment with alectinib, F-NaF PET/CT demonstrated resolution of bone lesions. The present case show rapid and good response to alectinib in metastatic ALK-positive non-small cell lung carcinoma.

A step forward in the management of a rare disease, the anaplastic lymphoma kinase-rearranged non-small cell lung cancer

The discovery of the anaplastic lymphoma kinase (ALK) gene rearrangement as an oncogenic driver in thoracic oncology has permitted to identify a subpopulation of non-small cell lung cancer (NSCLC) that can be considered as a rare oncologic disease.

P1.03-04 Molecular Characteristics of ALK Primary Point Mutations Non-Small-Cell Lung Cancer in Chinese Patients

Anaplastic lymphoma kinase (ALK) gene rearrangements have been identified in lung cancer at 3-7% frequency, thus representing an important subset of genetic lesions that drive oncogenesis in this disease. While the genetic locus of ALK primary point mutations NSCLC patients is unclear. The aim of this study is to investigate mutations and prognosis of NSCLC harboring ALK primary point mutations. A total of 339 patients with non-small-cell lung cancer were recruited between July 2012 and December 2015. The status of ALK primary point mutation and other genes were detected by next generation sequencing. ALK gene primary point mutation rate was 8.55% (29/339) in non-small cell lung cancer, including V163L (3 patients), F921Gfs*16 (2 patients), K1416N (2 patients), A585T (2 patients), P1442Q (1 patient), A348T (1 patient), K1525E (1 patient), S737L (1 patient), P115L (1 patient), Q515E (1 patient), E314D (1 patient), R395H (1 patient), S1219F (1 patient), S341G (1 patient), P1543S (1 patient), G129V (1 patient), Q167H (1 patient), L550F (1 patient), T1012M (1 patient), D302Y (1 patient), H755Q (1 patient), H331Q (1 patient), G1474E (1 patient) and E119D (1 patient), and median overall survival (OS) for these patients was 20.0 months. Among them, 27 patients with co-occurring mutations had a median OS of 20.0 months, and median OS of the 2 patients without complex mutations was 8.5 months. Statistically significant difference was found between the two groups (P=0.02). Briefly, patients with (n=8) or without (n=21) co-occurring EGFR mutations had a median OS of 24.0 months and 20.0 months respectively (P=0.73); patients with (n=21) or without (n=8) co-occurring TP53 mutations had a median OS of 20.0 months and 17.0 months respectively (P=0.83). EGFR and TP53 gene accompanied may have less correlation with ALK primary point mutation in NSCLC patients. Results of ongoing studies will provide a platform for further research to offer individualized therapy with the purpose of improving outcomes.

Current status of immune checkpoint inhibitors in treatment of non-small cell lung cancer.

Lung cancer remains a leading cause of cancer mortality worldwide, including in Korea. Systemic therapy including platinum-based chemotherapy and targeted therapy should be provided to patients with stage IV non-small cell lung cancer (NSCLC). Applications of targeted therapy, such as an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and anaplastic lymphoma kinase (ALK) inhibitors, in patients with NSCLC and an EGFR mutation or ALK gene rearrangement has enabled dramatic improvements in efficacy and tolerability. Despite advances in research and a better understanding of the molecular pathways of NSCLC, few effective therapeutic options are available for most patients with NSCLC without druggable targets, especially for patients with squamous cell NSCLC. Immune checkpoint inhibitors such as anti-cytotoxic T lymphocyte antigen-4 or anti-programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) have demonstrated durable response rates across a broad range of solid tumors, including NSCLC, which has revolutionized the treatment of solid tumors. Here, we review the current status and future approaches of immune checkpoint inhibitors that are being investigated for NSCLC with a focus on pembrolizumab, nivolumab, atezolizumab, durvalumab, and ipilimumab.

Immunohistochemical and selected genetic reflex testing of all uterine leiomyosarcomas and STUMPs for ALK gene rearrangement may provide an effective screening tool in identifying uterine ALK-rearranged mesenchymal tumors.

We examined the value of targeted molecular screening for the identification of uterine anaplastic lymphoma kinase (ALK)-rearranged mesenchymal tumors, including ALK immunohistochemistry followed by molecular genetic testing, in all uterine leiomyosarcomas and STUMPs (smooth muscle tumors of uncertain malignant potential). All leiomyosarcoma and STUMP cases diagnosed in a 10-year period (2006-2016) at Charles University Faculty of Medicine in Pilsen were retrieved and reviewed. Of 23 cases, one case (LMS [leiomyosarcoma]) was positive for ALK rearrangement, namely, PPP1CB-ALK fusion gene. No specific histologic features (i.e., lymphocytic infiltrate and stromal edema) were observed in this case. This suggests that inflammatory myofibroblastic tumor (IMT)-like histologic features may not be an initial reliable screening tool in identifying uterine IMT cases. Thus, we proposed a two-step IHC and molecular genetic testing (as a reflex test) for IMT in all uterine LMS and STUMP cases. This will enhance the proper detection of such tumors at the population level and ultimately offer patients available targeted therapies.

Discrepancies between ALK protein disruption and occurrence of ALK gene rearrangement in Polish NSCLC patients.

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) rearrangement are predisposed to molecularly targeted therapies. Proper diagnostic is crucial for quick and correct patients qualification to optimal treatment method. Genetic tests to detect predictive factors could be performed sequentially. After excluding EGFR mutations, abnormal ALK protein expression should be tested using immunohistochemistry (IHC) method. In patients with disrupted ALK expression, the rearrangement of the ALK gene should be confirmed by FISH method. Despite few years of experience in analysis of these predictive factors, there are still problems in interpretation of diagnostic tests results. Especially, some recommendations for ALK IHC diagnosis are not precise. Mutations in EGFR gene were examined using real-time PCR technique in 1,108 formalin-fixed paraffin-embedded (FFPE) tissues, 398 FFPE cell-blocks and 470 cytological specimens of NSCLC. The disrupted ALK protein expression was analysed in 1,100 samples including 782 histological and 306 cytological (cell-blocks) samples using IHC. Twelve materials (1.1%) were non-diagnostic in IHC. ALK gene rearrangement using FISH method was analysed in IHC positive cases. The frequency of EGFR mutations was 8.6%. EGFR mutations occurred significantly more often in females (P=0.00001, χ2=62.732) and in adenocarcinoma cases (P=0.0002, χ2=14.222). The exon 19 deletions (49%) and exon 21 Leu858Arg substitution (38%) were the most common, rare EGFR mutations occurred in 13% of patients. Any expression of abnormal ALK protein was detected in 202 cases (18.57%). ALK gene rearrangement was confirmed in 49 cases (4.5%). ALK gene rearrangement is significantly more common in female than in male (P=0.0105, χ2=6.541). In patients with ALK gene rearrangement, the median percentage of nuclei with ALK rearrangement was only 25.5%. The polysomy (≥4 gene copy number per nuclei) of ALK gene was observed in 39 cases (21.4% of patients with diagnostic result of FISH examination). Median number of ALK gene copy per nuclei was 2.9±0.77. Significant positive correlation between percentage of cells with abnormal ALK expression in IHC test and percentage of nuclei with ALK rearrangement in FISH method was detected (R=0.617, P<0.00001). Significant negative correlation between the number of copies of ALK gene and the percentage of cells with expression of abnormal ALK was observed (R=-0.2004, P<0.05). ALK gene rearrangement was significantly more frequently observed in the material with coarse-grained cytoplasmic and membranous IHC staining than in materials with light cytoplasmic stippling. The occurrence of cytoplasmic stippling correlated with the increase of ALK gene copy number. We indicated that diagnosis of ALK disruption in NSCLC patients should be notably careful using IHC and FISH methods. Recommendations for ALK diagnosis should include the way of interpretation of cases with low percentage of cells with abnormal ALK protein expression in IHC test, character of IHC reaction, and cases with ALK gene polysomy in FISH method.

ALK Rearrangements Are Infrequent in Cellular Blue Nevus and Deep Penetrating Nevus.

Recent studies have identified kinase fusions in Spitzoid melanocytic neoplasms, and approximately 10% of Spitzoid neoplasms harbor anaplastic lymphoma kinase (ALK) rearrangements and corresponding ALK immunoreactivity. Deep penetrating nevi (DPN), a subset of melanocytic neoplasms, have histologic and immunohistochemical overlap that have historically supported classification of DPN with blue/cellular blue nevi (CBN). However, HRAS mutations have rarely been detected in DPN, thereby also linking them to Spitz nevi. The purpose of this study was to see if DPN or CBN possess ALK rearrangements, thereby providing more evidence that these melanocytic lesions may be pathogenetically related to Spitzoid neoplasms. Using ALK immunohistochemistry as a surrogate for ALK rearrangement, the authors examined 26 DPN, 30 CBN, and 4 conventional blue nevi. ALK immunoreactive cases underwent fluorescent in situ hybridization to investigate for the presence of ALK gene rearrangement. Patchy and focal ALK immunostaining was found in only 1 case of DPN (1/26, 3.8%). Seven cases of CBN (7/30; 23%) showed ALK immunostaining (6 focal/patchy, 1 strong and diffuse). Fluorescent in situ hybridization using ALK break-apart probes showed various degrees of gain of 2p23 and rare ALK break-apart signals. Four CBN showed ALK rearrangement in 2%-4% of cells. Two cases of CBN showed gain of 2p23 in 10%-20% of cells. In our study, ALK rearrangements are uncommon in both CBN and DPN, making ALK an unlikely driver in tumorigenesis and classification of these melanocytic variants. However, our study did identify ALK molecular changes and immunohistochemical staining patterns that have not been previously described in CBN or DPN.

Histologic subtyping of poorly-differentiated solid lung cancer with molecular testing for epidermal growth factor receptor mutation and ALK gene rearrangement: an analyses of 167 cases

Objective: To study the histological subtyping of poorly differentiated solid lung cancer by using immunohistochemistry and mucin staining along with analysis of epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) gene rearrangement. Methods: Among 827 cases of non-small cell lung cancer at Beijing Hospital from April 2014 to April 2017, 167 cases of solid poorly differentiated lung cancer were identified and histopathologically subtyped by mucin staining (D-PAS) and immunohistochemistry using 10 antibodies (CK7, vimentin, Ki-67, CK5/6, p40, TTF1, Napsin A, CD56, chromogranin A, and synaptophysin). Paraffin embedded tumor samples were subjected to mutation analysis of exons 18, 19, 20 and 21 of the EGFR gene by amplification refractory mutation system (ARMS) method. Immunohistochemistry (Ventana D5F3) for ALK gene rearrangement was performed followed by ALK fluorescence in situ hybridization (FISH) verification. Results: There were 79 females and 88 males in the study cohort. The patient's age ranged from 35 to 77 years (mean 62 years). Cases with solid growth pattern (at least >10%) and without typical histological features of adenocarcinoma, squamous cell carcinoma or neuroendocrine carcinoma were further divided based on immunohistochemistry and mucin stain into 64 cases(38.32%)of adenocarcinoma, 34 cases(20.35%) squamous cell carcinoma, 21 cases(12.57%)large cell neuroendocrine carcinoma, 5 cases(2.99%)combined large cell neuroendocrine carcinoma, 2 cases(1.20%)adenosquamous carcinoma and 41 cases(24.55%)large cell carcinoma. The Ki-67 positive rate ranged from 5% to 65%. Mutations of EGFR were detected in 5 cases (2.99%, 5/167) of adenocarcinoma(19del in 3 cases and L858R in 2 cases). Two cases(1.20%, 2/167) with ALK-rearranged were identified by immunohistochemistry (Ventana D5F3) and confirmed by ALK FISH. Conclusions: Poorly differentiated solid lung cancer without distinct morphological features can be further histologically subtyped by mucin staining and immunohistochemistry. Molecular testing should be performed for accurate molecular target therapy to improve the prognosis.