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ALK

anaplastic lymphoma receptor tyrosine kinase;ALK;anaplastic lymphoma receptor tyrosine kinase

ALK tyrosine kinase receptor|CD246 antigen|mutant anaplastic lymphoma kinase

2p23

protein-coding

BACKGROUND: We investigated the diagnostic and prognostic usefulness of anaplastic lymphoma kinase (ALK) expression in Asian rhabdomyosarcoma (RMS) patients. PATIENTS AND METHODS: A total of 38 RMS tissue samples were collected over a 14-year period (1998-2012). ALK protein expression and gene copy number were analysed by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH). RESULTS: Ten of the 38 RMS patients (26.3%) showed positive ALK protein expression. ALK protein expression was predominantly positive in alveolar RMS (ARMS) compared with embryonal RMS (ERMS) (80% vs 20%, p=0.03). ALK protein expression was statistically associated with ARMS histology, metastatic disease at diagnosis, and primary trunk site. In FISH analysis, no translocations were detected and ALK gene copy number gain was observed more frequently in ARMS than in ERMS (40% vs 17%). The ALK-positive group showed inferior overall survival (OS) compared with ALK-negative group (p=0.014) for both alveolar and embryonal RMS patients. In multivariate analysis, positive ALK expression was an independent prognostic factor for OS (p=0.02; HR, 3.1; 95%

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase predominantly expressed in the developing nervous system. Recently, mutated ALK has been identified as a major oncogene associated with familial and sporadic neuroblastomas (NBL). Yet, a direct correlation between endogenous expression level of the ALK protein, oncogenic potential, and clinical outcome has not been established. We investigated ALK genetic mutations, protein expression/phosphorylation, and functional inhibition both in NBL-derived cell lines and in 34 localized and 48 advanced/metastatic NBL patients. ALK constitutive phosphorylation/activation was observed in high-ALK expressing cells, harboring either a mutated or a wild-type receptor. No activation was found in cell lines with low expression of wild-type ALK. After 72 hours of treatments, small molecule ALK inhibitor CEP-14083 (60 nmol/L) induced growth arrest and cell death in NBL cells overexpressing wild-type (viability: ALK(high) 12.8%, ALK(low) 73%, P = 0.0035; cell death: ALK(high) 56.4%, ALK(low) 16.2%, P = 0.0001) or mutated ALK. ALK protein expression was significantly up-regulated in advanced/metastatic compared with localized NBLs (ALK overexpressing patients: stage 1-2, 23.5%; stage 3-4, 77%; P < 0.0001). Interestingly, protein levels did not always correlate with ALK genetic alterations and/or mRNA abundance. Both mutated and wild-type ALK receptor can exert oncogenic activity in NBL cells. However, wild-type ALK receptor requires a critical threshold of expression to achieve oncogenic activation. Overexpression of either mutated or wild-type ALK defines poor prognosis patients. Alternative mechanisms other than direct mutations and/or gene amplification regulate the ALK level of expression in NBL cells. Wild-type ALK is a potential therapeutic target for advanced/metastatic NBLs.

BACKGROUND: The identification of molecular alterations has an important therapeutic implication in patients with lung adenocarcinomas. In the current study, the authors evaluated their experience with the identification of epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation, and anaplastic lymphoma kinase (ALK) gene rearrangement using cytological specimens of primary and metastatic lung adenocarcinoma. METHODS: A total of 54 cases of lung adenocarcinomas (11 primary and 43 metastatic tumors) in which molecular tests were performed were retrieved. Molecular tests were performed on the cell block material of 19 effusions and 35 fine-needle aspirates. EGFR mutation was evaluated by polymerase chain reaction sequencing analysis of exons 18, 19, 20, and 21. KRAS mutation was tested using polymerase chain reaction-single-strand conformational polymorphism analysis of codons 12 and 13. ALK gene rearrangement was evaluated by fluorescence in situ hybridization using an ALK break apart probe. RESULTS: Molecular tests were successful in 49 of 54 cases (91%). Evaluation of EGFR mutation, KRAS mutation, and ALK gene rearrangement were performed in 49 cases, 14 cases, and 22 cases, respectively. EGFR mutations were found in 14 of 49 cases (29%), including 5 primary and 9 metastatic tumors. Three metastatic/recurrent adenocarcinomas demonstrated an additional EGFR T790M mutation that was not identified in the original specimens. KRAS mutation was detected in 3 of 14 cases (21%) including 1 primary and 2 metastatic tumors. ALK gene rearrangement was evident in 3 of 22 cases (14%), all of which were metastatic tumors. CONCLUSIONS: The results of the current study have demonstrated the feasibility of using cytological specimens for EGFR mutation, KRAS mutation, and ALK gene rearrangement analysis. Repeating molecular testing in metastatic/recurrent lung adenocarcinomas may uncover newly acquired molecular alterations.

BACKGROUND: The discovery of distinct subsets of nonsmall cell lung cancer (NSCLC) characterized by activation of driver oncogenes has greatly affected personalized therapy. It is hypothesized that the dominant oncogene in NSCLC would be associated with distinct patterns of metastatic spread in NSCLC at the time of diagnosis. METHODS: A total of 209 consecutive patients with stage IV nonsquamous NSCLC with an EGFR (epidermal growth factor receptor) mutation (N = 39), KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) mutation (N = 49), ALK (anaplastic lymphoma receptor tyrosine kinase) gene rearrangement (N = 41), or wild-type for all 3 (triple negative, N = 80) were included. The percentage of patients with metastatic disease at a given site was compared between each molecular cohort (EGFR, KRAS, or ALK) and the triple negative cohort. RESULTS: ALK gene rearrangement was significantly associated with pericardial disease (odds ratio [OR] = 4.61; 95% confidence interval [CI] = 1.30, 16.37; P = .02) and pleural disease (OR = 4.80; 95%

BACKGROUND: metastatic melanoma is a devastating disease with limited therapeutic options. MicroRNAs (miRNAs) are small non coding RNA molecules with important roles in post-transcriptional gene expression regulation, whose aberrant expression has been implicated in cancer. RESULTS: We show that the expression of miRNAs from a large cluster on human chromosome 14q32 is significantly down-regulated in melanoma cell lines, benign nevi and melanoma samples relative to normal melanocytes. This miRNA cluster resides within a parentally imprinted chromosomal region known to be important in development and differentiation. In some melanoma cell lines, a chromosomal deletion or loss-of-heterozygosity was observed in the cis-acting regulatory region of this cluster. In several cell lines we were able to re-express two maternally-induced genes and several miRNAs from the cluster with a combination of de-methylating agents and histone de-acetylase inhibitors, suggesting that epigenetic modifications take part in their silencing. Stable over-expression of mir-376a and mir-376c, two miRNAs from this cluster that could be re-expressed following epigenetic manipulation, led to modest growth retardation and to a significant decrease in migration in-vitro. Bioinformatic analysis predicted that both miRNAs could potentially target the 3'UTR of IGF1R. Indeed, stable expression of mir-376a and mir-376c in melanoma cells led to a decrease in IGF1R mRNA and protein, and a luciferase reporter assay indicated that the 3'UTR of IGF1R is a target of both mir-376a and mir-376c. CONCLUSIONS: Our work is the first to show that the large miRNA cluster on chromosome 14q32 is silenced in melanoma. Our results suggest that down-regulation of mir-376a and mir-376c may contribute to IGF1R over-expression and to aberrant negative regulation of this signaling pathway in melanoma, thus promoting tumorigenesis and metastasis.

BACKGROUND: Cholangiocarcinoma, a type of malignant tumor, originates from epithelial cells of the bile duct. Perineural invasion is common path for cholangiocarcinoma metastasis, and it is highly correlated with postoperative recurrence and poor prognosis. It has been reported that muscarinic acetylcholine receptor M3 (mAChR M3) is widely expressed in digestive tract cancer, and may play an important role in the proliferation, differentiation, transformation and carcinogenesis of tumors. This study was to explore the effect of mAChR M3 on the growth of cholangiocarcinoma cells in vitro and provide a new approach to the pathogenesis and treatment of cholangiocarcinoma. METHODS: Streptavidin-biotin complex immunohistochemistry was carried out to assess the expression of mAChR M3 in surgical specimens of cholangiocarcinomas (40 cases) and normal bile duct tissues (9), as well as to investigate nerve infiltration. The cholangiocarcinoma cells were treated with different concentrations of selective M-receptor agonist pilocarpine and M-receptor blocker atropine sulfate to induce changes in cell proliferation. The experimental data were analyzed by the Chi-square test. RESULTS: The strongly-positive expression rate of mAChR M3 was much higher in poorly-differentiated (69%, 9/13) than in well- and moderately-differentiated cholangiocarcinomas (30%, 8/27) (X2=5.631, P<0.05). The strongly-positive mAChR M3 expression rate in hilar cholangiocarcinoma (50%, 14/28) was higher than that in cholangiocarcinomas from the middle and lower common bile duct (25%, 3/12) (X2=2.148, P<0.05). Cholangiocarcinomas with distant metastasis had a strongly-positive expression rate (75%, 9/12), which was much higher than those without distant metastasis (29%, 8/28) (X2=7.410, P<0.01). The absorbance value in the pilocarpine+atropine group was significantly higher than the corresponding value in the pilocarpine group. CONCLUSIONS: The expression of mAChR M3 is influenced by the extent of differentiation, distant metastasis and the site of cholangiocarcinoma. It also plays a key role in the proliferation and metastasis of cholangiocarcinoma.

INTRODUCTION: Many patients with oncogene-driven non-small-cell lung cancer (NSCLC) treated with tyrosine kinase inhibitors experience limited sites of disease progression. This study investigated retrospectively the benefits of local ablative therapy (LAT) to central nervous system (CNS) and/or limited systemic disease progression and continuation of crizotinib or erlotinib in patients with metastatic ALK gene rearrangement (ALK+) or EGFR-mutant (EGFR-MT) NSCLC, respectively. METHODS: Patients with metastatic ALK+ NSCLC treated with crizotinib (n = 38) and EGFR-MT NSCLC treated with erlotinib (n = 27) were identified at a single institution. Initial response to the respective kinase inhibitors, median progression-free survival (PFS1), and site of first progression were recorded. A subset of patients with either nonleptomeningeal CNS and/or four sites or fewer of extra-CNS progression (oligoprogressive disease) suitable for LAT received either radiation or surgery to these sites and continued on the same tyrosine kinase inhibitors. The subsequent median progression-free survival from the time of first progression (PFS2) and pattern of progression were recorded. RESULTS: Median progression-free survival in ALK+ patients on crizotinib was 9.0 months, and 13.8 months for EGFR-MT patients on erlotinib. Twenty-five of 51 patients (49%) who progressed were deemed suitable for local therapy (15 ALK+, 10 EGFR-MT; 24 with radiotherapy, one with surgery) and continuation of the same targeted therapy. Post-LAT, 19 of 25 patients progressed again, with median PFS2 of 6.2 months. DISCUSSION: Oncogene-addicted NSCLC with CNS and/or limited systemic disease progression (oligoprogressive disease) on relevant targeted therapies is often suitable for LAT and continuation of the targeted agent, and is associated with more than 6 months of additional disease control.

Anaplastic lymphoma kinase (ALK) gene rearrangements define a distinct molecular subset of non-small-cell lung cancer that is highly responsive to treatment with the ALK inhibitor crizotinib. Recently, it has been recognized that the brain is a frequent site of relapse among ALK-positive patients treated with crizotinib. In this report, we expand on these observations and present a series of ALK-positive patients with two distinct forms of metastatic, central nervous system involvement: intramedullary spinal cord metastasis and leptomeningeal carcinomatosis.

Anaplastic lymphoma kinase (ALK) gene aberrations are found in several tumor types including anaplastic large cell lymphoma (ALCL) and non-small cell lung cancer (NSCLC). Crizotinib, an inhibitor of ALK-fusion proteins, has shown clinical activity, but resistance mechanisms limit long-lasting disease control. It has been shown that ALK-NPM fusion upregulates platelet-derived growth factor receptor beta (PDGFRB) via JUN and transcription factor Jun B (JUNB) in ALCL. PDGFRB inhibition has been identified as therapy option for ALK-positive ALCL. Here, we investigated the ALK/JUN/JUNB/transcription factor Jun C (JUNC)/PDGFR axis in metastatic NSCLC with regard to ALK aberrations. We performed immunohistochemical analysis of platelet-derived growth factor receptor alpha (PDGFRA), PDGFRB, JUNB and JUNC expression in formalin-fixed, paraffin-embedded specimens of 15 NSCLC brain metastases (5 ALK translocations, 3 of them involving EML4, 5 ALK amplifications, 5 without ALK aberrations). We did not find a statistically significant difference in expression of PDGFRA, PDGFRB, JUNB or JUNC in tumor samples with normal ALK status, ALK amplification or ALK translocations (Kruskal-Wallis test p > 0.05). Interestingly, PDGFRB was not expressed in tumor cells (but in vascular and stromal cells) in any of our cases. Our data argue against PDGFRB activation in association with ALK gene aberrations in metastatic NSCLC and thus seem to imply differential pathobiological roles of ALK alterations in lung cancer and lymphoma, possibly depending on different fusion partner genes. These results may be relevant for targeted therapies, as they indicate that inhibition of PDGFRB in ALK translocated NSCLC seems to be no therapeutic opportunity.