Medline ® Abstracts for References 7,17
of 'Anaplastic lymphoma kinase (ALK) fusion oncogene positive non-small cell lung cancer'
Anaplastic lymphoma kinase immunoreactivity correlates with ALK gene rearrangement and transcriptional up-regulation in non-small cell lung carcinomas.
Boland JM, Erdogan S, Vasmatzis G, Yang P, Tillmans LS, Johnson MR, Wang X, Peterson LM, Halling KC, Oliveira AM, Aubry MC, Yi ES
Hum Pathol. 2009;40(8):1152.
Recently, the fusion gene EML4-ALK was identified in non-small cell lung carcinoma, which could be a potential therapeutic target. We investigated the prevalence of anaplastic lymphoma kinase protein expression in these tumors by immunohistochemistry and correlated the results with data from ALK molecular studies. Gene expression profiling was performed on 35 adenocarcinomas to identify cases with ALK gene up-regulation, which was correlated with protein overexpression by immunohistochemistry. Immunohistochemistry was also performed on an independent cohort consisting of 150 adenocarcinomas and 150 squamous cell carcinomas to evaluate the utility of anaplastic lymphoma kinase immunostaining as a screening tool. Florescence in situ hybridization for the ALK locus and reverse transcriptase-polymerase chain reaction for EML4-ALK were performed on tumors positive for anaplastic lymphoma kinase by immunohistochemistry. Transcriptional up-regulation of ALK was identified in 2 (6%) of 35 adenocarcinomas by gene expression profiling. These 2 cases were positive for anaplastic lymphoma kinase by immunohistochemistry, whereas the remaining 33 cases were completely negative. In the independent cohort, anaplastic lymphoma kinase immunostaining was positive in 1 of 150 squamouscell carcinomas and in 3 of 150 adenocarcinomas. The 6 cases positive for anaplastic lymphoma kinase by immunohistochemistry showed evidence of ALK locus rearrangement by florescence in situ hybridization but were negative for EGFR and KRAS mutation. The presence of EML4-ALK fusion transcript was confirmed in 2 cases by reverse transcriptase-polymerase chain reaction. In conclusion, anaplastic lymphoma kinase immunoreactivity in non-small cell lung carcinomas was associated with transcriptional up-regulation, ALK locus rearrangement, and the presence of EML4-ALK fusion transcript. Anaplastic lymphoma kinase immunohistochemistry may have utility as a screening tool or as a surrogate marker for the molecular techniques to detect the EML4-ALK fusion gene in these tumors.
Department of Laboratory Medicine and Pathology, Mayo Medical School, Rochester, MN 55905, USA.
EML4-ALK fusion is linked to histological characteristics in a subset of lung cancers.
Inamura K, Takeuchi K, Togashi Y, Nomura K, Ninomiya H, Okui M, Satoh Y, Okumura S, Nakagawa K, Soda M, Choi YL, Niki T, Mano H, Ishikawa Y
J Thorac Oncol. 2008;3(1):13.
INTRODUCTION: Very recently, we have found a novel fusion product between the echinoderm microtubule-associated protein-like4 (EML4) and the anaplastic lymphoma kinase (ALK) in non-small cell lung cancers (NSCLCs). Tumors featuring EML4-ALK fusion constitute one subtype of NSCLC that might be highly sensitive to ALK inhibitors. Herein, we present results of a first large scale study of EML4-ALK fusion in lung cancers.
METHODS: Using reverse transcription-polymerase chain reaction for EML4-ALK fusion mRNA, we investigated 149 lung adenocarcinomas, 48 squamous cell carcinomas, 3 large-cell neuroendocrine carcinomas, and 21 small-cell carcinomas. For EML4-ALK-positive cancers, we further investigated the presence of ALK fusion proteins by immunohistochemistry.
RESULTS: Five of 149 adenocarcinomas (3.4%) showed EML4-ALK fusion mRNA, this being totally lacking in carcinomas of other types (0/72). In all the fusion-positive cases, ALK fusion protein could be detected in the cytoplasm immunohistochemically. The five fusion cases featured two EML4-ALK variant 1 fusions and three variant 2 fusions. Histologically, both variant 1 cases were mixed type adenocarcinomas, showing papillary with bronchioloalveolar components. Interestingly, all three variant 2 cases were acinar adenocarcinomas, the link being statistically significant (p = 0.00018). None of the five fusion-positive cases demonstrated any mutations of EGFR or KRAS, pointing to a mutually exclusive relationship (p = 0.014). There was no association with smoking habits.
CONCLUSIONS: In the present first investigation of EML4-ALK fusion in a large study of lung cancers (5/221), we found an interesting histotype-genotype relationship. Furthermore, we could detect the fusion protein by immunohistochemistry, pointing to possible clinical applications.
Department of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research (JFCR), Tokyo, Japan.