The Research of Clinical Pathological Features of ALK Positive Lung Cancer 
in 525 Patients and the Discussion of Detection Methods

Abstract

Background and objective The fusion (rearrangement) of anaplastic lymphoma kinase (ALK) gene has been identified as an import factor to the tumorigenesis and development of lung cancer. ALK tyrosine kinase inhibitors (ALK-TKIs) have been proved to have good effects to ALK positive lung cancers. The increasement of the relevance ratio of ALK will be very important to patients. The aim of this study is to investigate the clinical pathological features of ALK positive lung cancer, and the roles of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in screening and confirming the ALK positive cases in the testing flow of ALK. Methods IHC analysis of ALK in tumor specimens was performed on 525 lung cancer patients. 34 cases among them were confirmed by FISH. Results The positive incidence of ALK by IHC was 5.14% (27/525). The ALK positive patients were significantly younger than ALK negative patients (P<0.05), and femal was predominant (P<0.05). The proportion of solid predominant adenocarcinoma was significantly higher in ALK positive patients (P<0.05). While acinar and lepidic predominant adenocarcinoma were significantly lower in ALK positive patients (P<0.05). FISH was applied in 34 cases. The coincidence rate was increased with the increasement of positive intensity of IHC staining. All the IHC positive cases with or without EGFR mutation must be confirmed by FISH. Conclusion IHC is a reliable detection method to screening the ALK in lung cancer, and then enhance the relevance ration. To make a definite diagnosis of ALK positive lung cancer, FISH is a significant detection method.

Keywords

• Lung neoplasms
• Anaplastic lymphoma kinase gene (ALK)
• Epidermal growth factor receptor (EGFR)
• Immunohistochemistry (IHC)
• Fluorescence in situ hybridization (FISH)