The diagnosis and incidence of epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) mutation in lung adenocarcinoma

Introduction: Lung cancer has been the leading cause of cancer death worldwide. Nowadays genetic mutation analysis is the guide of the cancer treatment. Aims and objectives: This study tried to figure out the condition of the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) mutation in lung adenocarcinoma. Methods: A total of 914 lung adenocarcinoma patients were enrolled at our study and the lung specimens were managed for the analysis of EGFR mutation by real time PCR. For the specimens with negative EGFR results, ALK mutation was firstly detected by immunohistochemical (IHC) staining. If the IHC staining is positive, real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH) was applied for the confirmatory test. Results: In our study, EGFR mutation was found in 53.6% patients. In EGFR negative cases, 215 specimens were processed for IHC staining of ALK mutation. 9.3% ALK mutation was identified in IHC staining. Real time PCR and FISH results are identical to the IHC finding. Conclusions: In Taiwan, EGFR mutation was considered the most important genetic alteration of lung adenocarcinoma. This result was different from the experience in Europe and United States. EGFR tyrosine kinase inhibitor was the first line treatment for advanced lung adenocarcinoma. ALK mutation was only found in a small population of EGFR negative patients and crizotinib was the first line treatment theoretically. IHC staining had high sensitivity and specificity to real time PCR or FISH. IHC staining may become a standard procedure for ALK mutation detection in the future.