Clinical characteristics of patients with non-small cell lung cancers harboring anaplastic lymphoma kinase rearrangements and primary lung adenocarcinoma harboring epidermal growth factor receptor mutations.

Echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) gene rearrangements and epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) have been intensively studied. The objective of this study was to determine the clinicopathological characteristics in genotype-specific subsets of patients with NSCLC to help ensure the optimal identification of patients whose tumors harbor these two driver mutations. The incidence of ALK rearrangements was investigated in 763 NSCLC specimens by immunohistochemistry using a D5F3 antibody, and EGFR mutations were assessed by amplification refractory mutation system (ARMS) in 222 patients with lung adenocarcinoma. Of these, 73 (9.6%) were detected as being ALK-positive; this designation was associated with young age, female gender, never-smokers, lymph node metastasis, and poor tumor differentiation, but not with histology. EGFR mutations were identified in 102 (45.9%) of 222 adenocarcinoma samples, and were more frequent in females and never-smokers. No difference in age was observed. Specifically, we identified several cases of complex EGFR mutations, and concomitant EGFR mutations and ALK rearrangements. These results suggest that young women and never-smokers are at risk for ALK rearrangement. We also identified concomitant mutations of EGFR and rearrangements of ALK in this study.