Evidence that the lung Adenocarcinoma EML4-ALK fusion gene is not caused by exposure to secondhand tobacco smoke during childhood.

BACKGROUND The EML4-ALK fusion gene is more frequently found in younger, never smoking patients with lung cancer. Meanwhile, never smokers exposed to secondhand tobacco smoke (SHS) during childhood are diagnosed at a younger age compared with never smoking patients with lung cancer who are not exposed. We, therefore, hypothesized that SHS, which can induce DNA damage, is associated with the EML4-ALK fusion gene. METHODS We compared the frequency of the EML4-ALK fusion gene among 197 never smoker patients with lung cancer with and without a history of exposure to SHS during childhood at Mayo Clinic. RESULTS The EML4-ALK fusion gene was detected in 33% of cases from never smokers with a history of SHS exposure during childhood, whereas 47% of never smoking lung cancer cases without a history of childhood SHS exposure tested positive for the fusion gene. CONCLUSIONS The EML4-ALK fusion gene is not enriched in tumors from individuals exposed to SHS during childhood. IMPACT These data suggest that childhood exposure to SHS is not a significant etiologic cause of the EML4-ALK fusion gene in lung cancer.