ObjectiveTo explore the relationship of OLFM1 expression with the development of lung cancer by comparing the OLFM1 expression in lung cancer specimens and matched normal lung specimens. MethodsThe OLFM1 mRNA expression was examined by semi-quantitative RT-PCR and fluorescence quantitative PCR in 21 lung cancer tissues and the paired normal lung tissues, and the protein expression of OLFM1 was detected by immunohistochemistry. ResultsThe OLFM mRNA expression levels in 8 primary lung squamous cell carcinoma tissues were decreased by 2.2 folds compared with that in the matched normal lung tissues, with the difference being significantly different (P=0.028). The OLFM1 protein was located in cytoplasm and only expressed in lung adenocarcinoma tissues（P<0.001）, and the expression was not associated with patients’ age, gender, tumor stage, and differentiation degrees（P>0.05). ConclusionThe lower expression of OLFM1 gene in lung squamous cell carcinoma may serve as a potential molecule marker for the condition. The expression of OLFM1 protein in lung adenocarcinoma, but not in lung squamous cell carcinoma and normal lung tissue, may suggest that different pathological types of lung cancers may have different pathological mechanisms.