ObjectiveTo explore the expression of senescence marker protein-30 (SMP-30) in human lung tissues and the significance in the pathogenesis of chronic obstructive pulmonary disease (COPD). MethodsLung tissue specimens ( > 5 cm away from cancerous tissues) obtained by surgery resection in 20 subjects with solitary peripheral carcinoma in Jiangsu Province Hospital were investagted. The subjects were divided into three groups according to lung function and smoking history, ie. a COPD group (6 cases), a healthy smoking group (7 cases) and a healthy control group (7 cases). Immunohistochemistry and Western blot were used to determine the distribution and expression of SMP-30 in human lung tissues. ResultsSMP-30 protein mainly expressed in the cytoplasm of alveolar macrophages (AM). The numbers of AM and SMP-30-positive AM were significantly increased in the COPD group. Western blot analysis confirmed a significant increase in SMP-30 expression in the healthy smokers compared with the non-smokers (2.16±0.23 vs. 1.10±0.14, P < 0.01) and further enhanced in the patients with COPD compared with the healthy smoking subjects (4.62±0.97 vs. 2.16±0.23, P < 0.05). The levels of the protein in different groups were: COPD group > smoking group > control group with significant difference. ConclusionThese results suggest that SMP-30 expression may be involved in the mechanism of prolonged survival and the increase in number of AM and may be involved in the pathogenesis of COPD.