Representative 2-DE gel images of lung SCC and adjacent normal tissues. (A) Fresh human lung SCC and paired adjacent normal tissues of Asian population were obtained from 8 patients suffering lung SCC who underwent surgical resections. Total protein extracts were separated on pH 3–10 nonlinear IPG strips in the first dimension followed by 12% SDS-PAGE in the second dimension and visualized by CBB staining. The arrows indicate the 31 differentially expressed proteins. (B) Cluster analysis of the changed proteins revealed that the altered proteins were involved in different biological processes, including metabolism (40%), calcium ion binding (13%), signal transduction (13%) and so on. (C) The identified proteins were categorized into four groups according to their subcellular locations. 58% of the total proteins were located in the cytoplasm, and the remainder was situated in the nuclear (26%), cell membrane (10%) and secreted protein (6%). (D) Expression profile of the 16 altered proteins (3-fold change) as shown in Figure 1A. The intensities of spots were quantified using PDQuest 2-D analysis software.