Proteomic profiling of cancer of the gingivo-buccal complex: Identification of new differentially expressed markers

Tobacco-related oral cancer is the most common cancer among Indian males, gingivo-buccal complex (GBC) being the most affected subsite due to the habit of chewing tobacco. Proteins from the lysates of microdissected normal and transformed epithelium from clinically well-characterized tissue samples of the GBC were separated by two-dimensional gel electrophoresis to identify differentially expressed proteins. Eleven protein spots showed differential expression, which could withstand the stringency of statistical evaluation. The observations were confirmed with additional tissues. Nine of these differentiators were identified by MS as lactate dehydrogenase B, α-enolase, prohibitin, cathepsin D, apolipoprotein A-I, tumor protein translationally controlled-1, an SFN family protein, 14-3-3σ and tropomyosin. Cluster analysis indicated that these proteins, as a coexpressed set, could distinguish normal and transformed epithelium. Functionally, these differentiator molecules are relevant to the pathways and processes that have been previously implicated in oral carcinogenesis and could therefore be investigated further as a panel of markers for management of cancer of the GBC.