Are proteins differentially expressed in cancers (compared to healthy tissues) relevant for drug target discovery?
Cancers are often viewed as systems diseases (Hornberg et.al, Biosystems 2006), because their occurrence is often strongly connected to large-scale modifications of signaling pathways, especially their cross-talks (Stelling et.al, Cell 2004). Accordingly, detecting which proteins (or cross-talks) are differentially expressed (utilized) in a carcinoma tissue may point out key causes of the given type of cancer and can help to identify novel systems-based drug targets (Tortora et.al, J. Chemoter 2004, Korcsmaros et.al, Exp. Op. Drug Discov. 2007). In Korcsmaros et. al. (2009) we merged the network of 8 human signaling pathways with protein expression data from two human liver carcinomas. We considered a signaling interaction to be altered in these two liver carcinomas, if, compared to healthy liver tissues, at least one of the participating proteins was differentially expressed. For details see Methods and the Supplementary Material of the paper.
