Search for protein markers for serum diagnostics of tumors by analysis of microRNA expression profiles

New algorithm of bioinformatic search for potential serum tumor markers has been worked out, including: (1) identification of microRNAs with the level of synthesis most evidently and often decreasing in tumors; (2) search for target mRNAs regulated by microRNAs; (3) selection of targets encoding secretory proteins; (4) comparative analysis of transcription level of the targets in normal and tumor tissues. Practical use of the algorithm has allowed us to detect seven potential serum markers of colon tumors: ADAMTS14, ANGPT2, CCL7, DEFA5, MMP11, MMP14, and PLAU. It has been experimentally indicated that the level of synthesis of two of seven proteins (MMP14 and DEFA5) is significantly increased in colon tumors compared to normal tissue.