| Despite tremendous progress in the past few decades, certain important aspects regarding the diagnosis, therapy, and follow-up of CRC still remain unsolved. The high incidence and not completely known pathogenetic background, origin, molecular biology of CRC necessitate further research of this disease. In my PhD thesis I searched for biomarkers of the development of colorectal carcinoma, and performed gene expression analysis for colorectal disease classification using whole genomic oligonucleotide and cDNA microarray technology and colonic biopsy samples. I have established that the oligonucleotide whole genomic microarray analyses of biopsy samples wholly fulfill the Affymetrix quality requirements, are highly standard and reproducible. I have established that the Taqman Microfluidic Card System which offers an opportunity for the analysis of the expression levels of 96 genes on 10-100 samples, is particularly suitable for high-throughput, quick and cost efficient RT-PCR validation of gene expression changes detected by microarrays. I have shown, that the sequential overexpression of osteopontin and osteonectin mRNAs and proteins significantly correlates with the progression of the colorectal adenoma-dysplasia-carcinoma sequence. I have identified and validated by RT-PCR ten novel tissue markers which show continuously increasing mRNA expression in line with the colorectal adenoma-dysplasia-carcinoma transition. These are the following: tissue inhibitor of metalloproteinases-1 and -3, von Willebrand factor, interleukin 8, melanoma cell adhesion molecule, thrombospondin 2, collagen 4A1, matrix Gla protein, interleukin 1 receptor antagonist and calumenin. I have established that the prostaglandin D2 receptor and the amnionless homolog are novel, validated sequentially downregulated markers of the colorectal adenoma-dysplasia-carcinoma sequence. During my analyses, I have identified the top 27, 13 and 10 genes associated with adenoma, CRC, and IBD, respectively. Using whole genomic microarrays I have also determined the top100 most differentially expressed discriminatory genes which are suitable for molecular-based discrimination of early (Dukes A and B stage) and advanced (Dukes C and D) colorectal cancer. |
