Toll-like receptors and the tendency of normal mucous membrane to transform to polyp or colorectal cancer.

The aim of this study was to identify differences in Toll-like receptor (TLR) expression patterns in normal and diseased tissues of patients with polyps and colorectal cancer. Eight patients were included in the study group (aged 38 to 72 years). Sixteen HG-U133A oligonucleotide microarrays were analysed including four of colonic polyps, four of adenocarcinoma with different degree of histological differentiation (2 poorly and 2 highly differentiated), and eight of macroscopically normal tissue. The levels of selected TLR mRNA transcripts were analysed. An analysis of all per cent variability values with regard to malignancy stage increasing from polyp to stages I to III adenocarcinoma, and normal colon mucosa shows a statistically significant relationship for TLR2 (increasing) and TLR3 (decreasing). In polyps, copy numbers of TLR3, TLR4 and TLR5 mRNA were the highest and TLR7 mRNA the lowest. In normal colon mucosa of polyposis patients the highest mRNA copy numbers were observed for TLR3, and the lowest for TLR7. TLR3 may serve as a marker of colon tissue metaplasia and may indicate the tendency of normal tissue to form polyps transforming to colorectal cancer.