Study of the Expression of Toll-Like Receptors in Different Histological Types of Colorectal Polyps and Their Relationship with Colorectal Cancer

Dysregulation of toll-like receptors (TLR) signaling can result in chronic inflammatory and over-exuberant repair responses. The aim of this study was to investigate the expression and clinical relevance of TLR in colorectal polyps. The expression levels of six TLR were analyzed in 70 patients with different histological types of colorectal polyps, 38 of which developed colorectal carcinoma (CC). These analyses were performed by real-time polymerase chain reaction, western blot, and immunohistochemistry. TLR9 expression was higher in hyperplastic or adenomatous polyps compared to other polyp types. Hyperplastic polyps also showed increased TLR7 levels compared to the other polyp types. TLR7 expression was lower in both hyperplastic and tubulovillous adenoma polyps from patients who developed CC. TLR9 expression was decreased in hyperplastic and villous polyps from patients who developed CC. Our findings suggest a possible protective role of TLR expression against malignant transformation in the colorectal mucosa. TLR may represent a pathological marker of CC risk in colorectal polyps. The role of these factors in the pathology of colorectal polyps deserves further investigation.