Immune reaction and colorectal cancer: friends or foes?

Abstract

The potential clinical impact of enhancing antitumor immunity is increasingly recognized in oncology therapeutics for solid tumors. Colorectal cancer is one of the most studied neoplasms for the tumor-host immunity relationship. Although immune cell populations involved in such a relationship and their prognostic role in colorectal cancer development have clearly been identified, still no approved therapies based on host immunity intensification have so far been introduced in clinical practice. Moreover, a recognized risk in enhancing immune reaction for colitis-associated colorectal cancer development has limited the emphasis of this approach. The aim of the present review is to discuss immune components involved in the host immune reaction against colorectal cancer and analyze the fine balance between pro-tumoral and anti-tumoral effect of immunity in this model of disease.

Keywords: Adaptive immunity; Antitumor immunity; Colitis-associated colorectal cancer; Innate immunity.

Figure 1

Model proposed by Rakoff-Nahoum et al[30]. Competent TLR4/TLR2/Myd88 pathway is physiologically activated by commensal micro-organisms and maintains epithelial homeostasis (A). Deficiency in TLR4/TLR2/Myd88 signal determines increased epithelial vulnerability and bacterial translocation with chronic colitis and cancer development (B). IECs: Intestinal epithelial cells; TLR: Toll-like receptor; CRC: Colorectal cancer; IL-6: Interleukin-6; MyD88: Myeloiddifferentiationfactor88.