[Immune response and colorectal cancer]. / Réponse immunitaire et cancers colorectaux.

Immune response has a crucial role in the control of tumoral progression in colorectal cancer (CRC). A close link between the rate of tumor infiltrating lymphocytes and prognosis has been found. Indeed, recent studies have shattered our dogmas as the rate of tumor infiltrating lymphocytes seems to be a better prognostic factor than TNM classification. This review is focused on immune response in CRC. Specific cell-mediated immunity is important for the control of tumoral growth. Specific T cell activation is induced by tumoral antigens process by dendritic cells. Among the numerous tumoral antigens that could induce an immune response in CRC, the carcinoembryonic antigen is the most studied but its immunogenicity remains low. In CRC with microsatellite instability, several immunogenic neo-antigens have been identified and could explain the high level of tumor infiltrating lymphocytes and the better prognosis of this type of tumour. However, CRC can escape immune response by immune response modulation or tumoral cells modifications conducting to immune resistance. These data should be considered for the treatment of CRC or the development of immunotherapy strategies.