Immune surveillance

Abstract of the chapter

Immunosurveillance or immunoediting inmunoedición of cancer?

José R. Regueiro

Immunity evolved to defend us against certain infections while tolerating the symbi-otic microbiota, but does it protect us against tumours? The second role, called im-munosurveillance, fails when cancer succeeds, meaning that cancer is a sort of immunodeficiency. Cancer should thus, like infections, be amenable to immunopro-phylaxis and immunotherapy. Immunosurveillance is however still a theory. In fact, current antitumor immunoprophylaxis and immunotherapy do not support it. The papillomavirus vaccine is not antitumoral but rather protects against an oncopatho-gen which only after long time and in certain unpredictable cases causes cancer. Two cancer immunotherapy strategies with monoclonal antibodies highlight their effectiveness: passive (such as anti-CD20) and active immunotherapy, which inter-feres with T cell inhibition (such as anti-CTLA-4). Both interfere however with self-tolerance and cause autoimmunity and none actually identify the tumour, as pre-dicted by immunosurveillance. The stubborn fact is that tumour progression is blind and accumulates random genetic changes that only intrinsic cellular control, induced apoptosis or anti-mitotic drugs may stop. In some cases, immunoediting may occur, but only in order to select tumour variants which, by sheer chance and if there are additional danger signs, fall in the realm of immunity.