ABSTRACT
This chapter considers aspects of how the immune system responds to neoplastic cells and the range of tumours of cells of the immune system. Tumour cells derive from normal body cells or tumour stem cells during the process of neoplastic transformation. Tumour cells become structurally and/or functionally modified; however, the immune system generally fails successfully to destroy most tumours. This suggests that for many cancers the immune system becomes tolerant to tumour antigens and allows progression of the neoplastic process. This tolerance may be mediated by specific populations of regulatory cells (‘tumour suppressor cells’), which would be sensible targets for the development of novel cancer immunotherapy. Such regulatory cells are identified in both human and canine cancer patients. Dogs with neoplastic disease have elevated numbers of Foxp3+
CD4+ Treg in blood and lymph nodes draining the site of the tumour.
