The primary function of the immune system is to protect the host against pathogens.Success of vaccination diseases has led to efforts to develop strategies to activate a specific immune response against cancer. However,this task has proved to be very challenging.In the last few years there has been rapid progress in the identification of the molecular mechanisms by which the immune system detects pathogens and initiates immune responses.
By contrast, recognition of neoplastic cells lags behind, and induction of specific anti-tumour immunity is even less understood.In this chapter we discuss evidence for the role of the immune system in the control of tumour growth. We also rewiev recent advances in the understanding of mechanisms that can alert the immune system ti the presence of neoplastic lesions, and we discuss recent data on the immunogenicity of tumour cells and their interaction with presenting cells.