Search

Cancer immunoediting, the process by which the immune system controls tumour outgrowth and shapes tumour immunogenicity, is comprised of three phases: elimination, equilibrium and escape. Although many immune components that participate in this process are known, its underlying mechanisms remain poorly defined. A central tenet of cancer immunoediting is that T-cell recognition of tumour antigens drives the immunological destruction or sculpting of a developing cancer. However, our current understanding of tumour antigens comes largely from analyses of cancers that develop in immunocompetent hosts and thus may have already been edited. Little is known about the antigens expressed in nascent tumour cells, whether they are sufficient to induce protective antitumour immune responses or whether their expression is modulated by the immune system. Here, using massively parallel sequencing, we characterize expressed mutations in highly immunogenic methylcholanthrene-induced sarcomas derived from immunodeficient Rag2?/? mice that phenotypically resemble nascent primary tumour cells. Using class I prediction algorithms, we identify mutant spectrin-?2 as a potential rejection antigen of the d42m1 sarcoma and validate this prediction by conventional antigen expression cloning and detection. We also demonstrate that cancer immunoediting of d42m1 occurs via a T-cell-dependent immunoselection process that promotes outgrowth of pre-existing tumour cell clones lacking highly antigenic mutant spectrin-?2 and other potential strong antigens. These results demonstrate that the strong immunogenicity of an unedited tumour can be ascribed to expression of highly antigenic mutant proteins and show that outgrowth of tumour cells that lack these strong antigens via a T-cell-dependent immunoselection process represents one mechanism of cancer immunoediting. [ABSTRACT FROM AUTHOR]

'Cancer immunoediting' is a process wherein the immune system protects hosts against tumor development and facilitates outgrowth of tumors with reduced immunogenicity. Although interferon-γ (IFN-γ) is known to be involved in this process, the involvement of type I interferons (IFN-α/β) has not been elucidated. We now show that, like IFN-γ, endogenously produced IFN-α/β was required for the prevention of the growth of primary carcinogen–induced and transplantable tumors. Although tumor cells are important IFN-γ targets, they are not functionally relevant sites of the actions of the type I interferons. Instead, host hematopoietic cells are critical IFN-α/β targets during development of protective antitumor responses. Therefore, type I interferons are important components of the cancer immunoediting process and function in a way that does not completely overlap the functions of IFN-γ. [ABSTRACT FROM AUTHOR]