How tumors escape immune destruction and what we can do about it

There is strong circumstantial evidence that tumor progression in cancer pa tients is controlled by the immune system. As will be detailed below, this conclusion is based on observations that turner progression is often associ ated with secretion of immune suppressive factors and/or downregulation of MHC class I antigen presentation functions. The inference is that tumors mu st have elaborated strategies to circumvent an apparently effective immune response. Importantly, a tumor-specific immune response cannot be detected in most individuals. While this failure is in part technical, it also sugge sts that the magnitude of the immune responses to which tumors have to resp ond is low. This raises the concern. which is the underlying theme of this commentary, that a more robust immune response elicited by deliberate vacci nation will exacerbate the rate of immune escape and nullify the potential benefits of immune-based therapies.