Rolf M. Zinkernagel of the University of Zürich, Switzerland, and colleagues have come up with some new rules of T-cell induction and maintenance that "not only change previous views but also rationales for anti-tumor immunotherapy."
Controversially, they suggest that tumor-specific induction of protective cytotoxic T cells depends on sufficient tumors cells reaching secondary lymphatic organs early enough, and for long enough.
|How clinically detectable tumors affect immune system:|
"Overall, we can conclude that tumors that reach the stage of being clinically detectable are likely to have done so in one of two ways."
"Either they have generated tolerance in the immune system or they have developed ways of resisting immune recognition," writes Drew Pardoll of Johns Hopkins University, Baltimore, Maryland, in an accompanying News and Views article.
"In terms of cancer treatment, we need ways of breaking tolerance or of activating mechanisms that will circumvent resistance mechanisms."