Spontaneous and treatment-induced cancer rejection in humans

Experimental observations suggest that human cancer cells actively interact with normal host cells and this cross-talk results, in most instances, in an increased potential of cancer cells to survive. On the other hand, it is also well documented that on rare occasions tumors can be dramatically destroyed by the host's immune response.

In this review, we argue that understanding the mechanisms that bring about the immune response and lead to cancer destruction is of paramount importance for the design of future rational therapies.

Here we summarize the present understanding of the phenomenology leading to cancer regression in humans and propose novel strategies for a more efficient study of human cancer under natural conditions and during therapy.

The understanding of tumor/host interactions within the tumor microenvironment is a key component of the study of tumor immunology in humans, much can be learned by a dynamic study of such interactions at time points related to the natural history of the disease or its response to therapy. Such understanding will eventually lead to novel and more effective therapies.