Hidden immunotherapy targets challenge dogma.

In this issue of Science Translational Medicine, Guo et al. discuss the intriguing possibility that intracellular tumor antigen-specific monoclonal antibodies (mAbs) inhibit tumor growth and metastasis and prolong survival of tumor-bearing mice. Here, I discuss the implications of using intracellular targets in mAb-based immunotherapy as well as the possible underlying mechanisms of action.