Classification of Advanced Human Cancers Based on Tumor Immunity in the MicroEnvironment (TIME) for Cancer Immunotherapy

The development of inhibitors targeting the programmed cell death 1/B7 homolog 1 (PD-1/B7-H1) (PD) pathway, a mechanism adaptively used by tumors to evade the immune response, has been groundbreaking in the treatment of a broad spectrum of advanced cancers, especially solid tumors. Antibody blockade of the PD pathway (anti-PD therapy) repairs this immune deficit in the tumor microenvironment, producing previously unseen durable responses in many patients with advanced-stage cancers, but a large fraction of patients still fail to respond.¹ As clinical responses to anti-PD therapy correlate with the presence of both (B7-H1) expression and immune responses in the tumor,² we propose a way of categorizing patients based on Tumor Immunity in the MicroEnvironment (TIME) and discuss its implications in cancer treatment.