The IL-6 feed-forward loop: a driver of tumorigenesis.

IL-6 signaling plays a prominent role in tumorigenesis and metastasis. In this review we discuss the recent evidence describing the tumor intrinsic and extrinsic functions of this signaling pathway. Although blockade of this pathway in pre-clinical models leads to a reduction in tumor growth and metastasis, its clinical success is less evident. Thus, identifying the features of tumors/patients that predict response to anti-IL6 therapy are needed.