Mammalian target of rapamycin (mTOR) is a key protein kinase controlling signal 
transduction from various growth factors and upstream proteins to the level of 
mRNA translation and ribosome biogenesis, with pivotal regulatory effects on 
cell cycle progression, cellular proliferation and growth, autophagy and 
angiogenesis. The mTOR pathway, and its upstream regulators in the PI3K/PTEN/AKT 
cascade, are altered in a variety of experimental and human malignancies.This 
has led to the prediction that mTOR inhibitors may be used as anticancer agents. 
With the recent approval of two mTOR-targeted drugs (temsirolimus and 
everolimus) for the treatment of renal cell carcinoma and mantle cell lymphoma, 
this paradigm has been effectively translated into the clinical setting. In this 
review, we discuss mTOR biology and regulation, the mode of action of mTOR 
inhibitors as anti-cancer agents, and current clinical evidence supporting the 
use of rapamycin-like mTOR inhibitors in cancer treatment.