Mammalian target of rapamycin is a downstream mediator of PI3K/AKT signalling, regulating proliferation, survival, mobility, and angiogenesis via targeting p70S6 kinase (p70S6K) and 4E-BP1 in breast cancers that exhibit constitutively activated PI3K/AKT signalling (Bjornsti and Houghton, 2004). This evidence concerns the gene RPS6KB1 and breast cancer.