Figure 6From: Signal transducer and activator of transcription 5 as a key signaling pathway in normal mammary gland developmental biology and breast cancerIncreased STAT5 initiates cancer and decreased STAT5 diminishes cancer promotion in genetically engineered mouse models. Increased levels of STAT5 expression and/or activation either directly by transgene-mediated STAT5 overexpression or indirectly through genetically engineered loss of caveolin-1 leads to initiation, promotion, and progression to mammary cancer. Decreased levels of STAT5 expression reduce cancer promotion initiated by transgene-mediated overexpression of prolactin, transforming growth factor-alpha (TGF-α), and estrogen receptor-alpha (ERα) as well as mammary-targeted simian virus 40 T antigen. STAT5, signal transducer and activator of transcription 5.Back to article page