KITLG and cancer: In cancer cells, some receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR/erbB1), HER2/erbB2/Neu, insulin-like growth factor-1 receptor (IGF1R), stem cell factor (SCF)/KIT receptor and also Notch, interleukin-6/IL-6R receptor and transforming growth factor-β/TGF-βR receptors can up-regulate the expression and/or stability of the HIF-1α subunit.