KIT and breast cancer: There is now abundant evidence indicating that signaling through the IGF-1R pathway is important in many cancers, including breast cancer [4,42,46-49], and recent preclinical work has shown that IGF-1R could be used as a successful cotarget with EGFR in primary human glioblastoma cells [13,50], with c-kit in small-cell lung cancer [15,17], and with HER2/erbB2 in breast cancer cells [12,16].