Similarly, the N-terminal domain (NTD) of STAT3 is considered to be mainly involved in STAT3-interactomes, and structural data available allowed for the rational design of analogs of the helix 2 of STAT3 able to directly and selectively bind STAT3 but not STAT1 and to induce apoptosis in BC but not in normal breast cells or STAT3-deficient fibroblasts (Timofeeva et al., 2007). This evidence concerns the gene STAT3 and breast cancer.