STAT3 and breast cancer: To further confirm the selectivity of LLL12B in breast cancer cells, we tested its effects on the phosphorylation of STAT3, STAT1, or ERK following the stimulation with IL-6, IFN-γ, or EGF in the T47D breast cancer cells, which express lower basal levels of P-STAT3 (Figure 2C), and in the MDA-MB-231 TNBC cells (Figure 2D).