ERBB2 and breast cancer: Due to the clinical evidence that co-activation of the tGLI1 and IL-6/IL-6R/GP130 signaling pathways is associated with more aggressive subtypes in breast cancer patients (Figure 1), we next examined the role of tGLI1 and GP130 in the HER2-enriched breast cancer and TNBC stem cell subpopulation in vitro.