ERBB2 and breast cancer: In breast cancer cells, the OA derivative CDDO-Im (2) (Figure 2) in combination with the Gemini vitamin D analogue, ABXL0124, reduced cell proliferation and the levels of the proteins HER2, receptor tyrosine kinase 2 (Erb-B2), phosphorylated extracellular signal-regulated kinase 1/2 (pErk1/2), phosphorylated protein kinase B (pAKT), c-Myc, cyclin D1, and Bcl-2 [111].