ERBB2 and breast cancer: In addition, lapatinib as a small molecule inhibitor of HER2, has been developed to expand the options for treating HER‐positive breast cancer.[69] We found that the combination of carnitine palmitoyltransferase‐1 (CPT‐1) inhibitor etomoxir and lapatinib inhibited luminal B cells better than using lapatinib alone.