ERBB2 and orbit neoplasm: Because numbness and peripheral sensory neuropathy appeared as an adverse effect, we switched to combination therapy with Letrozole (an aromatase inhibitor: 2.5 mg/day per os) and Abemaciclib (a CDK4/6 inhibitor: 300 mg/day per os) for hormone receptor-positive, HER2-negative advanced breast cancer after three courses of nab-paclitaxel therapy, and this resulted in marked reduction of the orbital tumor (Figures 3A–C).