In the present study, we used three different types of breast cancer cell lines, MCF-7 (Luminal A; ER+, PR+/−, HER2−, good outcome), SK-BR-3 (HER2; ER−, PR−, HER2+, poor outcome), MDA-MB-231 (Claudin-low; ER−, PR−, HER2−, poor outcome)26 and demonstrated that shikonin inhibits the growth of these cancer cells including arresting the progression of the cell cycle and inducing apoptosis. Here, ERBB2 is linked to breast carcinoma.