Ly2603618, on the other hand, was almost eight times more toxic against BL-CL breast cancers (average EC50 = 0.72 μM) as compared with luminal/HER2 breast cancer (average EC50 = 5.73 μM), which was also a significant difference (p = 0.001, Figure 4B). Here, ERBB2 is linked to breast carcinoma.