ERBB2 and breast cancer: In breast cancer, approximately 82.2% of bone metastases are osteolytic, typically exhibiting irregular or moth-eaten margins, while osteoblastic or mixed patterns are also observed, with the former more common in HER2-negative or poorly differentiated tumors.[19] CT reveals osteolytic lesions with soft tissue infiltration or osteoblastic lesions with increased density, whereas magnetic resonance imaging (MRI) is highly sensitive for early bone marrow involvement.