Furthermore, we discuss the impact of targeted therapies in LM from solid tumors with actionable mutations, such as epidermal growth factor receptor (EGFR)-mutated and anaplastic lymphoma kinase (ALK)-gene rearranged NSCLC, human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) and BRAF-mutated melanoma. The gene discussed is ERBB2; the disease is breast cancer.