For example, first-line therapy can be selected based on the gene mutation profiles of individual tumors, including epidermal growth factor receptor-tyrosine kinase inhibitors for lung cancer, mammalian target of rapamycin inhibitors for renal cell carcinoma, and human epidermal growth factor receptor-2 inhibitors for breast cancer [20,21,22,23]. The gene discussed is ERBB2; the disease is lung cancer.