RB1 and breast cancer: At the same time, 1/6 of the mice implanted with metastatic tumors had p53, PTEN, and RB1 mutations, and 1/2 had p53, PTEN, RB1, and NF1 mutations, and these tumors respond to both chemotherapy and endocrine therapy, improving understanding and awareness of specific molecular subtypes of breast cancer (88).