TKT and breast carcinoma: The addition of GO increases the specific surface area of nHAp, providing a large number of binding sites for HSV-TK. GO also serves as a new type of efficient gene carrier for tumor therapy, delivering a “suicide” gene into human breast cancer cell lines MDA-MB-231 and MCF7. Upon administration of GCV, which induces tumor cell apoptosis in response to DNA damage, the system exhibits a significant antitumor effect