For example, thyroid carcinoma can take in 131I by itself, but most tumors are nonselective to this treatment. hepatoma. 1. Introduction Undoubtedly, an ideal malignancy treatment must meet two aspects: good therapeutic effect and no or little side effect [1, 2]. However, most current therapies, such as radiation and chemotherapy, destroy normal tissue and cause serious side effects while killing tumor cells. Traditional administration by intravenous injection ensures that drugs RU 24969 are uniformly distributed in the system. Generally, once administered, a drug undergoes many actions where loss can occur, including combination with plasma proteins, metabolism, and decomposition, before it gets to the tumor site. Only a small proportion of drugs finally reaches the tumor due to lack of specific affinity for tumor tissues or cells. This not only greatly decreases the therapeutic effect, but also increases the nonspecific side effect on normal tissue [3]. Traditional external radiation is currently well accepted as one of the most effective remedies for malignancy, but it may inflict severe damage on normal tissue. Compared to external radiation, internal nuclide radiation provides prolonged low dose rate exposure and shows some advantages, but only a small minority of cancers can actively absorb nuclides unassisted. For example, thyroid carcinoma can take in 131I by itself, but most tumors are nonselective to this treatment. In recent years, suicide gene therapy has been explored for cancer treatment. Among suicide genes, herpes simplex virus type thymidine kinase (HSV-TK) is most commonly used. It can express thymidine kinase to convert nontoxic prodrug ganciclovir (GCV) into toxic GCV-TP to kill tumor cells by blocking DNA synthesis. Studies have shown that better curative effects can be obtained when the anticancer effects of the HSV-TK/GCV system are combined with radiotherapy [4]. In our previous study, we succeeded in constructing recombinant plasmids of pEgr1-HSV-TK and transferring them into hepatoma cells. Upon irradiation, radiation promoter Egr1 could induce HSV-TK gene to express efficiently and the encoded products could convert GCV into a tumor killing drug [4, 5]. However, the ultimate goal to kill the cancer without damage to normal tissue cannot be achieved unless the radiation is localized to the tumor site and suicide genes only express effectively in tumor cells not in normal cells or the prodrugs are delivered selectively to the tumor. Therefore, it is important to develop drugs or nuclides into tumor-targeted agents to improve curative effect and minimize side effect. Monoclonal antibody (McAb) is a very powerful F2rl1 cancer-targeted tool and has been widely used in targeting treatment [6C9]. Owing to its high specificity, strong affinity for the corresponding tumor, RU 24969 and little injury to normal cells, great progress in cancer-targeted therapy has been made. Studies have shown that monoclonal antibodies can specifically target tumor cells with the corresponding antigen and can carry therapeutic agents such as nuclides or drugs to tumor site to kill the tumor [10, 11]. McAb has become a preferred choice for a guiding drug vector because of its unique superiority, but the lethality of drugs RU 24969 carried by a single monoclonal antibody molecule is poor. Nanoparticle drug delivery system using nanospheres as delivery vectors can accommodate much more antitumor drug molecule and increase the drug-loading significantly. In particular, bovine serum albumin (BSA) nanospheres, which use BSA as vectors to encapsulate drugs, show very good qualities for a delivery vector including good stability, high drug-loading, and slow release. BSA nanospheres bearing paclitaxel, adriamycin, or nuclides (125I and 188R) showed RU 24969 a much improved antitumor effect [12C15]. As a result of good targeting, drug-loaded nanospheres cross-linked with monoclonal antibodies have a greater ability to kill target cells specifically [16, 17]. Drug-loaded immune nanospheres have been used to label or separate cells and diagnose or treat disease because of the antibody adsorbed on the particles which results in nanospheres’ immunocompetence [18]. For example, if combined with fluorescent protein, drug-loaded immune nanospheres can be used for detection and diagnosis. At present, nanosized BSA targeting agents mediated by McAb and radioimmune therapy are active areas in tumor-targeted therapy. Advances in protein cross-linking technology have paved the way for construction of radioactive targeting immune nanospheres by applying drug-loaded BSA nanospheres to radiation RU 24969 immunotherapy. As a type of specific tumor antigen in the membrane and cytoplasm of cells, in vitroandin vivowere investigated, with the aim of providing theoretical and experimental insights for further high-efficiency radiation-gene therapy of hepatoma. 2..