Tumor-oriented therapy is the use of certain specific carrier, the anti-cancer drugs or other substances selectively delivered to the tumor site in order to improve the therapeutic effect of a treatment. Selectivity of the existing anti-cancer drugs is not high, not only kill tumor cells, it also undermines the body's cells reproduce strong or certain specific types of normal cells, often appear more pronounced toxicity. Tumor-oriented therapy can be as much as possible through a special carrier of anticancer drugs will be directed into the body lesions selectively kill cancer cells, so that the anticancer drugs into the body to destroy not only focus on the tumor tissue but also avoid or reduce its normal tissue and cell damage. This is like a military missile, as with explosive warheads, to be carried in the carrier and guidance to effectively hit the target.
In cancer therapy can guide the "warhead" of the material can be divided into: (1) of radionuclides: such as 1311, 1251, 90Y, 212Bi, etc. of which the most commonly used in clinical 1311. These nuclides of mass destruction warheads strong. (2) Chemical substances: such as doxorubicin, fluorouracil Anhui, vincristine, a ridge of ammonia and other chatter. The destruction of these warheads is relatively weak, the required amount of more carriers. (3) toxic protein: such as contempt Ma toxic protein, diphtheria toxin protein. Highly lethal warheads of such toxins and called for higher specific carrier. (4) biological response modifiers: such as interleukin-II, etc., under the guidance of its arrival on the carrier's tumor, the tumor vascular permeability increase, so that more drugs into tumor-oriented but can also activate the LAK cells to kill tumor cells. IL-II, if not combined with the carrier, makes the body organs were increased vascular permeability, cause some adverse reactions. (5) enzymes: enzymes as warhead material itself does not have anti-tumor cell activity, but it is combined with the carrier to reach the tumor tissue, the joint use of the non-associated activity of prodrug activation of a substance with anti-tumor cells . Treatment in tumor-oriented selection of warheads and carrier must match, if the carrier and the binding force between the warhead is not strong, or specific carrier is not high, the destruction of warheads may also result in a large normal tissue cells more casualties.
Tumor-oriented therapy vector is generally used different principles of pro-tumor substances, generally divided into two categories:
First, the antibody class
This is the most current research and use of the carrier. Has its own because the tumor-associated antigen, which antigen but also with the corresponding antibodies (as vector) to produce specific binding, and thus play a guidance role. Currently used antibody carriers are: (1) prepared for various malignancies and selected monoclonal antibodies. (2) ferritin antibodies. (3) alpha-fetoprotein antibody. (4), carcinoembryonic antigen antibodies. Monoclonal antibodies and other antibodies as compared to recent years, it has a higher specificity of monoclonal antibodies as a carrier of a more in depth. Connection with the warhead material monoclonal antibody product from said immunoconjugate, which were connected with the said radionuclide conjugate radioimmunotherapy with drug connections are known toxic chemical immunoconjugate connection with those who say the immune toxins.
Second, the non-antibody class
Although the antibody class of non-carrier antibody as carrier of the present study, but because it is not immune antibody response vector has an important position. Non-antibody affinity tumor material can be divided into: (1) pro-tumor compounds, such as adjacent duo wake up a 5 – methyl tryptophan, tyrosine acid Gly delay, the fluorescent dye rhodamine and so on. (2) physical-oriented material, such as the magnetic field to guide the magnetic field to attract the material can be concentrated to the tumor area. (3) tumor blood vessels oriented. Very widely used in recent years, blood clots, imaging with the shy and bashful benzene vinegar, oil has proved to have significant guiding role in hepatocellular carcinoma.
Directed therapy is currently used in clinical research more in-depth treatment of liver cancer, in addition to the B-cell lymphoma, human neuroblastoma, ovarian cancer, proved to have a certain effect Dengjun. The therapeutic effect of orientation is affected by many factors, including tumor blood vessels, tumor necrosis, vector specificity, tumor cell sensitivity of radionuclides, tumor size, drug dose, cross-reactive antibodies, and hematopoietic tissue internal radiation sensitive and can not use the higher dose. Except for a very sensitive person, its difficult to cure a single application, it is treated in the same direction combined treatment should be more reasonable.
Although the tumor-oriented therapy is not very mature, but the results are exciting in recent years, I believe that in the near future, the tumor targeting therapy will become the surgery, radiation, chemical, interventions, biological therapy is another outside the conventional treatment.