Standard treatment for breast cancer has greatly improved survival for women, but the fact remains that 40% of women still ultimately die from the disease. This fact highlights theneed for new and better therapies. Traditional anticancer therapies mostly consist of drugs and ionizing radiation that damage DNA and DNA machinery. Such treatments preferentially kill certain kinds of cancer cells because these cells have a diminished ability to survive the damage. However, normal cells, can suffer DNA damage, but have the ability to repair their DNA. Unfortunately, the same genetic defects may render some cancer cells resistant to treatment, since they may also be less adept at activating cell death in the face of DNA damage. The challenge of cancer treatment now is to take advantage of properties of cancer cells that distinguish them from normal cells and to subsequently and specifically target cancer cells. A growing understanding of cancer cell biology is leading to better methods for treating the disease by directly exterminating only cancer cells. Listed are some of the latest new and adventurous strategies that are being developed for future breast cancer diagnosis and treatment.
Six new breast cancer treatment strategies
- Oncolytic viral therapy – takes advantage of molecules that tumor cells lack. Tumor cells usually lack the protein p53 which controls the cell cycle and cell replication. Viruses can attach to a host cell and replicate continuously inside the cell. They then burst out when their numbers are sufficient, killing the cell and infecting its neighbors. An adenovirus has now been constructed that lacks the gene for the p53 protein; this virus can therefore only replicate in cells in which p53 is already inactivated-including many types of cancer cells. If this modified adenovirus is injected into a tumor, it will replicate in and kill only the cancer cells that lack p53, leaving normal cells unharmed. This strategy is presently undergoing clinical trials.
Interventional Radiology – Scientists are investigating a technique in which magnets are used to pull chemotherapy drugs into tumors. Microscopic magnetic particles are attached to the cancer drugs and infused into the blood vessel that feeds the tumor. A rare earth magnet is positioned directly above the tumor site. The magnet pulls the drug-carrying particles out of the blood vessel directly into the tumor. This technique is still experimental; however, early research is promising. Scientists hope that it will bolster the effects of chemotherapy and avoid drug side effects.
Gene Therapy – involves the alteration of the patient’s genetic material to fight or prevent cancer. Although the science of gene therapy is still in the experimental stages, researchers hope that in the future the therapy can be used as follows:
- Alter the cells of a patient’s natural immune system with cancer-fighting genes that allow cells to more forcefully attack the cancer;
- Genetically alter cancer cells so that the patient’s own immune system will defend against them and allow the altered cancer cells to act as a cancer vaccine;
- Replace genes responsible for cancer growth with “good” genes; and inject a tumor with genes that will make it more susceptible to cancer-fighting agents.
- Make normal tissue resistant to chemotherapy, so that drugs will destroy tumors without damaging healthy tissue.
Breast Cancer vaccines – Vaccination strategies are being developed that engage the patient’s own immune system to eradicate cancer cells. The advantage of this is low toxicity, and high specificity as well as a sustained antibody effect due to cell memory.
Use of breast cancer resistance genes – Researchers at the Dana Faber Cancer Institute have found a gene that can predict a high risk of cancer recurrence in some breast cancers that have been treated with chemotherapy drugs. This finding could guide the physician in the choice of anti-tumor drugs to use and eliminate wrong ineffective choices.
More precise breast cancer diagnosis – Breast cancer can now be characterized at a molecular level by obtaining expression profiles for thousands of genes within the cancer. These profiles can be grouped into subclasses of breast cancers that share common features such as prognosis and probable response to certain treatments. More precise treatments can then be made for each subclass of cancer
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