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Gene-Chip Technology
Today's cancer researchers don't just rely on microscopes and test tubes; they are using powerful computer analyses to predict the structure and function of genetic material, DNA, and the products of those genes: proteins. Thousands of genes can be placed on a small silicon chip, called a DNA microarray, and differences in gene activity are observed by sophisticated software. Forms of lymphoma, leukemia, and breast and ovarian cancer that pathologists cannot tell apart microscopically but that respond differently to therapy have already been identified by these techniques. Eventually, researchers may be able to subtype tumors so precisely that they will be able to design drugs that address the causes rather than the symptoms of disease.
Targeted Drug Design
Some drugs inhibit the growth and spread of cancer by targeting aberrant proteins in cancer cells themselves. Such drugs can treat certain non-Hodgkin lymphomas (Rituxan, Zevalin, Bexxar); acute myelogenous leukemia (Mylotarg); and breast cancer (Herceptin). Two drugs that have been approved for treatment of colon cancer (Avastin, Erbitux) are also being studied for possible benefit in lung cancer. Gleevec, taken as a pill, has shown spectacular success in the treatment of chronic myelogenous leukemia since its apprroval in 2001. More recently, the FDA has approved Tarceva for the treatment of the most common form of lung cancer and Velcade for the treatment of multiple myeloma.
Chemoprevention
Drugs that act selectively against estrogen, such as tamoxifen (Nolvadex) and raloxifene (Evista), reduce the risk of breast cancer in certain groups of women, and now these two drugs are being compared in an ongoing clinical trial. Three aromatase inhibitors, Arimidex, Aromasin, and Femara, which reduce the amount of non-ovarian estrogen produced in the body, have been approved for prevention of breast cancer recurrence. A recent chemoprevention trial of the drug finasteride (Proscar), which prevents the male hormone testosterone from being converted into a form that stimulates the prostate gland to grow, showed that the incidence of prostate cancer was reduced by 25% in men over 55. Other possible cancer chemopreventatives under investigation are nonsteroidal anti-inflammatory agents, calcium, lycopenes, and certain forms of vitamin A.
Nanotechnology
An exciting new frontier in cancer research is the development of incredibly small particles to diagnose and treat cancer. Nanoparticles, tiny structures only a fraction as wide as a human hair, can detect early signs of cancer by measuring critical changes in the DNA of a single cell. They can transmit these changes to an external measuring device - the equivalent of a "molecular mammogram" or a "bar-code colonoscopy." Because of their unique physical properties, nanoparticles can be designed to carry drugs or toxins specifically to cancer cells. The ultimate goal is to create a repertoire of nanoparticles that can circulate through the body, detect cancer-associated molecular changes, assist with imaging, deliver a therapeutic agent, and monitor the effectiveness of treatment.