• It is not yet possible to get the corrective genes into all the cancer cells in a patient's body.
• The amount of protein currently produced in cells bearing a newly transferred gene is often too low to expect
complete correction of the tumor-causing defect.
Other Approaches Researchers are investigating anticancer vaccines and antibodies directed against oncoproteins such as HER-2/neu and EGFR (epidermal growth factor receptor). The therapeutic use of antibodies, alone or as carriers of powerful drugs, cell toxins or radionuclides, has already been shown to interfere with the tumor-causing action of oncoproteins. Such antibodies can selectively inhibit cell growth in cell cultures and in cancer patients and will likely be the most easily realized anti-oncogene therapy.
A different approach involves new drugs that can inactivate oncoproteins such as ras or associated enzymes such as protein tyrosine kinases. Yet another approach focuses on DNA- or RNA-binding drugs that recognize specific gene sequences such as antisense oligomers directed against the c-myc and c-myb transcripts that can inhibit intracellular expression of specific oncogenes .
These approaches all attempt to develop cancer treatments that target specific genetic defects. In theory, such treatments will be able to reduce the uncomfortable and life-threatening side effects now associated with chemotherapy .
Most important, some form of oncogene therapy could potentially be used to prevent tumors in people who are at a higher than normal risk for cancer because of their family history or environmental exposure.
