"We can replace a defective gene, and it's like reprogramming a computer in the cancer cells." -- Dr. Jack A. Roth, University of Texas M.D. Anderson Cancer Center

Scientists have long believed that genetic therapy holds the promise of curing many catastrophic illnesses. Developments in 1996 suggest the promise will become a reality. But although there is scientific reason to hope, researchers caution that practical genetic therapy is still years away.

To find a cure, scientists first must find the gene. The Human Genome Project is providing federal funds to map an estimated 50,000 to 100,000 genes by the year 2005.

A version of what's already been mapped is available on the Internet:

• Gene Map of the Human Genome

Here are the results of some of the year's major studies:

LUNG CANCER: The first gene therapy study in people with lung cancer showed that treatment can shrink tumors or stop their growth. The study, at a Houston cancer center, was the first to use an injection of genes to correct a genetic flaw in cancer cells. Other studies manipulate the immune system to attack the cells. No patients in the small study were cured, but the study indicates gene therapy works in principle and deserves further study in lung and other cancers. "It's an important milestone," said Dr. John Minna, of the University of Texas Southwestern Medical Center.

• August 28 -- Researchers find gene injection slows cancer

CARDIOVASCULAR DISEASE: The first evidence that gene therapy might work with cardiovascular disease came from researchers at St. Elizabeth's Medical Center and Tufts University School of Medicine near Boston. They reported that a woman whose leg arteries were so clogged she was developing gangrene grew new blood vessels after injection with genes. Blood flow in her leg increased 82 percent. "This research is monumentally important," said Dr. Steven Nissen of the Cleveland Clinic Foundation.

PARKINSON'S DISEASE: For the first time, scientists have found the location of a gene for Parkinson's disease, a brain disease afflicting as many as 1.5 million Americans, leaving them with tremors or immobilized. The next step is pinpointing the precise gene, but researchers at the National Institutes of Health said they were closing in fast.

"I can say correctly and historically -- in a historical perspective -- this is the most important advance in Parkinson's disease in this century," said Dr. Roger Duvoisin, of Robert Wood Johnson Medical School.

• November 21-- Scientists identify genetic cause for Parkinson's disease

BREAST CANCER: Research shows a defective gene may be responsible for most of the so-called sporadic breast cancers, which account for 90 percent of all breast cancer. The research has determined the properties of the gene, and offers hope that a healthy mimic of the protein it generates could be used to inhibit cancer.

• January 18 -- Defective gene linked to hereditary breast cancer

PROSTATE CANCER: Researchers have located the gene predisposing men to prostate cancer. They hope to use the discovery to develop blood tests which could give high-risk patients early warning.

• November 21 -- Researchers locate prostate cancer gene

RHEUMATOID ARTHRITIS: Researchers at the University of Pittsburgh Medical Center became the first to test gene therapy against rheumatoid arthritis, an incurable disease of the joints. They injected genetically altered cells into a woman's knuckles to block inflammation. This first phase of the study only tests safety.

GENETIC TIME BOMB: A researcher at Johns Hopkins University reported research on killer genes introduced into the body to act like a time bomb -- waiting until a cell produces proteins tied to cancer, and then releasing genetic material to kill it. The method would spare healthy cells. Success has been reported in a test tube. Testing on humans is probably years away.

Genetic links were also found for basal-cell carcinoma, the most common form of human cancer, alcoholism, and even anxiety. But researchers stressed that when it comes to behavior disorders, environment and life experiences also play pivotal roles.

• May 31 -- Research turns up genetic clue to alcoholism
• November 28 -- Researchers find genetic root for anxiety

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OTHER CNN INTERACTIVE REPORTS

• February 1 -- Fat Gene
  
• August 9 -- Genetic mutation may shield against HIV infection
  
• September 13 -- Gene therapy no quick fix
  
• October 19 -- Anti-cancer discovery excites scientists
  
• October 24-- As gene technology improves, so does possibility of discrimination

RELATED SITES

• Gene Map of the Human Genome
• American Cancer Society
• Stanford University Department of Genetics
• Time Magazine: Genetics: Keys to the Kingdom

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