Medical scientists are centering a considerable amount of research on the use of a patient's own bone marrow as a possible cure for leukemia and other blood disorders.

The procedure is called an autologous bone marrow transplant, in which some of the patient's own marrow is removed, stored and "cleansed." The patient is given massive doses of chemotherapy and radiation, then the treated marrow is reinfused.The treated marrow then resumes its vital function of producing new red blood cells and immune system cells.

For a number of years, bone marrow transplants from genetically acceptable donors have been used to treat patients with certain types of cancers and leukemia.

Dr. Julia Smith, an oncologist at New York University Medical Center, said bone marrow transplants allow leukemia patients to receive large doses of radiation and chemotherapy in an effort to eradicate their cancer.

"Given those very high doses of treatment without the bone marrow transplant," she said, "they would develop potentially fatal infections. The bone marrow transplant, in effect, gives a person a new immune system."

Smith said results from the use of autologous transplants have been impressive - to a point where the procedure has become the treatment of choice for lymphomas and leukemia, with cure rates above 50 percent in some situations.

She said researchers hold out hope, too, that the technique might eventually be used to help treat patients with widespread breast cancer, ovarian cancer and melanoma.

Research is also beginning to focus on the use of genetic engineering in the treatment of blood disorders. This complex process involves removing some of the patient's marrow, manipulating or altering a gene through a process called "transection," then returning the corrected gene back into the patient.