WASHINGTON (Reuters) - An early try at making a universal cancer vaccine seems to be safe, and shows some indication that it may even work, researchers at Geron Corp. said on Monday.

The first few cancer patients immunized with the vaccine showed no bad reactions and in fact seemed to mount an immune response against their own cancers, the Menlo Park, California-based company said.

The results are very preliminary but suggest the research approach is valid, Geron said in a statement.

Geron was scheduled to present its findings at a meeting of the American Association of Cancer Research in Toronto, but the meeting was canceled because of fears about an outbreak of severe acute respiratory syndrome, or SARS.

Many groups are working on cancer vaccines. The body's immune system sometimes does recognize and destroy cancer cells, but not always.

The idea behind a vaccine is to boost this response. But a big question is what part of a cancer cell can be best used to stimulate the immune system, especially as doctors do not want to accidentally cause the destruction of healthy cells.

Geron's approach targets telomerase, a protein that gives cells a kind of immortality. It is important early in life, but seems to be turned off once the body matures.

Cancer cells, however, over-produce telomerase, giving themselves extra-long lives and allowing themselves to proliferate wildly.

Geron's vaccine uses immune cells known as dendritic cells. They are taken from the patient, spliced with genetic signals from telomerase, and then returned to the patient. The hope is that other immune cells will become primed to destroy anything with extra telomerase.

The first few patients vaccinated this way showed no serious adverse effects, Geron said. It is a Phase I trial meant to show safety, and is only partly finished, the company said.

"Because telomerase is present in all major types of cancer cells, telomerase holds great promise for use in a universal cancer vaccine for the treatment of a broad range of tumor types, either alone or in combination with other antigens, " Dr. Thomas Okarma, Geron's president and chief executive officer, said in a statement.

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