An anti-cancer vaccine made with a patient’s own brain tumor has helped several sufferers live much longer than expected, U.S. researchers reported on Thursday.

They found three specific targets called antigens in brain tumor cells, and customized a vaccine that, apparently, stalled the growth of the deadly brain cancers.

While the 14 patients were not cured, they lived an average of about two and a half years compared to seven and a half months for similar patients who did not get the vaccine, the researchers said.

Writing in the journal Cancer Research, Dr. Keith Black and colleagues at Cedars-Sinai medical center in Los Angeles and a team at the National Cancer Institute said they found the antigens in the most common and aggressive type of malignant brain tumor, glioblastoma multiforme.

“This is the first time that a specific response to brain tumor antigens has been demonstrated as the result of an immunotherapy strategy,” said Dr. John Yu, who helped lead the study.

Their trial was designed only to show the vaccines were safe, but they apparently helped the patients survive longer.

Immune cells called T lymphocytes can attack cancer cells but usually do not because the cancer cells also carry the signature of normal, healthy cells.

Researchers working on a cancer vaccine are looking for antigens that are made only by cancer cells, so the body can be trained to recognize and attack them.

They took cells from the patient’s own brain tumors and grew them in the lab alongside immune cells that had been primed to recognize each of the three antigens.

The resulting “trained” immune cells were then injected back into the patients.

In another study, a team at Harvard Medical School used a slightly different approach to shrink tumors in two breast cancer patients.

Writing in the journal Clinical Cancer Research, Dr. Donald Kufe and colleagues at Harvard’s Dana-Farber Cancer Institute said they fused tumor cells from the patients with T-cells.

“This approach increased the number of antigens that immune system cells can recognize,” said Dr. David Avigan, who helped lead the study.

They tested 10 people with breast cancer and 13 with kidney cancer, vaccinating them with the fused cells, each customized to the patient.

One-third of the patients had some kind of positive response, the Harvard team reported.

In a third study a team at the Mayo Clinic in Rochester, Minnesota manipulated a human antibody and used it to vaccinate mice, curing some of them of melanoma, a deadly form of skin cancer.

Writing in Cancer Research, Larry Pease and colleagues said they had trained T-cells to seek and destroy malignant melanoma by using a molecular manipulation technique called “cross-linking.”

They vaccinated the mice and then injected them with human melanoma tumors.

They said 48 percent of the 29 mice that got the antibodies had no tumors. All the mice that received dummy antibodies developed large numbers of tumors in their lungs.

SOURCE: Cancer Research, July 15, 2004.