Cancer-cell vaccine halts tumor spread.

Scientists have shown in mice that genetically altered tumor cells can stimulate the immune system to halt the spread of an otherwise lethal cancer, says cell biologist Michael Feldman of the Weizmann Institute of Science in Rehovot, Israel.

Working with U.S. and Japanese researchers, Feldman and his colleagues treated mice with rapidly spreading tumors on their feet. After removing the tumors, the scientists inserted the gene coding for a type of interferon into the tumor cells. Interferon revs up white-blood-cell activity and causes the tumor cell to express proteins on its surface that make it a more visible target for the white blood cells. The scientists then injected the genetically altered tumor cells into half the mice weekly for five weeks. New tumors developed in untreated mice, but the vaccinated mice remained healthy, the researchers report in the Feb. 15 JOURNAL OF IMMUNOLOGY.

"The almost complete prevention of metastasis under conditions where the animal would almost certainly die makes it very attractive:' says Feldman. "This is a model that people would like to apply to humans."

Researchers have already used genetically altered cancer cells to bolster the immune system% fight against advanced melanoma, the most deadly skin cancer (SN: 10/19/91, p.253).