
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: WEDNESDAY, May 23, 1990                   TAG: 9005230580
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A/4   EDITION: EVENING 
SOURCE: Associated Press
DATELINE: WASHINGTON                                LENGTH: Medium

VITAMIN A USED TO MAKE CANCER CELLS NORMAL AGAIN

In a unique assault on leukemia, doctors have found that a form of vitamin A will turn cancer cells into normal ones.

Medicine's usual way of combating cancer is to kill it. Doctors administer powerful toxic drugs in the hopes that they will destroy more cancerous cells than healthy ones.

The new approach instead tries to reform cancer cells. It changes the cells' genetic program, bypassing the genetic mix-up that makes them kill. In this way, the treatment induces the cancer cells to live, to grow and eventually to die by the same rules that govern the rest of the body.

The drug, a synthetic form of vitamin A called all-trans retinoic acid, was developed in China and tested in France. Though it has drawbacks and works in just one rare form of leukemia, doctors hope it will provide clues for short-circuiting the basic errors that underlie all cancers.

"The dogma has been to try to kill cancer cells," said Dr. Laurent Degos. "Is it possible to change a cell, and not kill it, so it becomes normal?"

Degos, a researcher at Hopital Saint-Louis in Paris, presented evidence that this indeed is possible in a report Tuesday at the annual meeting of the American Society of Clinical Oncology.

He tested the drug on victims of acute promyelocytic leukemia, a rare blood cancer that strikes a few hundred people in the United States each year. All of them had failed earlier standard therapy.

He achieved complete, though often temporary, elimination of all signs of the disease in 16 of 17 patients who had relapsed for the first time. There was complete remission in one of four patients who had relapsed a second time.

"There was no killing of cells, but they change," said Degos. "We see more mature cells."

This form of leukemia is caused by a specific genetic defect, the misplacement of a piece of one string of genes, or chromosome, onto another chromosome. As a result, the cells get stuck in their juvenile stage. They fail to mature normally and eventually die.

by CNB