One of the advances against blood cancers, doctors consider the usage of gene therapy to transform patients' blood cells into soldiers that seek and destroy cancer, CBS News reports.

A few patients with one type of leukemia were given this one-time, experimental therapy several years ago and some remain cancer-free today. Now, at least six research groups have treated more than 120 patients with many types of blood and bone marrow cancers, with stunning results.

"It's really exciting," said Dr. Janis Abkowitz, blood diseases chief at the University of Washington in Seattle and president of the American Society of Hematology. "You can take a cell that belongs to a patient and engineer it to be an attack cell."

In one study, all five adults and 19 of 22 children with acute lymphocytic leukemia, had a complete remission.

Cancer was so advanced in 8-year-old Emily Whitehead, that doctors said her major organs would fail within days. She was the first child given the gene therapy and shows no sign of cancer today, nearly two years later.

Many patients are successfully treated with chemotherapy or bone marrow or stem cell transplants, but transplants are risky and donors can't always be found. So far, gene therapy has been tried on people who were in danger of dying because other treatments failed.

Of the first 14 patients with CLL, four had complete remissions, four had partial ones and the rest did not respond. However, some partial responders continue to see their cancer shrink a year after treatment.

The doctors also treated 27 ALL patients. All five adults and 19 of the 22 children had complete remissions.

At the National Cancer Institute, Dr. James Kochenderfer and others have treated 11 patients with lymphoma and four with CLL, starting roughly two years ago. Six had complete remissions, six had partial ones.