Scientists used gene therapy to successfully destroy cancer tumors in patients with advanced disease.  University of Pennsylvania researchers engineered patient's own T-cells in order to target a molecule on the surface of leukemia cells. 

The altered T-cells were infused into patients with late-stage chronic lymphocytic leukemia (CLL), the most common form of leukemia. 

CLL is a progressive blood and bone marrow disease.  It often occurs during or after middle age and is rare in children.

Two of the individuals in the Phase I trial have been in remission for almost a year and a third responded favorably. 

The results provide "a tumor-attack roadmap for the treatment of other cancers," including those of the lung and ovaries as well as myeloma and melanoma," researchers told Reuters.

The findings were published Wednesday in the New England Journal of Medicine and Science Translational Medicine.

The method, "adoptive T-cell transfer," is different from other treatments in that it uses the patient's own immune system to fight tumors.