The Harvard team has exploited such dogged persistence by genetically engineering stem cells to make them produce a protein called cytosine deaminase.

ECONOMIST: Cancer treatment

The Glaxo gene therapy program will focus on a severe immune deficiency called ADA-SCID, in which kids cannot make a crucial enzyme called adenosine deaminase that is needed to create immune system cells.

FORBES: Glaxo Brings Gene Therapy Back From The Dead