Blood cancers develop when immune cell DNA editing hits off-target spots
This is a scanning electron micrograph of a human T lymphocyte from the immune system of a healthy donor. Sometimes when the immune system makes small mistakes, the body amplifies its response in a big way: Editing errors in the DNA of developing T and B cells can cause blood cancers. Now, researchers from the Perelman School of Medicine, University of Pennsylvania have shown that when the enzyme key to cutting and pasting segments of DNA hits so-called "off-target" spots on a chromosome, the development of immune cells can lead to cancer in animal models. Knowing the exact nature of these editing errors will be helpful in designing therapeutic enzymes based on these molecular scissors. The Penn team's findings appear online this week in Cell Reports ahead of the print issue.