Researchers continue to move rapidly in advancing the state of the art in induced pluripotent stem cells: "A team of scientists has advanced stem cell research by finding a way to endow human skin cells with embryonic stem cell-like properties without inserting potentially problematic new genes into their DNA. ... This is not the first time that scientists have endowed differentiated cells like skin cells with the capacity to develop into any of the roughly 220 types of cells in the body, a process known as induced pluripotency. But it is the first time that they have done so without using viruses, which can insert potentially harmful genes into the cells' genetic material and trigger cancer. [The] new method imports the necessary genes on a small circle of DNA known as a plasmid. Over time, the plasmid disappears naturally from the cell population, avoiding the danger posed by using viruses. Scientists view pluripotent cells as invaluable to studies of normal and disease processes and to understanding the effects of certain drugs. In the future, doctors might be able to use such cells therapeutically to replace those affected by diseases such as Alzheimer's and Parkinson's or lost to traumatic injuries."