"We know that in 2001 it was believed 78 stem cell lines existed. But now we know there are only 22 that are viable, and they have been contaminated with mouse stem cells"

This quote by Russ Carnahan is referring to the state of stem cell research in 2001. At the time, it was thought that 78 stem cell lines existed, and now it is known that only 22 of those lines are practical. Furthermore, it has actually been found that these 22 lines have actually been polluted with mouse stem cells. This is a significant advancement in the field of stem cell research study, as it means that the potential of these lines is restricted and additional research is required to create brand-new, feasible lines. This quote highlights the importance of continuing to research study and develop brand-new stem cell lines, as the existing ones are not sufficient for the potential applications of stem cell research.