A team of Harvard researchers at the Harvard Stem Cell Institute recently made a significant step in creating clinically-safe, induced pluripotent stem cells, an advance that could be “revolutionary” in treating patients with neuromuscular diseases like Huntington’s and Parkinson’s Diseases, according to the study’s senior author, Lee Rubin.

Induced pluripotent stem cells have the potential to differentiate into any cell type, meaning that they can be introduced as replacements for dead or dysfunctional cells. Unlike embryonic stem cells, which have never differentiated, they are created by altering existing adult cells.

In 2006, Japanese scientist Shinya Yamanaka first induced stem cells from adult mouse fibroblasts—cells most commonly found in connective tissue—by using viruses to insert four genes into the fibroblasts. These genes worked to reprogram the cells into pluripotent stem cells.

But two of these genes and the viral vectors used in the process can cause cancer, so this system is not ideal for clinical use.

The Harvard study, published in last week’s issue of the journal Cell, identified small molecules that can eliminate the need to use two of the four genes,

“This demonstrates that we’re halfway home, and remarkably we got halfway home with just one chemical,” said Kevin Eggan, assistant professor in Harvard’s Department of Stem Cell and Regenerative Biology and another senior author on the paper, in a press release announcing the paper.

According to Rubin, the team is now searching for small molecules to eliminate the need to use the other two genes.

“We think we can succeed in reprogramming cells completely for unhealthy people,” Rubin said.

Rubin also said this method may prove more practical in a clinical setting as the cells can be induced “using easy-to-buy molecules.”

The advance may also help researchers better understand neuromuscular diseases, Rubin said, because they will be able to convert a patient’s skin cells into the cell type of interest and study the difference between their own healthy and diseased cells.

“This is an important advance, but they’re at the fifty yard line, and need to reach the goal,” said Irving Weissman, professor for clinical investigation in cancer research and professor of developmental biology at Stanford University. “Now that [they have the cells], they need to see how the neurons degenerate.”