She cautioned that “the results are preliminary,” noting that they mainly show “the effect of p53 in one particular cell line.” At this point, it’s unclear whether this happens to these cells exclusively, or other types.
Professor Robin Lovell-Badge, group leader at The Francis Crick Institute, added that the need to reduce p53 activity was known previously through the study of pig cell lines.
Noting that the retinal cells in the second study were likely suffering from cellular stress, he suggests that the issues raised by these two studies may be relatively specific. He also stressed that cells used in CRISPR should always be checked for p53 mutations and not used if found to contain them.
“It is therefore not apparent that the problems identified by these two papers, and certainly the scary press releases, are entirely justified,” he concluded.
Researchers who are keen to investigate CRISPR’s potential aren’t blindly unaware that we still need to understand what side-effects snipping parts of an organism’s genetic code may have. One oft-cited worry is that of mosaicism, which refers to edited embryos that, as they divide, still contain unedited DNA.
The other frequently discussed problem is that of the accidental triggering of cancer. New Scientist recently suggested that this was becoming less of a concern over time, but this new study moves it back into the spotlight. It appears that investors in CRISPR are taking a hit on this news, and MIT Technology Review suggests this research may be why a human CRISPR study in the US was canned by the Food and Drug Administration back in May.
The second papers' authors emphasized that they aren't saying CRISPR is “bad or dangerous.” Affirming that it will clearly be a vital biomedical tool, they are merely pointing out that safety concerns must be investigated thoroughly.
As Prof. Darren Griffin, a professor of genetics at University of Kent, put it, this work “provides reason for caution, but not necessarily alarm.”