Large (left, inset) and small (right, inset) centromeres allow for detection of chromosome loss events in ES cells.

Stambrook/NAS

Any cell therapy risks introducing mutated and possibly tumorigenic cells. Now results from Peter Stambrook (University of Cincinnati, Cincinnati, OH) and colleagues underline this concern for embryonic stem (ES) cells, which are one possible source for therapeutic cells.

Stambrook constructed a cell line in which he could detect loss or mutation of a heterozygous marker gene. Loss (rather than mutation) of the functional allele was the proximate cause in ∼80% of the events with both mouse embryonic fibroblasts (MEFs) and ES cells. But marker-deficient colonies arose 400-times faster in MEFs than in ES cells—good news for ES cell proponents.

But a closer look revealed complications. Whereas all the loss events in MEFs were caused by mitotic recombination, a full 57% of the ES cell events were...

The Rockefeller University Press
2002
The Rockefeller University Press
2002
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