A study just published in the journal Cell Stem Cell has highlighted the erratic and abnormal nature of pluripotent stem cells such as embryonic stem cells, and the inherent danger of such cells for clinical applications. The new study found significant genetic abnormalities in human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cell lines. The team identified regions in the genome that had a greater tendency to become abnormal in pluripotent cell lines.

According to lead author Louise Laurent:

"We found that human pluripotent cells (hESCs and iPSCs) had higher frequencies of genomic aberrations than other cell types. We were surprised to see profound genetic changes occurring in some cultures over very short periods of time."

Genetic aberrations have been strongly associated with cancers. They found that the degree of abnormality differs more between hESC lines than hiPSC lines, and that the reprogramming process was associated with deletions of tumor-suppressor genes, whereas time in culture was associated with duplications of oncogenic genes.

Previous studies have documented numerous genetic and chromosomal problems with embryonic stem cells, including a substantial number of pluripotent cell lines with full and partial chromosomal aberrations. This new study used a high-resolution molecular technique called "single nucleotide polymorphism" (SNP) analysis, allowing the researchers to check genetic changes at more than a million sites in the human genome.