Cancer-Related Mutations are Not Enriched in Naïve Human Pluripotent Stem Cells

A recent paper reported multiple oncogenic point mutations in naïve human pluripotent stem cells (hPSC) and implicated selective culture conditions. However, we observed that those “polymorphisms” are only found when naïve hPSCs are co-cultured with mouse feeder cells. Inspection of the reads containing the reported mutations revealed that they are identical to mouse sequences. Filtering the data sets to remove reads contributed by mouse feeder cells reveals that the actual incidence of cancer-related polymorphisms is close to zero. Therefore, culture conditions for naïve hPSCs do not select for tumorigenic point mutations. Total RNA was extracted from two biological replicate cultures of each cell line and time point