Fig. 1.

Detection of undifferentiated hiPSCs in primary cardiomyocytes using the LIN28/qRT-PCR method. (A) LIN28, NANOG, REX1, SOX2, OCT3/4, KLF4 and c-MYC relative mRNA expression in cardiomyocytes was determined using qRT-PCR analysis. (B) qRT-PCR analysis of hiPSCs spiked into three lots of primary cardiomyocytes. Single-cell hiPSCs (0.1%, 1 × 10³ cells; 0.01%, 1 × 10² cells; 0.001%, 1 × 10¹ cells) were spiked into 1 × 10⁶ primary cardiomyocytes, and total RNA was isolated from the mixed cells. All values are expressed as mRNA levels relative to those in undifferentiated hiPSCs. hCM: human cardiomyocyte. The expression levels of target genes were normalized to those of the GAPDH transcript. Results are presented as the mean ± standard deviation (n = 3).