ISL1 and myxoma: Also, these clonogenic c-kitpos/CD45neg/CD31neg myxoma-derived CSCs express OCT-4, NANOG, BMI-1, NKX2.5, and ISL-1 (Figure 3A) and form cardiospheres at a rate similar to normal human CSCs even though serial spherogenesis was reduced (Figure 3B and Supplementary material online, Figure S3A).