SIX1 and neoplasm: Because our RNA-seq data suggest that SIX1 is largely promoting EMT gene expression in both ES lines, in a similar manner to its regulation in other tumor types10,11,18, and yet we observed pro-metastatic cell behaviors associated with SIX1 loss, we reasoned it is unlikely that SIX1 is regulating a bona fide EMT phenotype in ES.