Chromatin was prepared from 1x10^6 SCC cells or2x10^6 sorted cells using the ChIPmentation protocol described in Schmidl et. al, Nat Methods. 2015 Oct; 12(10): 963–965, DOI: 10.1038/nmeth.3542 using 4ug of anti-Pitx1 (Santa Cruz, 18922), anti-Klf4 (R&D, AF3758) and anti-H3K27Ac (Abcam, ab4729). Library prep was performed acording to Schmidl et. al, Nat Methods. 2015 Oct; 12(10): 963–965, DOI: 10.1038/nmeth.3542, using Tn5 to tagment the DNA fragments previous elution of the DNA.