SOX2 and neoplasm: A closer examination of the H3K27ac-enriched regions in each tumour type indicated that unlike the H3K27ac-marked loci that were common to all samples, which were devoid of H3K27me3, the uniquely SCC- or ADC-enriched loci were very often bivalently marked with H3K27me3 and H3K37ac in ADC, and became monovalently marked with H3K27ac in SCC due to a loss of PRC2-mediated gene repression (Sox2 is an example) (Fig. 5d).