Through assay for transposase-accessible chromatin using sequencing (ATAC-seq), we detected increased chromatin openness of squamous markers (TP63, KRT5, KRT6A and KRT14) and reduced chromatin accessibility of adenomatous markers (KRT7 and MLPH) in the DR tumor cells (Fig. 1B and Fig. S1K, M). Here, KRT6A is linked to neoplasm.