ChIP-seq analysis was performed in primary NKTL (Natural killer T-cell lymphoma) samples, normal tonsil samples and 2 cell lines to analyze acetylation of histone H3K27ac. Overall design: Three primary NKTL tumor samples and their matched normal tonsils (controls) and NKYS and HANK1 cell lines were crosslinked with formaldehyde for 10 min. DNA was enriched by chromatin-immunoprecipitation (ChIP) and analyzed by Illumina Hiseq 4000. A sample of whole cell extract (WCE) was sequenced and used as the background to determine enrichment. ChIP was performed using an antibody against histone H3 lysine 27 acetylation (H3K27Ac: Abcam, ab4729).