Notably, the importance of the autoinhibitory function of the TAZ2 domain on p300 HAT activity is underscored by the recent reports that TAZ2 deletion mutants of p300/CBP found in many human cancers are associated with histone hyperacetylation at H3K27 and H3K18 in chromatin, two known substrates for p300/CBP9, and recurrence following radiation in squamous cell carcinoma cohorts50. This evidence concerns the gene EP300 and squamous cell carcinoma.