Although H2BK5 acetylation was increased in the protein as a whole following SAHA treatment (Additional file 1: Fig. S2), our results indicate that repression of PRELP gene expression involves deacetylation of H2BK5ac in the promoter region, and SAHA treatment reverses the repression via H2BK5ac in bladder cancer cells. Here, PRELP is linked to urinary bladder cancer.