HDAC4 and prostate cancer: Similarly to HMEC-1, in colon cancer cells downregulation of HDAC1 and HDAC3 in response to EGCG was also found [20,21], but in lung cancer cells downregulation of HDAC4, 5 and 6 was observed upon the co-treatment with EGCG and synthetic retinoid Am80 [40], whereas in the prostate cancer cells increased level of histone acetylation was correlated with HATs inhibition [41], contrary to the results obtained in the presented study where upregulation of CREBP and p300 was found.