HDAC1 and cancer: For instance, the downregulation of histone deacetylase 1 (HDAC1) or increased H3S10 phosphorylation, H3K4 tri‐methylation and histone H3 acetylation can all lead to the activation of ABCG2 transcription, finally resulting in enhanced drug efflux capability,34 suggesting that epigenetic alterations may be potential targets for cancer treatments.