EP300 and breast cancer: In comparison to this, deacetylated mPD‐L1 tends to bind to HIRP1 and promotes clathrin‐mediated endocytosis, thus triggering nuclear translocation under the influence of vimentin and importin‐α.[17b] In addition, mammalian hepatitis B X‐interacting protein (HBXIP) can also initiate acetylation modification of mPD‐L1 through p300 in breast cancer cells.[55] Specifically, HBXIP interacts with p300 and then induces the PD‐L1 acetylation at the K270 site.