EP300 and osteosarcoma: In addition, p300 can play an antitumour role in epidermal tumours, osteosarcoma, myelodysplastic syndrome (MDS)-associated leukaemia and human papilloma virus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) [8,9,10,11], and tumours with high EP300 mutation rates have enhanced antitumour immunity [12].