TAP1 and neoplasm: It has also been reported that histone deacetylase inhibitor (HDACi)-treated tumor cells, including trichostatin A (TSA) and valproic acid, are capable of presenting antigens via the MHC class II pathway and also of enhancing the expression of molecules (TAP1, TAP2, LMP2, LMP7, Tapasin and MHC class I) involved in antigen processing and presentation via the MHC class I in melanoma cells.