HSP90AA1 and neoplasm: In addition, Haggerty et al. investigated that twelve different HSP90 inhibitors increase the expression of melanocyte differentiation antigens, Melan-A/MART-1, gp100, and TRP1, as well as MHC Class I. This finding suggests that HSP90 inhibition facilitates recognition of tumor cells by T cells by increasing the expression of intracellular antigen pool available for processing and presentation by MHC Class I, along with the increased expression of MHC Class I itself [141].