In the 19-carbon-substitutedseries, the compounds are markedly less toxic to normal human cellsthan GA itself, while retaining Hsp90 inhibitory activity, suggestingpossible applications in other arenas such as neurodegenerative disease.Also, following promising initial results with BQAs in NRF2-activatedcancers, C-19 quinone-modified geldanamycin derivatives should beinvestigated for such applications to determine their efficacy coupledwith lower off-target toxicity. This evidence concerns the gene HSP90AA1 and neurodegenerative disease.