HSP90AA1 and Alzheimer disease: As the interactions between MMPs and extracellular Hsp90 have been previously described in the context of tumour cell invasion and metastasis (Eustace et al. 2004; Garcia-Carbonero et al. 2013), we may speculate that elevated serum levels of Hsp90 could be involved in AD progression via promotion of MMP activation, the latter being known as an important pathophysiological factor in AD (Devillers et al. 2007; Harper et al. 2010).