The role of the extracellular HSP90 (eHSP90) has been extensively studied in the cancer microenvironment, where it regulates metalloproteinase activity (Baker-Williams et al., 2019) and fibronectin matrix assembly (Chakraborty et al., 2020) and promotes cancer cell survival, migration, and invasion (Calderwood, 2018). The gene discussed is HSP90AA1; the disease is cancer.