(Summarized in Table 2) Numerous studies, including those by Becker et al. and Crowe et al., have demonstrated the presence of tumor cell surface-bound Hsp90, particularly in malignant tumor types, while Milani et al. reported a 10- to 15-fold increase in soluble Hsp90 in the plasma of mice grafted with primary human acute lymphoblastic leukemia compared to healthy controls [38,105,106]. Here, HSP90AA1 is linked to neoplasm.