Interestingly, although both isoforms engage with the chaperone heat shock protein 90 (Hsp90), increase invasion and motility through activation of Rho-GTPase Ras-related C3 botulinum toxin substrate 1 (Rac-1) and Cell division control protein 42 (Cdc-42) in vitro, only GSDMB-2 relies on Hsp90 for its stability, and promotes metastasis and tumor progression in xenograft mouse models [247]. The gene discussed is RAC1; the disease is neoplasm.