HSP90AB1 and keratoconus: Data from transcriptomic research on EBS cells confirmed the involvement of the UPR in severe EBS, as the ubiquitin-conjugating enzyme E2K (UBE2K) and a variant of the stress-induced chaperone HSP90, HSP90AB1, were reliably identified to be more abundant in EBS (KEB7) than in healthy control (NEB1) KC lines.