HSP90AA1 and interstitial cystitis: Interestingly, HSP90AA1 showed lower expression both in the bladder tissue of IC/BPS patients, compared with normal controls and in cluster A, compared with cluster B. Meanwhile, the correlation between IRGs and immune characteristics indicated that HSP90AA1 was negatively correlated with the activation of immune cells, activation of immune responses and HLA expressions in IC/BPS patients.