HMMR and chronic cystitis: In addition, RHAMM as a regulator of CD44–ERK-1/2 fibroblast signalling, is required for mucosal regeneration and to improve urothelial lining defects in cystitis rats (Iavazzo et al., 2007; Ahmad et al., 2008; Cervigni et al., 2008; Lee et al., 2017).