HSPB2 and bladder transitional cell carcinoma: Given the fact that bladder is a hollow smooth muscle organ lined by a mucous membrane [45], and while it is known that HSPB2 is mainly expressed in skeletal and smooth muscles, where it forms oligomers with HSPB3 [46], to the best of our knowledge the potential role of HSPB2 and HSPB3 in tumorigenesis or progression of BlCa has not been studied yet.