HSP27-S15 was strongly and moderately phosphorylated in 91.7% of normal bladder tissues (n = 12), compared with 89.6% in low-grade (n = 29) and 52.7% in high-grade BLCA tissues (n = 38) (Fig. 5E), suggesting that the phosphorylation level of HSP27-S15 decreased significantly (Chi-square test, P < 0.001) with the progression of BLCA. Here, HSPB1 is linked to bladder transitional cell carcinoma.