Expression of SFRP1 mRNA in representative (Nos. 1–5) bladder cancer specimens and normal tumor-adjacent tissues. N, normal tumor-adjacent tissues; T, tumor tissue. In the 5 bladder cancer tissues in which the SFRP1 gene was methylated, SFRP1 mRNA expression was significantly lower than that in corresponding normal tissues. SFRP1, secreted Frizzled-related protein 1. GAPDH, Glyceraldehyde 3-phosphate dehydrogenase.