To understand the GDF15 expression in human bladder cells, the levels of GDF15, alpha-smooth muscle actin (α-SMA), and UPK2 were compared in human normal primary bladder epithelial cells (HBdEC) and stromal cells, i.e. bladder smooth muscle cells (HBdSMC) and bladder stromal fibroblasts (HBdSF), and four lines of cultured bladder carcinoma cells (RT-4, HT1376, T24, and TSGH-8301). The gene discussed is GDF15; the disease is urinary bladder carcinoma.