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). This evidence concerns the gene ACTA1 and urinary bladder carcinoma.