It has been reported that human urothelial cells (UROtsa) that are malignantly transformed through chronic arsenite exposure (UROtsa As) behave as a basal muscle-invasive bladder cancer with high expression of basal markers (KRT1, KRT5, KRT6, and EGFR) and low expression of luminal markers (GATA3 and FOXA1) [11,23,24]. This evidence concerns the gene KRT5 and urinary bladder cancer.