The mucin1 protein (MUC1), is a cell-surface associated glycoprotein of the mucin family,2 which contains a hydrophobic membrane-spanning domain of 31 amino acids, a cytoplasmic domain of 69 amino acids, and an extracellular domain consisting of a region of nearly identical repeats of 20 amino acids per repeat.3,4 MUC1 presents in a variety of malignant tumors and is over-expressed in almost all human epithelial, including breast, gastric, colorectal, lung, prostate, ovarian, pancreatic and bladder carcinomas;5 but, low levels or no expression in normal healthy tissues in normal cells. The gene discussed is MUC1; the disease is urinary bladder carcinoma.