<prompt> Malignant cells in urine cytology are most commonly seen inRenal cell carcinomaProstate carcinomaUrothelial carcinomaBladder carcinoma  <response>: Ans. c Urothelial carcinoma. Ref. Harrisons Medicine 17th ed. 555 Urothelial malignancy classically shows polychronotropism multicentricity. In urothelial or transitional carcinoma of renal pelvis or ureter, the examination of urine for malignant cells is positive and even may indicate whether tumor is well or poorly differentiated. There is evidence that those with poorly differentited tumors do better if they have a short course of radiotherapy before surgery. It is hence useful to obtain cells from tumorurine by sampling a brush or catheter passes up the ureter under radiological control. 