Leopold G. Koss, MD

pplication of the techniques of flow cytometry and image analysis to quantitation of DNA and estimation of events in the cell cycle in human tumors has achieved considerable popularity as a laboratory procedure but so far has failed to be of practical clinical value. As brilliantly summarized by Dr. Ross, retrospective studies have repeatedly shown abnormal DNA values to be of prognostic significance in several organ systems, among them, tumors of the urothelium [1] and prostate [2] and, perhaps to a lesser extent, mammary carcinomas [3].