Reviewing studies of alterations of the TP53 tumor suppressor gene in human breast carcinomas gives cautious optimism about TP53 alterations as a prognostic marker in this disease. For the time being, breast carcinomas should be screened for TP53 alterations at both the protein and gene levels. Improved mutational screening techniques are needed for this purpose. We consider constant denaturant gel electrophoresis, a modification of denaturing gradient gel electrophoresis, to represent such an improvement. With the recent development of the BioRad D GENE system, constant denaturant gel electrophoresis screening for TP53 mutations can easily be performed on large series of breast carcinomas.