Ventana Medical Systems, Inc. CONFIRM p53 790-2912

The wild type p53 molecule has a role in transcription, in cell cycle control, and in many other metabolic functions. It is also a tumor suppressor in that it halts abnormal growth in normal cells; however, a mutation in one of its 393 amino acids can eliminate the surveillance capability of the protein and allow expression of malignant phenotype. Approximately 50% of all human cancers contain a mutation in p53. The wild type molecule has a short half life, is present in low concentrations, and cannot usually be detected by IHC. Many of the mutations in p53 increase its half life and cause intranuclear accumulation of the mutant protein. Thus in many malignancies of the colon, stomach, bladder, breast, lung, and testes and in melanomas and soft tissue sarcomas, p53 protein can be readily detected in the malignant cells by IHC, and immunostaining closely correlates with the presence of amutation. The staining pattern with the CONFIRM p53 (DO-7) is exclusively nuclear, and may be present in a heterogeneous pattern.