Association of overexpression of p53 oncoprotein with the state of cell proliferation in oral carcinoma.
p53 is a nuclear phosphoprotein recognised as important in the regulation of normal cell growth and proliferation, the wild-type protein suppressing cell division. Expression of presumptive mutant protein, detected by immunohistochemistry, is used increasingly as a diagnostic and prognostic marker in human neoplasms. A question arises as to whether or not p53 (over)expression in a lesion is any more or less informative than other markers of cell proliferation. Twenty well-differentiated oral squamous cell carcinomas which had earlier been examined for immunoreactivity against a panel of p53 antibodies were examined for the status of cell proliferation--both in islands of invading neoplastic cells and in the non-malignant epithelial margins. The status of epithelial cell proliferation was found to be significantly higher in p53-positive tumours when enumerated by Ki-67 antibody, both within the tumour as well as its margins. This may confer a growth advantage to these neoplasms and reflect a status of inactivated p53 protein, although the actual cause of the rapid proliferation may lie in activation/inactivation of other genes. The PCNA labelling indices, on the other hand, were closely similar in both p53-positive and -negative groups, suggesting that stabilisation of p53 protein does not influence the proliferative advantage in these carcinomas via a deregulation step of PCNA-related gene products.
Warnakulasuriya
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KA
Royal College of Surgeons Department of Dental Sciences/Department of Oral Medicine and Pathology, King's College School of Medicine and Dentistry, London, England.
Johnson
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NW
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000473:pathology; D002455:Cell Division; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G; D019394:Ki-67 Antigen; D009062:Mouth Neoplasms / Q000737:chemistry* / Q000473:pathology; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011379:Prognosis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D007074:Immunoglobulin G; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53