Correlation between p53 gene expression and tumor‐cell proliferation in oropharyngeal cancer

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Abstract
The aim of our study was to analyze the correlation between tumor‐cell kinetics measured in vivo and p53 gene expression in a series of 49 oropharyngeal cancers. The duration of the S phase (TS), the labelling index (LI) and the potential doubling time (Tpot) were obtained by flow‐cytometry measurements of a tumor biopsy obtained after i.v. injection of 200 mg bromode‐oxyuridine into patients. An adjacent section of the same samples was studied by immunohistochemistry for the detection of p53 protein. Over‐expression of the p53 protein, as defined by strong p53 immunostaining of tumor nuclei, was found in 23/49 of the samples. Aneuploid tumors showed a higher LI, a shorter Tpot and a higher proportion of p53 gene over‐expression. A significant correlation was seen between p53 over‐expression and short Tpots. Indeed 87.5% of the tumors with a very short Tpot (⩽ 3 days) had p53 over‐expression, as compared with 27% of tumors with a longer Tpot (>3 days). Our data strongly suggest that over‐expression of the p53 gene is associated with rapid tumor‐cell proliferation in this type of cancer.