Flow cytometry expression of p53 and PCNA in oral/oropharynx carcinomas and their lymph node metastases

The aim of this work was to characterize p53 and PCNA expression in primary tumours and lymph node metastases of oral/oropharynx carcinomas by flow cytometry and to evaluate the possibility of a relationship between these parameters in primary tumours and locoregional metastasis, clinical-histopathological parameters and survival time. A group of 28 patients was retrospectively selected: 13 with metastasis and 15 without metastasis. The following clinical and histopathological parameters were considered: degree of keratinization, Broders' grading of histological differentiation, invasive cell grading, thickness and tumour size. The nuclei of appropriately prepared cells were stained using anti-p53 and anti-PCNA FITC conjugated monoclonal antibodies. Analyses were performed by a Coulter Epics Elite flow cytometer. The following results were obtained: a close relationship between p53 and PCNA in primary tumours but no correlation between them and clinical-histopathological parameters; no correlation between p53 and PCNA expression in primary tumours and in lymph node metastasis; no correlation between p53 and PCNA values in primary tumours and survival. In conclusion, the difference in expression of these biological parameters in primary tumours and in lymph node metastases supports the theory that tumour cells in lymph nodes can display an independent behaviour. Since these biological parameters fail to correlate either with clinical-histopathological parameters or survival, their prognostic role is questionable.