Absence of p53 alterations in nasopharyngeal carcinoma Spanish patients with Epstein-Barr virus infection.

The objective of this study was to analyse the relationships between the Epstein-Barr virus (EBV) infection and the molecular abnormalities of the p53 oncoprotein in the nasopharyngeal carcinoma (NPC). Fifty-five NPC paraffin samples from a group of Spanish patients with EBV demonstrated presence by nested-PCR and non-isotopic in situ hybridisation, were analysed for p53 expression using immunohistochemistry. The positive samples by immunohistochemistry were studied for p53 gene alterations in the exon 5 by single strand conformation polymorphism (SSCP). Among the 55 specimens, 14 (25.5%) showed expression of p53 protein. All these positive samples corresponded to the late stage of the tumour. Of the 14 samples, p53 gene alterations were found only in three cases using SSCP. These results indicate that the p53 mutations are an infrequent event in NPC in Spanish patients needing exogenous factors as the EBV infection for the development of this malignancy.