Klin Onkol 2004; 17(3): 91-95.
Abstract:
Background: The tumour suppressor protein p53 is a latent, short-lived transcription factor. Its stabilisation and functional activation occurs in response to DNA damage via a complex mechanism that includes protein phosphorylation at Nand C-terminal amino acid residues and nuclear retention of the oligomerised protein. However, very little is known about phosphorylation and localisation of mutant p53.
Patients and methods: We analysed expression of p53 and its phosphorylated form in breast carcinoma (23), carcinoma of endometrium (3), ovary (6), uterine cervix (2) and vulva (1) using monoclonal and polyclonal p53 specific antibodies recognising target non-phosphorylated epitope or target phosphorylated epitope with phosphorylated serine 15 and serine 392. Functional status of p53 was evaluated using FASAY.
Results: FASAY detected p53 mutation in 16 analysed cases. 11 of 16 tumours with p53 mutation expressed high level of total p53. In 10 of these cases there was also high level of serine 392 phosphorylation. In all cases with high p53 level, the protein was also phosphorylated at serine
15. In 13 of 19 tumours with wild-type p53 and low or intermediate level of p53, the immunostaining for serine 15 phosphorylation was negative.
Conclusion: Analysis of expression of p53 and phosphorylated form of p53 at serine 15 and serine 392 revealed high level of both phosphorylated forms as a typical phenomena for p53 mutants with high level of expression.
