[Overexpression of p53 protein in gliomas]

We analyzed the levels of p53 protein in 10 frozen astrocytoma specimens by using an ELISA kit. p53 protein was detected in seven of ten specimens, and ranged from 0.4 to 18.0ng/ml. To confirm that the p53 protein detected in this study actually represented mutations occurring within the p53 gene, we determined the nucleotide sequence in five of six positive cases, and in three of four negative cases. We amplified exons 5 to 9 by the PCR and sequence analysis was carried out by the dideoxy chain termination method. Point mutations resulting in amino acid substitutions were found in four of five positive cases but not in negative cases. Then we analyzed the presence of p53 protein in sera of 42 patients with malignant astrocytoma and 34 healthy donors, by the same method. p53 protein was detected in sera of 7 of 42 patients and 6 of 34 healthy donors, suggesting that this result may be due to non-specific responses. In conclusion, using the ELISA kit, overexpression of p53 protein, resulting from p53 mutations, in frozen astrocytoma specimens can be detected. This may be a good screening method for the detection of overexpression of p53 protein.