Variations in sensitivity to ionizing radiation in relation to p53 mutation point.

Mutation of p53 is the most common genetic alteration observed in human tumours and is reported to lead to variations in cell radiosensitivity. However, the relationship between the mutation point and the degree of radiosensitivity is unclear. Saos-2 cells with different mutations of p53 were prepared and examined for radiosensitivity. Cells with p53 mutations at codons 175, 244, 245, 273 and 282 were radioresistant, whereas those with mutations at codons 123, 195, 238 and 242 were radiosensitive. Mutations at codons 130, 143, 157, 168, 277, 280 and 286 resulted in medium radiosensitivity. Thus the sensitivity of Saos-2 cells to ionizing radiation varies with the mutation point of the p53 gene.