|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥1,500,000 (Direct Cost : ¥1,500,000)
In this study, I investigated the p53 expression expression in 52 patients with esophageal cancer and its relation to clinicopathologic factors and radiation response and prognosis. Of37 cases biopsied before radiotherapy, 25 cases (68%) showed positive nuclear immunoreacitivity for p53 protein. No significant association was detected between p53 expression and clinicopathologic parameters. No significant association was observed between p53 expression and local response to radiotherapy and prognosis. Of 15 cases biopsied after the start of radiotherapy (total dose of2-12Gy), 11 cases (73%) showed positive p53 expression. The cumulative survival rate of patients with p53 negative expression was significantly lower than that of patients with positive expression. The overexpression of the p53 gene product during radiotherapy may become an important prognostic factor.
In animal experiment, relationships between radiation-induced apoptosis and oncogenes or suppressor genes (p53, MDM2, c=myc, p21^<ras> and bcl-2) were immunohistochemically studied in 7 human tumors transplanted to nude mice. The most radiosensitive ependymoblastoma was negative for p53 and c-myc. Following irradiation, the ependymoblastoma became p53 positive and showed the highest incidence of apoptosis. Squamous cell carcinoma showed strong positivity for p53 both before irradiation and after 10 Gy.