1998 Fiscal Year Final Research Report Summary
Immunohistochemical and Clinical Research for Prognostic Factors in Radiation Therapy for Lung Cancer
| Project/Area Number |
08457237
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | Gunma University School of Medicine |
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Principal Investigator |
NIIBE Hideo Gunma University School.of Medicine, Professor, 医学部, 教授 (90008293)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Yoshihiro Gunma University School of Medicine, Assistant Professor, 医学部, 講師 (50170543)
HASEGAWA Masatoshi Gunma University School of Medicine, Assistant Professor, 医学部, 講師 (50251111)
HAYAKAWA Kazushige Gunma University School of Medicine, Assist.Prof., 医学部, 講師 (70114189)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Lung cancer / Non-small cell lung cancer / Apoptosis / Radiation therapy / Radiosensitivity / Oncogene / Immunohistochemistry / Paclitaxel |
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| Research Abstract |
1) Relationships between p53 protein expression and radiation-induced apoptosis in five human tumors transplanted to nude mice were studied immunohistochemically. The results suggested that radiation-induced apoptosis in a radiosensitive human tumor is related to wild-type p53 protein expression. In contrast, the p53 expression of the human tumors that did not appear radiation-induced apoptosis should be mutant type.
2) The prognostic significance of nuclear p53 protein expression in survival and local control was investigated immunohistochemically in 36 patients with inoperable or unresectable non-small cell lung cancer who were treated with radiation therapy (RT). Response to RT was found in all p53 negative cases versus 72% in p53 positive cases (P< 0.05). The 2-year survival rate for p53 negative cases was superior to that for p53 positive cases, although this difference was not statistically significant. The results suggested that p53 protein expression may be of predictive value on response to RT in non-small cell lung cancer.
3) From the clinical analysis, TI tumors may require 70-75 Gy for long-term control, and T2 tumors less than 5 cm may require 75 Gy for 50-70% control. Among progression-free patients with non-small cell lung cancer at the end of 2 years, 97% of patients with squamous cell carcinoma survived without evidence of disease over 5 years. In patients with squamous cell carcinoma treated with RT, therefore, disease-free 2-year survival should be substituted for 5-year survival.
4) Paclitaxel (Taxol) had the same cytotoxic effect in two cell lines with different radio- sensitivities in vitro due to the induction of apoptosis. A Supra-additive effect to radiation was observed with 12h pretreatment in both cell lines. Paclitaxel may be effective for tumors with a component of different radiosensitivity in combination with irradiation.
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