@misc{oai:repo.qst.go.jp:00070907,
 author = {澤井, 知子 and 尚, 奕 and 立花, 章 and 島田, 義也 and 柿沼, 志津子 and その他 and 澤井 知子 and 尚 奕 and 島田 義也 and 柿沼 志津子},
 month = {Sep},
 note = {Cancer requires multiple mutations. Clonal expansion is essential to create an initiated cell large enough for the progeny cells to acquire the next mutation. We previously reported that ENU at the dose of 50 ppm increased mutant frequency in thymus, some of which oligoclonally expanded as early as 4 weeks post-treatment. But, it did not induce thymiclymphoma, suggesting that clonal expansion of mutants is prerequisite, but not sufficient for lymphoma development, and that clonally expanded cells happens to spontaneously regress by unknown mechanism. We here extended our observation to lung tissue, which has much longer tumor latency. Four weeks old female B6C3F1 gpt delta transgenic mice were treated with ENU at the doses of 0.8 to 50 ppm for 4 weeks, and sacrificed at 8th and 34th weeks after the end of ENU treatment. Mitotically dormant lung epithelial cells accumulated mutants just after ENU treatment, but failed to clonally expand at 8 weeks post-treatment. This may be due to a slow tissue turnover rate of lung, i.e., 71-460 days. The results at 34th weeks post-treatment, when the first lung tumors could be detected macroscopically, and lung tumor incidence will be shown., 第71回日本癌学会学術総会},
 title = {発がんにおけるクローン拡大は必須か?臓器による違い},
 year = {2012}
}