@misc{oai:repo.qst.go.jp:00071277,
 author = {Imaoka, Tatsuhiko and Nishimura, Mayumi and Ishikawa, Kenichi and Yamashita, Satoshi and Ushijima, Toshikazu and Imai, Takashi and Shimada, Yoshiya and 今岡 達彦 and 西村 まゆみ and 石川 顕一 and 今井 高志 and 島田 義也},
 month = {Oct},
 note = {Background: Mechanisms underlying combined effects of more than one carcinogens have not been well illustrated in experimental carcinogenesis models. 
Materials and Methods: Female Sprague-Dawley rats at 7 weeks of age were treated with ionizing radiation (IR; 0.2-2 Gy) and/or with 1-methyl-1-nitrosourea (MNU, 20 or 40 mg/kg) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP, 40 mg/kg/day for 10 days) and observed until 50 weeks of age. 
Results: Carcinoma incidence increased linearly as a function of IR dose in the absence of chemicals. Mathematical analysis suggested an additive increase when IR and chemicals were combined. Hras mutations were characteristic of carcinomas induced by chemicals and were overrepresented in carcinomas induced by the combination of IR and MNU, suggesting their interaction at the initiation level. Comprehensive screening using microarrays failed to identify differences in gene expression among carcinomas induced by different treatments. 
Conclusion: A complex interaction may underlie the combined effect of IR and carcinogenic chemicals in the experimental model., 第72回日本癌学会学術総会},
 title = {Complex interactions between ionizing radiation and carcinogenic chemicals on rat mammary carcinogenesis},
 year = {2013}
}