@article{oai:repo.qst.go.jp:00044129,
 author = {Imaoka, Tatsuhiko and Okamoto, Mieko and Nishimura, Mayumi and Nishimura, Yukiko and Ootawara, Masami and Kakinuma, Shizuko and Tokairin, Yutaka and Shimada, Yoshiya and 今岡 達彦 and 西村 まゆみ and 西村 由希子 and 太田原 雅美 and 柿沼 志津子 and 東海林 裕 and 島田 義也},
 journal = {Radiation Research},
 month = {},
 note = {The ApcMin/+ (Min) mouse is a genetically predisposed model of both intestinal and mammary tumorigenesis. We investigated age-related changes in the susceptibility to radiation-induced mammary tumorigenesis using this model. Female Min and wild-type mice having the C57BL/6J background were irradiated with 2 Gy of X-rays at 2, 5, 7 and 10 weeks and sacrificed at 18 weeks of age. Min mice irradiated at 7-10 weeks of age developed mammary tumors with squamous metaplasia, whereas their wild-type littermates did not. Interestingly, irradiation of Min mice at 2-5 weeks did not induce mammary tumors but rather cystic nodules with metaplasia. The mammary tumors exhibited increased nuclear beta-catenin protein and loss of the wild-type Apc allele. Our results show that susceptibility to radiation-induced mammary tumorigenesis increases with age in Min mice, suggesting that the tumorigenic effect of ionizing radiation targets the lobular-alveolar progenitor cells, which increase in number with age and are controlled by beta-catenin signaling.},
 pages = {165--173},
 title = {Mammary tumorigenesis in ApcMin/+ mice is enhanced by X irradiation with a characteristic age dependence},
 volume = {165},
 year = {2006}
}