@misc{oai:repo.qst.go.jp:00069516,
 author = {Nakata, Akifumi and Yoshida, Mitsuaki and Akiyma, Miho and Kakinuma, Shizuko and Sado, Toshihiko and Nishimura, Mayumi and Shimada, Yoshiya and 中田 章史 and 吉田 光明 and 穐山 美穂 and 柿沼 志津子 and 西村 まゆみ and 島田 義也},
 month = {Jul},
 note = {Mouse thymic lymphomas (TLs) are one of the classical models for spontaneously developed, and radiation- or chemical carcinogen-induced malignancy and are a model for mechanistic study of human acute lymphoblastic leukemia. In the early studies of chromosome abnormality, trisomy of chromosome 15 was identified frequently in TLs and seemed to be the specific change associated with the development of this malignancy. Recent studies have demonstrated that radiation-induced TLs show frequent loss of heterozygosity (LOH) on chromosomes 4 (p15/p16), 11 (Ikaros), 12 (Bcl11b), 19 (Pten) and X. Since cytogenetic analysis of murine thymic lymphoma has not been studied for these two decades, we think it worthy to re-evaluate cytogenetics of TL using both classical cytogenetic method and molecular cytogenetics using FISH with chromosome-specific probes focusing on the region with frequent LOH or loss and gain of 
genetic materials. In this study, C57BL/6 (B6), C3H and F1 (B6 x C3H) mice were used. TLs were induced by whole-body irradiation with 4- to 5-week-old mice exposing to X-irradiation (1.2 or 1.6 Gy/exposure) once a week for four consecutive weeks using a PANTAK X-ray generator at 0.7 Gy/min (200 kVp, 20 mA, with filters of 0.5 mm Cu and 0.5 mm Al). The mice were observed for 3 months or until moribund and were sacrificed under ether anesthesia to remove the enlarged thymus. Chromosomally abnormal cells were present in 25 TLs examined (25/26, 96%). The most frequent abnormality was trisomy or partial trisomy of chromosome 15 (16/26, 62%), being consistent with previous studies. Structural abnormalities of chromosome 11 with interstitial deletion of the proximal region and chromosome 12 translocations with deletion of the distal region were newly identified in 7 (27%) and 12 (46%) cases, respectively. Monosomy of chromosome X was also found in 4 cases (15%). No apparent aberrations were detected in chromosomes 4 and 19. Only three cases had a reciprocal translocation, t(X;17), t(3;X) and t(1;12). These results indicate that a distinct mechanism contributes to LOH of each tumor suppressor gene in different chromosomal locations., 13th international Congress of Radiation Research},
 title = {Distinct structural abnormalities of chromosomes 11 and 12 associated with loss of heterozygosity in X-ray-induced mouse thymic lymphomas},
 year = {2007}
}