Susceptibility to colon carcinogenesis in C3H<-->C57BL/6 chimeric mice reflects both tissue microenvironment and genotype.
Considerable rodent strain differences have been documented with regard to susceptibility to colon carcinogens. To clarify mechanisms, chimeras of susceptible strain C3H and relatively resistant strain C57BL/6N (B6) mice were exposed to a colonotropic carcinogen, 1,2-dimethylhydrazine (DMH) and tumor incidence and multiplicity were assessed. In the chimeras, incidence was as high as the C3H level. Multiplicity of lesions of B6 cells was also increased (P<0.001), but maintenance of the strain difference. When tumor localization was analyzed, tumors of B6 genotype in chimeras demonstrated a greater spread of distribution than in the parental case. The chimeric environment may thus stimulate tumor initiation but cell autonomous suppressive factors may be retained.
Tsukamoto
Tetsuya
T
Division of Oncological Pathology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan. ttsukamt@aichi-cc.jp
Yamamoto
Masami
M
Fukami
Hiroko
H
Yoshikawa
Akemi
A
Sakai
Hiroki
H
Hirata
Akihiro
A
Kusakabe
Moriaki
M
Tatematsu
Masae
M
D000818:Animals; D002678:Chimera; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology*; D004198:Disease Susceptibility; D005838:Genotype; D007150:Immunohistochemistry; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL