c-myc gene amplification during hepatocarcinogenesis by a choline-devoid diet.
Liver tumors arise in rats fed a choline-devoid diet without added carcinogens. We found amplification of the c-myc gene in 13/13 of these tumors. The amplification ranged from 2- to 70-fold and was accompanied by an increase in c-myc gene expression. Amplification of c-myc was larger in tumors of rats fed a choline-devoid diet followed by a choline-supplemented diet than in tumors from animals fed a choline-devoid diet exclusively. In the former animals, low levels of c-myc gene amplification were also detected in nontumorous regions of tumor-bearing livers. The choline-devoid diet provides an in vivo experimental model for the induction of gene amplification in the rat liver. In this setting, amplification of the c-myc gene may be an early and critical event in carcinogenesis.
Chandar
N
N
Department of Pathology, University of Pittsburgh, PA 15261.
Lombardi
B
B
Locker
J
J
D000818:Animals; D015139:Blotting, Southern; D002455:Cell Division; D002796:Choline Deficiency / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D005784:Gene Amplification; D005786:Gene Expression Regulation; D008099:Liver / Q000502:physiology; D008113:Liver Neoplasms / Q000235:genetics*; D008114:Liver Neoplasms, Experimental / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics
D004273:DNA, Neoplasm; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D012334:RNA, Neoplasm