Abnormal expression and structural modification of the insulin-like growth-factor-II gene in human colorectal tumors.
The insulin-like growth factor II (IGF-II) is a small protein implicated in fetal growth and development. It may play a role in the neoplastic process. The IGF-II gene is located on the short arm of chromosome II near insulin and c-Ha-ras I genes. Three distinct promoters control the transcription of this gene, leading to different IGF-II mRNA species. We have analyzed 21 human colorectal tumors and found overexpression of IGF-II in 6 of them (30%). When compared with expression in normal adjacent tissues, IGF-II mRNA increase in these tumors was either moderate (2- to 15-fold) or very marked (200- to 800-fold). In situ hybridization experiments confirmed that high IGF-II mRNA amounts were localized in cancer cells of the tumors overexpressing the IGF-II gene. In addition, DNA analysis revealed a structural modification of one IGF-II locus in one tumor characterized by very high IGF-II mRNA.
Lambert
S
S
Laboratory of Molecular Oncology, University of Liège, Belgium.
Vivario
J
J
Boniver
J
J
Gol-Winkler
R
R
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D000368:Aged; D001345:Autoradiography; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D007335:Insulin-Like Growth Factor II / Q000235:genetics* / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015336:Molecular Probe Techniques; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000378:metabolism; D015183:Restriction Mapping; D013002:Somatomedins / Q000235:genetics*
D012333:RNA, Messenger; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II