Tumor IGF-II content in a patient with a colon adenocarcinoma correlates with abnormal expression of the gene.
We have recently reported abnormal insulin-like growth factor-II (IGF-II) mRNA levels in a number of human colorectal adenocarcinomas. Using an IGF-II radioimmunoassay, we have now detected high levels of both 10-kDa and 7.5-kDa IGF-II species (2,370 ng/g) in a right colon tumor showing a 800-fold IGF-II gene over-expression in comparison to the normal adjacent tissue. The higher-molecular-mass form represents 74% of the total immunoreactive IGF-II detected in the tumor. This form appears to be less reactive in the radioreceptor assay than in the radioimmunoassay. The insulin-like growth factor-I (IGF-I) concentration in the tumor is low. The patient's pre-operative serum IGF-II level is not increased and the proportion of the 10-kDa species is normal. In addition, the IGF-II/IGF-I ratio is 3 in the serum and 308 in the tumor. Our results show that the very high IGF-II level produced by the tumor does not influence the seric concentration of the growth factor.
Lambert
S
S
Laboratory of Molecular Oncology, University of Liège, Sart Tilman, Belgium.
Collette
J
J
Gillis
J
J
Franchimont
P
P
Desaive
C
C
Gol-Winkler
R
R
D000230:Adenocarcinoma / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000601:surgery; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000097:blood; D002352:Carrier Proteins / Q000032:analysis; D003110:Colonic Neoplasms / Q000097:blood / Q000737:chemistry* / Q000235:genetics / Q000601:surgery; D005500:Follow-Up Studies; D015870:Gene Expression; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007335:Insulin-Like Growth Factor II / Q000032:analysis* / Q000235:genetics; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D008875:Middle Aged; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains
D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II