Abstract
Levels of carcinoembryonic antigen (CEA) and glucose phosphate isomerase (GPI) have been compared in the circulating blood of hamsters bearing intra-muscular grafts of GW-39 human colonic tumour. CEA in the sera of GW-39 tumour-bearing hamsters ranged from 2-6 to 8-4 ng/ml (mean = 4-5 +/- 1-7 ng/ml). GPI in the sera of normal hamsters ranged from 332 to 749 iu/1 (mean = 602 +/- 110 iu/1) while those with 14-week-old intra-muscular grafts of a hamster amelanotic melanoma, (A.Mel.3), or GW-39 human colonic carcinoma had a range of 664 to 1267 iu/1 (mean = 1024 +/- 220 iu/1) and 1430 to 4719 iu/1 (mean = 2065 +/- 601 iu/1) respectively. Thus, the ratio of enzyme activity in GW-39, A.Mel.3, and normal hamsters was 3-4:1-7:1, indicating a significant elevation (P less than 0-01) in animals bearing a human colon carcinoma or a hamster melanoma, with particularly high values obtained in hamsters with GW-39. Sequential determinations of CEA and GPI in a group of hamsters transplanted intra-muscularly with GW-39 tumours revealed that both markers increased proportionately with duration of tumour growth, suggesting that both serum CEA and GPI may be used as measures of tumour growth. The concentration of GPI in GW-39 human colonic carcinoma xenografts was also significantly higher than that measured in normal human colon, primary human colonic cancer, or normal hamster tissues. These results support the view that GPI, in addition to CEA, is a quantitatively increased marker in this tumour model, and is liberated into the circulation in proportion to the increase in tumour mass.
Highlights
Summary.-Levels of carcinoembryonic antigen (CEA) and glucose phosphate isomerase (GPI) have been compared in the circulating blood of hamsters bearing intra-muscular grafts of GW-39 human colonic tumour
Sequential determinations of CEA and GPI in a group of hamsters transplanted intra-muscularly with GW-39 tumours revealed that both markers increased proportionately with duration of tumour growth, suggesting that both serum CEA and GPI may be used as measures of tumour growth
The concentration of GPI in GW-39 human colonic carcinoma xenografts was significantly higher than that measured in normal human colon, primary human colonic cancer, or normal hamster tissues
Summary
Tumours.-GW-39 tumours were propagated in the hind limb musculature of unconditioned adult hamsters (SpragueDawley, Madison, Wisc.) of both sexes, weighing 60 to 80g. Ten hamsters bearing Fortner's hamster amelanotic melanoma, A.Mel. (Fortner, Mahy and Schrodt, 1961), at the same growth site, as well as 25 untreated hamsters, served as controls Another group of 5 hamsters bearing intra-muscular (i.m.) grafts of GW-39 was sequentially bled by cardiac puncture up to 16 weeks after transplantation. The same serum sample was used for CEA and GPI tests. Measurement of CEA and GPI levels.CEA in the serum (0-5 ml/specimen) was measured by an indirect radioimmunoassay using Hansen's Z-gel procedure (Hansen, Lance and Krupey, 1971), with standard reagents supplied by Hoffmann-La Roche, Inc., Nutley, N.J. Appropriate standard curves were made with normal hamster sera and the samples were diluted in 0.9% NaCl before extraction with equal volumes of 1 2M percholoric acid. The concentration of GPI in tissue extracts was calculated as iu/g protein
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
