The detection and assay of urinary fibronectin fragment (uFN) was performed in a rabbit tongue cancer (VX2 graft) model using multiple anti-rabbit FN domain monoclonal antibodies and one-step sandwich EIA. Tumor volume, the presence of metastasis, and the amount of uFN were studied in four experimental groups: a normal group, a group 1 week after receiving a cancer graft, a group 2 weeks after receiving a cancer graft, and a group 3 weeks after receiving a cancer graft.
The results were as follows:
1. In VX2 tongue cancer rabbits, uFN was present as a small fragment (about 40 to 55 kDa), which corresponded to the fragmented (low molecular weight) FN domain II (gelatin affinity domain).
2. When the cut-off value for uFN concentration was set at 200, μg/mg·Cr, the positive rates were 0% in normal rabbits and 96% in cancer-bearing rabbits. There was a positive correlation between the concentration of uFN and tumor volume, with a correlation coefficient of 0.95.
3. The Metastasis group was compared with the non-metastasis group.
There was a significant difference in mean tumor volume between the two groups (1092.7±299.94 mm³ and 290.5±59.33 mm³ respectively)(p<0.05).
A significant difference was also observed in uFN concentration, being 981.6±331.53μg/mg·Cr and 458.5±173.31μg/mg·Cr, respectively (p<0.05).
These results suggest that uFN may become an excellent tumor marker.