Significance of transforming growth factor beta 1 as a new tumor marker for colorectal cancer

Transforming growth factor beta 1 (TGF- beta 1) is thought to be involved in cancer growth and progression. TGF- beta 1 changes to its active form after being secreted in its latent form. Our aim was to clarify the significance of plasma concentrations of active and total TGF- beta 1 of patients with colorectal cancer. Plasma concentrations of active and total TGF- beta 1 in 45 patients with colorectal cancer and 23 healthy volunteers were measured using ELISA and the activation rate (ratio of active to total TGF- beta 1) was determined. Plasma concentrations of active TGF- beta 1 (21.9 plus or minus 12.8 pg/ml) were significantly higher in patients with colorectal cancer than in healthy volunteers (9.9 plus or minus 5.9 pg/ml; p < 0.001, Welch's t-test). Concentration of total TGF- beta 1 was also significantly higher for patients with colorectal cancer (18.0 plus or minus 13.0 ng/ml vs. 11.1 plus or minus 6.4 ng/ml; p < 0.01, Welch's t-test). However, there was no significant difference in the TGF- beta 1 activation rate between the 2 groups. There was a correlation between Dukes' stage and plasma concentration of active or total TGF- beta 1 (p < 0.01, Spearman's rank correlation test) and on day 7 the active TGF- beta 1 levels for patients recovering from curative resection were similar to those of the control group of healthy volunteers. These results suggest that active TGF- beta 1 might be used as a tumor marker for colorectal cancer.