Increased serum angiogenin concentration in colorectal cancer is correlated with cancer progression

We have previously demonstrated that the increased expression of angiogenin (ANG) in pancreatic cancer is related to cancer aggressiveness; however, the relationship between ANG expression and its clinical relevance in colorectal cancer has not been demonstrated. We therefore investigated the correlation between serum ANG (sANG) concentration and colorectal cancer progression or the changes in sANG concentrations before and after cancer resection. To determination sANG concentration by ELISA, sera were obtained from colorectal cancer patients (the cancer group) preoperatively (n = 34) and postoperatively (n = 25), from hernia patients (the nonneoplastic group) preoperatively (n = 9) and postoperatively (n = 4), and from 23 healthy volunteers. The amount of ANG in the colorectal cancer tissues (n = 19) was determined by the same method. Before surgery, the mean sANG concentration in the cancer group (411.8 +/- 106.3 ng/ml) was significantly higher than that in both the nonneoplastic group (344.0 +/- 60.7 ng/ml; P = 0.04) and in the healthy volunteers (321.7 +/- 59.7 ng/ml; P = 0.0001). The degree of elevation of sANG concentration in the cancer group was more significant in the more progressed subgroups as compared with that in the normal group (versus T(is) + T1 + T2 cancer, P = 0.01; versus T3 + T4 cancer, P = 0.002; versus stage 0 + I cancer, P = 0.02; versus >stage III cancer, P = 0.001; versus Dukes' A cancer, P = 0.02; versus Dukes' C cancer, P = 0.006). After cancer resection, the mean sANG concentrations in each subgroup decreased to the same levels as those of the normal group; the degrees of reduction were more significant in the more progressed subgroups. The tissue ANG amount correlated significantly with sANG concentration (P = 0.007). These results suggest that the increased concentration of sANG that is derived from colorectal cancer correlates with cancer progression.