PURPOSE:We studied serum ELAM‐1 levels in colon cancer patients.METHODS AND RESULTS:Serum ELAM‐1 levels were significantly higher in 52 patients with colon cancer (mean ± standard deviation, 69.3±28.6 U/ml) compared with 32 healthy volunteers (36.5±11.9 U/ml;P<0.001). The mean serum ELAM‐1 level in patients with metastatic tumors was significantly greater than that of patients with nonmetastatic tumors. Sensitivity and specificity of serum ELAM‐1 elevation in detecting metastasis was 75 and 87.5 percent, respectively. Those of carcinoembryonic antigen and carbohydrate antigen 19‐9 elevations were 71.4 and 62.5 percent and 35.7 and 91.7 percent, respectively. Twenty‐five (89.3 percent) of 28 metastatic tumors showed either serum ELAM‐1 or carcinoembryonic antigen elevation. There were weak but significant correlations found between serum ELAM‐1 and carcinoembryonic antigen or carbohydrate antigen 19‐9 levels. Moreover, serum ELAM‐1 increased before detecting the recurrency by imaging in five of seven recurrent colon cancer patients.CONCLUSION:These findings suggest that serum ELAM‐1 could be a useful tumor marker for colon cancer, especially in synchronous and metaclonous metastasis.