Abstract: Objective:To confirm the potential of growth- related gene productβ (GRO β ) as a biomarker for colorectal cancer. Methods:Serum GROβ levels in 123 subjects with colorectal cancer, 88healthy controls, and 125 subjects with other diseases were measured using enzyme-linked immunosorbent assay. Serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19- 9 (CA 19- 9) in all subjects were measured using immunoluminometric assay. Statistical analyses were conducted to determine the associa -tions between serum GRO β levels and clinical parameters for colorectal cancer. The receiver operating characteristic (ROC) curves of GROβ , CEA, and CA 19- 9 were analyzed.Results: The serum GRO β levels were higher in patients with colorectal cancer (median= 96.15pg/mL) than in the healthy controls (median=43.28pg/mL, P<0.01) and in patients with other diseases (median= 57.30pg/mL, P< 0.01). The serum GRO β levels in patients with colorectal cancer were positively correlated with the tumor-node-metastasis staging ( P< 0.01) and depth of infiltration ( P<0.05), but not with the histological grade, tumor embolus, lymph node metastasis, gross pathologic tu-mor type, or gender of the patients. The sensitivity and specificity of the assay for serum GRO β were 56.1% (69/123) and95.31% (203/213), respectively. The diagnostic sensitivity was 22.2% (4/18) for stage I and 66.7% (26/39) for stage II when the data of GRO β were combined with the data of CEA and CA19- 9. The ROC curve constructed with the data of GRO β (0.834) was larger than that construct -ed with the data of CEA ( 0.739) or CA19- 9 (0.676) for discriminating colorectal cancer from the matched controls. Conclusion:These preliminary results indicated that the serum GRO β level could be a useful biomarker for colorectal cancer diagnoses.