Abstract: ObjectiveTo investigate the expressions of hexokinase type Ⅱ (HK-Ⅱ), thymidylate synthase (TS) protein and Ki-67 nuclear antigen (Ki-67), and to reveal their clinical significance in young patients with colon cancer. MethodsThe protein expressions of HK-Ⅱ, TS and Ki-67 in 78 patients (≤ 40 years ) with colon cancer and 75 patients (＞ 40 years ), were detected by immunohistochemical technique with retrospective comparison. ResultsThe positive expression rates of HK-Ⅱ and TS were 82.1% (64/78) and 65.3% (49/75), 69.2% (54/78) and 52.0% (39/75), respectively, in young group and older group. Moreover, the Ki-67 proliferation indexes of both groups were (59.1±3.0)% and (48.5±3.2)%, respectively. Compared the young group with the older group, there were significant differences in the three positive expressions (both, P<0.01). Moreover, compared these positive expressions of HK-Ⅱ, TS and Ki-67 with those negative expressions in the young colon cancer patients, there were significant differences in cancer's differentiation and stage (both, P<0.01). The positive expression of HK-Ⅱ was consistent with the positive expressions of TS and Ki-67, respectively, in young patients with colon cancer. Conclusion The positive protein expressions of HK-Ⅱ, TS and Ki-67 may be malignant biomarkers.