ObjectiveTo study the expression of p27 in hepatocellular carcinoma (HCC) and its clinical significance.MethodsFortyfive specimens of HCC and 30 specimens of adjacent noncancerous lesions obtained from 45 patients who underwent surgery were examined for p27 expression by immunohistochemistry SABC method. The diameter of tumor ranged from 1 cm to 19 cm (d ≤5 cm, 9 samples; 5 cmlt;d≤10 cm, 19 samples; d＞10 cm, 17 samples). These tumors were graded according to the criteria described by EdmondsonSteiner: highdifferentiated HCC group (Grade Ⅰ＋Ⅱ), 26 samples; lowdifferentiated HCC group (Grade Ⅲ＋Ⅳ), 19 samples. According to the clinicopathological features: 19 samples were poorly encapsulated, 15 samples had portal invasion, 11 samples had extrahepatic metastasis, 12 samples had intrahepatic metastasis; all of the above were classified as the invasive and metastatic group, while the others were classified as the noninvasive and nonmetastatic group. ResultsThe average labeling index (LI) of p27 in HCC was significantly higher than that of adjacent noncancerous lesions (45.87±14.21 vs 33.77±12.92, Plt;0.001). The LI of p27 in lowdifferentiated HCC group (stage Ⅲ＋Ⅳ) was significantly lower than that of highdifferentiated group (stage Ⅰ＋Ⅱ), 34.46±12.29 vs 52.80±11.36 (Plt;0.001). The LI of p27 had significant difference between the large ones (d＞10 cm, 37.59±13.12) and the small ones (d≤5 cm, 53.28±15.17 or 5 cmlt;d≤10 cm, 49.50±10.96) (Plt;0.05). The LI of p27 in the invasive and metastatic group was significantly lower than that in the noninvasive and nonmetastatic group (41.42±12.86 vs 51.44±14.10, Plt;0.05).ConclusionThe expression of p27 is more frequently detected in HCC than in adjacent noncancerous lesions. It indicates that p27 might be a compensatory factor during HCC carcinogenesis. The LI of p27 significantly decreases in poor differentiation group, invasive and metastatic group. It indicates that p27 might be related with the differentiation, invasion and metastasis of HCC.