[Prognostic significance of Ki67 and p53 protein in small bowel stromal tumor immunopositive for CD117].

OBJECTIVE

To investigate the correlative factors of the prognosis by observing the immunohistochemical features of small bowel stromal tumors(SBST).

METHODS

Thirty-three cases of stromal tumors with expressed CD117 were examined by the light microscope. The expressions of Ki67 and p53 protein with EnVision + staining were detected in the tumors and compared with the morphology.

RESULTS

The group included 20 males and 13 females whose ages ranged from 21 to 71 years (median: 46 years); the tumors were situated in duodenum (5 cases), jejunum (22 cases) and ileum (6 cases). Grossly, tumors size was from 1.5 to 20 cm. In eleven cases tumors showed foci of tumor cell necroses. In all these cases, mitotic counts ranged from 0 to 62 mitotic figures per 50 HPF (high-power fields), six of 33 tumors had no mitotic figures per 50 HPF, 5 cases had 1-2 mitotic figures and 22 cases had > or = 3 mitotic figures. Histologically, 4 cases classified as benign, 4 cases as borderline and 25 cases as malignant. Follow-up of 7 cases with benign and borderline tumors were alive without tumor. In the malignant group of 23 cases, 6 patients died of disease, 10 patients were alive with evidence of metastatic disease, and 7 patients were alive without tumor. Immunohistochemically, 31 of 33 stromal tumors were positive for Ki67, 16 cases of malignant tumors showed significant staining (> 5% cells). 31 of 33 tumors were positive for p53 protein, and all the 25 (100%) malignant tumors showed staining. In 12 of the 25 cases, the staining was strong and diffuse(> 50% cells). When the Ki67 and p53 proteins were negative or showed focal expressions (Ki67 < 1% and p53 < 10%), the patients presented a good prognosis. And when there were strong expressions (Ki67 > 5% and p53 > 50%), the patients portended a poor prognosis.

CONCLUSION

Immunohistochemical analysis of Ki67 and p53 protein was a better method in the prognosis. When Ki67 showed strong position, it was a bad sign. When p53 protein showed strong position, it might be the potential malignant parameter. When Ki67 and p53 proteins were all strong expressions, these patients portended a poor prognosis. In addition to the invasion and metastasis, tumor size, mitotic counts and tumor cell necrosis were also helpful parameters for diagnosis of malignancy.