Abstract: Objective: To investigate the expression of apolipoprotein A-Ⅰ(ApoA-Ⅰ) in eight histological types of renal neoplasms and to explore a new biomarker for differential diagnosis.Methods: The immunochemistry was used to detect the expression of ApoA-Ⅰ in 23 cases of renal tumors, including clear cell carcinoma,papillary cell carcinoma, chromophobe cell carcinoma, oncocytoma,multilocular cystic carcinoma, renal pelvis invasive urothelial carcinoma,metanephric adenoma and collecting ducts carcinoma. Five cases of cancer-adjacent normal tissues were obtained from another five renal tumor patients and were chosen as control group. Results: In the 23 cases of renal tumors, ApoA-Ⅰ was expressed in 21 cases(positive rate was 91.3%).There were only two in five cases of normal tissues which expressed this protein(positive rate was 40.0%).A significant differentiation was observed between the two groups(Z=-2.829,P=0.003). In renal clear cell carcinoma(RCC), ApoA-Ⅰ expression level was correlated with the grade and stage of tumor tissues. ApoA-Ⅰ was stained much more stronger in RCCⅡ-Ⅲ than in RCCⅠ(Z=-2.070,P=0.038).In various histological types of renal cancer, ApoA-Ⅰ was all expressed to some degrees. Conclusion: ApoA-Ⅰ can be chosen as a tumor biomarker to differentiate various histological types of renal neoplasms.

Key words: Apolipoprotein A-Ⅰ, Kidney neoplasms, Immunohistochemistry, Biological markers