Expression of DLK1 protein and its correlation with renal cell carcinoma pathological characteristics

Abstract

：Objective To identifythe expression of DLK1 protein in different types of renal cell carcinomas and itscorrelations with pathological characteristics and metastasis. MethodsImmunohistochemistry analysis was performed to evaluate the expression of DLK1 protein in94 cases of primary clear cell renal cell carcinoma, 76 cases of papillary renal cellcarcinoma, 45 cases of chromophobe renal cell carcinoma, 71 cases of distal metastatic and24 cases of lymph node metastatic clear cell renal cell carcinoma, as well as 18 cases ofnormal renal tissue. The correlations of DLK1 protein expression with pathologicalcharacteristics were analyzed. Results DLK1 protein was expressed in proximal and distalrenal tubular epithelial cells in all the normal renal cases. In contrast, DLK1 proteinexpression was lower in different types of renal cell carcinoma. The low or negativeexpression of DLK1 protein in clear cell renal cell carcinoma, papillary renal cellcarcinoma and chromophobe renal cell carcinoma was 33.0% (31/94), 27.6% (21/76) and 33.3%(15/45), respectively. Compared to normal renal tissue, DLK1 protein expression wassignificantly down-regulated in renal cell carcinomas (P＞0.05), whereas there was nosignificant difference on DLK1 protein expressions among the different types (P＞0.05)of renal cell carcinomas. DLK1 protein expression was not correlated with sex (60 male and34 female cases), age (≥55, 50 cases and 55, 44 cases), grade (41 cases ingrade I, 9 cases in grade II, 21 cases in grade III and 23 cases in grade Ⅳ respectively) and lymph node metastasis (76 cases with and 18 caseswithout lymph node metastasis) in clear cell renal cell carcinoma (P＞0.05).There was also no significant difference among primary, lymph node and distal metastaticlesions of clear cell carcinoma (P＞0.05). Conclusions DLK1 protein expression is commonlydown-regulated in different types of renal cell carcinomas. Down-regulation of DLK1protein expression is not associated with pathological characteristics and metastasis inclear cell renal cell carcinoma. Key words: Kidney neoplasmas; Gene, DLK1; Biological markers; Pathology,clinical