DIFFERENTIAL EXPRESSION OF CATHEPSIN D IN GERMINAL CENTER OF FOLLICULAR LYMPHOMA AND FOLLICULAR HYPERPLASIA AND ITS SIGNIFICANCE / 解放军医学杂志

ABSTRACT

Objective To study the expression of aspartic proteinase cathepsin D in the germinal center of follicular lymphoma and follicular hyperplasia. Methods Immunohistochemical staining was performed to detect the expression of cathepsin D in paraffin sections of 10 cases of follicular lymphoma and 9 cases of follicular hyperplasia. Results Cathepsin D was weakly expressed in the plasma of dendritic cells and histiocytes in the germinal centers of 9 out of 10 cases of follicular hyperplasia. The number of positive cells were smaller in the center of follicles, but larger in the periphery. It was more strongly expressed in the plasma of dendritic cells and histiocytes located predominantly in the peripheral areas of germinal centers of follicular lymphoma in 10 patients. Some germinal centers were surrounded by T lymphocytes in 4 cases of follicular lymphoma, and cathepsin D positive cells in these germinal centers were more in number than that in the germinal centers without being surrounded by T cells in other 6 cases of follicular lymphoma, in which positive sign even absent in some germinal centers. Conclusion Cathepsin D is a good marker for the dendritic cells and histiocytes, and its differential expression in follicular lymphoma and follicular hyperplasia is helpful for differential diagnosis of the diseases. Based on the former reports of cathepsin D with its important roles in antigen processing, we suppose that lower expression of this protease is probably due to the decreased ability of immunological response to tumor in follicular lymphoma patients.