Significance of SHP-1 expression in benign lesions of lymphoid tissues and lymphomas

Purpose To investigate the clinicopathologic significance of the SHP-1 gene expression in the benign lesions of lymphoid tissues and lymphomas. Methods Using the SP immunohistochemical method, the expression of SHP-1 gene was examined in paraffin-embedded samples from 111 cases of lymphomas and 27 various benign lesions of lymphoid tissues. Results (1)In relatively normal lymph nodes and tonsils SHP-1 was strongly expressed in the mantle and marginal zones, partly interfollicular zones. In spleen SHP-1 was expressed in marginal zone and partly periarterial lymphatic sheath. Expression of SHP-1 in lymphomas was weaker than that in normal lymphoid tissues.(2)The expression rate of SHP-1 was 100% (27/27) in the benign lesions of lymphoid tissues, which was significantly higher than those in Hodgkin's lymphoma (62.5%, 5/8), B-cell lymphoma (37.68%, 26/69) and T-cell lymphoma (26.47%, 9/34). The rates of SHP-1 protein expression were different in various subtypes of lymphomas, including MALT lymphoma (12.5%, 2/16), diffuse large B-cell lymphoma (50%, 11/22), follicular lymphoma (42.11%, 8/19), anaplastic large cell lymphoma (80%, 4/5), NK/T cell lymphoma (16.67%, 1/6), precursor T-lymphoblastic lymphoma (14.29%,1/7), and peripheral T-cell lymphoma (0, 0/7), which were not consistent with the previous reports. (3)In follicular lymphomas SHP-1 was expressed in neoplastic follicles in some cases (42.11%), and other cases (57.89%) were negative. Conclusions SHP-1 may be a useful molecular marker for diagnosing and distinguishing lymphoma, and SHP-1 gene silencing is one of the critical events in the pathogenesis and development of malignant lymphomas. These data support the possibility that the SHP-1 gene is one of the tumor suppressor genes.