Expression of P-glycoprotein and Apoptosis in Diffuse Large B-cell Lymphoma

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common type of malignant lymphoma which responds well to conventional chemotherapy. However, quite a few patients have a recurrence with more aggressive forms after completion of therapy. Multidrug resistance proteins (MRP) are related to this process in several ways such as cell cycle alteration and modulation of apoptosis. METHODS: We investigated the expression of P-glycoprotein (Gp), one of the well-known MRP, as well as apoptosis associated proteins in DLBCL. Immunohistochemical staining for Gp, p53, Bcl-2, Ki-67, active caspase 3 and FADD was done in forty DLBCL cases. The association between MRP and apoptosis associated proteins to clinical findings was also tested. RESULTS: Twenty-nine patients out of 40 (73%) with DLBCL were positive for Gp, and 26 cases (65%) had a strong positive for Gp. Gp expression was stronger in high-grade lesions than in low-grade lesions and was associated to Bcl-2 expression. However, we could not find an adverse impact of Gp expression on patients' overall survival or relapse free survival rate. CONCLUSIONS: Our study revealed a high frequency of expression for Gp in DLBCL with a possible relationship between the expressions of Gp to apoptosis associated proteins.

Detection of SV40 Large T Antigen in Malignant Lymphomas

BACKGROUND: The association of simian virus 40 (SV40) with certain types of human cancers, including malignant lymphomas, has been a topic of interest for some time. Although the virus is distributed worldwide, its incidences vary according to the specific types of tumors, and the epidemiological areas. The aim of this study was to investigate the frequency of SV40 in malignant lymphomas among Korean patients. METHODS: One hundred seventy three cases of malignant lymphomas were evaluated by immunohistochemical staining for SV40 large T antigen (TAg), using an extremely sensitive, tyramide based, catalyzed signal amplification method. RESULTS: From 158 non-Hodgkin's lymphomas, including 115 diffuse large B-cell lymphomas, and 15 Hodgkin's lymphomas, none of the cases were positive for SV40 TAg. CONCLUSIONS: SV40 does not appear to be related to the pathogenesis of malignant lymphomas among Koreans.