The Significance Of The Detection Of Bcl-6, CD10, MUM-1 Expression And Bcl-2 Gene Rearrangement In Diffuse Large B Cell Lymphoma

Background and objective: Diffuse large B-cell lymphoma (DLBCL) represents the most frequent type of non-hodgkin lymphoma (NHL), Although combination chemotherapy has improved the outcome, long-term cure is now possible for approximately 50% of all patients, but other 50% of them can't get full therapeutic outcome, making the search for parameters identifying patients at high risk particularly needed. Nowadays, DLBCL have been divided into germinal center B-cell-like (GCB) type and non-germinal center B-cell-like (non-GCB) type according to the origin of its B cell, The prognosis of GCB is significantly better than that of non-GCB. The presence of bcl-2 gene rearrangement in de novo DLBCL suggests a possible follicle center cell origin and perhaps a distinct clinical behavior. Namely bcl-2 gene rearrangement may represent GCB subtype. Overseas, The combined expression of CD10,BCL-6,MUM-1 have been detected by immunohistochemistry technique to study the origin of the B cell in DLBCL. The report on the effectiveness of this combined detection technique is rare in China.In hopes of give a scientific basis to the treatment and prognostic judgement of DLBCL. we study of the origin of B cell in DLBCL through combined detection the expressions of BCL-6,CD10 MUM-1 and bcl-2 gene rearrangement, and we appraise the validity of immunohistochemistry by compare the result of immunohistochemistry to that of the bcl-2 gene rearrangement.Materials and Methods: A total of 40 patients with denovo nodal DLBCL treated at the First affiliated hospital of Zhengzhou University and the People's Hospital of Henan province were investigated. Formalin-fixed, paraffin-embedded sections were analyzed for:1) bcl-2 gene rearrangement including major break point region (mbr) , minor cluster region (mcr) and intermediate cluster region (icr) by polymerase chain reaction (PCR), and 2) BCL-6,CD10,MUM-1 protein expression by immunohistochemistry using monoclonal antibody. All patient were subclassified according to the following criteria: Cases were assigned to the GCB group if CD10 alone was positive or if both BCL-6 and CD10 were positive. If both BCL-6 and CD10 were negative, the case was assigned to the non-GCB subgroup. If BCL-6 was positive and CD10 was negative, the expression of MUM1 determined the group: if MUM1 was negative, the case was assigned to the GCB group; if MUM1 was positive, the case was assigned to the non-GCB group. After subclassification we compare the difference between the result of immunohistochemistry and that of bcl-2 gene rearrangement.Results:1. Histological variants: The tumor cell of all cases are consisted of large cell and thick staining nucleus. Histopathological variants presented as centroblastic variant (35 cases), immunoblastic variant (3 cases), anaplastic variant (1 cases), T-cell-rich/histocyte-rich variant (1 case). And all tumor cell are CD20 positive.2. Results of the expression of CD10, BCL-6 and MUM-1 in DLBCL: The positive expression of CD10, BCL-6 and MUM-1 in 40 lymphonodal DLBCL are account for 25.0% (11/40), 45.8% (16/40) and 58.3% (29/40) respectively. And the positive expression of CD10 was observed in membrance of tumor cell. While bcl-6 and MUM-1 at nuclei.3. The results of subclassification of DLBCL: 40 cases nodal DLBCL were subdivided into germinal center B-cell-like (GCB, 13 cases) and non-germinal center B-cell-like (non-GCB 27 cases).4. bcl-2 gene rearrangement in DLBCL: All 40 cases 9 bcl-2 gene rearrangement are positive, the positive rate of mbr/JH, mcr/JH and icr/JH are 20.0%(8/40),2.5%(1/40), 2.5%(1/40) respectively. And we subclassified all cases into GCB 9 cases and non-GCB 31 cases.5. Comparison between the results of immunohistochemsitry and that of bcl-2 gene rearrangement: There is not. statistical difference between immnunohistochemistry and bcl-2 gene rearrangement in subclassification of DLBCL (P>0.05),and the expression of Bcl-6 have no statistical relationship with bcl-2 rearrangement(P>0.05), while the expression of CD10 have positive relationship with bcl-2 gene rearrangement(r=0.339,P<0.05). The expression of MUM-1 have negative relationship with bcl-2 gene rearrangement(r=-0.339, P<0.05).6. Detection of the combination of immunohistochemistry with bcl-2 gene rearrangement: It can significantly enhance the detection rate of GCB through combination of the technique of immunohistochemistry and bcl-2 gene rearrangement from immunohistochemistry alone 37.5%(15/40) and bcl-2 gene rearrangement alone 22.5%(9/40) to combined two 40%(16/40).Conclusions:1. Combination of CD10 ,BCL-6 and MUM-1 can be used to distinguish the origin of B cell and make subclassification in DLBCL It have useful value to the clinical prognostic judgment.2. There is the same result between immnunohistochemistry and bcl-2 gene rearrangement in subclassification of DLBCL. CD10 is a good marker of GCB subtype and it can used to subclassify DLBCL but it should combined other antibody to enchance the detection rate of GCB subtype.3. Immunohistochemistry is more accessibility than bcl-2 gene rearrangement in subclassification of DLBCL.4. It can significantly enhance the detection rate of GCB subtype that combination of the technique of immunohistochemistry and bcl-2 gene rearrangent.