BCL-2and Bcl-6Protein Expression In Pediatric B-cell Non-hodgkin’s Lymphoma And Its Clinic-pathological Significance

Objective Pediatric malignant lymphoma is the third tumor with rapid progress and poor prognosis. The disease pose a serious threaten to children’s life. The majority is mature B-cell non-Hodgkin’s lymphoma (B-NHL). According to the latest WHO lymphatic hematopoietic tissue tumor classification criteria, it includes Burkitt’s lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), and unable to classify between BL and DLBCL (BL/DLBCL). Generally, it is believed that the clinical features, histological features, immunophenotyping and genetic characteristics in children with B-NHL were different from adults’. BCL-2gene is an inhibitor of apoptosis, located on chromosome18q21in B-cell lymphoma firstly. BCL-6gene is also a proto-oncogene, it can encode a class of transcriptional repressor proteins that are the substance for the formation of B cells in germinal centers. The relationship between the protein expression and gene abnormalities of BCL-2and BCL-6and malignant lymphoma was focus on adults with DLBCL. The study was designed to investigate the protein expression of BCL-2and BCL-6in children with B-NHL and its clinic-pathological significance.Method Between July1999and October2011,92consecutive untreated patients (age16years or less) with newly diagnosed B-NHL (including BL, DLBCL and BL/DLBCL) were enrolled. We use the immunohistochemical technique (Envision TM) to detect BCL-2, BCL-6protein expression levels. The expression of BCL-2and BCL-6and its association with clinic-pathological features and prognosis were analyzed.Results BL comprised the majority (57.6%) of all pediatric NHLs in our study, and DLBCL constituted41.3%of all the cases. The mean age of patients with B-NHL was7.2years with a range of2-15years and a M/F ratio of3:1. Abdominal presentation was the most common clinical presentation (54/92,59%) followed by neck mass (20/92,22%) and others (18/92,19%). Stage Ⅲ-Ⅳ was detected in81 patients (89%). The number of B-NHL is increasing during the ten years with41.3%of all the patients in the last three years. The median follow-up time of pediatric B-NHL was18.5months with a range of0-153months and the two-year event-free survival (EFS) was65.9%for all patients. In BL groups, it was66%. In DLBCL group, it was65.9%. There was no significant difference between BL group and DLBCL group in survival rate (P>0.05). BCL-2protein expression was performed in46B-NHL, only8was positive (17%), including3BL and5DLBCL. There was significant difference between them (P=0.047). BCL-6protein expression was performed in31B-NHL, only20was positive (64.5%), including13BL and7DLBCL. However, there was no significant difference between them. Children with positive BCL-6protein expression had better prognosis (20/31, P<0.05).Conclusion First, BL was the commonest histological subtype in children with B-NHL.The number of male was more than female. And the most common initial presenting site was located in the abdomen. All of them were concordance with sporadic BL reported from western countries. Second, the stage at presentation of patients in our study was late. Third, the number of pediatric B-NHL was increasing in the ten years. Fourth, BCL-2protein expression was useful for distinguish BL from DLBCL and BCL-6protein expression is a prognosis factor of B-NHL.