Expression of JL1 in Burkitt lymphoma is associated with improved overall survival

Abstract

JL1 is a novel molecule expressed in the surface of hematopoietic precursor cells, but not on any other mature human tissue. Accordingly, JL1 is expressed in acute lympho- blastic leukemia (ALL) cells and can be used both for specific diagnosis and as a target for treatment. However, expression of JL1 by lymphomas has not been thoroughly assessed. Burkitt lymphoma is a potentially curable aggressive lymphoma, but prognostic markers that stratify risk have not been established. We therefore assayed JL1 expression in Burkitt lymphoma patients to assess its value as a prognostic marker for this disease. Tissue microarray blocks of formalin-fixed paraffin- embedded tissue samples from patients with Burkitt lympho- ma and other B-cell lymphomas, at the Asan Medical Center and Seoul National University Hospital from January 1998 to December 2008 were immunohistochemically assayed using a mousemonoclonal antibody against JL1.We found that 30.2% of Burkitt lymphoma samples, but no other lymphoma samples, were positive for JL1. JL-1 expression was signifi- cantly correlated with patient survival (P =0.022), but not with other clinical manifestations of the disease, with 91.6% of JL1-positive patients achieving complete remission in re- sponse to chemotherapy and 6.25% experiencing disease recurrence. JL1 positivity was significantly correlated with prolonged overall survival by both Kaplan–Meier survival (P =0.035) and Cox proportional hazard model (P =0.043) analysis. JL1 expression in Burkitt lymphoma was positively correlated with overall survival and better response to chemotherapy, suggesting that JL1 may be a prognostic marker for risk stratification in these patients. Keywords: JL1 . Burkitt lymphoma . Predictive factor . Prognosis . Immunohistochemistry