Diffuse Large B-Cell Lymphoma with Overexpression of HSP90 Associate Better Prognosis
Z Mo, P Hou, C Goldblatt, L Qian. Conemaugh Memorial Medical Center, Johnstown, PA; Washington University, St Louis, St. Louis, MO
Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma. It is very aggressive. Based on the gene expression profiling, DLBCL is divided into prognostically different subgroups according to cell of origin. The germinal center (GC) subtype is characterized by CD10 and/or BCL6 expression and correlates with a better prognosis, whereas the activated B-cell like (ABC) group, characterized by the absence of GC markers and the presence of the MUM1/IRF4 antigen, has poor clinical outcome. Heat shock protein 90 (HSP90) is a molecular chaperone. The molecular chaperone Hsp90 is involved in the stabilization and conformational maturation of many signaling proteins that are deregulated in cancers. Recent study showed that HSP90 also expressed in DLBCL.
Design: Paraffin-embedded DLBCL specimens (21 GC subtype; 23 ABC subtype). All the cases have 1-7 years follow-up. The specimens were stained for HSP90. The staining was scored on percentage basis: 0= <10%, 1=10-25%, 2=26-50%, 3=51-75%, 4=>75%. The overall survival interval were calculated from the date of diagnosis. Nonparametric statistics were used for the comparison of HSP90 expression in the two subtypes of DLBCL. The follow-up cut-off is at 84 months. Kaplan-Meier will be used for survival curves. The curves were examined by log-rank tests. Exact confidence interval was calculated at the 95% level.
Results: HSP90 was expressed in 61% (27/44) of the specimens. In GC subtype, the level of HSP90 expression is higher compared to ABC subtype (P<0.005). The patients with higher level expression of HSP90 had longer survival rate (P<0.001).
Conclusions: The expression of HSP90 in GC subtype is higher than that in ABC subtype. The higher level expression of HSP90 in DLBCL associates better prognosis.
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 190, Wednesday Morning