Abstract

In recent years, diffuse large B cell lymphoma (DLBCL) has been classified by a cDNA microarray, an oligonucreotide microarray, or a tissue microarray. From the prognostic point of view, DLBCL consists of germinal center B-cell-like (GC) type, activated B-cell-like (ABC) type and type 3. ABC type and type 3 can be collectively categorized as non-GC (NGC) type. GC type has favorable prognosis compared with NGC type. Escape from apoptosis is considered to be an important mechanism for the progression of lymphoma. Fas is the major protein which leads to apoptosis by binding with Fas-ligand (FasL). We evaluated the prognostic significance of such markers as CD10, Bcl-6, MUM1, Fas and FasL, as well as GC or NGC type with paraffin embedded sections from 69 DLBCL patients immunohistochemicaly. The patients were 40 men and 29 women with median age of 67 years old (range, 20–82 years old). The median follow-up of surviving patients was 43 months. The 3-year OS for the entire group was 56%. There was no significant difference in sex, age, clinical stage, lactate dehydrogenase, or International Prognostic Index between GC and NGC type. Expression of CD10 was seen in 29% (20 of 69 of the patients), Bcl-6 in 27% (19 of 69), MUM1 in 27% (19 of 69), Fas in 51% (36 of 69), and FasL in 50% (35 of 69). We divided 69 DLBCLs to 26 GC type (CD10 positive or Bcl-6 positive and MUM1 negative) and 43 NGC type (the other). Positive CD10 was the best marker to indicate favorable overall survival (p=0.0156). GC type had tendency to have better overall survival than NGC type, though it was not significant (p=0.0723). Although Fas or FasL expression was not significant for overall survival in all DLBCL, it predicted significantly a longer over all survival (Fas; p=0.0021, FasL; p=0.0165) in GC type. These results may suggest that the presence of a subtype of DLBCL in which Fas/FasL system works effectively. This group is approximately 20% of DLBCL and mainly belongs to the GC type. Fas expression in GC type of DLBCL may predict the prognosis and be useful to choose the appropriate therapy. Furthermore, CD10 was more significant than GC type and, thus, we may need to build the strict consensus for GC type.

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