A Study of the Newer Prognostic Markers in Diffuse Large B Cell Lymphomas

Diffuse large B cell lymphomas (DLBCL) encompass a pathogenetically heterogeneous group of aggressive tumours that are rapidly fatal if untreated. Gene expression profiling studies have identified distinct molecular subtypes of DLBCL, one with an expression profile similar to normal germinal centre B cells (GCB subtype) and a second mimicking activated peripheral blood B cells (ABC subtype) having different prognostic significance allowing risk stratification of lymphoma patients and development of specific therapeutic strategies.

Twenty cases of DLBCL were included in the study and categorized into germinal centre and non germinal centre subtypes using the following antibody panel. CD10, Bcl-6, MUM1 and CD138. The germinal centre and non germinal centre subtypes were defined as under Germinal centre (DLBCL) CD10 + and/or Bcl-6 +, MUM1 -, CD138 - and Non germinal centre (DLBCL) CD10, Bcl-6 ±, MUM1 ±, CD138 ±.

In our study of twenty cases thirteen were germinal centre DLBCL while seven of the twenty cases were non germinal centre type of DLBCL. 75% of the nodal cases and 62.5% of extra nodal cases were germinal centre B cell type. Overall survival in the GCB and non GCB groups was 91% and 14% respectively and the difference was highly significant statistically.

This study validates the existence of prognostic subgroups of DLBCL in the Indian population.