Prognostic significance of immunohistochemistry-based markers and algorithms in immunochemotherapy-treated diffuse large B cell lymphoma patients.

AIMS: To reassess the prognostic validity of immunohistochemical markers and algorithms identified in the CHOP era in immunochemotherapy-treated diffuse large B cell lymphoma patients. METHODS AND RESULTS: The prognostic significance of immunohistochemical markers (CD10, Bcl-6, Bcl-2, MUM1, Ki-67, CD5, GCET1, FoxP1, LMO2) and algorithms (Hans, Hans*, Muris, Choi, Choi*, Nyman, Visco-Young, Tally) was assessed using clinical diagnostic blocks taken from an unselected, population-based cohort of 190 patients treated with R-CHOP. Dichotomizing expression, low CD10 (<10%), low LMO2 (<70%) or high Bcl-2 (≥80%) predicted shorter overall survival (OS; P = 0.033, P = 0.010 and P = 0.008, respectively). High Bcl-2 (≥80%), low Bcl-6 (<60%), low GCET1 (<20%) or low LMO2 (<70%) predicted shorter progression-free survival (PFS; P = 0.001, P = 0.048, P = 0.045 and P = 0.002, respectively). The Hans, Hans* and Muris classifiers predicted OS (P = 0.022, P = 0.037 and P = 0.011) and PFS (P = 0.021, P = 0.020 and P = 0.004). The Choi, Choi* and Tally were associated with PFS (P = 0.049, P = 0.009 and P = 0.023). In multivariate analysis, the International Prognostic Index (IPI) was the only independent predictor of outcome (OS; HR: 2.60, P < 0.001 and PFS; HR: 2.91, P < 0.001). CONCLUSIONS: Results highlight the controversy surrounding immunohistochemistry-based algorithms in the R-CHOP era. The need for more robust markers, applicable to the clinic, for incorporation into improved prognostic systems is emphasized.

A 9 series microRNA signature differentiates between germinal centre and activated B-cell-like diffuse large B-cell lymphoma cell lines.

The microRNAs are endogenous, non-coding RNAs that play key roles in a range of pathophysiological processes by up- or down-regulating gene expression. Recent studies have shown that some microRNAs have oncogenic or tumour suppressor activity. Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin's lymphoma with a heterogeneous biology, which has impeded the clinical assessment of patients. The currently-used clinically-based IPI provides useful information for treatment decision making, but has limited predictive power. Recent immunohistochemical approaches have identified two different prognostic groups: the more indolent germinal centre (GC)- and the higher risk activated B-cell (ABC)-like phenotypes. Although useful, prediction based on immunophenotype has limitations. The present study uses microRNA profiling and a number of well-characterised B-cell lymphoma cell lines to identify microRNA signatures that are correctly assigned to the DLBCL prognostic subgroups and distinguish DLBCL from other more indolent lymphoma, including follicular lymphoma (FL). MicroRNA microarray analysis was based on miRBase version 12.0 and analysis was performed using an unsupervised hierarchical clustering model. Discriminatory microRNAs were validated by qRT-PCR. We identified a 9 microRNA signature that discriminated between ABC- and GC-like DLBCL. This included 3 newly identified microRNAs, not previously associated with DLBCL and predicted to target genes that are de-regulated in lymphoma. DLBCL was distinguished from FL by 4 microRNAs and a total of 18 microRNAs were identified that differentiated between all lymphoma and control populations. Most of the discriminatory microRNAs have been reported previously to be known oncomiRs or act as tumour suppressors. In conclusion, the present study identified a microRNA signature that correctly classified GC and ABC phenotypes in DLBCL cell lines. This signature has yet to be assessed for prediction in clinical samples.

Immunophenotyping of diffuse large B-cell lymphoma (DLBCL) defines multiple sub-groups of germinal centre-like tumours displaying different survival characteristics.

Diffuse large B-cell lymphoma (DLBCL) forms a heterogeneous collection of aggressive non-Hodgkin's Lymphoma in which three principle classes of neoplasia have been defined according to gene expression and immunophenotyping studies. The present investigation sought to examine the immunophenotype of proposed subgroups and relate these to patient survival. A series of 155 DLBCL treated uniformly with anthracycline therapy in clinical trials, were stratified upon the basis of common biomarker expression with combination immunophenotype being related to patient overall survival. Stratification of tumours with respect to combined expression profiles of the three biological markers (CD10, Bcl-6 and MUM-1) revealed six groups showing significant differences in survival (p=0.014). The greatest difference resided between distinct populations of germinal centre (GC) cell tumours; the first being CD10-, Bcl-6+, MUM-1- and the second CD10+ Bcl-6+ MUM-1+ (p=0.002). The former group displayed median survival time of 143 months, the latter only 11 months. A third population of GC tumours (CD10+ Bcl-6+ and MUM-1-) also displayed a relative short median survival (32 months). Of the three groups presenting a non-GC or activated B cell (NGC/ABC) phenotype, only one (CD10-, Bcl-6+ and MUM-1+) presented short-term median survival (27 months) comparable with poor prognosis GC sub-populations. Within the remaining ABC tumour groups (CD10- Bcl-6- MUM-1- and CD10- Bcl-6- MUM-1+) patients presented intermediate median survival times of 54 and 58 months, respectively. Thus, the GC phenotype did not act as a universal indicator of good clinical prognosis, but rather multiple groups of GC tumours were associated with distinct overall survival profiles. Ultimately, the data allowed definition of a predictive algorithm defining three groups predicting poor, intermediate and good clinical prognosis. The first of these comprised two patient sub-populations with GC-like tumours together with one sub-population of NGC/ABC, the second two sub-populations of ABC-like tumours, and the final a single group of GC-like tumours associated with optimal long-term survival.