Lymphoma classification: the quiet after the storm

Ki67 Proliferation Index in Germinal and Non-Germinal Subtypes of Diffuse Large B-Cell Lymphoma

Introduction

Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma. The 2016 World Health Organization (WHO) update on hematopoietic tumors suggested that all DLBCL cases should be subtyped into germinal and non-germinal center phenotypes. Ki67 immunohistochemistry is a maker of cell proliferation and thus is used as a prognostic and predictive marker in various tumors of human body. Only a few studies evaluated the proliferative index of DLBCL subtypes in our population. Therefore, in this study, we evaluated the frequency of subtypes of DLBCL in our population and K67 index in each subtype.

Methods

A retrospective observational study was conducted in the Department of Histopathology, Liaquat National Hospital and Medical College, from January 2018 till December 2020, over a period of three years. A total of 101 cases with a histopathological diagnosis consistent DLBCL were included in the study. Immunohistochemical (IHC) stains CD10, B-cell lymphoma 6 (Bcl-6), and multiple myeloma oncogene 1 (MUM1) were applied for the further sub-categorization of DLBCL into germinal center B-cell-like (GCB) and non-GCB subtypes according to the Hans algorithm. The Ki67 index was interpreted in hot spots of the tumor and reported as an average percentage.

Results

Out of 101 DLBCL cases, 47.5% of DLBCL were GCB, while 52.5% were non-GCB subtypes. Bcl-2, Bcl-6, MUM1, c-Myc, CD10, and CD30 expression were noted in 62.4%, 45.5%, 42.6%, 44.6%, 39.6%, and 7.9% cases, respectively. The mean Ki67 index was 72.94±16.69%. The mean Ki67 index in non-GCB-type DLBCL was 77.67±14.80%, which was significantly higher than the mean Ki67 index in GCB-type DLBCL (67.70±17.22%) with a significant p-value (p=0.002). Cervical lymph node was the most common site of DLBCL, while the stomach was the most common extra-nodal site. A significant association of Ki67 index was noted with subtypes of DLBCL. A higher proportion of non-GCB-type DLBCL exhibited greater than 80% Ki67 index than GCB subtype DLBCL. Moreover, a significant association Ki67 index was noted with c-Myc positivity. A higher proportion of c-Myc-positive DLBCL had greater than 80% Ki67 index.

Conclusion

We found that non-GCB-type DLBCL had a higher Ki67 index than GCB subtype DLBCL, portending a poor prognostic significance of non-GCB subtype of DLBCL. Moreover, c-Myc expression was associated with a higher Ki67 index.

A comparison of R-EPOCH and R-CHOP as a first-line regimen in de novo DLBCL patients with high Ki-67 expression in a single institution

Diffuse large B-cell lymphoma (DLBCL) patients with high Ki-67 expression receive limited benefits from R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) therapy. This study aims to compare the R-EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin) and R-CHOP regimens as first-line therapy in DLBCL patients with high Ki-67 expression. Data from 44 untreated DLBCL patients with high Ki-67 expression receiving R-EPOCH therapy were matched with those from 132 untreated DLBCL patients with high Ki-67 expression receiving R-CHOP therapy based on the International Prognostic Index (IPI: age, Ann Arbor stage, performance status, LDH level, number of extranodal sites), gender, and Ki-67 expression. In the R-EPOCH group, 42/44 patients were eligible for response evaluation. A total of 35 patients (83.3%) achieved complete remission (CR); 6 patients (14.3%) achieved partial remission (PR); and one patient (2.4%) exhibited progressive disease (PD) after 2 cycles of therapy. Patients in the R-EPOCH group presented better survival outcomes than those in the R-CHOP group (3-year overall survival [OS]: 89.9% vs. 70.2%, p = 0.041; 3-year progression-free survival [PFS]: 86.6% vs. 59.7%, p = 0.024). The survival superiority of the R-EPOCH over the R-CHOP regimen persisted when considering only patients of low-to-intermediate IPI risk, but it was not observed in those of high IPI risk. Our data suggest that R-EPOCH could be superior to R-CHOP as a first-line regimen in DLBCL patients with high Ki-67 expression, especially in those of low-to-intermediate IPI risk.

BCL2/Ki-67 index predict survival in germinal center B-cell-like diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. BCL2 apoptosis regulator (BCL2) and marker of proliferation Ki-67 (Ki-67) are established prognostic markers, which have traditionally been assessed separately in DLBCL. However, no studies have evaluated the prognostic value of the combination of BCL2 and Ki-67 index. Thus, the present study aimed to analyze the prognostic value of combination of these two markers. Immunohistochemical analysis was used to assess the expression of BCL2 and Ki-67 in 274 cases of DLBCL. The BCL2/Ki-67 index demonstrated a significant association with decreased overall and progression free survival of patients with DLBCL, particularly for the germinal center B-cell-like subtype of DLBCL. Following multivariate analysis, the BCL2/Ki-67 index retained prognostic significance. Patients with coexpression of BCL2 and Ki-67 constituted a unique group with poor survival, thus novel therapies targeting BCL2 protein and high proliferative activity may improve the outcome of these patients.

Pathology of Extranodal Lymphoma

An overview of the pathology of extranodal lymphoma is presented. The emphasis of this presentation is on the classification system of extranodal lymphomas, including both B-cell and T-cell lymphomas, based on their morphology, phenotype, and molecular alterations.

Expression of BAFF-R, but not BAFF, is an independent prognostic factor in diffuse large B-cell lymphoma patients treated with R-CHOP

B-cell activating factor (BAFF) and BAFF-receptor (BAFF-R) play crucial roles in the progression of malignant B-cells. The aim of the present study was to evaluate the expression profiles and the clinical significance of BAFF and BAFF-R in diffuse large B-cell lymphoma (DLBCL). Paraffin-embedded specimens from 136 patients with newly diagnosed DLBCL, treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy (R-CHOP), were examined for BAFF and BAFF-R expression by immunohistochemistry. BAFF and BAFF-R were expressed in 72.1 % (98/136) and 47.1 % (64/136) of the DLBCL tissues, respectively. Negative BAFF-R expression was significantly correlated with elevated serum lactate dehydrogenase (LDH) levels (P = 0.036), an International Prognostic Index (IPI) score of 2 or higher (P < 0.001), and a poor revised IPI (R-IPI) risk score (P = 0.043). The complete response rate after R-CHOP was higher in patients with positive BAFF-R expression than in those with negative BAFF-R expression (73.4 vs. 56.9 %, P = 0.045). Negative expression of BAFF-R, but not of BAFF, was significantly associated with inferior progression-free survival (PFS; P = 0.020) and overall survival (OS; P = 0.028). Only negative BAFF-R expression was correlated with inferior PFS and OS in multivariate analysis (P = 0.049 and 0.040, respectively). Taken together, our results showed that the majority and approximate one-half of patients with DLBCL were positive for BAFF and BAFF-R, respectively. Negative expression of BAFF-R, but not of BAFF, could be an independent risk factor for PFS and OS in patients with DLBCL treated with standard R-CHOP.

Prognostic effect of Ki-67 expression in rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone-treated diffuse large B-cell lymphoma is limited to non-germinal center B-cell-like subtype in late-elderly patients

This study evaluated the effect of age and cell of origin on the prognostic significance of Ki-67 labeling index (Ki-67 LI) on overall survival (OS) of diffuse large B-cell lymphoma (DLBCL) in a cohort of 697 patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP). Multivariate analysis revealed no prognostic significance of high Ki-67 LI (≥ 85%) for OS. However, on subgroup analysis, high Ki-67 LI was significantly associated with poor OS in late-elderly patients (aged ≥ 70 years) (p = 0.021) and non-germinal center B-cell-like (GCB) subtype (p = 0.015). In particular, high Ki-67 LI was associated with a poor prognosis in late-elderly patients with non-GCB subtype. No correlation was observed in young adults (aged < 60 years) or early-elderly (aged 60-70 years) patients or GCB subtype. The present study shows that high Ki-67 LI is a risk factor for poor OS in the late-elderly age group and non-GCB subtype in patients with DLBCL treated with R-CHOP.

Receptor tyrosine kinases MET and RON as prognostic factors in diffuse large B-cell lymphoma patients receiving R-CHOP

Receptor tyrosine kinases MET and RON (MST1R) form non-covalent complexes on the cell surface, a critical step in tumor progression. A recent study suggested a prognostic role for MET expression in diffuse large B-cell lymphoma (DLBCL). The aim of this study was to examine the impact of MET and RON expression in uniformly treated DLBCL patients. The expression of MET and RON was retrospectively examined by immunohistochemistry in 120 DLBCL patients treated with rituximab combined with a CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisone). The median follow-up time was 42.5 months (range, 1-89 months). Thirty-two (26%) and 30 patients (25%) expressed MET or RON, respectively. Seventy-five patients (62.5%) were negative for both MET and RON (MET(-) RON(-) ). MET negativity was associated with worse overall survival (P = 0.029). In multivariate analysis, negativity for both MET and RON (MET(-) RON(-) ) was strongly associated with inferior overall survival (P = 0.008). Interestingly, the MET(-) RON(-) phenotype retained its prognostic impact after subgroup analysis according to the international prognostic index or by the cell of origin by immunohistochemical algorithm by Choi et al. This study suggests that the MET(-) RON(-) phenotype is an independent prognostic factor in DLBCL patients receiving R-CHOP, and may identify a subgroup of DLBCL patients who require more intensive therapy.

Detection of Epstein-Barr virus and genotyping based on EBNA2 protein in Mexican patients with hodgkin lymphoma: a comparative study in children and adults

BACKGROUND

Epstein-Barr virus (EBV) is a member of the Herpesviridae family and is associated with Hodgkin lymphoma (HL). Isolates of EBV are classified according to sequence variation in the latency genes such as Epstein-Barr virus nuclear antigen (EBNA). EBNA2 contains the most divergent locus and is classified into type 1 and type 2 or EBNA2A and EBNA2B, respectively. We compared the frequency of EBV and the distribution of EBNA genotypes in Mexican children and adults with HL.

PATIENTS AND METHODS

Lymph node biopsy specimens from children and adults with HL were embedded in paraffin. EBV was identified by LMP1 amplification and Epstein-Barr-encoded RNA EBER by in situ hybridization (ISH) and genotyped as EBNA2A or EBNA2B using nested polymerase chain reaction (PCR) and specific primers for the detection of subtype.

RESULTS

Sixty-six samples were obtained from 3 hospitals-42 (63%) from children and 24 (37%) from adults with HL. Thirty-two of the 42 samples (76.1%) were positive for EBV in children and 16 of 24 (66.6%) samples were positive in adults (P = .41). In both children and adults, EBV was found more frequently in male patients. Thirty-four of 48 cases could be typed (70.8%). EBNA2A was found in 7/21 (33.3%) children and in 4/13 (30.8%) adults (P = 1.0), and EBNA2B was found in 10/21 (47.6%) children and in 9/13 (69.2%) adults (P = .22). A mix of subtypes was found in 4/21 (19%) children.

CONCLUSION

EBV was found frequently in both children and adults with HL. EBNA2B was the most frequent subtype, and a high frequency of mixed subtypes was found in children.

Blood lymphocyte-to-monocyte ratio identifies high-risk patients in diffuse large B-cell lymphoma treated with R-CHOP

Background

Recent research has shown a correlation between immune microenvironment and lymphoma biology. This study aims to investigate the prognostic significance of the immunologically relevant lymphocyte-to-monocyte ratio (LMR), in diffuse large B-cell lymphoma (DLBCL) in the rituximab era.

Methodology/Principal Findings

We analyzed retrospective data from 438 newly diagnosed DLBCL patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy. We randomly selected 200 patients (training set) to generate a cutoff value for LMR by receiver operating characteristic (ROC) curve analysis. LMR was then analyzed in a testing set (n = 238) and in all patients (n = 438) for validation. The LMR cutoff value for survival analysis determined by ROC curve in the training set was 2.6. Patients with low LMR tended to have more adverse clinical characteristics. Low LMR at diagnosis was associated with worse survival in DLBCL, and could also identify high-risk patients in the low-risk IPI category. Multivariate analysis identified LMR as an independent prognostic factor of survival in the testing set and in all patients.

Conclusions/Significance

Baseline LMR, a surrogate biomarker of the immune microenvironment, is an effective prognostic factor in DLBCL patients treated with R-CHOP therapy. Future prospective studies are required to confirm our findings.