Expression of p53, c-Myc, or Bcl-6 suggests a poor prognosis in primary central nervous system diffuse large B-cell lymphoma among immunocompetent individuals

Primary central nervous system lymphoma: Comprehension of cell-of-origin subtypes

Primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) is an uncommon extranodal lymphoma that accounts for more than 95% of all the CNS lymphomas. Unlike its systemic/nodal counterpart, which is currently subtyped into cell-of origin (COO) subtypes, its feasibility and utility are largely debatable in PCNS-DLBCL.

Objectives

To classify PCNS-DLBCL into COO-subtypes based on immunohistochemical algorithms by Hans and Choi and evaluate concordance between the two. A further aim is to investigate the clinicoradiological and histomorphological parameters of the subtypes thus obtained.

Materials and Methods

As many as 143 cases of primary CNS lymphoma were evaluated by immunohistochemistry for CD10, BCL6, MUM1, GCET, and FOXP1 and based on which the said 143 cases were further classified into COO subtypes using Hans and Choi algorithms.

Results

Mean age was 53.8 years with marginal male preponderance and predominantly centroblastic morphology (75.5%). CD 10 was positive in 8.9% of the cases, BCL6 in 58.6%, MUM1 in 89.9%, GCET in 32.9%, and FOXP1 in 79.5%. As much as 84.9% cases were of non-germinal center B-cell (GCB) subtype and 15.1% cases were of GCB subtype as determined based on Hans algorithm. Furthermore, 90.7% cases were of activated B-cell (ABC) subtype and 9.3% cases were of GCB subtype according to Choi algorithm. A 91.8% concordance was observed between Hans and Choi algorithms. Among the 6 discordant cases, 5 cases were subtyped as GCB by Hans and ABC by Choi and 1 case as ABC by Hans and GCB by Choi.

Conclusion

Most of PCNS-DLBCLs are of non-GCB/ABC COO subtype, but inconsistences abound in the utility of IHC algorithms in PCNS-DLBCL COO subtypes.

Elevated expression of transforming acidic coiled-coil-containing protein 3 (TACC3) reflects aggressiveness of primary central nervous system lymphomas

Transforming acidic coiled-coil-containing protein 3 (TACC3) plays an important role in centrosome/microtubule dynamics. Deregulation of centrosomes/microtubules causes mitotic spindle defects, leading to tumorigenesis. However, the correlation between TACC3 and primary central nervous system lymphomas (PCNSLs) is unknown. The present study investigated the association between the immunohistochemical expression of TACC3, p53, and Ki-67, and the clinical factors in 40 PCNSLs. We evaluated the staining of TACC3 based on the histoscore (H-score) that contains a semiquantitative evaluation of both the intensity of staining, and the percentage of positive cells. Expression level of each component was classified as low or high according to the median H-score value. Patients with PCNSLs were divided into groups depending on TACC3 expression levels (no expression and low expression, 18; high expression, 22). Disease-free survival and overall survival of patients with high TACC3 expression were significantly shorter (p < 0.01 and p < 0.05, respectively). These results suggest that elevated expression of TACC3 could reflects aggressiveness of primary central nervous system lymphomas.

MYC, BCL2, and BCL6 expression as prognostic indicators in primary central nervous system lymphoma: A systematic review and meta-analysis

BACKGROUND

We conducted a meta-analysis to comprehensively assess the predictive role of MYC, BCL2, and BCL6 genetic alterations and protein expression in PCNSL for clinical application.

METHODS

A systematic retrieval was performed on PubMed, Embase, the Cochrane library, Web of Science, Scopus, and 2 Chinese databases. Cohort studies discussing the prognostic impact of MYC, BCl2, or BCL6 genetic alterations or gene expression in PCNSL were selected. The pooled hazard ratio (HR) and median survival ratio (MSR) were calculated.

RESULTS

31 studies involving 1739 patients fulfilled our inclusion criteria. MYC expression was significantly associated with short median OS (MSR = 0.62; 95%CI, 0.44-0.88) and PFS (HR = 1.53; 95%CI, 1.06-2.20). No significant association was found between BCL2 expression and OS or PFS (P > 0.05). BCL6 protein positivity was significantly associated with extended median OS (MSR = 1.62; 95%CI, 1.10-2.40). MYC and BCL2 coexpression was significantly associated with short median OS (MSR = 0.61; 95%CI, 0.45-0.84). Subgroup analysis demonstrated that MYC protein positivity remained as a significant indicator for short median OS in studies whose sample size ≥ 45, treatment without WBRT, quality scale score ≥ 7, and positivity threshold set at 40% stratum (MSR < 1 and P < 0.05), but failed to reach a statistically significant difference in the other stratum.

CONCLUSIONS

MYC expression predicts inferior median OS and PFS in PCNSL. BCL6 protein positivity is associated with a favorable prognosis. The sample size, average age of subjects, WBRT treatment, study quality, and cut-off values for discriminating positive and negative protein expression in IHC may be origins of heterogeneity.

New genetic prognostic biomarkers in primary central nervous system lymphoma (PCNSL)

BACKGROUND

PCNSL is a rare extranodal NHL with poor prognosis. Tumorigenesis has been associated with hyperactivation of BCR downstream and NFkB pathways. We studied the prognosis of the relative expression profile of target genes of NFkB pathway (MYC, BCL2), the essential transcriptional regulator in hematopoiesis LMO2, the checkpoint regulation pathway MGMT, the transcription factor POU2F1, the immune checkpoint gene PDCD1, and the proto-oncogene and transcriptional repressor gene BCL6 and its proteins in PCNSL.

METHODS

This study is a retrospective cohort study; 35 immunocompetent PCNSL-DLBCL patients had their gene expression (RT-qPCR) normalized to internal control gene GUSB.

RESULTS

Median patient age was 62 years, median OS was 42.6 months (95% CI: 26.6-58.6), PFS was 41 months (95% CI: 19.7-62.4), and DFS was 59.2 months (95% CI 31.9-86.6). A moderate correlation was found between the gene/protein expressions of MYC (kappa = 0.596, p = .022) and of BCL2 (kappa = 0.426, p = .042). Relative gene expression of MYC ≥ 0.201 (HR 6.117; p = .003) was associated with worse 5-year OS. Relative gene expression of MYC ≥ 0.201 (HR 3.96; p = .016) and MGMT ≥ 0.335 (HR 3.749; p = .056) was associated with worse PFS. Age > 60 years and IELSG score moderate/high were also associated with worse prognosis.

CONCLUSIONS

Overexpression of MYC and overexpression of MGMT were prognostic markers associated with unfavorable clinical outcomes in PCNSL.

Clinicopathological features of primary central nervous system diffuse large B cell lymphoma: Experience from a Tertiary Center in North India

BACKGROUND

Primary central nervous system-diffuse large B-cell lymphoma (PCNS-DLBCL) is a rare extra-nodal Non-Hodgkin lymphoma. There is relative paucity of literature on PCNSL from Indian subcontinent. We aimed to analyze the clinicopathological features of PCNSL and categorize them into germinal center B cell (GCB) and non-GCB subtypes to assess their prognostic significance in Indian context.

METHODS

All patients with histopathologically diagnosed PCNSLs at our center over a period of 6 years were recruited and classified into GCB and non-GCB using Han's algorithm (immunohistochemistry for CD10, BCL6 and MUM1). In situ hybridization (ISH) for Epstein-Barr virus (EBV)-encoded RNA was performed.

RESULTS

Eighty-six cases of PCNS-DLBCL were included with median age of 55 years. Majority of them were supratentorial in location (n = 62). All patients were immunocompetent. On immunohistochemical assessment, 69 (80.2%) were of NGCB subtype, 10 (11.6%) were of GCB subtype, and 7 (8.1%) were unclassified. Overall, MUM1, BCL-6, and CD10 expressions were seen in 69 (80.2%), 28 (32.6%), and 2 cases (2.3%), respectively. Four cases (4.6%) showed C-MYC expression. The median overall survival (OS) was 675 days. None of the factors (age, sex, location, immunomarkers, and GCB vs. NGCB phenotype) showed correlation with OS; however, BCL6 positive cases showed slight better OS (P > 0.05). All cases were negative for EBV-LMP1 on ISH.

CONCLUSION

The majority of the CNS DLBCL belongs to non-GCB phenotype and uniformly carry poor prognosis, irrespective of their phenotype. Individual markers, such as BCL-6, MUM1, or CD10, are unable to predict outcome in PCNS-DLBCL.

Analysis of primary central nervous system large B-cell lymphoma in the era of high-grade B-cell lymphoma: Detection of two cases with MYC and BCL6 rearrangements in a cohort of 12 cases

High-grade diffuse large B-cell lymphoma (HG-DLBCL) refers to DLBCL with MYC and BCL2 and/or BCL6 rearrangements (double-hit or triple-hit DLBCL) that exhibits poor prognosis. Double-expressor DLBCL (c-myc+/bcl-2+) has intermediate prognosis when compared to HG-DLBCL. Primary central nervous system lymphoma (PCNSL) has distinct pathophysiology (frequent non-germinal center-like subtype and double-expressor) and has worse prognosis than systemic DLBCL. By fluorescence in situ hybridization (FISH), 25-30% of PCNSLs harbor BCL6 abnormalities with rare alterations in MYC, BCL2, double-hit or triple-hit events. We describe the clinicopathologic features and status of MYC, BCL2 and BCL6 in 12 PCNSLs (7 women, 5 men; median age 63 years; range: 28-79). Six cases showed focal starry-sky pattern. Immunohistochemically, all (100%) were of non-germinal center-like subtype, and 8/10 (80%) cases were double-expressors. Ki-67 ranged from 70 to 100%. FISH was positive in 9/12 (75%) cases: 4 (33%) harbored a BCL6 rearrangement, 3 (25%) had a gain of BCL2, 2 (17%) cases each had a gain of BCL6 and gain of IGH, and gain of MYC and deletion of MYC were observed in 1 case each (8%). Two (16%) cases were MYC/BCL6 double-hit PCNSLs. No MYC/BCL2 or triple-hit cases were identified. Eleven (92%) patients received chemotherapy and one also received whole brain radiation. The median time of follow-up was 4.4 months (range, 0.3-40.3). Seven (58%) patients are alive, 4 (33%) have died, and 1 (8%) had no follow-up. Five alive patients are in remission, including one MYC/BCL6 double-hit PCNSL. Our results add two new cases of rare double-hit PCNSL to the literature.

High-mobility group box (TOX) antibody a useful tool for the identification of B and T cell subpopulations

Thymocyte selection-associated high-mobility group box (TOX) is a DNA-binding factor that is able to regulate transcription by modifying local chromatin structure and modulating the formation of multi-protein complexes. TOX has multiple roles in the development of the adaptive immune system including development of CD4 T cells, NK cells and lymph node organogenesis. However very few antibodies recognizing this molecule have been reported and no extensive study of the expression of TOX in reactive and neoplastic lymphoid tissue has been performed to date. In the present study, we have investigated TOX expression in normal and neoplastic lymphoid tissues using a novel rat monoclonal antibody that recognizes its target molecule in paraffin-embedded tissue sections. A large series of normal tissues and B- and T-cell lymphomas was studied, using whole sections and tissue microarrays. We found that the majority of precursor B/T lymphoblastic, follicular and diffuse large B-cell lymphomas, nodular lymphocyte-predominant Hodgkin lymphomas and angioimmunoblastic T-cell lymphomas strongly expressed the TOX protein. Burkitt and mantle cell lymphomas showed TOX expression in a small percentage of cases. TOX was not found in the majority of chronic lymphocytic leukemia, myelomas, marginal zone lymphomas and classical Hodgkin lymphomas. In conclusion, we describe for the first time the expression of TOX in normal and neoplastic lymphoid tissues. The co-expression of TOX and PD-1 identified in normal and neoplastic T cells is consistent with recent studies identifying TOX as a critical regulator of T-cell exhaustion and a potential immunotherapy target. Its differential expression may be of diagnostic relevance in the differential diagnosis of follicular lymphoma, the identification of the phenotype of diffuse large B-cell lymphoma and the recognition of peripheral T-cell lymphoma with a follicular helper T phenotype.

Prognostic factors for primary central nervous system lymphomas treated with high-dose methotrexate-based chemo-radiotherapy

Background

Primary central nervous system lymphoma (PCNSL) remains an aggressive and refractory tumor despite high-dose methotrexate-based chemo-radiotherapy. Age and performance status have been shown to be important clinical prognostic factors, however others, especially molecular factors, affecting the prognosis are still uncertain.

Methods

We investigate clinical, neuroimaging and immunohistochemical data in tissue from 41 PCNSL patients treated primarily with methotrexate-based chemo-radiotherapy and evaluate the influence of potential prognostic factors on clinical outcome as well as correlation among these factors.

Results

Median progression-free survival (PFS) and overall survival (OS) were 29 and 73 months, respectively. Expression of the mismatch repair (MMR) proteins, MLH1, MSH2, MSH6 and PMS2, correlated tightly with each other and high expression of MSH2 was significantly associated with better OS and PFS (P = 0.005 and P = 0.007), while methotrexate metabolism-related proteins did not affect survival. In addition, low expression of PMS2 was an independent predictor of methotrexate resistance (P = 0.039). Among neuroimaging findings, involvement of the fornix and tegmentum/velum were significantly associated with poorer OS (P < 0.001 and P = 0.013) and PFS (P = 0.014 and P = 0.043, respectively). Germinal center B cell (GCB)-PCNSL subtype as opposed to non-GCB subtype, tended toward better survival. Regarding oncogenes, cMYC-positive cases showed unfavorable OS (P = 0.046). By multivariate analysis, MSH2 and involvement of the fornix were independent predictors for both OS and PFS, whereas tegmentum/velum location and cMYC expression were significantly associated with OS.

Conclusions

Although further studies are needed, these results suggest that MMR protein expression, as well as specific deep locations and cMYC expression, may be a novel prognostic and predictive markers for PCNSL.

Novel tumor markers provide improved prediction of survival after diagnosis of human immunodeficiency virus (HIV)-related diffuse large B-cell lymphoma

Existing prognostic tools for HIV + diffuse large B-cell lymphoma (DLBCL) fail to accurately predict patient outcomes. To develop a novel prognostic algorithm incorporating molecular tumor characteristics and HIV disease factors, we included 80 patients with HIV-related DLBCL diagnosed between 1996 and 2007. Immunohistochemistry staining was used to analyze the expression of 26 tumor markers. Clinical data were collected from medical records. Logistic regression and bootstrapping were used to select and assess stability of the prognostic model, respectively. Of the tumor markers examined, expression of cMYC, Ki 67, CD44, EBV, SKP2, BCL6, p53, CD20 and IgM were associated with two-year mortality. The final prognostic model, confirmed in bootstrapped samples, included IPI, circulating CD4 cell count, history of clinical AIDS, and expression of CD44, p53, IgM and EBV. This model incorporating HIV disease history and tumor markers, achieved better prediction for two-year mortality [AUC = 0.87, 95% CI: 0.78-0.96] compared with IPI alone [AUC = 0.63 (0.51-0.75)].

Case-based review: primary central nervous system lymphoma

Primary CNS lymphoma (PCNSL) is a rare diffuse large B-cell lymphoma originating within the central nervous system. The overall incidence of PCNSL is rising, particularly in the elderly population. Immunosuppression is a strong risk factor, but most patients with this tumor are apparently immunocompetent. Diagnosis of PCNSL can be challenging. Non-invasive or minimally invasive tests such as ophthalmological evaluation and spinal fluid analysis may be useful, but the majority of patients require tumor biopsy for definitive diagnosis. Our knowledge concerning optimum treatment of PCNSL is fragmentary due to paucity of adequately sized trials. Most patients are now initially treated with high-dose-methotrexate-based chemotherapy alone, as the addition of whole-brain radiotherapy at standard doses has not been shown to increase survival and does increase the risk of neurological toxicity. Ongoing trials are addressing issues such as the roles of reduced-dose radiotherapy, the addition of the CD20 antibody rituximab to chemotherapy, high-dose chemotherapy followed by autologous stem cell transplantation, and maintenance therapy in the primary management of PCNSL.

Prognostic impact of MYC protein expression in central nervous system diffuse large B-cell lymphoma: comparison with MYC rearrangement and MYC mRNA expression

The prognostic role of MYC has been well documented in non-central nervous system diffuse large B-cell lymphoma; however, it remains controversial in central nervous system diffuse large B-cell lymphoma. To investigate the prognostic value of MYC, we analyzed the MYC protein expression by immunohistochemistry, mRNA expression by RNA in situ hybridization, and gene status by fluorescence in situ hybridization in 74 cases of central nervous system diffuse large B-cell lymphoma. Moreover, we examined the correlation between MYC translocation, mRNA expression, and protein expression. The mean percentage of MYC immunopositive cells was 49%. Using a 44% cutoff value, 49 (66%) cases showed MYC protein overexpression. The result of mRNA in situ hybridization using the RNA scope technology was obtained using the H-scoring system; the median value was 34.2. Using the cutoff value of 63.5, 16 (22%) cases showed MYC mRNA overexpression. MYC gene rearrangement was detected in five out of 68 (7%) cases. MYC translocation showed no statistically significant correlation with mRNA expression; however, all MYC translocation-positive cases showed MYC protein overexpression, with a higher mean percentage of MYC protein expression than that of translocation-negative cases (78 vs 48%, P=0.001). The level of MYC mRNA expression was moderately correlated with the level of MYC protein expression (P<0.001). The mean percentage of MYC protein expression in the high MYC mRNA group was higher than that in the low MYC mRNA group (70 vs 47%, P<0.001). A univariate analysis showed that age over 60 years, Eastern Cooperative Oncology Group (ECOG) performance status ≥2 and MYC protein overexpression were significantly associated with an increased risk of death. MYC translocation and MYC mRNA expression had no prognostic significance. On multivariate analysis, MYC protein overexpression and ECOG score retained prognostic significance.

MYC and BCL2 overexpression is associated with a higher class of Memorial Sloan-Kettering Cancer Center prognostic model and poor clinical outcome in primary diffuse large B-cell lymphoma of the central nervous system

Background

Primary diffuse large B-cell lymphoma of the central nervous system (PCNS-DLBCL) is a distinct clinicopathological entity with a poor prognosis. Concurrent MYC and BCL2 overexpression predicts inferior prognosis in systemic DLBCLs. However, the prognostic significance of MYC and BCL2 in PCNS-DLBCL remains elusive.

Methods

Immunohistochemistry (IHC) of MYC, BCL2 and BCL6 was performed on tumor samples from 114 patients with PCNS-DLBCL. IHC score was assigned based on the proportion of immunostained cells.

Results

MYC, BCL2, and BCL6 IHC scores were 18.16 ± 19.58, 58.86 ± 35.07, and 39.39 ± 37.66 % (mean ± SD), respectively. Twenty-one cases (18.1 %) were designated as MYC-positive with a cutoff score of 40. BCL2 positivity was found in 87 cases (75.0 %) using a cutoff score of 30. MSKCC (Memorial Sloan-Kettering Cancer Center prognostic model) class 2 and 3 had higher rates of MYC and/or BCL2 positivity (MYC, P = 0.012; BCL2, P = 0.008; dual-positive, P = 0.022). Poor KPS (Karnofsky Performance Status score <70), multifocal disease, Nottingham-Barcelona score ≥2, and MSKCC class 2 and 3 were related to shorter progression-free survival (PFS) (P = 0.001, 0.037, 0.001, and 0.008, respectively). Patients with older age (>60 years) showed poorer overall survival (OS) (P = 0.020). MYC positivity was associated with poor PFS (P = 0.027), while patients with BCL2 positivity exhibited a shorter OS (P = 0.010). Concomitant MYC and BCL2 positivity was related to poor PFS (P = 0.041), while the lack of both MYC and BCL2 expression was related to prolonged OS (P = 0.014). MYC and BCL2 expression had no independent prognostic implication by multivariate analysis in overall patients with PCNS-DLBCL. However, among patients treated with combined high-dose methotrexate, vincristine and procarbazine and radiotherapy, dual MYC and BCL2 overexpression (a cutoff score of 60) was an independent poor prognostic indicator (P = 0.010).

Conclusions

Evaluation of MYC and BCL2 expression may be helpful for the determination of PCNS-DLBCL prognosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2397-8) contains supplementary material, which is available to authorized users.

TP53 hotspot mutations are predictive of survival in primary central nervous system lymphoma patients treated with combination chemotherapy

Primary central nervous system lymphoma (PCNSL) is an aggressive variant of diffuse large B-cell lymphoma (DLBCL) confined to the CNS. TP53 mutations (MUT-TP53) were investigated in the context of MIR34A/B/C- and DAPK promoter methylation status, and associated with clinical outcomes in PCNSL patients. In a total of 107 PCNSL patients clinical data were recorded, histopathology reassessed, and genetic and epigenetic aberrations of the p53-miR34-DAPK network studied. TP53 mutational status (exon 5-8), with structural classification of single nucleotide variations according to the IARC-TP53-Database, methylation status of MIR34A/B/C and DAPK, and p53-protein expression were assessed. The 57/107 (53.2 %) patients that were treated with combination chemotherapy +/- rituximab (CCT-treated) had a significantly better median overall survival (OS) (31.3 months) than patients treated with other regimens (high-dose methotrexate/whole brain radiation therapy, 6.0 months, or no therapy, 0.83 months), P < 0.0001. TP53 mutations were identified in 32/86 (37.2 %), among which 12 patients had hotspot/direct DNA contact mutations. CCT-treated patients with PCNSL harboring a hotspot/direct DNA contact MUT-TP53 (n = 9) had a significantly worse OS and progression free survival (PFS) compared to patients with non-hotspot/non-direct DNA contact MUT-TP53 or wild-type TP53 (median PFS 4.6 versus 18.2 or 45.7 months), P = 0.041 and P = 0.00076, respectively. Multivariate Cox regression analysis confirmed that hotspot/direct DNA contact MUT-TP53 was predictive of poor outcome in CCT-treated PCNSL patients, P = 0.012 and P = 0.008; HR: 1.86 and 1.95, for OS and PFS, respectively. MIR34A, MIR34B/C, and DAPK promoter methylation were detected in 53/93 (57.0 %), 80/84 (95.2 %), and 70/75 (93.3 %) of the PCNSL patients with no influence on survival. Combined MUT-TP53 and MIR34A methylation was associated with poor PFS (median 6.4 versus 38.0 months), P = 0.0070. This study suggests that disruption of the p53-pathway by MUT-TP53in hotspot/direct DNA contact codons is predictive of outcome in CCT-treated PCNSL patients, and concomitant MUT-TP53 and MIR34A methylation are associated with poor PFS.

MYC protein expression in primary diffuse large B-cell lymphoma of the central nervous system

Primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) is a rare, aggressive subtype of DLBCL, the biology of which is poorly understood. Recent studies have suggested a prognostic role of MYC protein expression in systemic DLBCL, but little is known about the frequency and significance of MYC protein expression in CNS DLBCL. Hence, we investigated MYC protein expression profiles of CNS DLBCL and assessed the relationship between MYC expression and a variety of histopathologic, immunophenotypic, genetic, and clinical features. Fifty-nine CNS DLBCL diagnosed at our institution over the past 13 years were evaluated. The majority of cases (80%) showed centroblastic morphology, and 12 (20%) displayed a perivascular pattern of infiltration. According to the Hans criteria, 41 (69%) cases had a non-germinal center B-cell and 18 (31%) had a germinal center B-cell cell-of-origin (COO) phenotype. Mean MYC protein expression was 50% (median: 50%, range: 10-80%). Forty-three cases (73%) showed MYC overexpression (≥ 40%), and 35 (60%) showed MYC/BCL2 coexpression. MYC overexpression was seen in the single case harboring MYC translocation and in the cases showing increased copies of MYC (27%); however, no significant difference in mean MYC expression was seen between groups harboring or lacking MYC aberrations. In our series, age was associated with a significantly increased risk of death, and the perivascular pattern of infiltration was associated with a significantly increased risk of disease progression. Neither MYC expression (with or without BCL2 coexpression) nor other variables, including COO subtype were predictive of clinical outcome. Our findings indicate that the proportion of CNS DLBCL overexpressing MYC is higher compared to systemic DLBCL, and MYC overexpression appears to be independent of genetic MYC abnormalities. Thus, MYC expression and other immunophenotypic markers used for prognostication of systemic DLBCL might not apply to CNS DLBCL due to differences in disease biology.

LMO2 and BCL6 are associated with improved survival in primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is an aggressive sub-variant of non-Hodgkin lymphoma (NHL) with morphological similarities to diffuse large B-cell lymphoma (DLBCL). While methotrexate (MTX)-based therapies have improved patient survival, the disease remains incurable in most cases and its pathogenesis is poorly understood. We evaluated 69 cases of PCNSL for the expression of HGAL (also known as GCSAM), LMO2 and BCL6 - genes associated with DLBCL prognosis and pathobiology, and analysed their correlation to survival in 49 PCNSL patients receiving MTX-based therapy. We demonstrate that PCNSL expresses LMO2, HGAL(also known as GCSAM) and BCL6 proteins in 52%, 65% and 56% of tumours, respectively. BCL6 protein expression was associated with longer progression-free survival (P = 0·006) and overall survival (OS, P = 0·05), while expression of LMO2 protein was associated with longer OS (P = 0·027). Further research is needed to elucidate the function of BCL6 and LMO2 in PCNSL.

Beyond high-dose methotrexate and brain radiotherapy: novel targets and agents for primary CNS lymphoma

BACKGROUND

While there has been significant progress in outcomes for patients diagnosed with primary central nervous system (CNS) lymphoma (PCNSL), survival rates will likely plateau with the current armamentarium of agents used to treat these patients. Moreover, given that PCNSL increasingly impacts an older population, a significant proportion of patients are not eligible for intensive therapies such as high-dose chemotherapy or whole-brain radiation. There is a need for the development of novel agents, which target key survival pathways in order to continue to make progress in this disease.

PATIENTS AND METHODS

We reviewed the key molecular pathways and genomic aberrations in PCNSL in order to identify candidate targets. We focused on molecules and pathways that have been identified and confirmed by more than one investigator or methodology.

RESULTS

While PCNSL tumors usually express a BCL6+, MUM1+ 'activated, germinal center' immunophenotype, they exhibit multiple shared genetic properties with ABC-type diffuse large B-cell lymphomas. Candidate targets and pathways include NFkB, the B-cell receptor, the JAK/STAT pathway, IRF4, BCL-6 as well as PIM kinases. Elements of the tumor microenvironment that may be exploited therapeutically include chemokine pathways, as well as macrophage and T-cell responses.

CONCLUSIONS

There is a significant need for developing novel therapies in PCNSL, given that an increasing proportion of patients are not eligible for high-dose chemotherapy and brain radiation is associated with detrimental cognitive side-effects. We provide an overview of potential drug targets and novel agents that may be integrated with existing strategies in order to make further progress in this disease.

Intensive chemotherapy and immunotherapy in patients with newly diagnosed primary CNS lymphoma: CALGB 50202 (Alliance 50202)

PURPOSE

Concerns regarding neurocognitive toxicity of whole-brain radiotherapy (WBRT) have motivated development of alternative, dose-intensive chemotherapeutic strategies as consolidation in primary CNS lymphoma (PCNSL). We performed a multicenter study of high-dose consolidation, without WBRT, in PCNSL. Objectives were to determine: one, rate of complete response (CR) after remission induction therapy with methotrexate, temozolomide, and rituximab (MT-R); two, feasibility of a two-step approach using high-dose consolidation with etoposide plus cytarabine (EA); three, progression-free survival (PFS); and four, correlation between clinical and molecular prognostic factors and outcome.

PATIENTS AND METHODS

Forty-four patients with newly diagnosed PCNSL were treated with induction MT-R, and patients who achieved CR received EA consolidation. We performed a prospective analysis of molecular prognostic biomarkers in PCNSL in the setting of a clinical trial.

RESULTS

The rate of CR to MT-R was 66%. The overall 2-year PFS was 0.57, with median follow-up of 4.9 years. The 2-year time to progression was 0.59, and for patients who completed consolidation, it was 0.77. Patients age > 60 years did as well as younger patients, and the most significant clinical prognostic variable was treatment delay. High BCL6 expression correlated with shorter survival.

CONCLUSION

CALGB 50202 demonstrates for the first time to our knowledge that dose-intensive consolidation for PCNSL is feasible in the multicenter setting and yields rates of PFS and OS at least comparable to those of regimens involving WBRT. On the basis of these encouraging results, an intergroup study has been activated comparing EA consolidation with myeloablative chemotherapy in this randomized trial in PCNSL, in which neither arm involves WBRT.

Current and emerging pharmacotherapies for primary CNS lymphoma

Primary central nervous system lymphoma (PCNSL) constitutes a rare group of extranodal non-Hodgkin's lymphoma (NHL) primarily of B cell origin. It occurs in both immuno-competent and immune-compromised patients. High dose m ethotrexate (HD-MTX) based chemotherapy is the standard therapy. Chemotherapy with whole brain radiation therapy (WBRT) improves response rates and survival compared with WBRT alone. However, due to the increased risk for neurotoxicity with WBRT, recent studies have focused on using chemotherapy alone. Methotrexate based multi-agent chemotherapy without WBRT is associated with similar t reatment rates and survival compared with regimens that include WBRT although controlled trials have not been performed. Because of the low incidence of this disease, it is difficult to conduct randomized controlled trials. In this article we have discussed about the past, present and emerging treatment options in patients with PCNSL.

Biomarker robustness reveals the PDGF network as driving disease outcome in ovarian cancer patients in multiple studies

Background

Ovarian cancer causes more deaths than any other gynecological cancer. Identifying the molecular mechanisms that drive disease progress in ovarian cancer is a critical step in providing therapeutics, improving diagnostics, and affiliating clinical behavior with disease etiology. Identification of molecular interactions that stratify prognosis is key in facilitating a clinical-molecular perspective.

Results

The Cancer Genome Atlas has recently made available the molecular characteristics of more than 500 patients. We used the TCGA multi-analysis study, and two additional datasets and a set of computational algorithms that we developed. The computational algorithms are based on methods that identify network alterations and quantify network behavior through gene expression.

We identify a network biomarker that significantly stratifies survival rates in ovarian cancer patients. Interestingly, expression levels of single or sets of genes do not explain the prognostic stratification. The discovered biomarker is composed of the network around the PDGF pathway. The biomarker enables prognosis stratification.

Conclusion

The work presented here demonstrates, through the power of gene-expression networks, the criticality of the PDGF network in driving disease course. In uncovering the specific interactions within the network, that drive the phenotype, we catalyze targeted treatment, facilitate prognosis and offer a novel perspective into hidden disease heterogeneity.

Differential micro-RNA expression in primary CNS and nodal diffuse large B-cell lymphomas

Most primary CNS lymphomas (PCNSL) are diffuse large B-cell lymphomas (DLBCL). However, clinical behavior and prognosis differ considerably from those for nodal DLBCL (nDLBCL), and their pathogenesis is still not fully understood. Micro-RNAs (miRNAs) have been associated with cancer development and progression. We investigated a large miRNA panel for differential expression in PCNSL and nDLBCL, to determine new mechanisms potentially involved in PCNSL pathogenesis. Using paraffin-embedded biopsy specimens from 21 HIV-negative patients with newly diagnosed PCNSL (n = 11) and nDLBCL (n= 10), we measured the expression of 365 miRNA species by quantitative real-time PCR using low-density PCR arrays. We found that 18 miRNAs were differentially expressed: median expression levels of 13 miRNAs were 2.1-13.1 times higher in PCNSL, and median expression levels of 5 miRNAs were 2.6-3.3 times higher in nDLBCL. MiRNAs upregulated in PCNSL were associated with the Myc pathway (miR-17-5p, miR-20a, miR-9), with blocking of terminal B-cell differentiation (miR-9, miR-30b/c), or with upregulation by inflammatory cytokines (miR-155). Putative tumor-suppressor miRNAs (miR-199a, miR-214, miR-193b, miR-145) were downregulated in PCNSL. There was no overlap of miRNAs dysregulated in PCNSL with those differentially expressed between immunohistologically defined germinal center B cell-like (GCB) and non-GCB types or, apart from miR-9, with miRNAs known to be overexpressed in human brain. We conclude that PCNSL exhibits a distinct pattern of miRNA expression compared with nDLBCL. This argues for the involvement of different molecular mechanisms in the pathogenesis of these two lymphoma types.

Most primary central nervous system diffuse large B-cell lymphomas occurring in immunocompetent individuals belong to the nongerminal center subtype: a retrospective analysis of 31 cases

Primary central nervous system lymphomas are rare neoplasms characterized by a dismal prognosis relative to other extranodal lymphomas. Approximately 98% of primary central nervous system lymphomas are of B-cell origin, and most belong to the diffuse large B-cell type. Recently, diffuse large B-cell lymphomas have been subcategorized into germinal center and nongerminal center types based on gene expression profiles and immunohistochemical expression of CD10, Bcl-6, and MUM1. Studies have shown that the overall survival rate of the germinal center group is better than that of the nongerminal center lymphomas. In this study, 31 cases of primary central nervous system lymphomas of the diffuse large B-cell type were retrieved, reviewed, and immunostained for CD10, Bcl-6, MUM1, and Ki-67. Subclassification was carried out as described earlier, where CD10 and/or Bcl-6 positivity and negativity for MUM1 were considered characteristic of germinal center subtype and the opposite expression of nongerminal center subtype. Furthermore, the proliferative activity was semiquantitatively assessed using percent positive cells staining with Ki-67. Of the 31 cases examined, 26 (84%) were found to belong to the nongerminal center type. The Ki-67 index in these 26 cases ranged from 30 to 90% (mean, 69%). Five cases were categorized as the germinal center subtype. They had an Ki-67 index between 70 and 90% (mean, 78%). Interestingly, none of our patients were known to be HIV positive. One patient had a 10-year history of orthotopic liver transplant. We also performed fluorescence in situ hybridization analysis on formalin-fixed material and found that 38% of the cases where tissue was available had abnormalities of MYC/IGH and/or IGH/BCL2. We conclude that most primary central nervous system diffuse large B-cell lymphomas are of the nongerminal center origin. Regardless of the germinal center status, all cases showed a high proliferative rate. A statistically significant difference in the overall survival between the two groups was not seen.

Immunohistological profiling by B-cell differentiation status of primary central nervous system lymphoma treated by high-dose methotrexate chemotherapy

Primary central nervous system lymphoma (PCNSL) remains a devastating disease with poor prognosis, despite the improvement offered by methotrexate (MTX)-based chemotherapy. Several studies have attempted to identify biomarkers predictive of prognosis, which are expected to be both clinically useful and biologically important for understanding PCNSL. The present study attempts to classify human immunodeficiency virus (HIV)-unrelated PCNSL patients treated with radiation combined with rapid high-dose MTX chemotherapy according to B-cell differentiation status, and retrospectively examines the prognostic impact. Initial response to MTX was a strong predictor of favorable prognosis in terms of both progression-free survival (PFS) and overall survival (OS). Thirteen out of 29 cases were CD10(-)/BCL-6(+)/MUM-1(+), being more frequent compared with systemic peripheral nodal lymphoma. Although post-germinal-center B-cell-originating PCNSLs (CD10(-)/BCL-6(-)/MUM-1(+)) showed a trend towards better response to MTX and progression-free survival than did germinal-center-related B-cell-originating PCNSLs (CD10(+) OR CD10(-)/BCL-6(+)/MUM-1(+)), the difference was only marginal (P = 0.04 Gehan-Breslow-Wilcoxon, P = 0.17 log-rank). Our results imply that different B-cell stages in PCNSL have significant relevance in terms of biological behavior. However, clinical use as a prognostic marker requires further investigation.

Primary central nervous system lymphoma: immunohistochemical profile and prognostic significance

Primary central nervous system lymphoma (PCNSL) is a rare subtype of non-Hodgkin lymphoma (NHL) with extranodal location affecting only the CNS, meninges and eye, without visceral or lymph node involvement. Its incidence has increased sharply over the past three decades, especially in immunocompetent subjects. Most PCNSL cases are diffuse large B-cell lymphomas (DLBCLs). However, it differs from nodal DLBCL in that it has a worse prognosis. DLBCLs are a heterogeneous entity and according to new genomic discoveries, classifications into prognostic subgroups have been embarked upon. Two prognostic algorithms were then prepared using a panel of immunohistochemical markers (CD10, Bcl6, MUM1/IRF-4, and Bcl2), thus categorizing DLBCL into two subgroups, GCB (germinal centre B-cell-like) or non-GCB, and into Group 1 or Group 2. Our goal is to apply both of these two sub-classifications to 39 PCNSLs, in order to assess their usefulness and prognostic relevance. 74.3% of our PCNSLs were of a non-GCB phenotype, corresponding to an activated postgerminal origin. They were evenly distributed across G1 and G2. Two- and 5-year overall survival rates were 34.8% and 19.6%, respectively. Younger age (<65) and a therapeutic combination of chemotherapy and radiotherapy significantly improved our patients' survival rates. The other clinical or biological markers tested had no prognostic impact. The two classifications did not reveal any significant survival difference. The recent discovery of a specific "transcriptional signature" of PCNSL, marking them out of DLBCL could account for the irrelevance of such prognostic classifications to PCNSL.

Pediatric diffuse large B-cell lymphoma demonstrates a high proliferation index, frequent c-Myc protein expression, and a high incidence of germinal center subtype: Report of the French-American-British (FAB) international study group

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) makes up 10-20% of pediatric non-Hodgkin lymphoma, and these patients have a significantly better prognosis than adults with DLBCL. The difference in prognosis may be related to clinical, phenotypic, and/or biological differences between adult and pediatric DLBCL. In adult DLBCL, the germinal center (GC) phenotype is associated with a better prognosis than the activated B-cell (ABC) phenotype. However, a high proliferative index and expression of Bcl2 and c-Myc protein have all been associated with worse outcomes. While multiple studies have addressed the phenotype and expression patterns of adult DLBCL, relatively little is known about these biological variables in pediatric DLBCL. The goal of this study was to investigate the proliferative index, the relative frequencies of the GC and non-GC subtypes, and the expression of Bcl2 and c-Myc protein in a cohort of children with DLBCL treated in a uniform manner.

PROCEDURE

We performed immunohistochemistry (IHC) for MIB1, CD10, Bcl6, MUM1, Bcl2, and c-Myc on DLBCL tissue from children treated uniformly in the FAB LMB96 trial (SFOP LMB96/CCG5961/UKCCSG/NHL 9600).

RESULTS

Compared to published adult DLBCL studies, pediatric DLBCL demonstrated moderate to high proliferation rates (83%), increased c-Myc protein expression (84%), decreased Bcl2 protein expression (28%), and an increased frequency of the GC phenotype (75%).

CONCLUSIONS

These findings suggest that there are significant biologic differences between pediatric and adult forms of DLBCL, which may contribute to the superior prognosis seen in the pediatric population relative to adult disease.

Histological complexities of pancreatic lesions from transgenic mouse models are consistent with biological and morphological heterogeneity of human pancreatic cancer

Although pancreatic cancer is the fourth leading cause of cancer death, it has received much less attention compared to other malignancies. There are several transgenic animal models available for studies of pancreatic carcinogenesis, but most of them do not recapitulate, histologically, human pancreatic cancer. Here we review some detailed molecular complexity of human pancreatic cancer and their reflection in histomorphological complexities of pancreatic lesions developed in various transgenic mouse models with a special concern for studying the effects of chemotherapeutic and chemopreventive agents. These studies usually require a large number of animals that are at the same age and gender and should be either homozygote or heterozygote but not a mixture of both. Only single-transgene models can meet these special requirements, but many currently available models require a mouse to simultaneously bear several transgene alleles. Thus it is imperative to identify new gene promoters or enhancers that are specific for the ductal cells of the pancreas and are highly active in vivo so as to establish new single-transgene models that yield pancreatic ductal adenocarcinomas for chemotherapeutic and chemopreventive studies.

c-Myc-induced chemosensitization is mediated by suppression of cyclin D1 expression and nuclear factor-kappa B activity in pancreatic cancer cells

PURPOSE

Pancreatic cancer is a highly aggressive disease that remains refractory to various chemotherapeutic agents. Because the proto-oncogene c-myc can modulate apoptosis in response to cytotoxic insults and is commonly overexpressed in pancreatic cancer, we investigated the value of c-myc as a potential modulator of cellular response to various chemotherapeutic agents.

EXPERIMENTAL DESIGN

Stable overexpression or small interfering RNA (siRNA)-mediated knockdown of c-myc and restoration of cyclin D1 were done in the Ela-myc pancreatic tumor cell line. Cell viability after cisplatin treatment of c-myc-overexpressing, control, and siRNA-transfected cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and drug-induced apoptosis was measured by DNA fragmentation, sub-G(1), and poly(ADP-ribose) polymerase cleavage analyses. Protein expression profile after cisplatin treatment was determined by Western blotting and DNA binding activity of nuclear factor-kappaB was examined by electrophoretic mobility shift assay.

RESULTS

Ectopic overexpression of c-myc in murine and human pancreatic cancer cell lines, Ela-myc and L3.6pl, respectively, resulted in increased sensitivity to cisplatin and other chemotherapeutic drugs. Increased sensitivity to cisplatin in c-myc-overexpressing cells was due, in part, to the marked increase in cisplatin-induced apoptosis. Conversely, down-regulation of c-myc expression in stable c-myc-overexpressing cells by c-myc siRNA resulted in decreased sensitivity to cisplatin-induced cell death. These results indicate an important role of c-myc in chemosensitivity of pancreatic cancer cells. The c-myc-induced cisplatin sensitivity correlated with inhibition of nuclear factor kappaB activity, which was partially restored by ectopic cyclin D1 overexpression.

CONCLUSIONS

Our results suggest that the c-myc-dependent sensitization to chemotherapy-induced apoptosis involves suppression of cyclin D1 expression and nuclear factor kappaB activity.

Reactive perivascular T-cell infiltrate predicts survival in primary central nervous system B-cell lymphomas

Well-established histopathological prognostic factors are lacking in primary central nervous system (CNS) lymphomas (PCNSL). The present study investigated the presence and prognostic role of tumour necrosis (TN) and reactive perivascular T-cell infiltrate (RPVI), defined as a rim of small reactive T-lymphocytes occurring alone or located between the vascular wall and large neoplastic cells, in tumour samples from 100 immunocompetent patients with PCNSL. World Health Organization histotypes of the patients were: 96 diffuse large B-cell lymphomas, two Burkitt-like lymphomas, one anaplastic large T-cell lymphoma and one unclassified B-cell lymphoma. TN was observed in 24 (24%) cases and RPVI in 26 (36%) of 73 assessable cases. Patients with RPVI-positive lesions exhibited a significantly better overall survival (OS) than patients with RPVI-negative lymphoma, particularly among patients treated with high-dose methotrexate-based chemotherapy (3-year OS: 59 +/- 14% vs. 42 +/- 9%, P = 0.02). By contrast, the presence of TN did not demonstrate prognostic significance. Multivariate analysis confirmed an independent association between RPVI and survival. In conclusion, the presence of RPVI is independently associated with survival in PCNSL. This parameter can be easily and routinely assessed at diagnosis on histopathological specimens.

Comparison of ataxia-telangiectasia mutated protein expression in diffuse large B-cell lymphomas of primary central nervous system and non-central nervous system origin

CONTEXT

The ataxia-telangiectasia mutated (ATM) gene encodes a nuclear 370-kd phosphoprotein known to be associated with chromosomal regions containing double-strand breaks. The mutations in the ATM gene may be involved in the development of some subtypes of sporadic lymphomas and leukemias. In primary central nervous system diffuse large B-cell lymphomas (PCNS DLBCLs), the pathogenetic role of ATM mutation has not been investigated.

OBJECTIVE

To investigate ATM protein expression in PCNS DLBCLs, in comparison with that in non-central nervous system (non-CNS) DLBCLs and to study the relationship of ATM protein loss with several clinicopathologic parameters.

DESIGN

This study included 42 cases of PCNS DLBCL and 33 cases of non-CNS DLBCL from immunocompetent patients. The ATM protein loss was analyzed by immunohistochemical staining. For the subclassification of DLBCL and analysis of the relationship between ATM and other prognostic markers, we performed immunohistochemical evaluation to detect the following markers: Bcl-6, CD10, multiple myeloma-1, CD138, Bcl-2, Ki-67, and p53.

RESULTS

The loss of ATM expression was statistically more frequent in PCNS DLBCLs (21/42 cases [50.0%]) than in non-CNS DLBCLs (0/33 cases [0.0%]; P < .001). The loss of ATM expression was not a prognostic marker in PCNS DLBCLs (P = .64). The loss of ATM expression had a strong correlation with the germinal center B-cell-like subtype (P = .01), a low Ki-67 labeling index (P = .03), and low Bcl-2 expression (P = .01) among several clinicopathologic parameters.

CONCLUSIONS

Our results suggest that the ATM protein is more strongly correlated with PCNS DLBCL lymphomagenesis than with non-CNS DLBCLs, especially in germinal center B-cell-like subtypes demonstrating low Ki-67 labeling indexes and low Bcl-2 expression.

Endoglin (CD 105) is expressed on endothelial cells in the primary central nervous system lymphomas and correlates with survival

Endoglin (CD105) is predominantly expressed on the cellular lineages within the vascular system and it is overexpressed on proliferating endothelial cells that participate in neoangiogenesis, with a weak or negative expression in the vascular endothelium of normal tissues. To investigate the correlation between the CD105 expression and possible prognostic markers or progression in the primary central nervous system lymphomas (PCNSLs), the present study assessed 26 cases of PCNSL by immunostaining for CD105 and CD34. Intratumoral microvessel density (IMVD) was determined in the hotspots and interfaces at a magnification of x200. According to the mean value, the patients were classified into lower-IMVD and higher-IMVD groups. When CD34 was used as a marker of angiogenesis, the survival rates of these two groups demonstrated no significant difference. In contrast, when CD105 was used as a marker of angiogenesis, the survival rate of the lower-IMVD group was significantly higher than that for the higher-IMVD group (P < 0.01). In the group of CD34-immunostained vessels, no difference was observed in IMVD between the hotspots and interfaces (P = 0.31). In the group with CD105-immunostained vessels, a greater IMVD was observed in the hotspots than in the interfaces (P < 0.01). These results suggested that the growth of PCNSLs was dependent on angiogenesis, that IMVD as determined by anti-CD105 monoclonal antibody was a reliable prognostic marker in PCNSLs, and that PCNSLs may therefore not require sufficient neoangiogenesis at the start of PCNSLs, however, it may instead require a higher rate of neoangiogenesis as they infiltrate and destroy the brain parenchyma.

Pathology of primary central nervous system lymphoma

✓ The understanding of primary central nervous system lymphoma (PCNSL) has lagged behind that of the much more common systemic, nodal lymphomas. Reasons for this include the relative rarity of PCNSL and the fact that these lesions differ in some ways from their histologically similar systemic counterparts. The purpose of this paper is twofold: first, the author provides concise descriptions of the pathological features of both common and uncommon types of PCNSL while discussing issues such as the confusion surrounding histological classification of PCNSLs, problems related to intraoperative diagnosis, and the appropriate diagnostic work up. Second, the author discusses a small number of molecular studies to demonstrate the great promise they offer. Such studies have already clarified some issues, including the category of lymphocyte from which the majority of PCNSLs are derived. Hopefully in the future these studies will help guide treatment decisions.

Detection of the bcl-2 t(14;18) translocation and proto-oncogene expression in primary intraocular lymphoma

PURPOSE

Primary intraocular lymphoma (PIOL) is a diffuse large B cell lymphoma that initially infiltrates the retina, vitreous, or optic nerve head, with or without central nervous system involvement. This study examined the expression of the bcl-2 t(14;18) translocation, the bcl-10 gene, and high expression of bcl-6 mRNA in PIOL cells.

METHODS

Microdissection and PCR analysis were used to examine vitreous specimens in patients with PIOL for the presence of bcl-2 t(14;18) translocations, the bcl-10 gene, and expression of bcl-6 mRNA. A medical record review was also conducted to determine whether the bcl-2 t(14;18) translocation correlated with prognosis.

RESULTS

Forty of 72 (55%) PIOL patients expressed the bcl-2 t(14;18) translocation at the major breakpoint region. Fifteen of 68 (22%) patients expressed the translocation at the minor cluster region. The bcl-10 gene was detected in 6 of 26 (23%) patients, whereas 4 of 4 (100%) PIOL patients expressed higher levels of bcl-6 mRNA compared with inflammatory lymphocytes. An analysis of clinical outcome in 23 PIOL patients revealed no significant association between bcl-2 t(14;18) translocations and survival or relapse. However, patients with the translocation were significantly younger.

CONCLUSIONS

PIOL has unique molecular patterns of bcl-2, bcl-10, and bcl-6 when compared with other systemic lymphomas. This study lays the foundation for future studies aimed at exploring the genotypic classification of PIOL based on the quantitative molecular framework of gene expression profiling, with the goal of providing useful adjuncts to the pathologic diagnosis of this complex disease.

Individualized markers optimize class prediction of microarray data

Background

Identification of molecular markers for the classification of microarray data is a challenging task. Despite the evident dissimilarity in various characteristics of biological samples belonging to the same category, most of the marker – selection and classification methods do not consider this variability. In general, feature selection methods aim at identifying a common set of genes whose combined expression profiles can accurately predict the category of all samples. Here, we argue that this simplified approach is often unable to capture the complexity of a disease phenotype and we propose an alternative method that takes into account the individuality of each patient-sample.

Results

Instead of using the same features for the classification of all samples, the proposed technique starts by creating a pool of informative gene-features. For each sample, the method selects a subset of these features whose expression profiles are most likely to accurately predict the sample's category. Different subsets are utilized for different samples and the outcomes are combined in a hierarchical framework for the classification of all samples. Moreover, this approach can innately identify subgroups of samples within a given class which share common feature sets thus highlighting the effect of individuality on gene expression.

Conclusion

In addition to high classification accuracy, the proposed method offers a more individualized approach for the identification of biological markers, which may help in better understanding the molecular background of a disease and emphasize the need for more flexible medical interventions.

Sub-attomole oligonucleotide and p53 cDNA determinations via a high-resolution surface plasmon resonance combined with oligonucleotide-capped gold nanoparticle signal amplification

Oligonucleotide (ODN)-capped gold nanoparticles (Au-NPs) were used in a sandwich assay of ODN or polynucleotide by a flow injection surface plasmon resonance (SPR). A carboxylated dextran film was immobilized onto the SPR sensor surface to eliminate nonspecific adsorption of ODN-capped Au-NPs. The tandem use of signal amplification via the adlayer of the ODN-capped Au-NPs and the differential signal detection by the bicell detector on the SPR resulted in a remarkable DNA detection level. A 39-mer target at a quantity as low as 2.1 x 10(-20)mol, corresponding to 1.38 fM in a 15 microl solution, can be measured. To our knowledge, both the concentration and quantity detection levels are the lowest among all the gene analyses conducted with SPR to this point. The method is shown to be reproducible (relative standard deviation values <16%) and to possess high sequence specificity. It is also demonstrated to be viable for sequence-specific p53 cDNA analysis. The successful elimination of nonspecific adsorption of, and the signal amplification by, ODN-capped Au-NPs renders the SPR attractive for cases where the DNA concentration is extremely low and the sample availability is severely limited.

Immunohistochemical Expression of p53, bcl-2, and p21 waf1 in 48 Argentinean Children With Non-Hodgkin Lymphoma

BACKGROUND

Lymphoma accounts for 10% of all childhood cancers in developed countries. In Argentina, the incidence is 13.6%; of these, 53% are non-Hodgkin lymphomas (NHL) and 47% are Hodgkin lymphomas. Overexpression of p53, p21, and bcl-2 has been studied mainly in adults with NHL and correlated with clinical features and survival. The authors' aim was to analyze overexpression of these cellular oncogenes in children with NHL.

METHODS

Formalin-fixed paraffin-embedded lymph node biopsies from 48 children with NHL were studied by immunohistochemistry with monoclonal antibodies for p53, bcl-2, and p21.

RESULTS

Overexpression of p53 was detected in 81% of cases; bcl-2 positivity was 46% and p21 positivity was 42%. The p53/p21 expression patterns (types IV and V patterns), which correspond to the overexpression of nonfunctional p53, accounted for 46% of NHL. None of the studied oncogene patterns correlated with poor clinical patient outcome or histologic subtype.

CONCLUSIONS

Of 81% of cases with p53 overexpression, 46% exhibited a nonfunctional p53 pattern, and this may contribute to dysregulation of proliferation, bcl-2 expression in up to 46% of cases may reflect a failure of bcl-2 downregulation in pre-B and immature B cells.

Gene expression and angiotropism in primary CNS lymphoma

Primary CNS lymphoma is an aggressive form of non-Hodgkin lymphoma whose growth is restricted to the central nervous system. We used cDNA microarray analysis to compare the gene expression signature of primary CNS lymphomas with nodal large B-cell lymphomas. Here, we show that while individual cases of primary CNS lymphomas may be classified as germinal center B-cell, activated B-cell, or type 3 large B-cell lymphoma, brain lymphomas are distinguished from nodal large B-cell lymphomas by high expression of regulators of the unfolded protein response (UPR) signaling pathway, by the oncogenes c-Myc and Pim-1, and by distinct regulators of apoptosis. We demonstrate that interleukin-4 (IL-4) is expressed by tumor vasculature as well as by tumor cells in CNS lymphomas. We also identify high expression in CNS lymphomas of several IL-4-induced genes, including X-box binding protein 1 (XBP-1), a regulator of the UPR. In addition, we demonstrate expression of the activated form of STAT6, a mediator of IL-4 signaling, by tumor cells and tumor endothelia in CNS lymphomas. High expression of activated STAT6 in tumors was associated with short survival in an independent set of patients with primary CNS lymphoma who were treated with high-dose intravenous methotrexate therapy.

Primary central nervous system lymphoma

Primary central nervous system lymphoma is a stage 1E non-Hodgkin's lymphoma confined to the nervous system. It is seen in immunocompetent and immunodeficient populations, the latter group associated with the Epstein-Barr virus. Primary central nervous system lymphoma can affect the brain, leptomeninges, spinal cord or eyes. The institution of high-dose methotrexate-based regimens and whole-brain radiation therapy has significantly increased survival, but neurotoxicity is high in patients over 60 years of age. Despite these advances, 50% of patients initially treated will relapse. Recent investigations include the use of rituximab (immunotherapy) and stem-cell transplantation, as well as regimens without whole-brain radiation therapy in the elderly. The optimal treatment regimen is yet to been determined.

Prognostic factors in primary central nervous system lymphomas

Efforts to identify survival predictors in primary central nervous system lymphoma (PCNSL) have produced isolated, unconfirmed observations in small retrospective and prospective series. Age and performance status are two unanimously accepted prognostic factors. These and other independent predictors of survival were used by the International Extranodal Lymphoma Study Group (IELSG) to establish a prognostic scoring system able to distinguish risk groups in PCNSL. The IELSG score will improve further with better knowledge of these malignancies, especially with the inclusion of molecular and pharmacogenetic variables able to identify lymphomas with different chemosensitivities or degrees of aggressiveness. In the years ahead, a well-established prognostic score will allow the separation of patients into risk groups, which could result in the application of risk-tailored therapeutic strategies.

Treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) describes a malignant non-Hodgkin's lymphoma (NHL) whose sole site of involvement is the central nervous system (CNS). The diagnosis of PCNSL must be differentiated from systemic NHL with metastasis to the CNS, which usually occurs late in the course of systemic disease. PCNSL accounts for approximately 4% to 7% of primary brain tumors, and its incidence has been increasing since the mid-1970s. Compared with other more common malignant primary brain tumors, PCNSL tends to be more amenable to radiotherapeutic and chemotherapeutic intervention. In this article, the authors review the standard treatment for upfront and recurrent PCNSL.

A uniform activated B-cell-like immunophenotype might explain the poor prognosis of primary central nervous system lymphomas: analysis of 83 cases

Most primary central nervous system lymphomas (PCNSLs) in immunocompetent patients are diffuse large B-cell lymphomas (DLBCLs), characterized by poor prognosis, compared with systemic forms. A germinal center B-cell-like (GCB) origin of PCNSL was hypothesized on the basis of BCL-6 expression and ongoing mutational activity. Our goal herein was to determine, for 83 PCNSLs, the percentages of GCB and activated B-cell-like (ABC) phenotypes and their prognostic significance. CD10, BCL-6, MUM1, BCL-2, and CD138 antigens were immunohistochemically labeled on paraffin-embedded sections; the first 4 were positive in 2.4%, 55.5%, 92.6%, and 55.5% of the tumors, respectively. None of the 56 tested samples expressed CD138. Among the 82 patients with complete information, 79 (96.3%) were classified as ABC; 42 (51.2%) expressed BCL-6+ MUM1+, suggesting an "activated GCB" origin; 33 (40.2%) were exclusively MUM1+, and the remaining 4 (4.9%) were negative for all markers tested. These findings provide new insights into interpreting the poor PCNSL prognostic, which may, in part, be due to biologic aggressiveness associated with its activated B-cell-like pattern. We postulate assigning PCNSL a histogenetic "time-slot," overlapping late GC and early post-GC, that could explain the predominant ABC phenotype observed.

Evidence for distinct pathomechanisms in genetic subgroups of chronic lymphocytic leukemia revealed by quantitative expression analysis of cell cycle, activation, and apoptosis-associated genes

PURPOSE

In patients with chronic lymphocytic leukemia (CLL), the VH mutation status and genomic aberrations (13q-, +12q, 11q-, 17p-) identify distinct prognostic subgroups. The aim was to elucidate biologic mechanisms through which these genetic markers may exert their pathogenic influence.

PATIENTS AND METHODS

Twenty-four genes involved in apoptosis, cell cycle, B-cell activation, and B-cell receptor (BCR) signaling were analyzed by real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in 82 CLL cases constituting prototypic genetic CLL subgroups as defined by the VH mutation status and the genomic aberrations 13q-, +12, 11q-, and 17p-.

RESULTS

The VH mutation subgroups were characterized by a differential expression of the BCR associated genes ZAP70 and PI3K. Among the subgroups defined by genomic aberrations, there was a deregulation of candidate genes from the affected critical genomic regions such as CDK4 (up), ATM (down), and TP53 (down) in the groups +12, 11q-, and 17p-, respectively. Additionally, the genomic subgroups were characterized by a significant deregulation of cell cycle and apoptosis regulators: AKT (up) in 13q, E2F1 (up) in +12, MYC (up) and BCL-2 (down) in 17p-, and CCND3 (down) in 11q- as well as 17p-. The 17p- subgroup showed an additional down-regulation of BCR-associated genes such as SYK and PI3K.

CONCLUSION

The characteristic gene expression patterns observed implicate a differential regulation of cell cycle, apoptosis, and BCR signaling in the genetic subgroups illustrating distinct pathomechanisms and are evidence for a gene dosage effect being operative in CLL. These findings link the biologic diversity and clinical heterogeneity of CLL.

SHP-1 expression in primary central nervous system B-cell lymphomas in immunocompetent patients reflects maturation stage of normal B cell counterparts

SHP-1 is an important negative regulator involved in signaling through receptors for cytokine/growth factors, and differential patterns of SHP-1 expression in several types of B-cell lymphomas closely resemble the patterns seen in their normal B cell counterparts. In an effort to elucidate the origin of primary central nervous system lymphomas (PCNSL), the present study assessed 32 cases of PCNSL. Tumors were subclassified according to WHO classification and were evaluated by immunohistochemistry for expression of antigens associated with germinal center (GC) (CD10, Bcl-6) and non-GC stages (SHP-1, CD138). Twenty-nine cases showed diffuse large-cell centroblastic morphology, whereas three cases showed diffuse large-cell immunoblastic morphology. The immunophenotypes of PCNSL were as follows: SHP-1+/Bcl-6-/CD10-/CD138- (12 of 32 cases); SHP-1+/Bcl-6+/CD10-/CD138- (15 of 32 cases); SHP-1+/Bcl-6+/CD10+/CD138- (two of 32 cases); SHP-1+/Bcl-6-/CD10+/CD138- (one of 32 cases); and SHP-1-/Bcl-6-/CD10-/CD138- (two of 32 cases). These results indicate that PCNSL might be distinct lymphomas that originate from a late germinal center to an early postgerminal center.

Diagnosis and treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is an uncommon form of non-Hodgkin's lymphoma (NHL) that has been increasing in incidence over the past three decades. Unlike systemic extranodal NHL, the response to therapy for PCNSL patients has been somewhat unsatisfactory. However, methotrexate-based chemotherapy and whole-brain radiotherapy have improved the outcome of patients. Unfortunately, treatment-related neurotoxicity is common, especially in the elderly. Although progress has been made in treating PCNSL, there remains no optimal methotrexate dose or frequency. Treatment of recurrence also remains controversial. These important questions have prompted several clinical studies looking at novel ways to intensify chemotherapy and limit neurotoxicity.

VH gene analysis of primary CNS lymphomas

Primary CNS lymphomas (PCNSL) are highly malignant non-Hodgkin's lymphomas of B cell origin associated with a poor prognosis. These neoplasms show variable sensitivity to radio- and chemotherapy. A molecular basis for these differences in treatment responses has not yet been established for primary CNS lymphomas in a comprehensive series of patients. Here, we performed PCR analyses of the immunoglobulin (Ig) gene rearrangements of 18 PCNSL, including nine patients who responded well to therapy and nine patients who showed resistance to treatment. Variable gene segment distribution, mutation frequency of variable region genes, and clinical course were analyzed. Our data suggest a tendency towards a higher mean mutation frequency (17.2%) in patients responding to treatment and a lower mutation frequency (11.8%) in patients exhibiting a poor response to therapy, respectively. Furthermore, a restricted usage of the VH4 gene family was observed in the majority of nonresponding patients. To further validate the prognostic impact of these molecular parameters, studies in a larger cohort of patients will be required.

Histogenetic phenotypes of B cells in posttransplant lymphoproliferative disorders by immunohistochemical analysis correlate with transplant type: solid organ vs hematopoietic stem cell transplantation

We immunohistochemically defined the histogenesis of posttransplantation lymphoproliferative disorders (PTLDs; B-cell phenotype) occurring after allogeneic T cell-depleted hematopoietic stem cell transplantation (HSCT; n = 15) or solid organ transplantation (SOT; n = 11) to determine whether transplantation type or morphologic subtype of PTLD affected the histogenetic subtype. Immunohistochemical stains using histogenetic markers for germinal center (GC) B cells, late GC and post-GC B cells, and post-GC B cells were performed on paraffin-embedded samples. Morphologically, 14 cases were polymorphic; 12 were monomorphic. Histogenetic marker expression was as follows: 1 monomorphic case (4%), GC phenotype expressing bcl-6 and CD10; 17 cases (65%; polymorphic, 9; monomorphic, 8), late GC-early post-GC phenotype expressing MUM1/IRF4; 8 cases (31%; polymorphic, 5; monomorphic, 3), post-GC phenotype expressing MUM1/IRF4 and CD138 but not bcl-6. PTLD cases after HSCT more frequently were post-GC phenotype than after SOT (7/15 vs 1/11, respectively; P = .040) and were independent of morphologic subclassification. Results suggest that most PTLDs are late GC-early post-GC phenotype with a minor group of post-GC phenotype and rare cases of GC phenotype. Findings also suggest a correlation between histogenetic phenotype of B-cell PTLD and type of transplantation.

Primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare variant of non-Hodgkin's lymphoma that is increasing in incidence. Methotrexate-based chemotherapy in combination with whole-brain radiotherapy (WBRT) has dramatically improved the outcome of patients. However, treatment-related neurotoxicity is a significant complication, especially after radiotherapy in the elderly. Despite advances in therapy, several important questions remain regarding optimal methotrexate dose, dosing frequency, adjunct chemotherapy, and the impact of deferring WBRT. Advances in biologic therapy and strategies to intensify the delivery of chemotherapy may help to limit the use of radiotherapy, thus lessening potential neurotoxicity. Studies looking at oncogenic proteins as potential prognostic markers for PCNSL may help us to develop risk-adapted therapies.