Report of a workshop on malignant lymphoma: a review of molecular and clinical risk profiling

PARP1 expression in mantle cell lymphoma: the utility of PARP1 immunohistochemistry and its relationship with markers of DNA damage

Mantle cell lymphoma (MCL) is an aggressive disease with poor overall survival, attributable in part to frequent defects of the DNA repair genes. In such malignancies, additional inhibition of the ubiquitous DNA damage repair protein, poly-ADP ribose polymerase-1 (PARP1) has shown enhanced cytotoxicity (so-called synthetic lethality). We studied PARP1 expression in a series of clinical cases of MCL, with the secondary aim to ascertain the relationship between PARP1 expression and DNA repair gene expression (namely ATM and p53) by immunohistochemical methods. We also examined the relationship between PARP1 expression and the well-established prognostic biomarker Ki-67, in addition to correlating PARP1 expression with the overall survival. From amongst our series of 79 unselected cases of MCL, we detected PARP1 expression in all but two cases with variable intensity. We also noted correlations between PARP1 expression and ATM and p53 expression. As described in previous studies, we identified a significant survival difference on the basis of Ki-67 and p53 expression. When digital H-score analysis of PARP1 expression was performed, there was a distinct survival advantage noted in patients with lower levels of expression. When our biomarker data were assessed by Cox regression, furthermore, the dominant effects of p53 and PARP1 expression were highlighted. Our data support the need for further research into the potential utility of PARP1 as a biomarker in MCL and for the potential direction of future PARP1 inhibitor-targeted therapy studies.

Prolonged progression-free survival and preserved quality of life in the Canadian prospective study of tositumomab and iodine(131)-tositumomab for previously treated, rituximab-exposed, indolent non-Hodgkin lymphoma

Radioimmunotherapy offers a unique treatment modality for indolent non-Hodgkin lymphoma (iNHL). We report 5-year outcomes and quality of life (QoL) in tositumomab and iodine(131)-tositumomab (TST/I(131)-TST) treated patients with iNHL previously treated with rituximab. Ninety-three patients with ≥ 2 lines of therapy, responding to last treatment, were enrolled at 12 Canadian centers. Median age, disease duration and number of prior therapies (#PTx) were 59 years, 4.9 years and 5, respectively. Outcomes were response rate (43.0%), median progression-free survival (mPFS) (12.0 months), 5-year PFS (27%) and median overall survival (OS) (59.8 months). In responders, median response duration and mPFS were not reached. Improvements in QoL were seen by week 7. In univariate and multivariate analyses, hemoglobin, disease bulk and body surface area (BSA) predicted OS, whereas lactate dehydrogenase (LDH), bulk, BSA and #PTx predicted PFS. Most common adverse events (AEs) were fatigue and nausea. Two cases of myelodysplastic syndrome (MDS) were reported. TST/I(131)-TST was associated with durable responses, and prolonged OS and PFS in heavily pretreated iNHL.

The role of genotype in 104 cases of diffuse large B-cell lymphoma primary of breast

OBJECTIVES

To analyze the role of genotype in patients with diffuse large B-cell lymphoma primary of breast (DLBCL-PB) treated with chemotherapy or immunochemotherapy.

METHODS

We carried out a retrospective analysis in 104 patients with DLBCL-PB who were treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or immunochemotherapy: R-CHOP (adding rituximab) and also carried out an analysis of genotype, studied with immunohistochemistry, as a prognostic factor.

RESULTS

Seventy-seven percent of patients showed the non-GCB (germinal center B) genotype. Patients treated with CHOP had a complete response of 70%; actuarial curves at 5 years showed that disease-free survival was 66 % and overall survival was 52% and that it was not statistically different than patients treated with R-CHOP: 78%, 61%, and 53%, respectively. When genotype was analyzed to assess the impact in prognosis, no statistical differences were observed. Patients treated with R-CHOP and non-GCB genotype have a complete response of 77%, disease-free survival of 56%, and overall survival of 66% that were not statistically different than patients with GCB: 80%, 60%, and 60% respectively, (P: 0.81, 0.5, and 0.66, respectively).

CONCLUSIONS

We confirm that the non-GCB genotype is most frequent in DLBCL-PB, but the addition of rituximab did not improve outcome in primary breast lymphoma with non-GCB phenotype.

Diffuse large B-cell lymphoma primary of lung

Primary lung lymphoma (PLL) and diffuse large B-cell lymphoma (DLBCL) is a rare entity and the biological features, clinical presentation, prognosis markers and treatment have not been well defined. We present 82 cases of PLL-DLBCL in a uniform population and treated with conventional chemotherapy: CHOP (cyclophosphamide, doxorubicin vincristine and prednisone). To the best of our knowledge, this is the largest series with long term follow reported. We also performed immunohistochemical studies to determine if the cell of origin [germinal center (GC) and non-GC] have a prognostic significance. All patients were at an early stage and low-clinical risk without bulk disease and normal levels of lactic dehydrogenase and beta 2 microglobulin. Complete response was achieved in 77 cases (94%), actuarial curves at 10 years showed that event-free survival (EFS) was 90% and overall survival was 92%. Fifty-nine patients were of GC phenotype and 23 of non-GC phenotype. Complete response (93% versus 91%), EFS (91% versus 80%) and overall survival (89% versus 78%) respectively, were not statistically different. Treatment was well tolerated, and second late events have not been seen. We conclude that PLL-DLBCL is an extranodal lymphoma with a good prognosis event in patients of non-GC phenotype.

Pediatric follicular lymphoma--a clinico-pathological study of a population-based series of patients treated within the Non-Hodgkin's Lymphoma--Berlin-Frankfurt-Munster (NHL-BFM) multicenter trials

Background Pediatric follicular lymphoma has recently been recognized as a novel variant of follicular lymphoma in the World Health Organization classification of lymphomas. Given the rarity of the disease, histopathological and genetic data on this type of lymphoma are still scarce.

DESIGN AND METHODS

We analyzed 25 cases of pediatric follicular lymphoma (patients aged <or=18 years) by morphology, immunohistochemistry and interphase fluorescence in situ hybridization. All patients analyzed were treated within Non-Hodgkin's Lymphoma--Berlin-Frankfurt-Münster (NHL-BFM) multicenter trials, and the cohort was representative of the German population.

RESULTS

The genetic hallmark of adult follicular lymphoma, t(14;18)(q32;q21), was not detectable in any of the pediatric cases, although BCL2 protein was expressed in 55% of the latter cases. No correlation was found between BCL2 protein expression and outcome. Chromosomal breaks in the immunoglobulin heavy chain gene (IGH) and the BCL6 locus were detected in 5 of 17 and 1 of 18 cases, respectively. Patients with pediatric follicular lymphoma had long event-free survival and, in contrast to adult follicular lymphoma, the clinical course was not dominated by relapses. A simultaneous diffuse large B-cell lymphoma was frequently detected at initial diagnosis in children but did not indicate an aggressive clinical course. Conclusions Our data suggest that pediatric follicular lymphoma is a disease that differs from its adult counterpart both genetically and clinically.