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Despite recent advances in lymphoma treatment, mantle cell lymphoma (MCL) remains incurable, and we are still unable to identify patients who will not benefit from the current standard of care. Here, we explore the prognostic value of recurrent genetic aberrations in diagnostic bone marrow (BM) specimens from 183 younger patients with MCL from the Nordic MCL2 and MCL3 trials, which represent current standard-of-care regimens. In the univariate model, mutations of TP53(11%) and NOTCH1(4%), and deletions of TP53(16%) and CDKN2A(20%), were significantly associated with inferior outcomes (together with MIPI, MIPI-c, blastoid morphology, and Ki67 > 30%); however, in multivariate analyses, only TP53mutations (HR, 6.2; P< .0001) retained prognostic impact for overall survival (OS), whereas TP53mutations (HR, 6.9; P< .0001) and MIPI-c high-risk (HR, 2.6; P= .003) had independent prognostic impact on time to relapse. TP53-mutated cases had a dismal outcome, with a median OS of 1.8 years, and 50% relapsed at 1.0 years, compared to a median OS of 12.7 years for TP53-unmutated cases (P< .0001). TP53mutations were significantly associated with Ki67 > 30%, blastoid morphology, MIPI high-risk, and inferior responses to both induction- and high-dose chemotherapy. In conclusion, we show that TP53mutations identify a phenotypically distinct and highly aggressive form of MCL with poor or no response to regimens including cytarabine, rituximab, and autologous stem-cell transplant (ASCT). We suggest patients with MCL should be stratified according to TP53status, and that patients with TP53mutations should be considered for experimental frontline trials exploring novel agents.

The 2nd. Nordic Lymphoma Group mantle cell lymphoma (MCL2) protocol has demonstrated the importance of Ara-C and Rituximab in the induction chemotherapy and stem-cell mobilisation before high-dose therapy and autologous stem-cell transplant (1). By July 2005, 128 patients (83% stage IV) had completed protocol treatment consisting of 3 series of R-CHOP and 3 series of R-Ara-C, stem-cell harvest and high-dose therapy with BEAM/BEAC with ASCT. The 5-year failure-free and overall survival is 50% and 83% respectively, significantly higher than the historic control group of the Nordic MCL1 protocol with the same treatment without HD-Ara-C and Rituximab (P<0.0001). Patients with a molecular marker (t(11;14) or clonal IgH rearrangement) identified at the time of diagnosis in bone marrow and blood, undergo regular molecular follow-up posttransplant,. Patients who turn PCR-positive or increase their qPCR signal, without clinical disease, are offered preemptive treatment with Rituximab 375 mg/m2 Wx4. Of 75 patients with molecular markers who had completed treatment, 55 remain PCR-negative and 20 have become/remained PCR-pos. posttransplant. Clinical relapse ocurred significantly more often in the latter group (11 of 20) than in the PCR-neg. patients (4 of 55) (P<0.0001) (Fig.1). Ten of the 20 PCR-positive patient did not receive preemptive rituximab: five due to immediate clinical relapse, 2 due to stable qPCR signals, one due to protocol error and two await treatment. Of 10 patients who did receive preemptive rituximab 8 again became PCR-negative and 2 remain PCR-positive. Six of the 10 Rituximab treated patients remain in clinical and molecular remission 200–600 days after the Rituximab treatment (Fig. 2). Conclusions: In MCL, molecular relapse is a harbinger of imminent clinical relapse, whereas continuous molecular remission is associated with prolonged disease-free survival (89% at 4 years) Rituximab preemptive treatment can reinduce molecular remission and may delay clinical relapse. Following molecular relapse, only Rituximab treated patients (6 of 8 evaluable) remain disease-free. FIG. 1. NORDIC NCL-2 PROTOCOL: RELAPSE-FREE SURVIVAL ACC. TO MOLECULAR STATUS POSTTRANSPALNT FIG. 1. NORDIC NCL-2 PROTOCOL: RELAPSE-FREE SURVIVAL ACC. TO MOLECULAR STATUS POSTTRANSPALNT FIG. 2. NORDIC NCL-2 PROTOCOL: RELAPSE-FREE SURVIVAL FROM TIME OF MOLECULAR RELAPSE. FIG. 2. NORDIC NCL-2 PROTOCOL: RELAPSE-FREE SURVIVAL FROM TIME OF MOLECULAR RELAPSE.

We have recently identified and cloned a novel disease specific gene CLLU1, with a strong prognostic significance in a small test cohort of CLL patients (ASH 2004, #770). To validate this finding in a larger series, 176 newly diagnosed, previously untreated CLL patients referred to Rigshospitalet, Copenhagen in 1991–1999, were investigated. Clinical characteristics of the population were: 116 stage A patients (66 %), median age 69.9 years, 98 males (56%), median follow up 59 months. The end points for the statistical analysis were overall survival and time to initiation of treatment. At time of analysis 91 (52%) patients had died and 104 (59%) had commenced treatment. Frozen patient samples, taken at time of diagnosis, were investigated for CLLU1expression, as well as for mutational status, CD38 expression, ZAP-70 expression and cytogenetic aberrations. CLLU1expression was assayed by QRT-PCR using the cDNA1 splice variant, and expressed as fold upregulation above the CLLU1level in normal B-cells. CD38 and ZAP-70 analysis was performed by flow cytometry, using a 20 % cut-off level. Cytogenetic analysis was performed by FISH. The previously reported (ASH 2004, #770) median upregulation of CLLU1in CLL cells was accurately reproduced and confirmed (25.5-fold (N = 176) vs. 27.7-fold (N = 59) in test population). Also in accordance with the pilot study, segregation of the patients based on the median CLLU1expression level divided the population in two groups with significantly different times to initiation of treatment and borderline significant difference in overall survival. However, further analysis found an optimal cut-off level at 40-fold upregulation of CLLU1expression; use of this cut-off demonstrated a highly significant difference in overall survival for patients with upregulated expression of CLLU1(p = 0.0023). The median overall survival was 60.2 months for patients with CLLU1expression above 40-fold compared to 100.8 months for the group with lower expression level. Likewise the time to initiation of first treatment was significantly shorter in the high-level expression group (p = 0.0018, median time to first treatment 9.3 months vs. 54.9 months). Furthermore, CLLU1expression was upregulated in all poor prognostic subgroups investigated: Binet stage B or C, IgVHunmutated, unfavorable cytogenetics, high CD38 expression and high ZAP-70 expression. Our new study confirms that CLLU1is a strong prognostic factor in CLL, comparable to other established prognostic markers. The exclusive upregulation of CLLU1expression in CLL suggests a putative role for CLLU1in the pathogenesis of CLL, and makes this gene a strong candidate for future gene-targeted treatment strategies.