Favourable outcomes for high-risk diffuse large B-cell lymphoma (IPI 3-5) treated with front-line R-CODOX-M/R-IVAC chemotherapy: results of a phase 2 UK NCRI trial.

BACKGROUND: Outcomes for patients with high-risk diffuse large B-cell lymphoma (DLBCL) treated with R-CHOP chemotherapy are suboptimal but, to date, no alternative regimen has been shown to improve survival rates. This phase 2 trial aimed to assess the efficacy of a Burkitt-like approach for high-risk DLBCL using the dose-intense R-CODOX-M/R-IVAC regimen. PATIENTS AND METHODS: Eligible patients were aged 18-65 years with stage II-IV untreated DLBCL and an International Prognostic Index (IPI) score of 3-5. Patients received alternating cycles of CODOX-M (cyclophosphamide, vincristine, doxorubicin and high-dose methotrexate) alternating with IVAC chemotherapy (ifosfamide, etoposide and high-dose cytarabine) plus eight doses of rituximab. Response was assessed by computed tomography after completing all four cycles of chemotherapy. The primary end point was 2-year progression-free survival (PFS). RESULTS: A total of 111 eligible patients were registered; median age was 50 years, IPI score was 3 (60.4%) or 4/5 (39.6%), 54% had a performance status ≥2 and 9% had central nervous system involvement. A total of 85 patients (76.6%) completed all four cycles of chemotherapy. There were five treatment-related deaths (4.3%), all in patients with performance status of 3 and aged >50 years. Two-year PFS for the whole cohort was 67.9% [90% confidence interval (CI) 59.9-74.6] and 2-year overall survival was 76.0% (90% CI 68.5-82.0). The ability to tolerate and complete treatment was lower in patients with performance status ≥2 who were aged >50 years, where 2-year PFS was 43.5% (90% CI 27.9-58.0). CONCLUSIONS: This trial demonstrates that R-CODOX-M/R-IVAC is a feasible and effective regimen for the treatment of younger and/or fit patients with high-risk DLBCL. These encouraging survival rates demonstrate that this regimen warrants further investigation against standard of care. TRIAL REGISTRATION: ClinicalTrials.gov (NCT00974792) and EudraCT (2005-003479-19).

Central nervous system relapse of diffuse large B-cell lymphoma in the rituximab era: results of the UK NCRI R-CHOP-14 versus 21 trial.

BACKGROUND: Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is associated with a dismal prognosis. Here, we report an analysis of CNS relapse for patients treated within the UK NCRI phase III R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) 14 versus 21 randomised trial. PATIENTS AND METHODS: The R-CHOP 14 versus 21 trial compared R-CHOP administered two- versus three weekly in previously untreated patients aged ≥18 years with bulky stage I-IV DLBCL (n = 1080). Details of CNS prophylaxis were retrospectively collected from participating sites. The incidence and risk factors for CNS relapse including application of the CNS-IPI were evaluated. RESULTS: 177/984 patients (18.0%) received prophylaxis (intrathecal (IT) methotrexate (MTX) n = 163, intravenous (IV) MTX n = 2, prophylaxis type unknown n = 11 and IT MTX and cytarabine n = 1). At a median follow-up of 6.5 years, 21 cases of CNS relapse (isolated n = 11, with systemic relapse n = 10) were observed, with a cumulative incidence of 1.9%. For patients selected to receive prophylaxis, the incidence was 2.8%. Relapses predominantly involved the brain parenchyma (81.0%) and isolated leptomeningeal involvement was rare (14.3%). Univariable analysis demonstrated the following risk factors for CNS relapse: performance status 2, elevated lactate dehydrogenase, IPI, >1 extranodal site of disease and presence of a 'high-risk' extranodal site. Due to the low number of events no factor remained significant in multivariate analysis. Application of the CNS-IPI revealed a high-risk group (4-6 risk factors) with a 2- and 5-year incidence of CNS relapse of 5.2% and 6.8%, respectively. CONCLUSION: Despite very limited use of IV MTX as prophylaxis, the incidence of CNS relapse following R-CHOP was very low (1.9%) confirming the reduced incidence in the rituximab era. The CNS-IPI identified patients at highest risk for CNS recurrence. CLINICALTRIALS.GOV: ISCRTN number 16017947 (R-CHOP14v21); EudraCT number 2004-002197-34.

Outcome of elderly patients with diffuse large B-cell lymphoma treated with R-CHOP: results from the UK NCRI R-CHOP14v21 trial with combined analysis of molecular characteristics with the DSHNHL RICOVER-60 trial.

BACKGROUND: There is an on-going debate whether 2- or 3-weekly administration of R-CHOP is the preferred first-line treatment for elderly patients with diffuse large B-cell lymphoma (DLBCL). The UK NCRI R-CHOP14v21 randomized phase 3 trial did not demonstrate a difference in outcomes between R-CHOP-14 and R-CHOP-21 in newly diagnosed DLBCL patients aged 19-88 years, but data on elderly patients have not been reported in detail so far. Here, we provide a subgroup analysis of patients ≥60 years treated on the R-CHOP14v21 trial with extended follow-up. PATIENTS AND METHODS: Six hundred and four R-CHOP14v21 patients ≥60 years were included in this subgroup analysis, with a median follow-up of 77.7 months. To assess the impact of MYC rearrangements (MYC-R) and double-hit-lymphoma (DHL) on outcome in elderly patients, we performed a joint analysis of cases with available molecular data from the R-CHOP14v21 (N = 217) and RICOVER-60 (N = 204) trials. RESULTS: Elderly DLBCL patients received high dose intensities with median total doses of ≥98% for all agents. Toxicities were similar in both arms with the exception of more grade ≥3 neutropenia (P < 0.0001) and fewer grade ≥3 thrombocytopenia (P = 0.05) in R-CHOP-21 versus R-CHOP-14. The elderly patient population had a favorable 5-year overall survival (OS) of 69% (95% CI: 65-73). We did not identify any subgroup of patients that showed differential response to either regimen. In multivariable analysis including individual factors of the IPI, gender, bulk, B2M and albumin levels, only age and B2M were of independent prognostic significance for OS. Molecular analyses demonstrated a significant impact of MYC-R (HR = 1.96; 95% CI: 1.22-3.16; P = 0.01) and DHL (HR = 2.21; 95% CI: 1.18-4.11; P = 0.01) on OS in the combined trial cohorts, independent of other prognostic factors. CONCLUSIONS: Our data support equivalence of both R-CHOP application forms in elderly DLBCL patients. Elderly MYC-R and DHL patients have inferior prognosis and should be considered for alternative treatment approaches. TRIAL NUMBERS: ISCRTN 16017947 (R-CHOP14v21); NCT00052936 (RICOVER-60).

Breast cancer risk following Hodgkin lymphoma radiotherapy in relation to menstrual and reproductive factors.

BACKGROUND: Women treated with supradiaphragmatic radiotherapy (sRT) for Hodgkin lymphoma (HL) at young ages have a substantially increased breast cancer risk. Little is known about how menarcheal and reproductive factors modify this risk. METHODS: We examined the effects of menarcheal age, pregnancy, and menopausal age on breast cancer risk following sRT in case-control data from questionnaires completed by 2497 women from a cohort of 5002 treated with sRT for HL at ages <36 during 1956-2003. RESULTS: Two-hundred and sixty women had been diagnosed with breast cancer. Breast cancer risk was significantly increased in patients treated within 6 months of menarche (odds ratio (OR) 5.52, 95% confidence interval (CI) (1.97-15.46)), and increased significantly with proximity of sRT to menarche (Ptrend<0.001). It was greatest when sRT was close to a late menarche, but based on small numbers and needing reexamination elsewhere. Risk was not significantly affected by full-term pregnancies before or after treatment. Risk was significantly reduced by early menopause (OR 0.55, 95% CI (0.35-0.85)), and increased with number of premenopausal years after treatment (Ptrend=0.003). CONCLUSION: In summary, this paper shows for the first time that sRT close to menarche substantially increases breast cancer risk. Careful consideration should be given to follow-up of these women, and to measures that might reduce their future breast cancer risk.

Mir142 loss unlocks IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes.

AML is a genetically heterogeneous disease and understanding how different co-occurring mutations cooperate to drive leukemogenesis will be crucial for improving diagnostic and therapeutic options for patients. MIR142 mutations have been recurrently detected in IDH-mutated AML samples. Here, we have used a mouse model to investigate the interaction between these two mutations and demonstrate a striking synergy between Mir142 loss-of-function and IDH2R140Q, with only recipients of double mutant cells succumbing to leukemia. Transcriptomic analysis of the non-leukemic single and leukemic double mutant progenitors, isolated from these mice, suggested a novel mechanism of cooperation whereby Mir142 loss-of-function counteracts aberrant silencing of Hoxa cluster genes by IDH2R140Q. Our analysis suggests that IDH2R140Q is an incoherent oncogene, with both positive and negative impacts on leukemogenesis, which requires the action of cooperating mutations to alleviate repression of Hoxa genes in order to advance to leukemia. This model, therefore, provides a compelling rationale for understanding how different mutations cooperate to drive leukemogenesis and the context-dependent effects of oncogenic mutations.

Superiority of reduced-intensity allogeneic transplantation over conventional treatment for relapse of Hodgkin's lymphoma following autologous stem cell transplantation.

This study compares outcome of reduced-intensity conditioned transplant (RIT) with outcome of conventional non-transplant therapy in patients with Hodgkin's lymphoma relapsing following autograft. There were 72 patients in two groups who had relapsed, and received salvage therapy with chemotherapy+/-radiotherapy. One group (n=38) then underwent alemtuzumab-containing RIT. The second group-historical controls (n=34), relapsing before the advent of RIT-had no further high-dose therapy. This group was required to respond to salvage therapy and live for over 12 months post-relapse, demonstrating potential eligibility for RIT, had this been available. Overall survival (OS) from diagnosis was superior following RIT (48% at 10 years versus 15%; P=0.0014), as was survival from autograft (65% at 5 years versus 15%; P< or =0.0001). For the RIT group, OS at 5 years from allograft was 51%, and in chemoresponsive patients was 58%, with current progression-free survival of 42%. Responses were seen in 8 of 15 patients receiving donor lymphocyte infusions (DLI) for relapse/progression, with durable remission in five patients at median follow-up from DLI of 45 months (28-55). These data demonstrate the potential efficacy of RIT in heavily pre-treated patients whose outlook with conventional therapy is dismal, and provide evidence of a clinically relevant graft-versus-lymphoma effect.

Identification of three accessory cell populations in human bone marrow with erythroid burst-promoting properties.

Several laboratories have demonstrated a requirement for burst-promoting activity (BPA), a product of T cells, or T cell/monocyte collaboration in the induction of differentiation of peripheral blood erythroid burst-forming units (BFU-E) in vitro. The physiologic significance of this finding is brought into question by patients with severe mature T cell deficiency who have normal in vivo erythropoiesis. The studies described here were designed to determine whether the burst-promoting effects of marrow T cells and adherent cells are similar to those of peripheral blood, to define whether a third population of marrow cells is capable of production of BPA, and to describe the BPA requirements of immature and mature marrow erythroid progenitors. To that end we prepared adherence- and E-depleted low-density peripheral blood mononuclear cells as a source of BFU-E and demonstrated that their optimal erythropoietin-induced differentiation requires BPA. We then determined that both bone marrow and peripheral blood T cells and monocytes could provide the necessary BPA to induce their erythropoietin dependent differentiation. BPA production by T cells was sensitive to irradiation, but that of the whole bone marrow low-density population was considerably less sensitive. This in itself demonstrated that BPA production in marrow is not T cell dependent. We further demonstrated a potent, albeit infrequent, third population of BPA-producing marrow cells. These proved to be nonadherent, E receptor-negative, granulocyte antigen-negative, and gamma-Fc receptor-positive. Finally, we separated all of these BPA-producing cells from marrow erythroid progenitors and concentrated the latter into a population in which they comprised 6% of the cells. With this population we demonstrated that both immature (BFU-E) and mature (colony-forming units [CFU-E]) erythroid progenitors require BPA in addition to erythropoietin to induce them to form erythroid colonies in vitro. These results may explain the normal erythropoiesis found in patients with mature T cell deficiency. Though the differentiation of both BFU-E and CFU-E requires BPA, this need can be met by a special class of nonadherent, radioresistant, E receptor-negative, granulocyte antigen-negative, and gamma-Fc-positive cells.

Determination of the hemoglobin F program in human progenitor-derived erythroid cells.

The absolute adult and fetal hemoglobin (HbF) contents of the erythroid cells derived from the differentiation of normal human and simian erythroid progenitors and of the peripheral blood erythroid burst-forming units (BFU-E) of patients with nondeletion hemoglobinopathies have been measured with a sensitive radioligand immunoassay. The HbF content varied between 0.13 and 2.96 pg/cell, representing between 0.7% and 19.6% of the total hemoglobin with a mean value of 7.0%. The absolute content of HbF was indistinguishable in the well-hemoglobinized progeny of marrow erythroid colony-forming units, marrow or blood BFU-E, or of mixed colony-forming units. The term HbF program refers to this inherent capacity to produce fetal hemoglobin (HbF) in the erythroid cells derived from these progenitors in vitro. The HbF content of marrow erythroblasts as determined by the same radioligand immunoassay was similar to that found in the peripheral blood, suggesting that the switch off of gamma-chain production occurs after the erythroid colony-forming unit stage of maturation. Increasing concentrations of a crude erythropoietin-containing preparation induced higher numbers of erythroid colonies, which were larger in size, but the HbF program was unaffected. In contrast to the hemoglobin accumulation in human progenitor-derived colonies, simian progenitor-derived colonies produced considerably more HbF, and the amount of HbF was strongly influenced by progenitor maturity. Assays of the HbF content of erythroblasts derived from culture of the peripheral blood BFU-E of patients with nondeletion hemoglobinopathies and their parents showed that the HbF program in the progenitors of such patients is highly variable. Some produce only a slight excess of HbF in progenitor-derived erythroblasts, whereas others have extraordinarily high HbF programs. The molecular basis of this variability is presently unknown.

Influence of cell cycle phase-specific agents on simian fetal hemoglobin synthesis.

To determine the influence of cell cycle-specific agents on primate hematopoiesis and fetal hemoglobin production, two juvenile cynomolgus monkeys (Macaca fascicularis) were repeatedly bled to maintain their hemoglobins at approximately 6.5 g/dl and fetal hemoglobin levels at 3-5%. Six separate 5-d courses of hydroxyurea at 100 mg/kg per d were then administered over the next 200 d while phlebotomy was continued. These courses of hydroxyurea progressively raised the fetal hemoglobin levels to 17 and 18%, respectively. The drug had very little effect on the frequency of immature erythroid progenitors (BFU-E) in the bone marrow, but caused a marked reduction in the frequency of later progenitors (CFU-E) and a transient fall in the reticulocyte count. Following the courses of hydroxyurea, the number of F cells and the fetal hemoglobin level fell to base line over a period of 4 wk. Two control animals which were not phlebotomized showed no detectable increase in F cells or fetal hemoglobin when treated with the same regimen of hydroxyurea. A 5-d course of 5-azacytidine at 8 mg/kg per d was then given to each of the phlebotomized animals. This produced a more profound, albeit transient, reticulocytopenia, a fall in the CFU-E/BFU-E ratio, and a prompt increase in the fetal hemoglobin to levels even higher than were seen following a single 5-d course of hydroxyurea at 100 mg/kg/d. Subsequently, the animals were given a single dose of vinblastine at 0.4 mg/kg which reduced reticulocytes and CFU-E to the same extent as hydroxyurea; however, vinblastine at this dose had no effect on hemoglobin F (HbF) production. In contrast, when vinblastine was administered to the phlebotomized monkeys as a 5-d course at 0.2 mg/kg/d, prolonged reticulocytopenia followed by dramatic F cell and HbF responses were seen. Combinations of single dose vinblastine and a 5-d course of hydroxyurea were subsequently administered using two different schedules. When the animals received vinblastine on the first day of a 5-d course of hydroxyurea, the F cell response was double that seen following hydroxyurea treatment alone. In contrast, when vinblastine was administered on the final day of hydroxyurea treatment, the magnitude of the F cell response was the same as that which occurred following hydroxyurea treatment alone, but the onset of the rise was delayed for 4 d and HbF/F cell response was much higher. These results establish several important features of the fetal hemoglobin response to cytotoxic agents in the primate model. The response requires accelerated erythropoiesis and is preceded by transient reticulocytopenia. The response is produced by S phase- and M phase-specific agents when given in sufficient doses and at appropriate schedules. Passage of erythrocyte progenitors through M phase appears to be necessary for expression of the effect produced by S phase agents. The fetal hemoglobin response induced by cytotoxic drug administration occurs during the recovery of erythropoiesis following marrow suppression.

Investigations of the simian ontogenic switch from fetal to adult hemoglobin at the progenitor cell level.

The ontogenic switch from fetal to adult hemoglobin could result from discontinuous events, such as replacement of fetal erythroid progenitor cells by adult ones, or gradual modulation of the hemoglobin program of a single progenitor cell pool. The former would result in progenitors at midswitch with skewed fractional beta-globin synthesis programs, the latter in a Gaussian distribution. For these studies, we obtained bone marrow from rhesus monkey fetuses at 141-153 d (midswitch). Mononuclear cells were cultured in methyl cellulose with erythropoietin, and single BFU-E-derived colonies were removed and incubated with [3H]leucine. Globin synthesis was examined by gel electrophoresis and fluorography. The beta-globin synthesis pattern of single fetal colonies was skewed, and did not fit a normal distribution. The fetal pattern resembled the pattern of an artificial mixture of fetal and adult progenitors, suggesting that the fetal progenitor pool could contain populations with different beta-globin programs. This non-Gaussian distribution in the progenitors of midswitch fetuses is consistent with a discontinuous model for hemoglobin switching during ontogeny.

A second autologous transplant may be efficacious in selected patients with Hodgkin's lymphoma relapsing after a previous autograft.

Treatment options for patients who relapse following autologous transplantation for Hodgkin's lymphoma are limited. There are anecdotal reports of lengthy remissions following second autologous procedures, although treatment-related toxicity can be significant. We report a single centre experience of second autologous transplant performed in seven highly selected patients, who relapsed following initial high-dose therapy. They were all young and had slow tempo disease, which was still sensitive to conventional dose chemotherapy. All received BEAM conditioning for the first transplant, and six of the seven received BEAM for the second. All six of these patients regenerated successfully and with no delay, the final patient dying during the procedure following alternative conditioning. Only one case of presumed carmustine-related pneumonitis was seen, which responded rapidly to corticosteroid therapy. Four patients have subsequently relapsed, of whom three have died at 29, 33, and 38 months postprocedure. One is alive with active disease at 68 months, and the final two are alive and in continuing complete remission at 104 and 68 months.

Outcomes of diffuse large B-cell lymphoma patients relapsing after autologous stem cell transplantation: an analysis of patients included in the CORAL study.

In the CORAL study, 255 chemosensitive relapses with diffuse large B-cell lymphoma (DLBCL) were consolidated with autologous stem cell transplantation (ASCT), and 75 of them relapsed thereafter. The median time between ASCT and progression was 7.1 months. The median age was 56.1 years; tertiary International Prognosis Index (tIPI) observed at relapse was 0-2 in 71.6% of the patients and >2 in 28.4%. The overall response rate to third-line chemotherapy was 44%. The median overall survival (OS) was 10.0 months (median follow-up: 32.8 months). Thirteen patients received an allogeneic SCT, and three a second ASCT. The median OS was shorter among patients who relapsed <6 months (5.7 months) compared with those relapsing ⩾12 months after ASCT (12.6 months, P=0.0221). The median OS in patients achieving CR, PR or no response after the third-line regimen was 37.7 (P<0.0001), 10.0 (P=0.03) and 6.3 months, respectively. The median OS varied according to tIPI: 0-2: 12.6 months and >2: 5.3 months (P=0.0007). In multivariate analysis, tIPI >2, achievement of response and remission lasting <6 months predicted the OS. This report identifies the prognostic factors for DLBCL relapsing after ASCT and thus helps to select patients for experimental therapy.

Primary sciatic nerve lymphoma: a case report and review of the literature.

A patient with primary B cell non-Hodgkin's lymphoma of the sciatic nerve is described. He presented with neuropathic symptoms in the left leg, initially diagnosed as tarsal tunnel syndrome. Magnetic resonance imaging (MRI) identified the abnormality in the sciatic nerve. A fascicular biopsy of the sciatic nerve showed a diffuse large B cell non-Hodgkin's lymphoma. The patient was treated with chemotherapy and rituximab (anti-CD20 monoclonal antibody). Four months later he was in remission, and remains so 48 months from presentation. Primary lymphoma of single peripheral nerves may be a unique subtype of extranodal lymphoma, which usually follows an aggressive course and has a variable response to current therapeutic strategies. MRI is useful, alongside electrophysiological studies, in patients with atypical peripheral nerve symptoms.

PI3-kinase/Akt is constitutively active in primary acute myeloid leukaemia cells and regulates survival and chemoresistance via NF-kappaB, Mapkinase and p53 pathways.

The phosphoinositide 3-kinase (PI3-kinase) signalling pathway plays a key role in the regulation of cell survival and proliferation. We show that the PI3-kinase/Akt pathway is constitutively active in primary acute myeloid leukaemia (AML) cells and that blockade by the selective inhibitor LY294002 reduces survival of the total blast population (mean 52%). The ERK/MAPK module is also constitutively active and treatment with the MAPKK inhibitor U0126 reduces cell survival by 22%. In 10 of 18 samples, PI3-kinase contributes to MAPK activation as incubation with LY294002 leads to a marked reduction in its phosphorylation. PI3-kinase inhibition reduces survival of the CD34+38- AML progenitor subset by 44%, whereas MAPKK inhibition has little effect. Reporter assays in primary AML cells show that blocking PI3-kinase leads to a marked reduction of constitutive NF-kappaB activity and promotes p53-mediated transcription. This is associated with a synergistic interaction between LY294002 and Ara-C. An inducible activated form of Akt protects normal myeloid cells from Ara-C and etoposide-mediated apoptosis. These results show that blocking PI3-kinase has direct antileukaemic effects and potentiates the response to conventional cytotoxics via a number of targets including NF-kappaB, p53 and MAPK. Inhibitors of PI3-kinase and Akt may be useful in the treatment of AML.

Impact of PTEN abnormalities on outcome in pediatric patients with T-cell acute lymphoblastic leukemia treated on the MRC UKALL2003 trial.

PTEN gene inactivation by mutation or deletion is common in pediatric T-cell acute lymphoblastic leukemia (T-ALL), but the impact on outcome is unclear, particularly in patients with NOTCH1/FBXW7 mutations. We screened samples from 145 patients treated on the MRC UKALL2003 trial for PTEN mutations using heteroduplex analysis and gene deletions using single nucleotide polymorphism arrays, and related genotype to response to therapy and long-term outcome. PTEN loss-of-function mutations/gene deletions were detected in 22% (PTEN(ABN)). Quantification of mutant level indicated that 67% of mutated cases harbored more than one mutant, with up to four mutants detected, consistent with the presence of multiple leukemic sub-clones. Overall, 41% of PTEN(ABN) cases were considered to have biallelic abnormalities (mutation and/or deletion) with complete loss of PTEN in a proportion of cells. In addition, 9% of cases had N- or K-RAS mutations. Neither PTEN nor RAS genotype significantly impacted on response to therapy or long-term outcome, irrespective of mutant level, and there was no evidence that they changed the highly favorable outcome of patients with double NOTCH1/FBXW7 mutations. These results indicate that, for pediatric patients treated according to current protocols, routine screening for PTEN or RAS abnormalities at diagnosis is not warranted to further refine risk stratification.

Outcome of patients with relapsed diffuse large B-cell lymphoma who fail second-line salvage regimens in the International CORAL study.

Salvage chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard second-line treatment for relapsed and refractory diffuse large B-cell lymphoma (DLBCL). However, the strategy is less clear in patients who require third-line treatment. Updated outcomes of 203 patients who could not proceed to scheduled ASCT in the Collaborative Trial in Relapsed Aggressive Lymphoma (CORAL) are herein reviewed. In the intent-to-treat analysis, overall response rate to third-line chemotherapy was 39%, with 27% CR or CR unconfirmed, and 12% PR. Among the 203 patients, 64 (31.5%) were eventually transplanted (ASCT 56, allogeneic SCT 8). Median overall survival (OS) of the entire population was 4.4 months. OS was significantly improved in patients with lower tertiary International Prognostic Index (IPI), patients responding to third-line treatment and patients transplanted with a 1-year OS of 41.6% compared with 16.3% for the not transplanted (P<0.0001). In multivariate analysis, IPI at relapse (hazard ratio (HR) 2.409) and transplantation (HR 0.375) independently predicted OS. Third-line salvage chemotherapy can lead to response followed by transplantation and long-term survival in DLBCL patients. However, improvement of salvage efficacy is an urgent need with new drugs.

The phosphorylation state of the retinoblastoma (RB) protein in G0/G1 is dependent on growth status.

The product of the retinoblastoma gene (RB) is a nuclear phosphoprotein which is thought to regulate the proliferation of cells. Its phosphorylation state changes with passage through the cell cycle and it has been proposed that RB protein in its hypo-phosphorylated form prevents cells proliferating. We have investigated the phosphorylation state of the RB protein in an actively-dividing human B-lymphoblastoid cell line and after cell cycle arrest caused by alpha-Interferon (alpha-IFN). We show that the phosphorylation state of the RB protein in cells with 2N DNA content depends on whether the cells are actively cycling. Our data is compatible with the proposal that dephosphorylation of the RB protein allows cells to enter a quiescent state. This study sheds light on the molecular mechanisms which may mediate the cytostatic effects of alpha-IFN.

The relationship between mitogen-induced membrane potential changes and intracellular free calcium in human T-lymphocytes.

We have investigated the effects of mitogenic lectins on human T-lymphocytes, isolated from peripheral blood, and cells from the T-cell clone, HPB-ALL, using the fluorescent dyes, bis-thiobarbiturate tri-methineoxonol (bisoxonol) and quin2 to sense changes in membrane potential and intracellular free [Ca2+], respectively. The resting potential of both cell types is close to the K+ equilibrium potential. Changes from the resting level occur when mitogenic concentrations of either concanavalin A or phytohaemagglutinin are added. T-lymphocytes undergo a decrease in emission, maximal at 1 to 2 min, corresponding to a small membrane hyperpolarization. This is followed by a depolarization to approximately the resting level. HPB-ALL cells, on the other hand, respond to the mitogens by a sustained increase in fluorescence, denoting a depolarization, that is maximal at 4 to 5 min and 7 to 9 min, respectively. The Ca2+-dependence of these phenomena indicates that the membrane potential response, in both cell types, is the resultant of two opposing effects: a Ca2+-sensitive ion movement tending to hyperpolarize the cells and a Ca2+-insensitive effect that generates a depolarization. Our results suggest that Ca2+-activated K+ channels are responsible for the first effect and that an inward Na+ movement accounts for the depolarization signal in T-lymphocytes. In HPB-ALL cells only part of the depolarization is Na+-dependent. Although the effects elicited by phytohaemagglutinin occur more slowly than those produced by concanavalin A, similar membrane potential and [Ca2+]i changes occur.