Within-population spatial genetic structure in four naturally fragmented species of a neotropical inselberg radiation, Alcantarea imperialis, A. geniculata, A. glaziouana and A. regina (Bromeliaceae)

Studies of organisms on 'terrestrial islands' can improve our understanding of two unresolved issues in evolutionary genetics: the likely long-term effects of habitat fragmentation and the genetic underpinnings of continental species radiations in island-like terrestrial habitats. We have addressed both issues for four closely related plant species of the adaptive radiation Bromeliaceae, Alcantarea imperialis, A. geniculata, A. regina and A. glaziouana. All four are adapted to ancient, isolated inselberg rock outcrops in the Brazilian Atlantic rainforest and are thus long-term fragmented by nature. We used eight nuclear microsatellites to study within-population spatial genetic structure (SGS) and historical gene dispersal in nine populations of these species. Within-population SGS reflected known between-species differences in mating systems. The strongest SGS observed in A. glaziouana (Sp=0.947) was stronger than literature estimates available for plants. Analysis of short- and long-distance components of SGS identified biparental inbreeding, selfing and restricted seed dispersal as main determinants of SGS, with restricted pollen dispersal by bats contributing in some localities. The ability of Alcantarea spp. to colonize isolated inselbergs probably stems from their flexible mating systems and an ability to tolerate inbreeding. Short-ranging gene dispersal (average sigma=7-27 m) is consistent with a loss of dispersal power in terrestrial island habitats. Population subdivision associated with sympatric colour morphs in A. imperialis is accompanied by between-morph differences in pollen and seed dispersal. Our results indicate a high potential for divergence with gene flow in inselberg bromeliads and they provide base-line data about the long-term effects of fragmentation in plants.

Efficacy of 90Y ibritumomab-tiuxetan treatment in a case of resistant gastric MALT non-Hodgkin's lymphoma

Treatment modalities for resistant/relapsing gastric mucosa associated lymphoid tissue (MALT) non-Hodgkin's lymphoma (NHL) are not yet well standardized. In the past, most patients were treated surgically with a gastrectomy, while, more recently, radiotherapy and systemic approaches (chemotherapy and immunotherapy) have been used with improving results.Here, we report the case of a patient affected by MALT NHL resistant to antibiotics, chemotherapy and immunotherapy, who achieved a durable complete remission after radio-immunotherapy treatment with Zevalin ((90)Y ibritumomab-tiuxetan), administered in a single-standard dose. This observation must be confirmed on a larger series but suggests that radio-immunotherapy may be a valid approach in treating relapsing MALT NHL patients, or those resistant to conventional therapies, so avoiding more aggressive and toxic approaches.

Population differentiation and species cohesion in two closely related plants adapted to neotropical high-altitude 'inselbergs', Alcantarea imperialis and Alcantarea geniculata (Bromeliaceae)

Isolated granitic rock outcrops or 'inselbergs' may provide a window into the molecular ecology and genetics of continental radiations under simplified conditions, in analogy to the use of oceanic islands in studies of species radiations. Patterns of variability and gene flow in inselberg species have never been thoroughly evaluated in comparison to related taxa with more continuous distribution ranges, or to other species in the same kingdom in general. We use nuclear microsatellites to study population differentiation and gene flow in two diploid, perennial plants adapted to high-altitude neotropical inselbergs, Alcantarea imperialis and Alcantarea geniculata (Bromeliaceae). Population differentiation is pronounced in both taxa, especially in A. imperialis. Gene flow in this species is considerably lower than expected from the literature on plants in general and Bromeliaceae in particular, and too low to prevent differentiation due to drift (N(e)m < 1), unless selection coefficients/effect sizes of favourable alleles are great enough to maintain species cohesion. Low gene flow in A. imperialis indicates that the ability of pollinating bats to promote gene exchange between inselbergs is smaller than previously assumed. Population subdivision in one inselberg population of A. imperialis appears to be associated with the presence of two colour morphs that differ in the coloration of rosettes and bracts. Our results indicate a high potential for inselbergs as venues for studies of the molecular ecology and genetics of continental radiations, such as the one that gave rise to the extraordinary diversity of adaptive strategies and phenotypes seen in Bromeliaceae.

Imatinib mesylate in the treatment of newly diagnosed or refractory/resistant c-KIT positive acute myeloid leukemia. Results of an italian multicentric phase II study

We evaluated safety and efficacy of imatinib (600 mg) in 36 c-KIT+ acute myeloid leukemia patients not amenable to receive conventional chemotherapy. No patient achieved complete remission. One patient obtained a hematologic improvement (platelet increase with transfusion independence). Median overall survival was 3 months (0.5-44+). Non-hematologic toxicity was overall mild.

Quality of life and quality-adjusted survival (Q-TWiST) in patients receiving dose-intensive or standard dose chemotherapy for high-risk primary breast cancer

Quality of life (QL) is an important consideration when comparing adjuvant therapies for early breast cancer, especially if they differ substantially in toxicity. We evaluated QL and Q-TWiST among patients randomised to adjuvant dose-intensive epirubicin and cyclophosphamide administered with filgrastim and progenitor cell support (DI-EC) or standard-dose anthracycline-based chemotherapy (SD-CT). We estimated the duration of chemotherapy toxicity (TOX), time without disease symptoms and toxicity (TWiST), and time following relapse (REL). Patients scored QL indicators. Mean durations for the three transition times were weighted with patient reported utilities to obtain mean Q-TWiST. Patients receiving DI-EC reported worse QL during TOX, especially treatment burden (month 3: P<0.01), but a faster recovery 3 months following chemotherapy than patients receiving SD-CT, for example, less coping effort (P<0.01). Average Q-TWiST was 1.8 months longer for patients receiving DI-EC (95% CI, -2.5 to 6.1). Q-TWiST favoured DI-EC for most values of utilities attached to TOX and REL. Despite greater initial toxicity, quality-adjusted survival was similar or better with dose-intensive treatment as compared to standard treatment. Thus, QL considerations should not be prohibitive if future intensive therapies show superior efficacy.

Primary diffuse large B-cell lymphoma of the breast: prognostic factors and outcomes of a study by the International Extranodal Lymphoma Study Group

BACKGROUND

Primary diffuse large B-cell lymphoma (DLBCL) of breast is rare. We aimed to define clinical features, prognostic factors, patterns of failure, and treatment outcomes.

PATIENTS AND METHODS

A retrospective international study of 204 eligible patients presenting to the International Extranodal Lymphoma Study Group-affiliated institutions from 1980 to 2003.

RESULTS

Median age was 64 years, with 95% of patients presenting with unilateral disease. Median overall survival (OS) was 8.0 years, and median progression-free survival 5.5 years. In multifactor analysis, favourable International Prognostic Index score, anthracycline-containing chemotherapy, and radiotherapy (RT) were significantly associated with longer OS (each P < or = 0.03). There was no benefit from mastectomy, as opposed to biopsy or lumpectomy only. At a median follow-up time of 5.5 years, 37% of patients had progressed--16% in the same or contralateral breast, 5% in the central nervous system, and 14% in other extranodal sites.

CONCLUSIONS

The combination of limited surgery, anthracycline-containing chemotherapy, and involved-field RT produced the best outcome in the pre-rituximab era. A prospective trial on the basis of these results should be pursued to confirm these observations and to determine whether the impact of rituximab on the patterns of relapse and outcome parallels that of DLBCL presenting at other sites.

Current status and future perspectives for yttrium-90 ((90)Y)-ibritumomab tiuxetan in stem cell transplantation for non-Hodgkin's lymphoma

Haematopoietic SCT is currently considered a therapeutic option mainly in relapsed or refractory non-Hodgkin's lymphoma (NHL) owing to high post-transplantation relapse rates and significant toxicity of conventional myeloablative conditioning for allogeneic SCT. Radiolabelled immunotherapy combines the benefits of monoclonal antibody targeting with therapeutic doses of radiation, and is a promising advance in the treatment of malignant lymphomas. It is now under investigation as a component of conditioning prior to SCT, with the aim of improving outcomes following SCT without increasing the toxicity of high-dose chemotherapy pre-transplant conditioning. An expert panel met at a European workshop in November 2006 to review the latest data on radiolabelled immunotherapy in the transplant setting, and its potential future directions, with a focus on (90)Y-ibritumomab tiuxetan. They reviewed data on the combination of standard/high/escalating dose (90)Y-ibritumomab tiuxetan with high-dose chemotherapy, and high/escalating dose (90)Y-ibritumomab tiuxetan as the sole myeloablative agent, prior to autologous SCT, and also (90)Y-ibritumomab tiuxetan as a component of reduced intensity conditioning prior to allogeneic SCT. The preliminary data are highly promising in terms of conditioning tolerability and patient outcomes following transplant; further phase II studies are now needed to consolidate these data and to investigate specific patient populations and NHL subtypes.

Consolidation therapy for adult acute myeloid leukemia: a systematic analysis according to evidence based medicine

Post-remission therapy in acute myeloid leukemia (AML) remains problematic. It has been demonstrated that younger patients can maintain longer complete remissions (CR) with aggressive post-remission therapies after induction treatment: allogeneic (allo), autologous (auto) stem cell transplantation (SCT), or intensive chemotherapy (ICC). The purpose of our study was to identify the most important randomized and controlled studies comparing these three therapeutic options, in order to draw conclusions and possible suggestions for post-remission therapy of AML, according to the evidence based medicine (EBM) rules. We performed an exhaustive analysis of the literature, searching either in electronic databases or among the references of the identified articles (hand searching). We searched the MEDLINE computer database for reports from 1985 through January 2005 and selected for analysis the clinical trials conducted over adults affected by newly diagnosed AML aged less than 65 years. The study design had to satisfy strict methodological criteria and must consider global mortality and/or disease free survival as primary outcomes. Overall we found 7750 papers; by using the limits "clinical trial" as publication type, "all adults 19+ years", we were able to select 344 papers. Among these, a further selection was made, based on two main clinical queries: 1) is auto-SCT superior to ICC/no other therapy in improving DFS and/or OS in adult AML patients in first CR? 2) is allo-SCT superior to auto-SCT/other therapeutic options in improving DFS and/or OS in adult AML patients in first CR? Concerning the first query, a possible advantage of auto-SCT over ICC was not clearly supported by data from clinical trials; there is no evidence that auto-SCT is superior in terms of OS to chemotherapy. Nevertheless, the reported TRM has been significantly reduced within the past years. Thus, the percentage of patients suitable for auto-SCT in CR has increased. Moreover, the scarce data concerning the comparison between auto-SCT and chemotherapy in different subsets of patients are unable to suggest a differentiated approach in patients with high-risk, standard-risk or low-risk AML. Data from the literature show that patients with unfavorable risk disease are more often addressed to allo-SCT and patients with low-risk disease receive more often intensive consolidation chemotherapy. Concerning the second query, interpretation of data from the main prospective studies about the role of allo-SCT in previously untreated AML is not easy. The first problem is the lack of real randomized clinical trials; in fact, according to the reported studies, AML patients generally receive allo-SCT on the basis of donor availability (the so called "genetic randomization"). The second problem is the frequent absence of intention to treat analysis. Despite methodological limitations, it was possible to compare allo-SCT with auto-SCT on a donor versus no-donor analysis and within risk groups. No overall benefit of allo-grafting on survival was demonstrated by any trial. In conclusion, the EBM approach highlighted the limitations observed in the published studies concerning consolidation therapy in AML; some suggestions, emerging from non-randomized, as well as randomized studies, are adequate, but not conclusive. This point, coupled with the intrinsic complexity to study AML biological heterogeneity, is probably a major obstacle to draw conclusive evidences for consolidation therapy in AML. These observations should plan to address new randomized studies on AML therapy; however, due to the emergence of genetic subgroups and new drugs targeting specific abnormalities, these trials should probably be designed directly focusing on the single entities. In this way, the cure of AML could eventually become the cure of each specific AML subset with its peculiar biological, molecular and prognostic features.

Influence of electrode composition on the second-order nonlinearity profile in thermally poled silica glass

Silica glass plates (Infrasil from Heraeus) have been thermally poled with different types of electrodes (evaporated or pressed-on) having different chemical compositions (Au, Al, n-doped Si or p-doped Si). We show for the first time to our best knowledge that the profile of the induced second-order nonlinearity strongly depends on the composition of electrodes used for the thermal poling process.

Response dynamics to nilotinib depend on the type of BCR-ABL mutations in patients with chronic myelogenous leukemia (CML) after imatinib failure

7024

Background: Nilotinib (AMN107) is an oral, aminopyrimidine-derivative, selective inhibitor of the BCR-ABL tyrosine kinase with improved potency and specificity compared with imatinib. In preclinical models, activity of nilotinib was also demonstrated in 32/33 imatinib- resistant mutant cell lines. We sought to explore the efficacy of nilotinib in vivo according to the type of preexisting BCR-ABL mutations associated with imatinib resistance. Methods: We have investigated peripheral blood samples from 101 chronic phase (CP) and 41 accelerated phase (AP) CML patients (pts) who had been enrolled in a phase II study investigating the efficacy and safety of 400mg nilotinib bid after imatinib failure. Screening for BCR-ABL mutations was performed by D-HPLC combined with DNA sequencing. The analysis covered amino acids 207–517 of the BCR-ABL tyrosine kinase domain. Results: Prior to nilotinib, 24 different BCR-ABL mutations involving 20 amino acids were detected affecting 44% CP and 61% AP pts. After 6 mo of therapy, complete hematologic response was achieved in 59%, major cytogenetic response (MCR) in 25% being complete (CCR) in 16% of pts with mutations vs 81%, 51% and 33% of pts without mutations, respectively. Response dynamics were associated with preclinical activity of nilotinib: MCR was reached in 10/18 pts with mutations associated with preclinical IC50 to nilotinib of <100nM, 2/9 pts with IC50 of 100–1,000 nM, and 0/4 pts with mutation T315I demonstrating virtual resistance to imatinib and nilotinib. In AP pts, hematologic response was achieved in 56% and 31%, MCR in 24% vs 19%, and CCR in 24% vs 13% of pts with or without mutations, respectively. Conclusions: Nilotinib is efficacious in pts with BCR-ABL mutations, except T315I, as well as in patients with BCR-ABL-independent resistance. Time to response may depend on the individual type of the mutation and correlates with the IC50 to nilotinib. Thus, nilotinib may have an important therapeutic role in imatinib resistance as well as in frontline CML therapy to prevent emergence of resistant clones.

[Table: see text]

Bosutinib (SKI-606) exhibits clinical activity in patients with Philadelphia chromosome positive CML or ALL who failed imatinib

7006

Background: Bosutinib (SKI-606) is an orally available, dual Src/Abl kinase inhibitor. To assess safety and preliminary clinical activity of bosutinib, we conducted a phase 1/2 study in patients (pts) with Philadelphia chromosome positive (Ph+) chronic myelogenous leukemia (CML) or acute lymphocytic leukemia (ALL) who were imatinib resistant/intolerant. Methods: In part 1, 18 pts with imatinib- relapsed/refractory chronic phase (CP) CML received bosutinib 400 mg/day (3 pts), 500 mg/day (3 pts), or 600 mg/day (12 pts). Part 2 was an expanded cohort of 51 pts with all phases of Ph+ CML and ALL dosed at 500 mg daily. Timed blood samples were collected on days 1–3, 15 for PK analysis. Results: Of 69 pts, median age was 59 yrs; 48 were CP; 90% imatinib resistant. Drug-related grade 1/2 adverse events (AEs) occurring in =10% of CP pts: diarrhea (69%), nausea (44%), vomiting (19%), abdominal pain (13%), rash (13%). Grade 3/4 AEs occurring in =5% of CP pts: rash (6%), thrombocytopenia (6%). 17 pts required dose reductions. In evaluable imatinib-resistant CP-CML pts with no prior exposure to other Abl inhibitors, 16/19 (84%) had complete hematologic response (CHR); 4/21 had partial and 7/21 had complete cytogenetic responses for major cytogenetic response (MCyR) rate of 52%. Of 58 pts evaluable for mutations, 13 different imatinib-resistant mutations were found in 32 pts. 12/14 CP pts with non-P-loop mutations and 3/3 with P-loop mutations achieved CHR. 5/11 CP pts with non-P- loop mutations and 1/1 with P-loop mutation achieved MCyR. 4/9 evaluable advanced leukemia pts had CHR, 2 had MCyR. After oral administration, steady state exposure of bosutinib was nearly 2-fold higher than single-dose exposure. Mean elimination half-life was approximately 22–27 hours, supporting a once-daily dosing regimen. Conclusions: Bosutinib was well tolerated in pts with CML, with primarily low-grade gastrointestinal and dermatologic AEs. Bosutinib showed clinical activity in imatinib-resistant pts with cytogenetic responses and CHR across a range of mutations. Durability of response continues to be assessed.

[Table: see text]

A novel denaturing high-performance liquid chromatography (D-HPLC) based method for kit mutation screening of patients (pts) with systemic mastocytosis (SM)

7085

Background: SM is characterized by activating mutations of Kit tyrosine kinase. While the enzimatic site (ES) type mutation D816V renders Kit resistant to imatinib, regulatory type mutations are sensitive to inhibition. Kit mutations screening with sensitive methods is important for an appropriate therapeutic management of SM. Methods: Our aims were: to set up and optimize a D-HPLC-based screening method for mutations in critical regions of Kit; to assess the sensitivity and reliability of our D-HPLC assay as compared to RFLP analysis; to characterize additional mutations. The analysis was performed on 51 SM pts. Results: For each sample, a RT-PCR product spanning the catalytic and activation loops (ES) was screened in parallel by D-HPLC, followed by sequencing of D-HPLC-positive cases, and by RFLP according to an reported method for the D816V detection. By RFLP analysis, 34/51 pts were positive for the D816V. By D- HPLC analysis, an abnormal eluition profile was seen in 36/51 pts - all the 34 RFLP-positive cases as well as two additional pts. Direct sequencing confirmed the presence of the D816V in all the 34 RFLP-positive cases and showed that in two of these cases a I798I polymorphism was also present. The two pts scored positive by D-HPLC but negative by RFLP were found to have the I798I polymorphism. The 15 pts who did not harbour ES type mutations were further investigated by D-HPLC analysis of a RT-PCR product spanning the transmembrane (TM) and juxtamembrane (JM) domains. D-HPLC showed an abnormal elution profile in 5 pts. By direct sequencing one patient showed the K546K mutation and 4 pts showed the M541L polymorphism. Conclusions: Our D-HPLC-based assay proved a straightforward, reliable and sensitive method for Kit mutation analysis and highlighted the importance of screening for mutations other than the D816V.

No significant financial relationships to disclose.

Binding mode of the tyrosine kinase inhibitor bosutinib (SKI-606) to Abl kinase

7049

Background: Bosutinib (SKI-606) is a 4-anilino-3-quinolinecarbonitrile Src/Abl kinase inhibitor. The crystal structure of Abl kinase domain in complex with bosutinib has not yet been determined and the mode of binding of this inhibitor is therefore unknown. Methods: In the present study, we used a molecular docking approach to investigate the following: a) Which Abl conformation(s) bosutinib is more likely to bind? b) Which Abl residues are likely to be involved in bosutinib binding? c) Which imatinib-resistant Abl mutants bosutinib is likely to be active against? A three-dimensional model of bosutinib was generated by Chemsketch ( http://www.acdlabs.com ). Modelling of the human Abl kinase in its inactive (closed) conformation was performed with the software Modeller, v7.7 ( http://salilab.org/modeller ) adopting the highly related Mus musculus Abl homologue as a template structure (PDB entry: 1OPJ , 0.175nm resolution). Active (open) Abl conformation is available as PDB entry 1OPL . Flexible docking of bosutinib to Abl was performed with Autodock v3.0 ( http://www.scripps.edu/mb/olson ). Results: Our binding hypothesis predicts that a) similarly to IM, the interaction between bosutinib and Abl seems to be more stable when the latter is in its inactive (closed) conformation; b) 21 Abl residues (including Y253, T315, F317 and F359 among others) surround bosutinib and engage H-bonds or Van der Waals interactions; c) bosutinib is likely to retain the ability to bind and inhibit the IM-resistant Y253H, M351T, F359V, F317L and E255V Abl mutants. In contrast, bosutinib binding to E255K and T315I mutants is predicted to be less efficient. Detailed models will be presented. Conclusions: Bosutinib is a promising second-line treatment for Ph+ leukemia patients harbouring several IM-resistant Abl mutations. The T315I remains the biggest hurdle for pharmacological therapy of Ph+ leukemias. Supported by European LeukemiaNet, AIRC, AIL, COFIN and FIRB projects, and by Fondazione del Monte di Bologna e Ravenna.

No significant financial relationships to disclose.