Long term temporal and spatial changes in the distribution of polychlorinated biphenyls and polybrominated diphenyl ethers in Scottish soils

Long term changes in polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) concentrations in soil from four transects across Scotland were measured in three surveys conducted between 1990 and 2007-9. Overall PCB level declined during this period (22.5 to 4.55 ng/g, p<0.001) but PBDEs increased (0.68 to 2.55 ng/g, p<0.001), reflecting the ban on PCB use in the 1980s while PBDE use increased until about 2004 when the use of penta-mix congener ceased in Europe. The proportion of lighter PCB congeners (28+52) present declined (p<0.001) primarily between 1990 and 1999. However, the proportion of lighter PBDE congeners (47+99) in the soil samples increased (p<0.01) from 1990 to 1999 and declined (p<0.001) thereafter, probably reflecting the introduction of legislation banning penta-BDE products and the degradation of lighter congeners and their translocation. PCBs were slightly higher in two southernmost transects but PBDE concentrations were significantly higher (p<0.001) in the two southern transects than in the two northern transects. This may reflect proximity to areas of high population and industrial activity. It is concluded that temporal and spatial changes in the distribution of PCBs and PBDEs reflect geography, physical processes and legislation.

A phase I study of antisense Bcl-2 oligonucleotide (G3139) in combination with carboplatin (C) and paclitaxel (T) in patients with advanced solid tumors

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Background: G3139 is an 18-mer oligonucleotide that targets the mRNA of Bcl-2, a protein that inhibits apoptosis conferring treatment resistance, and is synergistic with taxanes in studies using Bcl-2 over-expressing xenografts. Here we conduct a study combining G3139 with C + T in order to define the recommended phase II dose, as well as evaluate the direct biologic effect of G3139 on tumor. Methods: Patients with advanced solid tumors were treated with a dose escalation of G3139 (3–7 mg/kg/day) by continuous infusion days 1–7, with C (AUC 5) and T (150 mg/m2) given on day 4, repeated in 3 week cycles. At the planned expanded cohort (G3139 7 mg/kg/day dose), 12 patients underwent paired tumor biopsies (baseline and day 4 pre-chemotherapy) for assessment of Bcl-2/Bax expression by RT-PCR and IHC, as well as intratumoral G3139 levels using ELISA. Likewise, peripheral blood mononuclear cells (PBLs) were assessed using flow cytometry and RT-PCR for changes in Bcl-2/Bax expression. Results: 34 patients have been treated: 11 melanoma, 7 bladder, 3 prostate, 2 esophageal, 3 non-small cell lung, and 1 head/neck, kidney, breast, pancreas, liver, gastrointestinal stromal, biliary, and unknown primary cancers. G3139/C/T appeared well tolerated at the doses administered with the main toxicities observed being attributed to the C + T chemotherapy (myelosuppression and thrombocytopenia). The maximal tolerated dose is yet to be achieved. Assessment of paired tumor biopsies on 12 patients show decreases in Bcl-2 transcription in laser capture microdissected tumor using RT-PCR, with concordance observed using IHC. Likewise, decrease in Bcl-2 gene expression in PBLs was seen. 2 confirmed PRs were observed, including a bladder patient with baseline Bcl-2 tumor expression 10-fold greater than any other patient assessed. Conclusions: G3139/C/T is well tolerated, with main toxicities attributable to the chemotherapy alone. Bcl-2 is suppressed in tumor and PBLs supporting that a biologically active dose of G3139 is being achieved. Currently, the C + T is being escalated to define a MTD. Complete clinical data, G3139 pharmacokinetics, and Bcl-2/Bax data will be presented in detail.

No significant financial relationships to disclose.

The Burkitt-like lymphomas: a Southwest Oncology Group study delineating phenotypic, genotypic, and clinical features

The Revised European-American Lymphoma classification gives Burkitt-like lymphoma (BLL) provisional status, leaving unresolved the differential diagnosis with Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). This study compared the biologic features of adult BLL and DLBCL. The phenotypic distinction between BLL and DLBCL was determined by immunohistochemical staining of frozen tissue from 13 patients with BLL and 55 patients with DLBCL by using an extensive antibody panel including Ki-67, CD10, CD11a/lymphocyte function-associated antigen 1alpha (LFA-1alpha), CD18/LFA-1beta, CD58/LFA-3, and CD54/intercellular adhesion molecule, CD8 for tumor-infiltrating cytotoxic T cells (T-TILs), CD44 homing receptor, and p53 and Bcl-2 oncogenic proteins. Compared with DLBCL, BLL had a higher proliferative rate (mean Ki-67, 88% versus 53%), greater expression of CD10 and p53 antigens, and decreased expression of Bcl-2. BLL cases had a consistent absence of one or more cell adhesion molecules (92% versus 27%), low T-TIL numbers, and absence of CD44 homing receptor (92% versus 14%). The t(8;14) translocation was identified in 80% of BLL cases, but no patients with BLL had the t(14;18) translocation. In a 10-year analysis, median survival of patients with BLL was 1.2 years, and that of patients with DLBCL was 2.5 years. Although the proportion of patients cured was similar in the 2 groups, BLL patients had an increased risk of early death. We conclude that BLL can be recognized by its combined morphologic and phenotypic features and that it represents a high-grade lymphoma much closer to BL than DLBCL. Retention of the BLL category or inclusion of BLL as a variant of BL is biologically and clinically more appropriate than absorbing the category of BLL into DLBCL. (Blood. 2001;97:3713-3720)

Multidrug resistance in leukemia

Resistance of tumors to chemotherapeutic agents is an important factor that limits the successful treatment of a wide range of malignancies. The multidrug resistant (MDR) phenotype is well recognized in clinical samples, and it has been extensively studied, particularly in acute myeloid leukemia. One of the principle mechanisms underlying this MDR phenotype is the active cellular extrusion of chemotherapeutic agents by the multidrug resistance protein MDR1 (p-glycoprotein). More recently, other drug resistance proteins, notably the multidrug resistance-associated protein, MRP, and the lung resistance protein, LRP, have also been implicated in multidrug resistance. This review summarizes recent contributions in this field. In particular, it focuses on recent efforts to better measure MDR in clinical samples, a critical step in correctly determining the MDR phenotype of a patient's tumor.