Correlation of P-glycoprotein expression and function in childhood acute leukemia: a children's cancer group study

Clinical drug resistance may be attributed to the simultaneous selection and expression of genes modulating the uptake and metabolism of chemotherapeutic agents. P-glycoprotein (P-gp) functions as a membrane-associated drug efflux pump whose increased expression results in resistance to anthracyclines, epipodophyllotoxins, vinca alkaloids, and some alkylating agents. This type of resistance occurs as both de novo and acquired resistance to therapy for leukemia. We have studied P- gp expression and function in childhood acute leukemias by developing a series of doxorubicin- and vincristine-selected CEM, T-cell lymphoblastoid cell lines that recapitulate the low levels of expression and resistance seen clinically. These cell lines have been used to develop flow cytometric assays for the semiquantitative measurements of P-gp expression with the MRK16 monoclonal antibody and P-gp function using the enhanced retention of rhodamine 123 in the presence of verapamil, a resistance modulator. Kolmogorov-Smirnov statistics, represented by the D measurement, are used to determine the difference in level of P-gp expression by comparing MRK16 staining to an IgG2a isotype control. When D is > 0.09, there is an excellent correlation (R = 0.82) between P-gp expression and function. The evaluation of 107 bone marrow specimens from 84 children with lymphoblastic or myelogenous leukemia showed a statistically significant (P = .004) increase in P-gp function at relapse. P-gp expression at relapse, however, approached but did not reach a significant level (P = .097). Using this methodology, we can identify patients with levels of P-gp expression and function that we can define clinically, as well as children with discordant multidrug resistance phenotypes. This study supports the role of P-gp-mediated drug resistance in childhood leukemia and confirms that P-gp expression and function are measurable in their leukemic blasts. These assays provide the means for the in vitro testing of resistance modulators and the monitoring of in vivo response to treatment with these agents.     

Nuclear expression of Survivin in paediatric ependymomas and choroid plexus tumours correlates with morphologic tumour grade

Survivin is a gene that is widely expressed throughout the development of the normal mammalian embryo. Subcellular localisation of Survivin to both the nucleus and cytoplasm has suggested multiple functional roles, including inhibition of cell death, especially as demonstrated within a variety of malignant cell types, as well as regulation of the mitotic spindle checkpoint. The expression of Survivin has been associated with an adverse clinical outcome in a large number of malignancies. However, nuclear Survivin expression has been described as an independent variable of favourable prognosis in two large clinical studies of breast and gastric carcinomas. Reports of Survivin expression in normal postnatal, differentiated tissues have been restricted to cell types with high proliferative capacities, including vascular endothelium, endometrium, colonic epithelium, and activated lymphocytes. Prior to this report, expression within the normal human brain had not been characterised. Here, we analyse the expression of Survivin in human brain sections obtained from perinatal and paediatric autopsy cases. We report a strikingly high level of expression of Survivin within normal ependyma and choroid plexus (CP). Analysis of corresponding neoplastic tissue in paediatric ependymomas and CP tumours shows that expression of the nuclear form of Survivin correlates with morphologic tumour grade, with a loss of nuclear expression associated with progressive cytologic anaplasia. This pattern of expression supports a hypothesis that Survivin plays a functional role in normal ependymal growth and/or neural stem cell differentiation, and that abnormally low levels of expression of the nuclear form of this protein may be a marker of more aggressive disease and/or higher morphologic grade in ependymal and CP tumours.     

Large Granular Lymphocyte Leukemia: Case Report of Chronic Neutropenia and Rheumatoid Arthritis-like Symptoms in a Child

Lymphoproliferative disorders of large granular lymphocytes (LGL) are heterogeneous, with a clinical/pathologic spectrum ranging from a benign polyclonal expansion to an aggressive clonal disease. Often these lymphoproliferative disorders are associated with autoimmune disease. The clonal form of the disorder, LGL leukemia, typically occurs in older adults with a median age of 55 years at diagnosis. Pediatric cases are referred to in review articles; however, no detailed reports of T-cell LGL leukemia in children exist. This report illustrates a case of a child who presented initially at age 2 and 1/2 years with psoriasis, juvenile rheumatoid arthritis-like symptoms, and neutropenia. Bone marrow examinations obtained throughout his course have demonstrated progressive hypercellularity with increased reticulin fibers and replacement of the normal marrow elements by lymphocytes, which were later identified as large granular lymphocytes. Further testing with immunophenotyping by flow cytometry and T-cell receptor gene rearrangement studies revealed a monoclonal proliferation of large granular lymphocytes and confirmed a diagnosis of LGL leukemia. Although rare, large granular lymphocyte leukemia should be included in the differential diagnosis of chronic neutropenia in children. Received September 15, 1999; accepted May 18, 2000.     

Syncope associated with concurrent amitriptyline and fluconazole therapy

OBJECTIVE: To report on a 12-year-old white male with prostatic rhabdomyosarcoma who experienced episodes of syncope attributed to concurrent amitriptyline and fluconazole therapy, confirmed by readministration. CASE REPORT: The patient began experiencing syncopal episodes periodically over a seven-month period. These repeated episodes occurred when fluconazole was administered for periodic mucositis secondary to chemotherapy. The patient had received fluconazole in the past with no difficulty and had been receiving a stable dose of amitriptyline for neuropathic pain. On discontinuation of amitriptyline, no further episodes were noted. DISCUSSION: Concurrent administration of fluconazole with amitriptyline likely resulted in the decreased metabolism of amitriptytine. Three case reports presented in the literature of adults receiving concurrent amitriptyline and fluconazole have shown an increase in serum amitriptyline concentrations with concurrent administration of fluconazole; however, none of these patients were rechallenged. Literature available on amitriptyline overdose confirms that syncope and the adverse events noted in the case studies may result from elevated amitriptyline plasma concentrations. CONCLUSIONS: The consistent presentation of syncope in our patient during readministration of amitriptytine and fluconazole strongly suggests a drug-drug interaction.     

The impact of CNS-directed treatment on quality of life in childhood cancer survivors

Purpose

Pediatric cancer survivors may have lower quality of life (QoL), but most research has assessed outcomes either in treatment or long-term survivorship. We focused on early survivorship (i.e., 3 and 5 years post-diagnosis), examining the impact of CNS-directed treatment on child QoL, as well as sex and age at diagnosis as potential moderators.

Methods

Families of children with cancer (ages 5–17) were recruited at diagnosis or relapse (N?=?336). Survivors completed the PedsQL at 3 (n?=?96) and 5 years (n?=?108), along with mothers (101 and 105, respectively) and fathers (45 and 53, respectively). The impact of CNS treatment, sex, and age at diagnosis on child QoL was examined over both time since diagnosis and time since last treatment using mixed model analyses.

Results

Parent-report of the child’s total QoL was in the normative range and stable between 3 and 5 years when examining time since diagnosis, while child reported QoL improved over time (p?=?0.04). In terms of time since last treatment, mother and child both reported the child’s QoL improved over time (p?=?0.0002 and p?=?0.0006, respectively). Based on parent-report, males with CNS-directed treatment had lower total QoL than females and males who did not receive CNS-directed treatment. Age at diagnosis did not moderate the impact of treatment type on total QoL.

Conclusions

Quality of life (QoL) in early survivorship may be low among males who received CNS-directed treatment. However, this was only evident on parent-report. Interventions to improve child QoL should focus on male survivors who received CNS-directed treatment, as well as females regardless of treatment type.

     

Coincidence FDG-PET in the evaluation of Langerhans' cell histiocytosis: preliminary findings

Background Bone involvement in Langerhans' cell histiocytosis (LCH) is common. Both bone scintigraphy and plain films are used to identify osseous lesions, but lack specificity for disease activity and response to therapy. FDG-PET is a sensitive technique for identifying bone lesions when histiocytes are present.Objective To describe the potential of coincidence FDG-PET (cFDG-PET) for identification of active bone lesions in LCH and to determine whether it can provide more specific information regarding lesional response to therapy than bone scintigraphy or radiography.Materials and methods The clinical data and imaging findings of three patients with osseous lesions of LCH were retrospectively reviewed.Results cFDG-PET identified all active LCH osseous lesions in these patients, differentiated active from healed lesions, and demonstrated normalization of uptake in a treated lesion earlier than bone scintigraphy and radiography.Conclusion cFDG-PET appears to have greater specificity than bone scintigraphy and radiography for the identification of active osseous lesions in LCH. It also may predict response to treatment earlier than conventional techniques. Its use in the evaluation of LCH warrants further study.Presented at the 2002 meeting of the Society for Pediatric Radiology, Philadelphia, Pennsylvania