Follow-up of minimal residual disease in acute childhood lymphoblastic leukemia by WT1 gene expression in the peripheral blood: the Hungarian experience.

The aim of the study was to investigate if monitoring WT1 gene expression in the peripheral blood is an appropriate approach to monitor the progression of childhood acute lymphoblastic leukemia (ALL). Forty-six patients have been enrolled into this study (24 ALL and 22 control, nonleukemic cases). The peripheral blood was tested for WT1 gene expression using a sensitive nested RT-PCR technique. The assay was sensitive enough to detect 10(2) leukemic cells among 10(6) normal leukocytes. In agreement with the literature 96% of childhood ALL (23/24) expressed WT1 independent of the prognostic factors of the disease. On the other hand, no WT1 gene expression was found in the peripheral blood of nonleukemic hematological diseases, except myelodysplasia. WT1 became negative in the peripheral blood of these patients at the end of the induction phase of the therapy in the majority of the cases (19/24), whereas clinical remission was achieved in all patients except one. WT1 gene expression changes in the peripheral blood was monthly monitored in 20 ALL patients for 1 year and in 16 cases during the second year (for a maximum of 21 months). Although continuous monitoring detected transient (1- to 3-month long) WT1 expression in the majority of the ALL cases (16/20), clinical relapse occurred in 2 cases only when the WT1 expression was maintained for 11-15 months. Follow up studies of the WT1 gene expression in the peripheral blood of WT1-positive childhood ALL may enable researchers to monitor MRD and detect a very low leukemic cell count (perhaps called "molecular relapse"). According to this study, the transient WT1 positivity for 1-3 months does not predict clinical relapse of childhood ALL, unlike a longer-lasting positivity.

Expression of metastasis associated proteins, CD44v6 and NM23-H1, in pediatric acute lymphoblastic leukemia.

Two metastasis-associated proteins, CD44v6 and NM23-H1, are expressed by normal lymphoid cells, the former serving as activation marker and the latter as a constitutive protein. CD44v6 is considered as a marker of poor prognosis of various hematological cancers but its expression was not demonstrated in childhood acute lymphoblastic leukaemia (ALL). On the other hand, NM23-H1 is considered as a differentiation inhibitory factor in various hematological cancers and as a marker of poor prognosis. Therefore we analyzed the expression of CD44v6 and NM23-H1 in the bone marrow of sixteen pediatric ALL patients using immunocytochemistry. For the first time, we have demonstrated the expression of CD44v6 protein epitopes on leukemic cells in a proportion of ALL cases (6 out of 16), primarily in the medium/high risk group (except one case), suggesting a possible association to an unfavourable outcome. On the other hand, NM23-H1 protein expression was maintained in leukaemic cells in 50% of both low and medium/high risk ALL cases. The majority of the pediatric ALL cases expressed only one of the metastasis-associated proteins (10 out of 16). This feature is similar to the observations made in several adult solid cancers. The potential of CD44v6 expression in leukaemic cells as prognosticator in pediatric ALL should be evaluated in a larger clinical trial.

[Expression of metastasis associated proteins, CD44v6 and NM23-H1, in pediatric acute lymphoblastic leukemia] / Metasztázis-asszociált fehérjék (CD44v6 és NM23-H1) expressziója gyermekkori akut limfoblasztos leukémiában.

Two metastasis associated proteins, CD44v6 and NM23-H1, are expressed by normal lymphoid cells, the former serving as activation marker and the later as a constitutive protein. CD44v6 is considered as a marker of poor prognosis of various hematological cancers but its expression was not demonstrated in childhood acute lymphoblastic leukemia (ALL). On the other hand, NM23-H1 is considered as a differentiation inhibitory factor in various hematological cancers and as a marker of poor prognosis. Therefore we have analyzed the expression of CD44v6 and NM23-H1 in bone marrow of sixteen pediatric ALL patients using immunocytochemistry. For the first time, we have demonstrated the expression of CD44v6 protein epitopes on leukemic cells in a proportion of ALL cases (6/16), primarily in the medium/high risk group (except one case), suggesting a possible association to an unfavorable outcome. On the other hand, NM23-H1 protein expression was maintained in leukemic cells in 50% of both low and medium/high risk ALL cases. The majority of the pediatric ALL cases expressed only one of the metastasis associated proteins (10/16). This feature is highly similar to the observations made in several adult solid cancers. The potential of CD44v6 expression in leukemic cells as prognosticator in pediatric ALL has to be evaluated in a larger clinical trial.

[Acute lymphoblastic leukemia in a patient with congenital hemolytic anemia: case report]. / Congenitalis haemolyticus anaemia és akut lymphoblastos leukaemia társulása: esetismertetés.

The authors present a case of a 13-year-old girl with a history of congenital hemolytic anemia (spherocytosis) who developed acute lymphoblastic leukaemia. She received treatment according to the ALL-BFM 91 protocol standard risk group. During maintenance therapy an aplastic crisis caused by Parvovirus B 19 infection had developed. Chemotherapy was stopped in September 1999, and the patient remained in complete remission. In January, 2000 the patient presented with jaundice, caused by a stone in the ductus choledochus. Cholecystectomy and splenectomy were performed, and the the girl became symptomfree. The authors review the most frequent complications of congenital hemolytic anemias (aplastic crisis, haemolytic crisis and cholelithiasis). The occurrence of acute lymphoblastic leukaemia in a patient with congenital hemolytic anemia has not been previously reported.

Differential diagnostic significance of the paucity of HLA-I antigens on metastatic breast carcinoma cells in effusions.

Distinction between benign reactive mesothelial cells and metastatic breast adenocarcinoma cells in effusions from patients with a known prior history of breast cancer is not the easiest task in diagnostic pathology. Here, we report the usefulness of testing the expression of class I HLA antigens (HLA A, B, C) in this respect. Cytospins were prepared from effusions of patients without the history of breast cancer (5 cases) and from effusions of patients with infiltrating ductal carcinoma (11 cases). Three effusions from cancerous patients were not malignant cytologically. The expression of HLA-A, B, C, HLA-DR and beta2-microglobulin as well as the macrophage antigen, CD14, was evaluated by immunocytochemistry. In 10 of 11 effusions the cytologically malignant cells expressed very weak or undetectable HLA-A,B,C as compared to the mesothelial cells and macrophages. The paucity of expression of HLA-A, B, C was detectable in those 3 cases where a definitive cytological diagnosis of malignancy could not be established. In contrast, mesothelial cells and macrophages from all samples were uniformly and strongly positive for both HLA-A, B, C and beta2-microglobulin. We conclude that the paucity of HLA-I antigens provides a marker helpful in distinguishing metastatic breast carcinoma cells from reactive mesothelial cells in effusions.

Transplantable human non-Hodgkin lymphoma line in artificially immunesuppressed mice.

Diffuse non-Hodgkin lymphoma of B-cell origin has been established as a serially transplantable xenograft line in artificially immunesuppressed mice. The take rate and growth rate increased with repeated passages compared to the first transplant generation. However the xenografted tumor preserved many of its characteristics, including morphology, cell surface markers and DNA index. Chromosome analysis proved the human origin of tumors grown in mice and revealed translocation 8,14. Cyclophosphamide, Methotrexate and Vincristine produced substantial inhibition of tumor growth, while Dianhydrogalactitol and Adriamycin were less effective. Human alpha interferon also produced a delay in tumor growth.

Chemotherapy of human non-Hodgkin lymphoma (NHL) xenografts.

Three human NHL (B-cell type) were established successfully as serially transplantable xenografts in artificially immunesuppressed CBA mice. All of them preserved the phenotypic characteristics of the original tumour even after several passages. The transplanted tumours were highly sensitive to cyclophosphamide and methotrexate, reflecting the results obtained in clinical practice, and relatively sensitive to dianhydrogalactitol.

Immunologic methods in cytology: definitive diagnosis of non-Hodgkin's lymphomas using immunologic markers for T- and B-cells.

The cytologic diagnosis of malignant lymphoma can be extremely difficult because the cytologic features of the malignant cells in small cell and mixed small and large cell lymphomas may be indistinguishable from those of reactive lymphoid cells. In addition, large cell lymphoma can be difficult to distinguish from undifferentiated carcinoma in cytologic specimens. Using the avidin-biotin immunoperoxidase technic and antibodies to the B-cell markers alpha, gamma, and mu heavy chains and kappa and lambda light chains, to the T-cell markers Leu-1, Leu-2a, and Leu-3a, to the lymphoid marker T200, to TdT, and to Leu-M3, the authors studied 35 cytologic specimens including pleural, cerebrospinal, and ascites fluids and fine-needle aspirations. Immunologic staining allowed them to make a definitive diagnosis of lymphoma or reactive effusion in every case studied and resulted in a significant modification of the morphologic diagnosis in over 50% of cases. In 16 cases the lymphoid cells were monoclonal B-cells: ten expressing IgM kappa; four expressing IgM lambda; one expressing IgA kappa; and one expressing kappa without demonstrable heavy chain expression. Although there are no good markers of monoclonality for T-cells, the authors were able to make a positive diagnosis in two cases of T-cell lymphoid malignancies by the expression of an aberrant phenotype on the malignant cells. The expression of TdT confirmed the diagnosis in one case of common ALL and one lymphoblastic lymphoma. In a patient with a "null cell" large cell lymphoma, the expression of T200 on the malignant cells ruled out the possibility of carcinoma. In 15 cases the marker studies indicated a reactive lymphoid proliferation. The authors conclude that immunologic markers are very useful in the cytologic diagnosis of lymphoma.

Potentiation of the antitumor action of 5-fluorouracil with 5-ethyl-2'-deoxyuridine in human colorectal tumor xenografts.

The tumor growth inhibitory effect of 5-ethyl-2'-deoxyuridine ( EUdR ) in combination with 5-fluorouracil (5-FU) has been studied on four human colorectal xenograft lines. In all lines the EUdR pretreatment potentiated the effect of 5-FU presumably due to the increased incorporation of 5-FU into RNA via elevated intracellular thymidine concentration and decreased rate of 5-FU catabolism.

Renal cell carcinoma--xenotransplantation into immuno-suppressed mice.

21 human renal cell carcinomas (RCC) were xenotransplanted into artificially immunosuppressed mice. 4 tumors grew successfully retaining some characteristics of the primary tumors (according to morphology and karyotype analysis), but losing metastatic capacity. One of the serially transplantable tumors (HT 40) with hyperdiploid cellular DNA content and estrogen receptor positivity failed to respond to the single maximally tolerated dose of several cytotoxic agents.