- Email: [email protected]
Clinical characteristics of patients with JMML according to mutational status
2. Therapy of JMML
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expressed only at basal levels and FLT3L expression was very low. MTT assays were performed to assess the response of JMML cells to the known FLT3 inhibitor PKC412 (Novartis). Consistent with the absence of mutatons and lack of FLT3 and FLT3L expression, no PKC 412 cytotoxicity was found in the JMML samples (n= 12), in contrast to leukemic cells of infants with MLL-rearranged ALL which expressed activated FLT3. These data suggest that constitutively activated FLT3 does not occur in JMML. Therefore targeting FLT3 by tyrosine kinase inhibitors like PKC 412 is unlikely to be effective in JMML.
a normal karyotype (1 missing). The 11 pts with an abnormal karyotype other than monosomy 7 or trisomy 8 belonged to the group with PTPNll (2), RAS mutation (4), no abnormality (4). In summary, these data suggest some genotype phenotype relationship in JMML pts with germline PTPNll mutations, acquired somatic PTPNll mutations, RAS mutations, NF1 or neither abnormality.
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~ - ] Case Forum: CUTANEOUS MANIFESTATION OF JMML WITHOUT MONOCYTOSIS IN A NEWBORN CHILD
CLINICAL CHARACTERISTICS OF PATIENTS WITH JMML ACCORDING TO MUTATIONAL STATUS
C.M. Niemeyer*, M. Tartaglia, A. Jung, M. Zecca, O.A. Haas, A. Biondi, E. Bergstrfi6er, H. Hasle, M.M. van den Heuvel-Eibrink, E Locatelli, J. Star~, M. Trebo, C. Kratz. For the
European Working Group of MDS in Childhood (EWOG-MDS) *E-mail: [email protected] Juvenile myelomonocytic leukemia (JMML) is a hematopoietic malignancy of early childhood. In uitro, JMML myeloid progenitor cells are characterized by aberrant growth with GM-CSF hypersensitivity. Several investigators have shown that activation of the RAS-MAPK signaling pathway is an important event in the pathophysiology of JMML. Somatic changes in JMML leukemic cells resulting in RAS-MAPK activation include oncogenic RAS mutations, loss of heterozygosity of the neurofibromatosis type 1 (NF1) gene, and missense mutations in PTPN11. PTPN11 encodes protein tyrosine phosphatase SHP-2 which is involved in GM-CSF receptor RAS signaling. We wanted to compare the clinical characteristics and outcome of 231 JMML patients (pts) of the different mutational groups. For comparison of clinical characteristics of the different mutational groups 15 pts with a Noonan like syndrome were excluded from the cohort. This group was characterized by young age at diagnosis (0.5-3.5mo), normal karyotype and spontaneous regression of disease. We studied 216 pts consecutively diagnosed between 1/1991 and 12/2004. There were 148 boys and 68 girls. Median age at diagnosis was 1.6 years (0.1-18.0). Data on karyotype at diagnosis were available in 201/216 pts. The karyotype was normal in 126 pts (63%), while 49 had monosomy 7 (24%), and 26 (13%) had other aberrations. Allogeneic stem cell transplantation (HSCT) had been performed in 174 pts with an estimated probability for the event-free survival (EFS) of 0.43(• at 5 years. Overall survival of the 216 pts at 5 years was 0.40(• For 160/216 pts DNA of bone marrow (BM) or peripheral blood (PB) was available for mutational secreening of the coding sequences of PTPNll and exon 1 and 2 of K-RAS and N-RAS. Pts characteristics of the groups with or without available DNA were similar to those of the total group. PTPN11 mutations were found in 50 pts (32%). N-RAS and K-RAS point mutations were detected in 48 pts (30%). Presence of mutations in PTPN11 or RAS and the clinical diagnosis of NF1 were mutually exclusive. NF1 had been diagnosed in 18 pts (11%). In 42 pts (27%) neither PTPN11 nor RAS mutations nor NF1 were present. There were no differences in age at diagnosis, liver or spleen size, WBC, hemoglobin, blast percentage in PB or BM or outcome between the 4 groups of pts with PTPNll mutations, /?AS mutations, NF1 or neither abnormality. In the groups of pts with NF1 the median platelet count was significantly higher (121 • 109/L) compared to the group with RAS mutations (48• 109/L), PTPN11 (45• 109/L) or no abnormality (73 • 109/L, p <0.01). More importantly, pts with NF1 were more likely to have a normal karyotype than pts with PTPN11, RAS mutations or no abnormality (p =0.03). Of the 18 pts with NF1 17 pts had
2. Therapy of JMML
C. Timke 1 *, A. Claviez 1, R. F61ster-Holst 2, M. Schrappe 1, M. Tiemann 3, C.M. Niemeyer4. Departments of 1Pediatrics,
2Dermatology and 3Hematopathology, Medical Uniuersity Center Schleswig-Holstein, Campus Kiel, Germany," 4Dept of Pediatrics, Uniuersity Hospital of Freiburg, Freiburg, Germany *E-mail: [email protected] Introduction: Diagnostic criteria of juvenile myelomonocytic leukemia (JMML) defined by the European Working Group for Myelodysplastic Syndromes in Childhood (EWOG-MDS) obligatorily include peripheral blood monocytosis, bone marrrow blast content of lower than 20% and absence of BCR/ABL gene rearrangement. For final diagnosis, two or more of secondary criteria have to be met as well: elevated fetal hemoglobin, leukocytosis, myeloic precursors in peripheral blood, and in-vitro G-CSF hypersensitivity. Beside common clinical features, skin involvement occurs in about one third of the patients at the time of diagnosis. Case report: A male newborn child of healthy unrelated Turkish parents in good general condition developed a macular papular skin rash at two weeks of age on the face and upper extremities. The patient was treated with antibiotic and antiviral drugs because of a presumed congenital infection without improvement. He was referred for further investigation. At that time the maculae had spread to the entire body surface showing central necrotic lesions, and marked hepatosplenomegaly was present. Laboratory investigation disclosed eosinophilia, neutropenia, thrombocytopenia (20/nl) but no monocytosis or leukemic blasts. Extensive investigations failed to identify an infectious agent. Skin biopsy revealed profound infiltration with myelomonocytic blasts with positivity for CD33, C D l l c and Ki-M8. Proliferation rate as shown by Ki-67 expression was only 15%. Bone marrow cytology showed myeloid dysplasia and a blast content of 5% with normal karyotype. PCR analysis of skin and bone marrow revealed a clonal rearrangement of the y-chain of T-cell receptor. No clinical signs of Noonan syndrome or PTPN11 mutation were identified. During the following months, the skin rash vanished and reappeared several times. Until identification of an HLA-compatible donor the boy was treated with retinoic acid. He received a cord blood transplant from a HLA-compatible unrelated donor following myeloablative conditioning with busulfan, cyclophosphamide and melphalan. The boy died on day +24 due to a cerebral edema of unknown origin. Permission for an autopsy was denied by the parents. Conclusion: The skin rash of our patient histologically showed extensive myelomonocytic infiltrates, while only few blasts were found in blood and bone marrow and monocytosis was absent. In atypical cases of JMML analysis of other compartments in addition to blood and marrow may be important for establishing the diagnosis.
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expressed only at basal levels and FLT3L expression was very low. MTT assays were performed to assess the response of JMML cells to the known FLT3 inhibitor PKC412 (Novartis). Consistent with the absence of mutatons and lack of FLT3 and FLT3L expression, no PKC 412 cytotoxicity was found in the JMML samples (n= 12), in contrast to leukemic cells of infants with MLL-rearranged ALL which expressed activated FLT3. These data suggest that constitutively activated FLT3 does not occur in JMML. Therefore targeting FLT3 by tyrosine kinase inhibitors like PKC 412 is unlikely to be effective in JMML.
a normal karyotype (1 missing). The 11 pts with an abnormal karyotype other than monosomy 7 or trisomy 8 belonged to the group with PTPNll (2), RAS mutation (4), no abnormality (4). In summary, these data suggest some genotype phenotype relationship in JMML pts with germline PTPNll mutations, acquired somatic PTPNll mutations, RAS mutations, NF1 or neither abnormality.
~-]
~ - ] Case Forum: CUTANEOUS MANIFESTATION OF JMML WITHOUT MONOCYTOSIS IN A NEWBORN CHILD
CLINICAL CHARACTERISTICS OF PATIENTS WITH JMML ACCORDING TO MUTATIONAL STATUS
C.M. Niemeyer*, M. Tartaglia, A. Jung, M. Zecca, O.A. Haas, A. Biondi, E. Bergstrfi6er, H. Hasle, M.M. van den Heuvel-Eibrink, E Locatelli, J. Star~, M. Trebo, C. Kratz. For the
European Working Group of MDS in Childhood (EWOG-MDS) *E-mail: [email protected] Juvenile myelomonocytic leukemia (JMML) is a hematopoietic malignancy of early childhood. In uitro, JMML myeloid progenitor cells are characterized by aberrant growth with GM-CSF hypersensitivity. Several investigators have shown that activation of the RAS-MAPK signaling pathway is an important event in the pathophysiology of JMML. Somatic changes in JMML leukemic cells resulting in RAS-MAPK activation include oncogenic RAS mutations, loss of heterozygosity of the neurofibromatosis type 1 (NF1) gene, and missense mutations in PTPN11. PTPN11 encodes protein tyrosine phosphatase SHP-2 which is involved in GM-CSF receptor RAS signaling. We wanted to compare the clinical characteristics and outcome of 231 JMML patients (pts) of the different mutational groups. For comparison of clinical characteristics of the different mutational groups 15 pts with a Noonan like syndrome were excluded from the cohort. This group was characterized by young age at diagnosis (0.5-3.5mo), normal karyotype and spontaneous regression of disease. We studied 216 pts consecutively diagnosed between 1/1991 and 12/2004. There were 148 boys and 68 girls. Median age at diagnosis was 1.6 years (0.1-18.0). Data on karyotype at diagnosis were available in 201/216 pts. The karyotype was normal in 126 pts (63%), while 49 had monosomy 7 (24%), and 26 (13%) had other aberrations. Allogeneic stem cell transplantation (HSCT) had been performed in 174 pts with an estimated probability for the event-free survival (EFS) of 0.43(• at 5 years. Overall survival of the 216 pts at 5 years was 0.40(• For 160/216 pts DNA of bone marrow (BM) or peripheral blood (PB) was available for mutational secreening of the coding sequences of PTPNll and exon 1 and 2 of K-RAS and N-RAS. Pts characteristics of the groups with or without available DNA were similar to those of the total group. PTPN11 mutations were found in 50 pts (32%). N-RAS and K-RAS point mutations were detected in 48 pts (30%). Presence of mutations in PTPN11 or RAS and the clinical diagnosis of NF1 were mutually exclusive. NF1 had been diagnosed in 18 pts (11%). In 42 pts (27%) neither PTPN11 nor RAS mutations nor NF1 were present. There were no differences in age at diagnosis, liver or spleen size, WBC, hemoglobin, blast percentage in PB or BM or outcome between the 4 groups of pts with PTPNll mutations, /?AS mutations, NF1 or neither abnormality. In the groups of pts with NF1 the median platelet count was significantly higher (121 • 109/L) compared to the group with RAS mutations (48• 109/L), PTPN11 (45• 109/L) or no abnormality (73 • 109/L, p <0.01). More importantly, pts with NF1 were more likely to have a normal karyotype than pts with PTPN11, RAS mutations or no abnormality (p =0.03). Of the 18 pts with NF1 17 pts had
2. Therapy of JMML
C. Timke 1 *, A. Claviez 1, R. F61ster-Holst 2, M. Schrappe 1, M. Tiemann 3, C.M. Niemeyer4. Departments of 1Pediatrics,
2Dermatology and 3Hematopathology, Medical Uniuersity Center Schleswig-Holstein, Campus Kiel, Germany," 4Dept of Pediatrics, Uniuersity Hospital of Freiburg, Freiburg, Germany *E-mail: [email protected] Introduction: Diagnostic criteria of juvenile myelomonocytic leukemia (JMML) defined by the European Working Group for Myelodysplastic Syndromes in Childhood (EWOG-MDS) obligatorily include peripheral blood monocytosis, bone marrrow blast content of lower than 20% and absence of BCR/ABL gene rearrangement. For final diagnosis, two or more of secondary criteria have to be met as well: elevated fetal hemoglobin, leukocytosis, myeloic precursors in peripheral blood, and in-vitro G-CSF hypersensitivity. Beside common clinical features, skin involvement occurs in about one third of the patients at the time of diagnosis. Case report: A male newborn child of healthy unrelated Turkish parents in good general condition developed a macular papular skin rash at two weeks of age on the face and upper extremities. The patient was treated with antibiotic and antiviral drugs because of a presumed congenital infection without improvement. He was referred for further investigation. At that time the maculae had spread to the entire body surface showing central necrotic lesions, and marked hepatosplenomegaly was present. Laboratory investigation disclosed eosinophilia, neutropenia, thrombocytopenia (20/nl) but no monocytosis or leukemic blasts. Extensive investigations failed to identify an infectious agent. Skin biopsy revealed profound infiltration with myelomonocytic blasts with positivity for CD33, C D l l c and Ki-M8. Proliferation rate as shown by Ki-67 expression was only 15%. Bone marrow cytology showed myeloid dysplasia and a blast content of 5% with normal karyotype. PCR analysis of skin and bone marrow revealed a clonal rearrangement of the y-chain of T-cell receptor. No clinical signs of Noonan syndrome or PTPN11 mutation were identified. During the following months, the skin rash vanished and reappeared several times. Until identification of an HLA-compatible donor the boy was treated with retinoic acid. He received a cord blood transplant from a HLA-compatible unrelated donor following myeloablative conditioning with busulfan, cyclophosphamide and melphalan. The boy died on day +24 due to a cerebral edema of unknown origin. Permission for an autopsy was denied by the parents. Conclusion: The skin rash of our patient histologically showed extensive myelomonocytic infiltrates, while only few blasts were found in blood and bone marrow and monocytosis was absent. In atypical cases of JMML analysis of other compartments in addition to blood and marrow may be important for establishing the diagnosis.