[The prospects for children with acute lymphoblastic leukemia of being cured has increased in the Czech Republic in the 21st century to 90% - outcome of the ALL-IC BFM 2002 trial]. / Sance na vylécení detí s akutní lymfoblastickou leukémií stoupla v Ceské republicev 21. století na 90 % - výsledky studie ALL IC-BFM 2002.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most frequent childhood malignancy. Treatment has been unified in the middle of 1980 in the Czech Republic. In 2002-2007 children and adolescents with acute lymphoblastic leukemia were treated in an international randomized trial ALL-IC BFM 2002 in the Czech Republic. 291 patients aged 1-18 years were enrolled; infants below 1 year entered a separate trial. METHODS AND RESULTS: Patients were stratified into three risk groups according to their age, initial leukocyte count, prednisone response, presence of fusion genes BCR/ABL or MLL/AF4, bone marrow D+15 and remission status D+33. The whole therapy took 24 months. Randomized late intensification compared standard BFM therapy with extended, usually more intensive experimental treatment. The median follow-up was 8.7 years. Complete remission was achieved in 97.9% patients, 1% died in remission. 11% of children relapsed, 1.7% with CNS involvement. Six children (2.1%) developed secondary malignancy. Event free survival (EFS) 8 years from diagnosis was 83.5%, overall survival (OS) 91.4%. EFS and OS of the risk groups were: standard risk: 89.4%; 98.1%; intermediate risk: 82.6%; 89.6%; high risk: 68.8%; 78.1%. Male sex and age above 10 years were adverse prognostic factors. CONCLUSIONS: In comparison with the previous trial ALL-BFM 95, significant improvement was achieved.

The Czech National Diamond-Blackfan Anemia Registry: clinical data and ribosomal protein mutations update.

Diamond-Blackfan anemia is a rare inherited bone marrow failure syndrome diagnosed in early infancy that is characterized by a (a) macrocytic anemia with no other significant cytopenia, (b) reticulocytopenia, and (c) normal bone marrow cellularity with a paucity of erythroid precursors. Physical anomalies are often present. Mutations in several ribosomal proteins have been associated with the disease. Here we present a detailed description of 39 patients from 34 families enrolled in the Czech National Diamond-Blackfan Anemia Registry. Erythrocyte adenosine deaminase activity and serum erythropoietin levels were measured and bone marrow analysis and clonogenic assays were carried out. Twenty-two different ribosomal proteins were sequenced. We identified mutations in five different ribosomal proteins in 28/39 patients (71.8%) from 23/34 families (67.6%). Several new mutations are described. The most interesting data relate to genotype-phenotype correlations. All patients with ribosomal protein L5 or ribosomal protein L11 mutations have a thumb defect usually with one or more other anomalies. Most of these patients were born small for gestational age and currently have short stature. We also described five patients with a ribosomal protein S26 mutation. All of the latter are transfusion-dependent and they exhibit skeletal abnormalities rather than thumb or craniofacial deformities. Patients with ribosomal protein S19 seem to bear mildest associated anomalies, usually in a craniofacial region.

Prognosis of children with mixed phenotype acute leukemia treated on the basis of consistent immunophenotypic criteria.

BACKGROUND: Mixed phenotype acute leukemia (MPAL) represents a diagnostic and therapeutic dilemma. The European Group for the Immunological Classification of Leukemias (EGIL) scoring system unambiguously defines MPAL expressing aberrant lineage markers. Discussions surrounding it have focused on scoring details, and information is limited regarding its biological, clinical and prognostic significance. The recent World Health Organization classification is simpler and could replace the EGIL scoring system after transformation into unambiguous guidelines. DESIGN AND METHODS: Simple immunophenotypic criteria were used to classify all cases of childhood acute leukemia in order to provide therapy directed against acute lymphoblastic leukemia or acute myeloid leukemia. Prognosis, genotype and immunoglobulin/T-cell receptor gene rearrangement status were analyzed. RESULTS: The incidences of MPAL were 28/582 and 4/107 for children treated with acute lymphoblastic leukemia and acute myeloid leukemia regimens, respectively. In immunophenotypic principal component analysis, MPAL treated as T-cell acute lymphoblastic leukemia clustered between cases of non-mixed T-cell acute lymphoblastic leukemia and acute myeloid leukemia, while other MPAL cases were included in the respective non-mixed B-cell progenitor acute lymphoblastic leukemia or acute myeloid leukemia clusters. Analogously, immunoglobulin/T-cell receptor gene rearrangements followed the expected pattern in patients treated as having acute myeloid leukemia (non-rearranged, 4/4) or as having B-cell progenitor acute lymphoblastic leukemia (rearranged, 20/20), but were missing in 3/5 analyzed cases of MPAL treated as having T-cell acute lymphobastic leukemia. In patients who received acute lymphoblastic leukemia treatment, the 5-year event-free survival of the MPAL cases was worse than that of the non-mixed cases (53+/-10% and 76+/-2% at 5 years, respectively, P=0.0075), with a more pronounced difference among B lineage cases. The small numbers of MPAL cases treated as T-cell acute lymphoblastic leukemia or as acute myeloid leukemia hampered separate statistics. We compared prognosis of all subsets with the prognosis of previously published cohorts. CONCLUSIONS: Simple immunophenotypic criteria are useful for therapy decisions in MPAL. In B lineage leukemia, MPAL confers poorer prognosis. However, our data do not justify a preferential use of current acute myeloid leukemia-based therapy in MPAL.

Identification of mutations in the ribosomal protein L5 (RPL5) and ribosomal protein L11 (RPL11) genes in Czech patients with Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a congenital red blood cell aplasia that is usually diagnosed during early infancy. Apart from defects in red blood cell maturation, the disorder is also associated with various physical anomalies in 40% of patients. Mutations in the ribosomal protein (RP) S19 are found in 25% of patients, while mutations in other proteins of the small ribosomal subunit--RPS17 and RPS24--have been found in a fraction of patients. Recently, mutations in RPL5, RPL11, and RPL35a of the large ribosomal subunit have also been reported in several DBA patients. Here, we present the identification of mutations in the RPL5 and RPL11 genes in patients from the Czech DBA Registry. Mutations in RPL5 were identified in eight patients from 6 out of 28 families (21.4%), and mutations in RPL11 in two patients from 2 out of 28 families (7.1%). Interestingly, all 10 patients with either an RPL5 or RPL11 mutation exhibited one or more physical anomalies; specifically, thumb anomalies (flat thenar) were always present, while no such anomaly was observed in seven patients with an RPS19 mutation. Moreover, 9 out of 10 patients with either an RPL5 or RPL11 mutation were born small for gestational age (SGA) compared to 3 out of 7 patients from the RPS19-mutated group. These observations may suggest that mutations, at least in RPL5, seem to generally have more profound impact on fetal development than mutations in RPS19. Since RPL5 and RPL11, together with RPL23, are also involved in the MDM2-mediated p53 pathway regulation, we also screened the RPL23 gene for mutations; however, no mutations were identified.

Identification of a new in-frame deletion of six amino acids in ribosomal protein S19 in a patient with Diamond-Blackfan anemia.

Ribosomal protein S19 (RPS19) is currently the only gene associated with Diamond-Blackfan anemia (DBA), a rare congenital pure red cell aplasia characterized by normochromic macrocytic anemia, reticulocytopenia, and normocellular bone marrow with a selective deficiency of erythroid precursors. RPS19 is mutated in 25% of DBA patients, but its role in DBA pathogenesis remains elusive. We have identified a novel heterozygous microdeletion in RPS19 in a DBA patient presenting with profound anemia after birth. The deletion of 18 nucleotides (233-250; A in start codon is +1) in exon 4 leads to the elimination of 6 amino acids 78IYGGRQ83, affecting the most conserved stretch of three amino acids (YGG) in RPS19. The mutated allele was not detected in the patient's family members, indicating de novo mutation. Both alleles were expressed at the same level. Using an immunofluorescence technique, the mutated RPS19 protein localized to nucleoli, and its intracellular distribution did not differ from the wild-type RPS19. The deletion of only a few amino acids of this protein with a preserved reading frame is rare, and this type of a mutation could be very helpful in further experiments to define the role of the RPS19 protein in DBA pathogenesis.