Burkitt lymphoma (BL): reclassification of 39 lymphomas diagnosed as BL or Burkitt-like lymphoma in the past based on immunohistochemistry and fluorescence in situ hybridization.

Burkitt lymphoma (BL) is a well characterized entity. For atypical findings a term Burkitt-like lymphoma (B-LL) was applied in the past, but the interpretation of the morphological appearances was subjective and poorly reproducible. We used a combined approach (morphology using classical histological staining; immunohistochemistry-IHC; fluorescence in situ hybridization-FISH on interphase nuclei; cytogenetics) to perform a retrospective study on 39 patients diagnosed as BL and B-LL at our department in the years 1982 to 2002. By FISH we demonstrated t(8;14)(q24;q32) in 31 patients; in further two we found a break at 8q24, suggestive of a variant translocation. In three patients with the cytogenetic investigation available we confirmed the findings of FISH--two lymphomas had the t(8;14)(q24;q32), one had t(2;8)(p12;q24). IHC showed CD20, CD10, BCL-6, p53 expression, and Ki-67 antigen in > 95% of the tumor cell population in a majority of the patients. There was a group of 4 patients in whom the t(8;14)(q24;q32) or a break at 8q24 were not found (FISH). These cases were reclassified within the WHO defined grey zone subgroup of B-cell lymphoma unclassifiable with features intermediate between diffuse large cell lymphoma (DLBCL) and Burkitt lymphoma--I-DLBCL/BL. Two further cases were reclassified as DLBCL based on a combined IHC and FISH findings. A lymphoma of one of these patients had breaks at 3q27 (BCL6) and at 14q32 (IGH) suggestive of t(3;14)(q27;q32). The overall survival estimate of 33 patients with the diagnosis of BL was 54%. Most of deaths occurred within 6 months after the tumor diagnosis. The unfavorable clinical outcome appears to be associated with a strong expression of the p53 protein in the tumor cell population. Individually utilized methods in the diagnosis of BL may lead to false diagnostic conclusions. A combined approach helps to establish a more reliable diagnosis of BL and to separate grey zone lymphomas I-DLBCL/BL and DLBCL with morphological mimics of BL to start adequate treatment. I-DLBCL/BL is a non-homogenous group of lymphomas necessitating further analysis in a prospective study.

[Clinical relevance of chromosomal aberrations in bone and soft tissue tumors in children and young adults]. / Klinický význam chromozomálních zmen u nádoru kostí a mekkých tkání detí a mladistvých.

BACKGROUND: We present the results of a cytogenetic and molecular cytogenetic analysis of a series of patients with bone and soft tissue tumors. PATIENTS ANDMETHODS: We analyzed a cohort of 26 patients with Ewing sarcoma/PNET, 15 patients with rhabdomyosarcoma, 5 with synovial sarcoma and one patient with an undifferentiated sarcoma using the cytogenetic and molecular cytogenetic techniques M-FISH and arrayCGH. RESULTS: We found nonrandom chromosomal structural and numerical changes with diagnostic and prognostic relevance in most patients. Eight patients with ES/PNET had only a t(11;22)(q24;q12), eight patients had secondary aberrations as well and six had only secondary aberrations. In the RMS patients we detected the t(1;13)(p36;q14) once and the t(2;13)(q35;q14) four times, both of them characteristic for the alveolar subtype with poor prognosis and numerical aberrations, characteristic for the embryonal subtype, in five patients. Four patients with synovial sarcoma had the diagnostic t(X;18)(p11.2;q11.2), one of them had a complex karyotype with a complex t(X;18;21) (p11.2;q11.2;q11.2) together with t(2;5)(q24-32;p13-14) and t(12;20)(p11;q13). We correlated the karyotype of cancer cells with histopathologic morphologic analysis, clinical outcome and foreign published results. CONCLUSION: Cytogenetic and molecular cytogenetic analysis is a valuable diagnostic tool in bone and soft tissue tumors, especially in less differentiated subtypes, and as such it should be an integral part of curative care.

Lipoblastoma in children: an analysis of 5 cases.

Lipoblastoma is a very rare benign tumour that is caused by embryonal fat. The present five cases of lipoblastoma operated on during the years 1996-2005. The localization of the lipoblastomas in our series were very unusual. A six-monthold girl with giant mediastinal lipoblastoma; a two-year old boy with very rare lipoblastoma of the kidney; a three-year old boy with mesenterial lipoblastoma; a seven-year old boy with mesenterial lipoblastoma; and an eight-week old girl with perineal localization. Histological diagnosis can be difficult. The basic differential diagnosis is to be made between lipoblastoma, myxoid, and round cell liposarcoma. In our sample group of patients all lipoblastomas were successfully and completely removed and we did not see any recurrence of the tumours. In only one case was more radical surgery needed. One patient with mesenterial lipoblastoma had to undergo a 30 cm long resection of the small intestine.

[Anaplastic large-cell lymphoma: review]. / Anaplastický velkobunecný lymfom: prehled problematiky.

Anaplastic large cell lymphomas (ALCLs) represent a heterogeneous group of malignant lymphoproliferative diseases. Most of the cases are of T-cell line with a loss of cell surface receptors but with a production of cytotoxic cytoplasmatic granules--immunohistochemically (IHC) positive perforin, granzyme B, and TIA-1. The diagnostics of ALCL is based on morphological findings and results of IHC, which further stratify ALCLs to basic immunophenotypes according to ALK (anaplastic lymphoma kinase) protein expression--ALCL CD30+ ALK+ and ALCL CD30+ ALK+. The morphological investigations are supplemented by karyotyping and/or by a demonstration of breakpoint at 2p23 harboring ALK gene (FISH), and by molecular detection of chimeric genes characteristic of ALK+ lymphomas (NPM-ALK, ATIC-ALK, TPM3-ALK, TFG-ALK, and some even rarer rearrangements). Molecular diagnostics is important in monitoring minimal residual disease. As some of the characteristic molecular changes were demonstrated in healthy individuals and in Hodgkin's disease by quantitative PCR, the validation of these findings demands further studies. ALK protein positive ALCLs affect patients in age categories up to the third decade, whereas ALK protein negative cases occur in older patients with an average age of 60 years. Both subgroups of lymphomas are aggressive but ALK+ lymphomas react well to systemic treatment, and have a more favorable prognosis. Primary skin ALCLs belong to a group of T-cell lymphoproliferative diseases of the skin and have, in the majority of cases, a favorable course without generalization.

Gene aberrations in childhood brain tumors.

We present the results of the examination of prognostic markers in 40 children suffering from brain tumors. Prognostic markers such as amplification of the N-myc and c-myc, deletion of the 17p, and DNA ploidy are indispensable factors for the determination of diagnosis. An increased number of c-myc gene copies was found in malignant brain tumors, especially embryonal, more often than reported in the literature. N-myc amplification occurs in our group seldom, but it seems to be a sign of worse prognosis in glial and embryonal brain tumors. DNA aneuploidy was not found very frequently, but in high-grade tumors only.

[Detection of minimal residual disease in Ewing's sarcoma using RT-PCR]. / Detekce minimální reziduální nemoci u Ewingova sarkomu pomocí RT-PCR.

BACKGROUND: More than 90% of Ewing's sarcomas (ES) contain a fusion of the EWS and FLI-1 genes, due to the t(11;22)(q23;q12) translocation. At the molecular level, the EWS-FLI-1 rearrangement shows great diversity. Specifically, many different combinations of exons from EWS-FLI-1 encode in-frame fusion transcripts and result in differences in length and composition of the chimeric protein, which function as an oncogenic aberrant transcription factor. The finding of this translocation gives evidence for the presence of ES cells. The aim of this prospective study was to verify applicability of the RT-PCR method for the detection of minimal residual disease in patients with ES. METHODS AND RESULTS: Conditions for the detection of Ewing's sarcoma cells by means of the reverse-transcriptase polymerase chain reaction (RT-PCR) at fusion transcripts in peripheral blood, bone marrow (BM) and autologous hematopoietic stem cell grafts in patients with ES were appointed. 31 samples of BM, 5 samples of blood and 7 peripheral blood grafts obtained from 23 patients were investigated. Presence of tumor cells was identified in 7 BM samples from 7 different patients (31 samples from 16 patients), all the peripheral blood and graft samples were negative. CONCLUSIONS: The high sensitivity of RT-PCR method in detection of cells bearing t(11;22)(q23;q12) was demonstrated in the experimental model and clinical samples. Likewise the literary statements, the RT-PCR method was found to be more sensitive than cytology.

Environmental genotoxicity monitoring using Salmonella typhimurium strains as indicator system.

Screening for mutagens in environmental complex mixtures is gradually accepted as a routine methodology in the monitoring processes. Examination of 70 drinking water samples showed that the variations in the degree of mutagenicity was dependent on the location of the water source and the type of drinking water tested. Analogous screening for mutagens in river and waste waters may help better assess the potential genotoxic hazard from various types of industrial technology. The recommended methods are routinely used for monitoring the mutagenicity and for checking the effectiveness of preventive measures.

Enzyme synthesis of L-tryptophan.

Enzyme synthesis of tryptophan from indole, pyruvate and ammonium salts was studied using Escherichia coli cells exhibiting a significant tryptophanase activity. In addition to the effect of cultivation medium composition and cultivation conditions, factors affecting the course of the conversion were investigated. Production of 32.4 g/L of L-tryptophan was reached after 48 h under optimal conditions.

Effect of cyclic adenosine-3',5'-monophosphate on the simultaneous synthesis of beta-galactosidase and tryptophanase in Escherichia coli.

When inducing simultaneously beta-galactosidase and tryptophanase in a batch culture either the synthesis of tryptophanase or of both enzymes is decreased due to an insufficient cAMP concentration. The addition of this nucleotide can overcome this decrease. In a continuous culture both enzymes are synthesized at the maximum rate, as the amount of cAMP produced during carbon limitation of growth is probably sufficient for the simultaneous synthesis of both enzymes. In the beta-galactosidase hyperproduction mutant cultivated continuously the level of beta-galactosidase markedly decreases when tryptophanase is simultaneously induced. Also this decrease is caused by cAMP insufficiency and can be overcome by increasing its concentration. cAMP is thus an important regulatory factor of both enzymes and becomes a limiting factor in their simultaneous synthesis; a competition for this regulatory compound apparently occurs and probably also a different mutual affinity of the regulatory complex with the promoter site of the enzyme operons is involved.

Simultaneous induction of three catabolic enzymes in Escherichia coli.

During a simultaneous induction of three enzymes which are subject to catabolite repression (beta-galactosidase, tryptophanase and amylomaltase, or beta-galactosidase, tryptophanase and D-serine deaminase) in a batch culture, the rates of synthesis of beta-galactosidase and tryptophanase decreases, while the rates of synthesis of amylomaltase and D-serine deaminase remain unaffected. The addition of cAMP brings about a considerable increase of the rate of synthesis of D-serine deaminase and a partial synthesis rate increase of beta-galactosidase whihle the synthesis rate of tryptophanase remains lowered and the synthesis rate of amylomaltase remains unaffected. In a continuous culture beta-galactosidase, tryptophanase and D-serine deaminase are synthesized simultaneously at a maximum rate without mutual influence. The addition of cAMP increases the rate of synthesis of all three enzymes.

Simultaneous and successive induction of synthesis of beta-galactosidase and tryptophanase in Escherichia coli K 12 in the chemostat.

beta-Galactosidase and tryptophanase were induced either simultaneously or successively during continuous cultivation of the inducible strain Escherichia coli K 12 in the chemostat. Growth was limited by glycerol and the dilution rate was 0.1 h-1. During both the simultaneous and successive induction specific rates of synthesis, as well as maximum enzyme levels, were identical with those obtained after independent induction of individual enzymes. As compared with batch cultivation, beta-galactosidase reached the same specific rate of synthesis in the chemostat, whereas the specific rate of synthesis of tryptophanase in the chemostat was up to five times higher.

Simultaneous and gradual induction of beta-galactosidase and tryptophanase synthesis in an Escherichia coli batch culture.

beta-Galactosidase and tryptophanase can be induced in Escherichia coli simultaneously or gradually during a batch cultivation. In the strain Escherichia coli K 12 and ML 30, in which the synthesis of the two enzymes was induced simultaneously, only the synthesis of tryptophanase partially decreased, whereas the synthesis of beta-galactosidase was not influenced. In the strains B 28 and ATCC 9637 the synthesis of both enzymes was partially decreased. On a gradual induction of these enzymes in the strain Escherichia coli K 12 only the synthesis of tryptophanase decreased. Thus, the results obtained here resemble those observed during the simultaneous induction. In addition, it was found that it is not important which of the two enzymes is induced as the first one.

Morphological changes in Escherichia coli and Bacillus cereus caused by external histone.

It was found that the externally added histone changes remarkably both the surface and the internal ultrastructure of cells of Escherichia coli. The interaction of histone with surface structures results in thickening of the inner layer of the cell wall. Cytoplasm becomes condensed, contains extensive electrontransport zones and neither ribosomes nor the nuclear structure are differentiated. The addition of histone to germinating spores of Bacillus cereus decelerates germination and postgerminative development of this organism and changes ultrastructure of the external surface of the exosporium. The addition of Mg2+ ions reverting the effect of histone results in a renewal of the original ultrastructure of the exosporium.