The skin redoxome

Redoxome is the network of redox reactions and redox active species (ReAS) that affect the homeostasis of cells and tissues. Due to the intense and constant interaction with external agents, the human skin has a robust redox signalling framework with specific pathways and magnitudes. The establishment of the skin redoxome concept is key to expanding knowledge of skin disorders and establishing better strategies for their prevention and treatment. This review starts with its definition and progress to propose how the master redox regulators are maintained and activated in the different conditions experienced by the skin and how the lack of redox regulation is involved in the accumulation of several oxidation end products that are correlated with various skin disorders.

Abstract B41: Genomic landscape of somatic mutations in osteosarcomas

Pediatric cancers are among the leading causes of childhood mortality, with osteosarcomas being the most prevalent bone tumors, characterized by an aggressive clinical course. However, knowledge about the molecular basis of osteosarcomas is still limited, hampering advances in diagnosis and treatment. In this context, we characterized the genomic landscape of somatic mutations in 28 osteosarcomas (24 pediatric patients and 4 adults) aiming to delineate the panel of prevalent mutations in Brazilian patients. Genomic libraries of these osteosarcoma samples were constructed using the TruSight One panel (Illumina), covering 4,813 clinically relevant genes, including known cancer genes. Generated data at high coverage (median >100x depth coverage) were annotated based on public databases containing population variant frequencies (including the Brazilian ABRAOM), as well as clinical information. For further analysis, we filtered only coding nonsynonymous variants absent from both population databases and an additional pool of 20 nonrelated germline samples. In total, 728 variants were identified mapping in 606 genes, with an average rate of 41 mutations per tumor. The panel of detected variants was composed by 93 loss-of-function mutations (38 frameshift, 25 splicing, and 30 premature stop codon) and 635 missense (43 inframe insertions/deletions and 592 single-nucleotide variations), some of them already reported in cancer databases (27 in COSMIC and 39 in ICGC). From 606 genes, 25 were previously associated with osteosarcomas, and they are related to apoptosis, cell growth and differentiation, DNA repair, transcriptional regulation, and tumor-suppression mechanisms. The most frequent mutations were detected in RB1 and TP53; other recurrently mutated genes were mostly linked to biologic pathways potentially related to the disease onset, such as hormonal response (AR), transcriptional regulation and muscle differentiation (FRG1), DNA repair (HERC2), cell signaling (KIR2DL4), and cell proliferation/differentiation (PTPRQ). Additionally, the tumors presented a highly complex pattern of copy number alterations, some of them resembling chromothripsis. This is the first assessment of a Brazilian cohort of osteosarcomas, and functional studies will be further applied to better understand the role of the disclosed mutations for tumor biology.

Citation Format: Sara F. Pires, Silvia S. Costa, Daniel O. Vidal, André van Helvoort Lengert, Érica Boldrini, Sandra R.M. da Silva, Carla Rosenberg, Luiz F. Lopes, Mariana Maschietto, Ana Krepischi. Genomic landscape of somatic mutations in osteosarcomas [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B41.

The Warburg Effect Is Associated With Tumor Aggressiveness in Testicular Germ Cell Tumors

Testicular Germ Cell Tumors (TGCTs) are a rare group of neoplasms and the most common solid malignancy arising in young male adults. Despite the good response of these tumors to platinum-based chemotherapy, some patients are refractory to treatment and present poor clinical outcomes. During carcinogenesis and tumor development, cancer cells reprogram energy metabolism toward a hyper-glycolytic phenotype, an emerging hallmark of cancer. This phenomenon, known as the Warburg effect or aerobic glycolysis, involves overexpression of metabolism-related proteins, like glucose and monocarboxylate transporters, pH regulators and intracellular glycolytic enzymes. The metabolic profile of TGCTs is very little explored and, recently, this metabolic rewiring of cancer cells has been associated with aggressive clinicopathological characteristics of these tumors. The overexpression of monocarboxylate transporter 4 (MCT4) in TGCTs has been pointed out as a poor prognostic factor, as well as a promising therapeutic target. As a result, the main aim of the present study was to evaluate the prognostic value of key metabolism-related proteins in TGCTs. The immunohistochemical expressions of CD44 (as a monocarboxylate transporter chaperone), glucose transporter 1 (GLUT1), carbonic anhydrase IX (CAIX), hexokinase II (HKII) and lactate dehydrogenase V (LDHV) were evaluated in a series of 148 adult male patients with TGCTs and associated with clinicopathological parameters. In addition, paired normal tissues were also evaluated. The sample included 75 seminoma and 73 non-seminoma tumors. GLUT1 and CD44 expression was significantly increased in malignant samples when compared to paired normal samples. Conversely, HKII and LDHV expressions were significantly decreased in malignant samples. Concerning the clinicopathological values, CAIX expression was significantly associated with disease recurrence, while HKII expression was significantly associated with aggressive characteristics of TGCTs, including higher staging and non-seminoma histology. In conclusion, this study brings new insights on the metabolic characteristics of TGCTs, showing alterations in the expression of proteins related with the Warburg effect, as well as associations of the hyper-glycolytic and acid-resistant phenotype with aggressive clinicopathological parameters.

Brachyury oncogene is a prognostic factor in high-risk testicular germ cell tumors

The T-box transcription factor Brachyury has been considered a cancer-specific marker and a novel oncotarget in solid tumors. Brachyury overexpression has been described in various cancers, being associated with epithelial-mesenchymal transition, metastasis, and poor prognosis. However, its clinical association with testicular germ cell tumor is unknown. We analyzed the expression of Brachyury by immunohistochemistry in a series of well-characterized testicular germ cell tumor samples and at transcript level by in silico analysis. Additionally, we aimed to investigate the clinical significance of Brachyury in testicular germ cell tumor. Brachyury cytoplasm immunostaining was present in 89.6% (86/96) of cases with nuclear staining observed in 24% (23/96) of testicular germ cell tumor. Bioinformatics microarray expression analysis of two independent cohorts of testicular germ cell tumors showed similar results with increased levels of Brachyury in testicular germ cell tumors and metastasis compared with normal testis. Clinically, Brachyury nuclear staining was statistically associated with lower event-free survival (p = 0.04) and overall survival (p = 0.01) in intermediate/high-risk testicular germ cell tumors. Univariate analysis showed that Brachyury nuclear subcellular localization was a predictor of poor prognosis (p = 0.02), while a tendency was observed by multivariate analysis (HR: 3.56, p = 0.06). In conclusion, these results indicate that Brachyury plays an oncogenic role in testicular germ cell tumors and its subcellular localization in the nucleus may constitute a novel biomarker of poor prognosis and a putative oncotarget for intermediate/high-risk testicular germ cell tumor patients.

The clinicopathological significance of monocarboxylate transporters in testicular germ cell tumors

Background

Metabolic reprogramming is one of the hallmarks of cancer. The hyperglycolytic phenotype is often associated with the overexpression of metabolism-associated proteins, such as monocarboxylate transporters (MCTs). MCTs are little explored in germ cell tumors (GCTs), thus, the opportunity to understand the relevance of these metabolic markers and their chaperone CD147 in this type of tumor arises. The main aim of this study was to evaluate the expression of MCT1, MCT2, MCT4 and CD147 in testicular GCT samples and the clinicopathological significance of these metabolism related proteins.

Results

MCT1, MCT4 and CD147 were associated with higher stages, higher M and N stages and histological type, while MCT4 was also associated with higher risk stratification, presence of vascular invasion, and lower overall and event free survival. MCT4 silencing in JEG-3 had no significant effect in cell viability, proliferation and death, as well as extracellular levels of glucose and lactate. However, MCT4-silenced cells showed an increase in migration and invasion.

Conclusion

The proteins herein studied, with the exception of MCT2, were associated with characteristics of worse prognosis, lower global and event free survival of patients with GCTs. Also, in vitro MCT4 silencing stimulated cell migration and invasion.

Materials and Methods

Immunohistochemical expression was evaluated on samples from 149 adult patients with testicular GCT, arranged in Tissue Microarrays (TMAs), and associated with the clinicopathological data. Also, MCT4 silencing studies using siRNA were performed in JEG-3 cells.

Characteristics of the phenotypic abnormalities of bone marrow cells in childhood myelodysplastic syndromes and juvenile myelomonocytic leukemia

BACKGROUND

Immunophenotyping of bone marrow (BM) hemopoietic precursors is useful for diagnosis of adult myelodysplastic syndrome (MDS), but data concerning pediatric patients are limited. We analyzed immunophenotypic features of BM cells at diagnosis of children who were referred to the Brazilian Pediatric Cooperative Group of Myelodysplastic Syndromes.

METHODS

Diagnosis was based on clinical information, peripheral blood counts, BM cytology and cytogenetics. Patients with Down syndrome were excluded. Children with deficiency anemias or transitory neutropenias were used as controls (CTRLs). Immunophenotyping was performed on an eight-color antibody platform evaluating myelomonocytic maturation and progenitor cells.

RESULTS

A total of 32 patients were examined: 6 refractory cytopenia of childhood [RCC]; 5 refractory anemia with excess of blasts [RAEB]; 8 refractory anemia with excess of blasts in transformation [RAEB-t]; 13 juvenile myelomonocytic leukemia [JMML] and 10 CTRLs. Median age was 66 months (RCC), 68 months (RAEB/RAEB-t), 29 months (JMML) and 70 months (CTRLs). Median number of phenotypic alterations was 4 (range 1-6) in RCC; 6 (range 2-11) in RAEB/RAEB-t and 6 (range 2-11) in JMML (P = 0.004). The percentage of CD34⁺ /CD117⁺ /CD13⁺ cells was 0.5% (range 0.1-2.8) in RCC; 4.2% (range 0.3-10.1) in RAEB/RAEB-t and 3.7 % (range 0.5-8.6) in JMML cases, compared with 0.7% (0.5-1.2) in CTRLs (P < 0.0005). Aberrancies in antigen expression of myeloid progenitors were seen in 63% of JMML and in 45% of RAEB/RAEB-t. CD34⁺ /CD19⁺ /CD10⁺ cells were decreased or absent in patients compared with age-matched controls. T lymphocytes were decreased in JMML.

CONCLUSIONS

Phenotypic abnormalities were similar to those found in adult MDS. A decrease in B-cell precursors was observed especially in RAEB/RAEB-t. JMML and RAEB showed a similar pattern.

Absence of microsatellite instability and BRAF (V600E) mutation in testicular germ cell tumors

Testicular germ cell tumors (TGCT) are the most common malignant neoplasm in young men. DNA mismatch repair deficiency can lead to microsatellite instability (MSI), an important mechanism of genetic instability. A mutation of the BRAF gene has been implicated in the pathogenesis of several solid tumors and has recently become an important therapeutic target. The role of MSI and BRAF gene mutation in TGCT, particularly in refractory disease, is poorly understood and reported findings are controversial. In this study, we aimed to determine the frequency and clinical impact of MSI status and BRAF mutations in TGCT. DNA was isolated from formalin-fixed paraffin embedded (FFPE) tissue from 150 TGCT cases. The MSI phenotype was evaluated using multiplex PCR for five quasimonomorphic mononucleotide repeat markers. Exon 15 of the BRAF oncogene (V600E) was analyzed by PCR, followed by direct sequencing. Sixteen percent of cases were considered to have refractory disease. In a small subset of cases (17 for MSI and 18 for BRAF), the quantity and quality of DNA recovery were poor and therefore, were unable to be analyzed. The remaining 133 TGCT cases showed a complete absence of MSI. Of the 132 cases successfully evaluated for BRAF mutations, all were V600E wild-type. In conclusion, despite a distinct response of testicular germ cell tumors to therapy, microsatellite instability, and the BRAF V600E mutation were absent in all testicular germ cell tumors tested in this study.

Shorter Maintenance Therapy in Childhood Acute Lymphoblastic Leukemia: The Experience of the Prospective, Randomized Brazilian GBTLI ALL-93 Protocol

AIM

Maintenance therapy is an important phase of the childhood ALL treatment, requiring 2-year long therapy adherence of the patients and families. Weekly methotrexate with daily 6-mercaptopurine (6MP) constitutes the backbone of maintenance therapy. Reduction in the maintenance therapy could overweight problems related with poverty of children with ALL living in limited-income countries (LIC).

OBJECTIVE

To compare, prospectively, the EFS rates of children with ALL treated according to two maintenance regimens: 18 vs. 24 months duration.

MATERIALS AND METHODS

From October 1993 to September 1999, 867 consecutive untreated ALL patients <18 years of age were treated according to the Brazilian Cooperative Group for Childhood ALL Treatment (GBTLI) ALL-93 protocol. Risk classification was based exclusively on patient's age and leukocyte count (NCI risk group) and clinical extra medullary involvement of the disease. Data were analyzed by the intention-to-treat approach.

RESULTS

Fourteen patients (1.6%) were excluded: wrong diagnosis (n = 7) and previous corticosteroid (n = 7). Of the 853 eligible patients, 421 were randomly allocated, at study enrollment, to receive 18-month (group 1) and 432 to receive 24-month (group 2) maintenance therapy. Complete remission rate was achieved in 96% of the patients (817/853). Twenty-eight patients (3.4%) died during the induction phase. Thirty-four patients (4.0%) were lost to follow-up. The overall EFS was 66.1 ± 1.7% at 15 years. No difference was seen according to maintenance: EFS_15y was 65.8 ± 2.3% (group 1) and 66.3 ± 2.3% (group 2; p = 0.79). No difference between regimens was detected after stratifying the analyses according to factors associated with adverse prognosis in this study (age group <1 year or >10 years and high WBC at diagnosis). Overall death in remission rate was 6.85% (56 patients). Deaths during maintenance were 13 in group 1 and 12 in group 2, all due to infection. Over 15 years of follow-up, two patients both from group 2 presented a second malignancy (Hodgkin's disease and thyroid carcinoma) after 8.3 and 11 years off therapy, respectively.

CONCLUSION

Six-month reduction of maintenance therapy in ALL children treated according to the GBTLI ALL-93 protocol provided the same overall outcome as 2-year duration regimen.

Cytogenetic studies of Brazilian pediatric myelodysplastic syndrome cases: challenges and difficulties in a large and emerging country

Myelodysplastic syndromes (MDS) and juvenile myelomonocytic leukemia (JMML) are rare hematopoietic stem cell diseases affecting children. Cytogenetics plays an important role in the diagnosis of these diseases. We report here the experience of the Cytogenetic Subcommittee of the Brazilian Cooperative Group on Pediatric Myelodysplastic Syndromes (BCG-MDS-PED). We analyzed 168 cytogenetic studies performed in 23 different cytogenetic centers; 84 of these studies were performed in patients with confirmed MDS (primary MDS, secondary MDS, JMML, and acute myeloid leukemia/MDS+Down syndrome). Clonal abnormalities were found in 36.9% of the MDS cases and cytogenetic studies were important for the detection of constitutional diseases and for differential diagnosis with other myeloid neoplasms. These data show the importance of the Cooperative Group for continuing education in order to avoid a late or wrong diagnosis.

Benefits of the Intermittent Use of 6-Mercaptopurine and Methotrexate in Maintenance Treatment for Low-Risk Acute Lymphoblastic Leukemia in Children: Randomized Trial From the Brazilian Childhood Cooperative Group—Protocol ALL-99

Purpose

To describe event-free survival (EFS) and toxicities in children with low-risk acute lymphoblastic leukemia (ALL) assigned to receive either continuous 6-mercaptopurine (6-MP) and weekly methotrexate (MTX) or intermittent 6-MP with intermediate-dose MTX, as maintenance treatment.

Patients and Methods

Between October 1, 2000, and December 31, 2007, 635 patients with low-risk ALL were enrolled onto Brazilian Childhood Cooperative Group for ALL Treatment (GBTLI) ALL-99 protocol. Eligible children (n = 544) were randomly allocated to receive either continuous 6-MP/MTX (group 1, n = 272) or intermittent 6-MP (100 mg/m2/d for 10 days, with 11 days resting) and MTX (200 mg/m2every 3 weeks; group 2, n = 272).

Results

The 5-year overall survival (OS) and EFS were 92.5% ± 1.5% SE and 83.6% ± 2.1% SE, respectively. According to maintenance regimen, the OS was 91.4% ± 2.2% SE (group 1) and 93.6% ± 2.1% SE (group 2; P = .28) and EFS 80.9% ± 3.2% SE (group 1) and 86.5% ± 2.8% SE (group 2; P = .089). Remarkably, the intermittent regimen led to significantly higher EFS among boys (85.7% v 74.9% SE; P = .027), while no difference was seen for girls (87.0% v 88.8% SE; P = .78). Toxic episodes were recorded in 226 and 237 children, respectively. Grade 3 to 4 toxic events for groups 1 and 2 were, respectively, 273 and 166 for hepatic dysfunction (P = .002), and 772 and 636 for hematologic episodes (P = .005). Deaths on maintenance were: seven (group 1) and one (group 2).

Conclusion

The intermittent use of 6-MP and MTX in maintenance is a less toxic regimen, with a trend toward better long-term EFS. Boys treated with the intermittent schedule had significantly better EFS.

Trends in childhood leukemia mortality in Brazil and correlation with social inequalities

BACKGROUND

Mortality from childhood leukemia has declined substantially in developed countries but less markedly in the developing world. This study was designed to describe mortality trends in childhood leukemia and the impact of social inequalities on these trends in Brazil from 1980 to 2002.

METHODS

Cancer mortality data by cause and estimates of resident population stratified by age and sex were obtained from the Brazilian Mortality Information System (SIM) for the years 1980 to 2002. Age-standardized (ages 0-19 years) mortality rates were calculated by the direct method using the 1960 world standard population. Trends were modeled using linear regression with 3-year moving average rates as the dependent variable and with the midpoint of the calendar year interval (1991) as the independent variable. The Index of Social Exclusion was used to classify the 27 Brazilian states. Pearson correlation was used to describe the correlation between social exclusion and variations in mortality in each state.

RESULTS

Age-standardized mortality rates for boys decreased from 2.05 per 100,000 habitants in 1984 to 1.44 100,000 habitants in 1995, whereas the observed corresponding decline among girls was from 1.60 per 100,000 habitants in 1986 to 1.14 per 100,000 habitants in 1995. Statistically significant declining trends in mortality rates were observed for boys (adjusted correlation coefficient [r(2)] = 0.68; P < .001) and girls (adjusted r(2) = 0.62; P < .001). Significant negative correlations between social inequality and changes in mortality were noted for boys (r = -0.66; P = .001) and for girls (r = -0.78; P < .001).

CONCLUSIONS

A consistent decrease in mortality rates from childhood leukemia was noted in Brazil. Higher decreases in mortality were observed in more developed states, possibly reflecting better health care.

Drug Resistance and Methylation in Myelodysplastic Syndrome

Myelodysplastic syndrome is a clonal hematopoietic stem cell disorder that presents a poor survival for patients treated with standard therapies other than stem-cell transplantation. Multi-drug resistance (MDR) to simultaneous drugs used in chemotherapy is a major concern in the treatment of cancer and also in MDS. ATP-binding cassette (ABC) transporters are involved in the main mechanism that confers drug resistance to cells. Increased expression of drug resistance genes, such as MDR1, MRP1 and LRP, is involved with multi-drug resistance in MDS. The expression of these drug efflux transporters acts in synergy with other alterations, such as epigenetic events, increases in multidrug resistance in MDS. Methylation, the main epigenetic mechanism is widely explored in other hematological malignancies; however, in MDS, this mechanism is poorly investigated. Clinical trials evaluated or are under ongoing evaluation of drugs that abrogated ABC transporters action or reversed the abnormal methylation of some genes in MDS. In this report, we explore the data available in the field of drug resistance and methylation both in pediatric and adult MDS.

Plasmodium yoelii: the effect of second blood meal and anti-sporozoite antibodies on development and gene expression in the mosquito vector, Anopheles stephensi

The sporogonic development of the malaria parasite takes place in the mosquito and a wide range of factors modulates it. Among those, the contents of the blood meal can influence the parasite development directly or indirectly through the mosquito response to the infection. We have studied the effect of a second blood meal in previously infected mosquitoes and the effect of anti-sporozoite immune serum on parasite development and mosquito response to the infection. The prevalence and intensity of infection and gene expression of both Plasmodium yoelii and Anopheles stephensi was analyzed. We verified that a second blood meal and its immune status interfere with parasite development and with Plasmodium and mosquito gene expression.

Effect of chloroquine on the expression of genes involved in the mosquito immune response to Plasmodium infection

Chloroquine has been described to increase Plasmodium infectivity to the mosquito vector and is known to affect the vertebrate host immune response including during malarial infection. Although knowledge of the mosquito immune response has recently improved, nothing is known about the impact of chloroquine on mosquito immunity. In order to characterize the influence of chloroquine on the mosquito immune system, we have analyzed the effect of chloroquine on Anopheles gambiae (i) serine proteases and (ii) antimicrobial peptide gene expression, in uninfected and Plasmodium berghei infected mosquitoes, using real-time PCR. We have demonstrated for the first time that mosquitoes fed on chloroquine-treated mice showed a significant down regulation of some immune-related genes. This effect was independent of midgut bacterial burden. These results suggest that chloroquine might act on the Anopheles serine proteases cascade, interfering with signal transduction pathways and at a transcriptional activation level.

Epstein-Barr virus infection and gastric carcinoma in São Paulo State, Brazil

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus, and most people have serological evidence of previous viral infection at adult age. EBV is associated with infectious mononucleosis and human cancers, including some lymphomas and gastric carcinomas. Although EBV was first reported in lymphoepithelioma-like gastric carcinoma, the virus was also found in conventional adenocarcinomas. In the present study, 53 gastric carcinomas diagnosed in São Paulo State, Brazil, were evaluated for EBV infection by non-isotopic in situ hybridization with a biotinylated probe (Biotin-AGACACCGTCCTCACCACCC GGGACTTGTA) directed to the viral transcript EBER-I, which is actively expressed in EBV latently infected cells. EBV infection was found in 6 of 53 (11.32%) gastric carcinomas, mostly from male patients (66.7%), with a mean age of 59 years old. Most EBV-positive tumors were in gastric antrum. Two EBV-positive tumors (33.3%) were conventional adenocarcinomas, whereas four (66.7%) were classified as lymphoepithelioma-like carcinomas. EBV infection in gastric carcinomas was reported elsewhere in frequencies that range from 5.6% (Korea) up to 18% (Germany). In Brazil, a previous work found EBV infection in 4 of 80 (5%) gastric carcinomas, whereas another study found 4.7 and 11.2% of EBV-positive gastric carcinomas of Brazilians of Japanese origin or not, respectively. In the present study, the frequency of EBV-positive gastric carcinomas is similar to that reported in other series, and the clinicopathologic characteristics of these EBV-positive tumors are in agreement with the data in the literature.

Bone marrow stroma in childhood myelodysplastic syndrome: composition, ability to sustain hematopoiesis in vitro, and altered gene expression

We studied bone marrow stromal cell cultures from patients with childhood myelodysplastic syndromes (MDS, refractory anemia with excess of blasts, RAEB) and from matched normal donors. Stromal cell monolayers were characterized as myofibroblasts by the expression of smooth muscle alpha-actin, collagen IV, laminin and fibronectin. When normal cord blood cells were plated onto myelodysplastic stromas, a pathologic cell differentiation was observed, indicating altered myelosupportive properties. cDNA array analysis showed that patient stromas expressed increased levels of thrombospondin-1, collagen-I alpha2-chain, osteoblast-specific factor-2 and osteonectin, indicating the presence of increased osteoblast content, as confirmed by enhanced alkaline phosphatase synthesis. Alterations in the myelodysplastic stroma environment might contribute to abnormal hematopoiesis in this pathology.

Necrobiotic xanthogranuloma with lambda paraproteinemia: case report of successful treatment with melphalan and prednisone

BACKGROUND

Necrobiotic xanthogranuloma (NXG) is a rare non-X histiocytosis with conspicuous lesions on the periorbital skin.

METHODS

A diabetic patient presented with NXG and a previous diagnosis of necrobiosis lipoidica on the legs over a period of almost 2 years before the development of the typical lesions of NXG on the periorbital regions, back, thighs and legs. The patient was found also to have developed lambda paraproteinemia.

RESULTS

Treatment with melphalan and prednisone resulted in great improvement of cutaneous lesions and paraproteinemia remission.

CONCLUSION

This case report details how melphalan and prednisone can be administered in the successful treatment of necrobiotic xanthogranuloma with lambda paraproteinemia.

Immunohistochemical detection of p53 protein expression as a prognostic indicator in Wilms tumor

BACKGROUND

Mutations of the tumor suppressor gene p53 are commonly found in several kinds of human cancer. In some types of neoplasms, accumulation of p53 protein has been reported to correlate with more aggressive clinical behavior. The role of p53 expression in Wilms tumors (WT) is not clear yet, but most studies have confirmed its correlation with anaplasia and advanced stage disease.

PROCEDURE

Ninety-seven WT were evaluated for p53 expression by immunohistochemistry in formalin-fixed paraffin-embedded tissue and correlated with outcome. Tumors were classified as p53-Negative (p53-N) when no positivity was observed or only few cells showed weak positivity (0/1+) and p53-Positive (p53-P) when there was a diffuse and strong nuclear positivity (2+/3+).

RESULTS

p53-P was detected in 13 out of 97 tumors and was associated with disease relapse (39 vs.17%; P = 0.06) but not with anaplasia. Among p53-N patients only 5% had metastatic disease compared with 31% of the p53-P sample. (P = 0.038). Overall survival was 94% for patients with p53-N vs. 85% for patients with p53-P at 1 year (P = 0.34).

CONCLUSIONS

p53 expression in Wilms tumor detected by immunohistochemistry seems to be associated with advanced disease and relapse.

Analysis of Vgamma/Jbeta trans-rearrangements in paediatric patients undergoing chemotherapy

The frequency of the hybrid Vgamma/Jbeta trans-rearrangement in peripheral blood lymphocytes (PBLs) was analysed in a transversal study of paediatric patients (n = 210) with acute lymphoblastic leukaemia (ALL) and solid tumours (ST). Different amounts of DNA were used as the template for a nested polymerase chain reaction to evaluate the frequency of hybrid Vgamma/Jbeta genes, using silver-stained gels. The frequency of the rearrangement was evaluated in groups before, during and after therapy. A greatly increased frequency of Vgamma/Jbeta trans-rearrangement was found in PBLs of both groups of patients during exposure to chemotherapeutic agents compared with patients before chemotherapy. In patients who had finished treatment, the frequency of the rearrangement fell promptly to the baseline levels in ST but showed a slow decrease in ALL in those in whom increased levels could be found until 4 years after the end of treatment. We hypothesize that the chemotherapeutic agents are able to induce the Vgamma/Jbeta trans-rearrangement, but this is transient in most cases. The exact relationship between the persistence of the rearrangement and the occurrence of secondary leukaemia remains to be determined.

Denitrification on the top of UASB reactors of rice wastewaters

Parboiled rice industry is one of main food industries in the south of Brazil. The main parts of the processing are the humidification and gelatinization of the grain. This procedure increases the productivity and nutritive and cooking values of the product. Some of these industries in the region utilize upflow anaerobic sludge blanket (UASB) reactors as a biological treatment for carbon removal. For nitrogen removal, the proposed system aims to eliminate an extra denitrification reactor, making this step in the top of the UASB, an anoxic zone of the reactor. Nitrification was performed in aerated mixed reactor of 3.6 L.A fraction of the NR was recycled in the top of UASB reactor above the sludge blanket. Recycled ratio varied from 0; 1:0.5; 1:1.0; to 1:1.5. The maximum removal efficiency of NTK was 80%. The results confirm the viability of the proposed system for denitrification.

Childhood myelodysplastic syndromes in a Brazilian population

Fourteen pediatric cases of myelodysplastic syndrome according to French-American-British Co-operative Group (FAB) criteria were identified in a retrospective review of all cases of hematologic malignancies referred to the Pediatric Oncology division of the Cancer Hospital A. C. Camargo over a 12-year period: 1 case of refractory anemia, 8 cases of refractory anemia with excess of blasts, and 1 case of refractory anemia with excess of blasts in transformation. Three children had features consistent with chronic myelomonocytic leukemia, and one child was diagnosed with secondary myelodysplastic syndrome. The median age was 3.5 years (1 month-11 years). In 11/14 cases the disease evolved to acute leukemia. In 3 patients blasts had morphological and cytochemical features of lymphoblasts. Two of these patients had a good response to acute lymphoblastic leukemia chemotherapy protocol. The time of progression to leukemia in these cases was shorter than in those who evolved to acute myeloid leukemia. The authors believe this to be the first series of pediatric myelodysplastic syndrome documented in Brazil. Cases were characterized by aggressive FAB type, conspicuous cell atypias in all 3 hemopioetic cell lines, and a high rate of evolution to acute leukemia.

The influence of parental age on the risk of Wilms' tumour

The Brazilian Wilms' Tumour Study Group carried out a hospital-based multicentre case-control study of potential risk factors for the disease between April 1987 and January 1989. The parents of 109 cases of Wilms' tumour (WT) were interviewed when they were admitted to hospital for diagnosis and treatment. Also interviewed were the parents of two controls per case, matched for age, sex and interviewer, who were admitted to the same or nearby hospitals for treatment of non-neoplastic conditions. Odds ratios adjusted for family income and parental education were calculated by conditional logistic regression. Among cases diagnosed before 25 months of age there was a marked gradient of increasing risk of WT with increasing maternal age at the time of the child's birth. There was no increased risk for cases diagnosed after 25 months of age. The effects of paternal age were less marked. Possible explanations for these results are discussed.

Response to high-dose cisplatin and etoposide in advanced germ cell tumors in children: results of the Brazilian Germ Cell Tumor Study

A trial was undertaken to assess the efficacy and toxicity of high-dose cisplatin and etoposide in children with newly diagnosed advanced malignant germ cell tumors. A total of eleven children and adolescents were treated with courses of high dose cisplatin 30 mg/m2/day and etoposide 120 mg/m2/day in five day cycles at 21 day intervals. There were eight girls and three boys, aged between 1 and 16 years (median: 120 months). Of nine unresectable tumors, six were in complete remission after three cycles and were completely resected. All patients are alive (median follow-up 17 months). Preliminary results shows that high dose cisplatin and etoposide is effective in controlling advanced malignant germ cell tumor.

Parental exposures to pesticides and risk of Wilms' tumor in Brazil

Wilms' tumor is one of the most common abdominal childhood malignancies. Wilms' tumor rates in Brazil are among the highest in the world. This prompted the Brazilian Wilms' Tumor Study Group to conduct a hospital-based, multicenter, case-control investigation of environmental risk factors for the disease. Between April 1987 and January 1989, the authors collected information on relevant occupational exposures by interviewing the parents of 109 Wilms' tumor cases admitted to hospitals in Sao Paulo, Salvador, Belo Horizonte, and Jau. Also interviewed were the parents of 218 age- and sex-matched control children who had been admitted for treatment of nonneoplastic diseases to the same or nearby hospitals. Odds ratios (ORs) adjusted for income and education were calculated by conditional logistic regression. Consistently elevated risks were seen for farm work involving frequent use of pesticides by both the father (OR = 3.24, 95% confidence interval (CI) 1.2-9.0) and the mother (OR = 128.6, 95% CI 6.4-2,569). These risk elevations were restricted to cases diagnosed after 2 years of age (ORs > 4), for paternal exposure, and after 4 years of age (OR = 14.8, 95% CI 2.2-98.8), for maternal exposure. Risk elevations were also more pronounced among boys (paternal exposure OR = 8.56, 95% CI 2.1-35.1; maternal exposure OR = 4.60, 95% CI 0.8-26.4) than among girls (paternal exposure OR = 1.31, 95% CI 0.4-4.1; maternal exposure OR = 2.03, 95% CI 0.5-8.9).

Increased survival, limb preservation, and prognostic factors for osteosarcoma

Preoperative intraarterial (IA) cisplatin (CDP) was administered to 92 patients with nonmetastatic osteosarcoma. The ages of the patients ranged from 4 to 28 years. Sixty-four patients (70%) received 2 or 3 preoperative courses and 28 (30%) received 4 or more. Sixty-two specimens were available for pathologic examination to assess the degree of tumor necrosis. More than 90% tumor destruction was observed in 16 of 42 patients (38%) who received 1 to 3 preoperative courses as opposed to 17 of 20 (85%) who received 4 or more courses. Patients who received 4 or more courses had a 2-fold probability of achieving more than 90% tumor necrosis, and 68% underwent conservative surgery. Of those who received 3 or less courses, 23% underwent conservative surgery. Postoperatively, patients were treated with intravenous (IV) CDP alternating with doxorubicin (ADR) (Adriamycin, Adria Laboratories, Columbus, OH). Pulmonary metastases developed in 36 patients, bone metastases in 2, and local recurrence in 6. Two patients died of cardiac failure without evidence of disease. Thus, 46 patients (50%) were continuously free of disease 18 to 78 months after diagnosis. Univariate and multivariate analyses showed that male sex, low grade preoperative chemotherapy-induced necrosis, and nonosteoblastic histologic condition were prognostic factors predictive of recurrence, while male sex and large tumor size were prognostic factors predictive of death. These results are comparable with those reported by other centers and are superior to our previous experiences that yielded survival rates of 5% to 10%. A substantial number of patients also had the opportunity to achieve tumor removal with conservative surgery.