Enrique López-Aguilar

Molecular Profiling Identifies Prognostic Subgroups of Pediatric Glioblastoma and Shows Increased YB-1 Expression in Tumors

PURPOSE Pediatric glioblastoma (pGBM) is a rare, but devastating brain tumor. In contrast to GBM in adults (aGBM), little is known about the mechanisms underlying its development. Our aim is to gain insight into the molecular pathways of pGBM. MATERIALS AND METHODS Thirty-two pGBM and seven aGBM samples were investigated using biochemical and transcriptional profiling. Ras and Akt pathway activation was assessed through the phosphorylation of downstream effectors, and gene expression profiles were generated using the University Health Network Human 19K cDNA arrays. Results were validated using real-time polymerase chain reaction and immunohistochemistry and compared with existing data sets on aGBM. RESULTS There are at least two subsets of pGBM. One subset, associated with Ras and Akt pathway activation, has very poor prognosis and exhibits increased expression of genes related to proliferation and to a neural stem-cell phenotype, similar to findings in aggressive aGBM. This subset was still molecularly distinguishable from aGBM after unsupervised and supervised analysis of expression profiles. A second subset, with better prognosis, is not associated with activation of Akt and Ras pathways, may originate from astroglial progenitors, and does not express gene signatures and markers shown to be associated with long-term survival in aGBM. Both subsets of pGBM show overexpression of Y-box-protein-1 that may help drive oncogenesis in this tumor. CONCLUSION Our work, the first study of gene expression profiles in pGBM, provides valuable insight into active pathways and targets in a cancer with minimal survival, and suggests that these tumors cannot be understood exclusively through studies of aGBM.

Intertumoral Heterogeneity within Medulloblastoma Subgroups

While molecular subgrouping has revolutionized medulloblastoma classification, the extent of heterogeneity within subgroups is unknown. Similarity network fusion (SNF) applied to genome-wide DNA methylation and gene expression data across 763 primary samples identifies very homogeneous clusters of patients, supporting the presence of medulloblastoma subtypes. After integration of somatic copy-number alterations, and clinical features specific to each cluster, we identify 12 different subtypes of medulloblastoma. Integrative analysis using SNF further delineates group 3 from group 4 medulloblastoma, which is not as readily apparent through analyses of individual data types. Two clear subtypes of infants with Sonic Hedgehog medulloblastoma with disparate outcomes and biology are identified. Medulloblastoma subtypes identified through integrative clustering have important implications for stratification of future clinical trials.

Gene Expression Profiling from Formalin-Fixed Paraffin-Embedded Tumors of Pediatric Glioblastoma

Purpose: Gene expression profiling has proved crucial for understanding the biology of cancer. In rare diseases, including pediatric glioblastoma (pGBM), the lack of readily available fresh frozen (FF) material limits the feasibility of this analysis, as well as its validation, on independent data sets, a step needed to ensure relevance, mandating the use of alternate RNA sources. To overcome the limitation of material number and to validate results we obtained on FF pGBM, we did microarray analysis on RNA extracted from formalin-fixed, paraffin-embedded archival samples from pGBM and control brains, wherein we had no control on the fixation process. Experimental Design: RNA from 16 pGBM and 3 control brains was extracted and linearly amplified. Reverse transcription–PCR on housekeeping and formerly identified tumor-associated genes and microarray analysis were done on this RNA source. Results were validated by immunohistochemistry. Results: Despite extensive RNA degradation, microarray analysis was possible on 16 of 19 samples and reproduced the pattern of results obtained on FF pGBM. Gene lists and ontology subgrouping were highly concordant in both sample types. Similar to the findings on FF samples, we were able to identify two subsets of pGBM based on their association/lack of association with evidence consistent with an active Ras pathway. Conclusions: Archival formalin-fixed, paraffin-embedded tissues are an invaluable resource as they are the most widely available materials often accessible in conjunction with clinical and follow-up data. Gene expression profiling on this material is feasible and may represent a significant advance for understanding the biology of rare human diseases.

Palonosetron Hydrochloride Is an Effective and Safe Option to Prevent Chemotherapy-induced Nausea and Vomiting in Children

BACKGROUND Emesis and nausea are common adverse effects of chemotherapy. Consequences include dehydration, acute renal failure, esophageal rupture, electrolyte imbalance and undernutrition, among others. First-generation 5-HT3 antagonists significantly reduce these symptoms but are expensive and require administration every 8-12h. Palonosetron, a second generation 5-HT3 antagonist has proven better results in adult populations. Other benefits include a one-dose administration with effect for up to 7 days and a lower treatment cost. No clinical studies have evaluated the safety and efficacy of palonosetron in children. METHODS Prior to every course, patients were randomized to receive palonosetron or ondansetron. Patients or guardians recorded the number of emetic events and the intensity of nausea over a 7-day period. They also reported any possible adverse effects. Statistical analysis included chi(2) test, relative risk, and Students t test. RESULTS Fifty courses were analyzed for each group. There was a significant reduction in emesis on the first 3 days and in the intensity of nausea in the first four days in the palonosetron group. There was an increased risk of presenting emesis and nausea in the acute phase when treated with ondansetron. No adverse effects were reported. The cost of treatment was also reduced when using palonosetron. CONCLUSIONS Palonosetron is a safe and effective antiemetic treatment in children, as well as being cost effective.

Phase II Study of Metronomic Chemotherapy with Thalidomide, Carboplatin-Vincristine-Fluvastatin in the Treatment of Brain Stem Tumors in Children

BACKGROUND Brain stem tumors (BST) constitute 20% of all intracranial tumors. Survival for these patients has been very poor worldwide. Four different treatment schemes have been evaluated at our institution, with only a discrete increment in survival when treated with carboplatin-vincristine and fluvastatin (CVF). Low-dose, continuous antiangiogenic treatment has been recently introduced in the treatment of cancer. Our objective was to determine tumor response to metronomic chemotherapy combined with an antiangiogenic drug and fluvastatin and to calculate the survival of pediatric patients with brain stem tumors. METHODS This was a phase II study. A magnetic resonance (MRI) study was made at inclusion and after the fourth course. Routine laboratory analyses were performed prior to each treatment scheme. Patients received four courses of chemotherapy every 28 days consisting of thalidomide alternating with fluvastatin every 14 days and combined with carboplatin and vincristine every 14 days followed by radiotherapy (56 cGy) and four more courses of the same chemotherapy. Toxicity was evaluated according to Miller criteria. RESULTS Nine recently diagnosed BST patients were included. Five patients had low-grade astrocytomas, three patients had glioblastoma multiforme, and one patient presented high-grade astrocytoma. There was a significant reduction in tumor volume and a significant increase in survival at 24 months. Two patients died. Toxicity included carboplatin allergy in one patient, grades 1 and 3 neutropenia in two patients, and grade 4 thrombocytopenia in two patients. CONCLUSIONS Metronomic treatment with carboplatin and vincristine associated with fluvastatin and thalidomide significantly increased survival of pediatric brain stem tumor patients. Tumor volume showed a significant reduction. Quality of life was also increased. Sample size must be increased in order to make final conclusions.

Security and Maximal Tolerated Doses of Fluvastatin In Pediatric Cancer Patients

BACKGROUND The role of cholesterol in neoplasic cell growth and its inhibition by drugs has recently been studied. Cholesterol biosynthesis inhibitors have been used as adjuvants in the treatment of cancer and possibly as prophylactic in carcinogenesis. OBJECTIVE The objective of the study was to determine the maximal tolerated doses (MTD) and toxic effects of fluvastatin in pediatric cancer patients. METHODS This study was carried out in a third level Social Security Hospital in Mexico City. We included pediatric patients from April 1996 to May 1997. All were terminal cancer patients who did not respond to conventional therapies. Fluvastatin was given p.o. at doses of 2 mg/kg/day for 14 days every 4 weeks in three patients. Subsequent cohorts of three patients each had increments of 2 mg/kg/day of the drug until maximal tolerated doses were found. Toxic effects of the drug were evaluated by physical exploration, laboratory assays and a questionnaire given to each patient. RESULTS Twelve patients were included. Diagnoses included two osteosarcomas, eight central nervous system tumors, one lung tumor, and one Ewings sarcoma. Ten patients died within 1 to 18 months. Two are alive 22 months after inclusion into the study, both with anaplasic astrocytoma. A total of 27 courses were administered. The MTD was 8 mg/kg/day. Toxic effects were insomnia, nausea, vomiting, abdominal distention and myalgias. Toxicity was dose-dependent. Laboratory assays demonstrated no significant changes during treatment. CONCLUSIONS Fluvastatin can be safely used at doses of 8 mg/kg/day in pediatric patients with cancer. This dose should be used in additional trials.

Preirradiation Ifosfamide, Carboplatin, and Etoposide for the Treatment of Anaplastic Astrocytomas and Glioblastoma Multiforme: A Phase II Study

BACKGROUND Central nervous system (CNS) tumors are the second most common pediatric tumors. Astrocytomas represent 35% of all CNS tumors in children. Traditional treatment of anaplastic astrocytoma (AA) and glioblastoma multiforme (GM) consisting of surgery-radiotherapy-chemotherapy with nitrosoureas has resulted in a survival rate of 26% at 1 year. Neoadjuvant chemotherapy has proven good results in the treatment of other solid tumors. Chemotherapy with ifosfamide, carboplatin, and etoposide (ICE) permits synergism among the different drugs and sensitizes the tumor to radiotherapy. Our objective was to evaluate the efficacy, security, and survival rate of postoperative chemotherapy with ICE in pediatric patients with AA or GM. METHODS Phase II study. We evaluated 11 children with AA or GM who had received no prior treatment. A magnetic resonance image (MRI) study of the tumor was made after surgery to evaluate residual tumor and routine laboratory analysis. Chemotherapy with carboplatin, ifosfamide and etoposide was given every 3 weeks for four courses. MRI studies were repeated after the second and last courses and laboratory analyses were carried out before each course to evaluate toxicity. Each patient then received hyperfractionated radiotherapy and a final MRI was done at the end of the treatment. RESULTS Sixty percent of the patients had partial response, 30% complete response after two courses, and 60% of CR after four courses. Supratentorial and infratentorial tumors had a good response to chemotherapy. Brainstem tumors had an initial response after two courses and then increased in size. AA was the tumor with the greatest reduction of residual tumor after treatment. Overall and free survival at 53 months was 70%. To date, three patients have died secondary to tumoral progression. There have been no relapses in the seven patients with a CR. CONCLUSIONS Postoperative chemotherapy with ICE reduces the tumor size and increases the survival rate of pediatric patients with malignant astrocytomas with minimal toxicity. Brainstem responded poorly to treatment.

A proteomic approach of pediatric astrocytomas: MiRNAs and network insight.

UNLABELLED Pediatric astrocytomas, a leading cause of death associated with cancer, are the most common primary central nervous system tumors found in children. Most studies of these tumors focus on adults, not on children. We examined the global protein and microRNA expression pattern by 2D SDS-PAGE, mass spectrometry (MALDI-TOF), and RT(2) miRNA PCR Array System. Proteomic studies revealed 49 proteins with changes on the expression. Interactome showed that vimentin, calreticulin, and 14-3-3 epsilon protein are hub proteins in these neoplasms. MicroRNA analyses demonstrated for the first time novel microRNAs involved in the astrocytoma biology. In conclusion, our results show that novel proteins and microRNAs with expression changes on pediatric astrocytoma could serve as biomarkers of tumor progression. BIOLOGICAL SIGNIFICANCE Astrocytomas are tumors that progress rapidly and that invade surrounding tissues. Although some drugs have been developed to treat these neoplasms, the mortality of patients is still very high. In this study, we describe for the first time, to our knowledge, some proteins and miRNAs associated with the biology of astrocytic tumors that could be postulated as possible diagnostic or prognostic biomarkers. Altogether, our results indicate that large-scale analyses allow making a fairly accurate prediction of different cellular processes altered in astrocytic tumors.

Epidemiological and some clinical characteristics of neuroblastoma in Mexican children (1996–2005)

BackgroundNeuroblastoma (NB) is the principal tumor of the sympathetic nervous system in children under one year of age. The incidence in developed countries is greater than that in developing countries. The aim of this article is to present the epidemiological and some clinical characteristics of Mexican children with NB.MethodsA population-based, prolective study, with data obtained from the Childhood Cancer Registry of the Instituto Mexicano de Seguro Social. Statistical analysis: The simple frequencies of the variables of the study and the annual average incidence (per 1,000,000 children/years) by age and sex were obtained. The trend was evaluated by calculating the annual percentage of change. The curves of Kaplan-Meyer were employed for the survival rate and the log-rank test was used to compare the curves.ResultsOf a total of 2,758 children with cancer registered during the period from 1996–2005, 72 (2.6%) were identified as having Group IV, defined according to the International Classification of Childhood Cancer. The incidence for NB was 3.8 per 1,000,000 children/year; NB was highest in the group of children under one year of age, followed by the group of children between the ages 1–4 years (18.5 and 5.4 per 1,000,000 children/years, respectively). The male/female ratio was 1.1 and there was no trend toward an increase. The time of diagnosis was 26 days (median), but varied according to the stage at diagnosis. Stages III and IV were presented in 88% of the cases. There was no association between the stage, the age at time of diagnosis, or the histological pattern. The overall five-year survival rate was 64%; the patients with stage I, II, III, or IVs did not die; and the five-year survival rate of cases in Stage IV was 40%.ConclusionIt is possible that the low incidence of neuroblastoma in Mexican children is due to the difficulty in diagnosing the cases with the best prognosis, some of which could have had spontaneous regression. There was no trend to an increase; the majority of the cases were diagnosed in the advanced stages; and the overall five-years survival rate was similar to that for developed countries.

Nutritional status and cytokine concentration during chemotherapy in Mexican children: A longitudinal analysis

OBJECTIVE The aim of this study was to assess whether the nutritional status of children with cancer is influenced by variations in cytokine concentrations observed during chemotherapy. We also evaluated whether this relationship could be modified by nutritional status at diagnosis and type of cancer. METHODS Mexican children with lymphoma or solid tumors were evaluated at diagnosis and at 2- and 6-mo follow-up visits. Blood samples were obtained to determine serum prealbumin, tumor necrosis factor (TNF)-α, interleukin (IL)-6, leptin concentrations, and hemoglobin. Children were classified as undernourished (UN) or well nourished (WN), according to prealbumin concentration. The influence of each cytokine on prealbumin concentration was analyzed by time-series regression model. RESULTS Fifty patients (ages 2-17 y) were enrolled. There were 17 children with lymphomas and 33 with solid tumors. At baseline, 56% were UN and 26% presented anemia; the frequencies of UN children were higher for those with lymphoma than for those with a solid tumor (P = 0.003). By nutritional status, UN children presented lower leptin (P = 0.002) but higher IL-6 concentrations (P = 0.009) than the WN group. Children with lymphoma presented lower prealbumin (P = 0.003), but higher TNF-α (P = 0.001) and IL-6 (P = 0.011) concentrations than those with solid tumors. At follow-up, the concentration of prealbumin increased and IL-6 decreased in children with lymphoma. Multivariate analysis demonstrated that decreases in prealbumin concentration at the end of follow-up were associated with increases in IL-6 and TNF-α concentration during chemotherapy. CONCLUSIONS These results suggest that the cytokine responses during chemotherapy are related to nutritional status at the end of 6 mo of treatment regardless of the initial nutritional status and the type of cancer.