Rocio Cardenas-Cardos

Complementary genomic approaches highlight the PI3K/mTOR pathway as a common vulnerability in osteosarcoma

Significance We present, to our knowledge, the first comprehensive next-generation sequencing of osteosarcoma in combination with a functional genomic screen in a genetically defined mouse model of osteosarcoma. Our data provide a strong rationale for targeting the phosphatidylinositol 3-kinase/mammalian target of rapamycin pathway in osteosarcoma and a foundation for rational clinical trial design. These findings present an immediate clinical opportunity because multiple inhibitors of this pathway are currently in clinical trials. Osteosarcoma is the most common primary bone tumor, yet there have been no substantial advances in treatment or survival in three decades. We examined 59 tumor/normal pairs by whole-exome, whole-genome, and RNA-sequencing. Only the TP53 gene was mutated at significant frequency across all samples. The mean nonsilent somatic mutation rate was 1.2 mutations per megabase, and there was a median of 230 somatic rearrangements per tumor. Complex chains of rearrangements and localized hypermutation were detected in almost all cases. Given the intertumor heterogeneity, the extent of genomic instability, and the difficulty in acquiring a large sample size in a rare tumor, we used several methods to identify genomic events contributing to osteosarcoma survival. Pathway analysis, a heuristic analytic algorithm, a comparative oncology approach, and an shRNA screen converged on the phosphatidylinositol 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway as a central vulnerability for therapeutic exploitation in osteosarcoma. Osteosarcoma cell lines are responsive to pharmacologic and genetic inhibition of the PI3K/mTOR pathway both in vitro and in vivo.

Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

BackgroundWorldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City.MethodsIncluded in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level).ResultsAlthough a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive correlation between the average number of persons per household and the incidence of the pre-B immunophenotype (Pearsons r, 0.789; P = 0.02).ConclusionsThe frequency of ALL in Mexico City is among the highest in the world, similar to those found for Hispanics in the United States and in Costa Rica.

Incidence of childhood cancer among Mexican children registered under a public medical insurance program

Prior to 2005, 51% of children in Mexico diagnosed with cancer received no standardized optimal multidisciplinary medical care. A government‐subsidized national cancer treatment program was therefore created for these patients and a National Cooperative Childhood Cancer Treatment Group was consequently formed for these patients. Pediatric patients with a proven diagnosis of leukemia, lymphoma or solid tumor and who were registered in the Popular Medical Insurance (PMI) program from January 2007 to December 2010, are described in this report. These patients had been enrolled and registered in one of the 49 nationwide certified medical institutions in Mexico. The national incidence and frequency data for childhood cancers were analyzed for the whole program. At the end of a 4‐year study, the analysis revealed that 8,936 children from across Mexico had been diagnosed with cancer. The incidence rate for the PMI patients was 150.3/million/year (2010) for children of 0–18 years. The highest age incidence rate was 51.9 between 0 and 4 years and boys were the predominant group for all types of cancer. The leukemia incidence was 75.3/million/year (2010), and an average frequency of 50.75% throughout the 4 years. The overall mortality rate was measured at 5.4/100,000/year (2010). This study demonstrates a high frequency and incidence of childhood cancer and a beneficial impact of the PMI program over the quality of life in these children.

Langerhans cell histiocytosis in children under 2 years of age

This is a retrospective study of 55 children under the age of 2 years diagnosed with Langerhans cell histiocytosis (LCH). They were classified according to age and organ function and dysfunction following Laheys criteria. The studied population was divided into four groups by age of diagnosis (0-6, 7-12, 13-18, and 19-24 months). Statistical analysis showed no significant difference in outcome between age groups, although the population under 6 months had a 81.3% fatality rate. The presence of organ dysfunction was a major cause of death in all age groups, being statistically significant in outcome (P > 0.005) compared with patients without organ dysfunction. The presence of thrombocytopenia and/or respiratory dysfunction was also highly associated with a fatal outcome. In the surviving population, no second malignancies have been reported. The late secondary effects of therapy include endocrine, orofacial, and osseous pathologies.

Allergy and acute leukaemia in children with Down syndrome: a population study. Report from the Mexican inter-institutional group for the identification of the causes of childhood leukaemia

Background:Allergies have been described as protective factors against the development of childhood acute leukaemia (AL). Our objective was to investigate the associations between allergy history and the development of AL and acute lymphoblastic leukaemia (ALL) in children with Down syndrome (DS).Methods:A case–control study was performed in Mexico City. The cases (n=97) were diagnosed at nine public hospitals, and the controls (n=222) were recruited at institutions for children with DS. Odds ratios (OR) were calculated.Results:Asthma was positively associated with AL development (OR=4.18; 95% confidence interval (CI): 1.47–11.87), whereas skin allergies were negatively associated (OR=0.42; 95% CI: 0.20–0.91).Conclusion:Our findings suggest that allergies and AL in children with DS share biological and immune mechanisms. To our knowledge, this is the first study reporting associations between allergies and AL in children with DS.

EWING'S SARCOMA: Prognosis and Survival in Mexican Children from a Single Institution

A retrospective analysis of 55 patients with Ewings sarcoma from an institution in Mexico was done between 1980 and 1993. The ages ranged between 2 and 16 years (mean 9.78); 39 were male and 16 female. The most frequent primary sites were in the humerus in 13 of 55 patients (23.6%), followed by the pelvis in 10 out of 55 (18%). Sixty percent of the patients had metastasic disease at diagnosis; the lungs and bones were the most frequently affected sites. Patients with localized disease (n = 22) had a disease-free survival (DFS) of 44%, compared with 20% of those with pulmonary metastasic disease (n = 7) and 8% of patients with metastasic disease to the lungs and elsewhere (n = 26) (p = .00061). Patients in regimen 3 had a DFS of 47% at 36 months of follow-up compared to 20 and 25% for patients in regimens 1 and 2, respectively (p = .01). In those with trunk presentation the DFS was of 25% and in those with presentation in the extremities DFS was 50% (p = .01). Patients with pulmonary metastasic disease at diagnosis have a DFS of 20% in comparison to those without (44%) (p = .00061).

Early death in children with acute lymphoblastic leukemia: does malnutrition play a role?

The study aim was to correlate malnutrition and early death in children with acute lymphoblastic leukemia (ALL). A study was conducted in 100 consecutive children with ALL. An analysis included clinical and laboratory parameters as well as co-morbidity factors. Forty patients were standard risk and 60 high risk. Multivariate analysis showed variables of statistical importance, including female gender (p 010), ALL high-risk (p 04), and infection (p 036). Malnutrition (p 1.0) and poverty (p 0.5) did not influence. Early mortality was documented in 15/100 (15%) patients. The study shows that high-risk ALL and infection represent the leading causes of early mortality.

Is the ancillary chemotherapy approach of any value in the treatment of infratentorial primitive neuroectodermal tumors with surgery and radiotherapy

Abstract A retrospective historical analysis of patients under 18 years of age with the histopathological diagnosis of infratentorial primitive neuroectodermal tumor (PNET) is presented. The survey embraced two different groups of children. Group 1 was defined as those patients treated from 1972 to 1984 with surgical resection plus neuraxis radiotherapy alone. Group 2 was made up of children treated from 1990 to 1996 with the same approach but with the addition of adjuvant chemotherapy: cisplatin (day 1) and etoposide (days 1–3) every 3 weeks for 6 months. Group 1 embraced 42 children with an age range of 1– 16 years (mean 6 years, SD 4.4 years). In group 2 there were 34 children, their ages ranging from 1 to 18 years (mean 7.2, SD 4.6 years). The prevalence of stages T2M0 and T3M0 was similar in both groups, but in group 1 there were 4 patients (9.5%) whose spinal fluid was positive for tumor cells (M1), while in group 2 there were 7 children (20.5%) with positive spinal fluid. There was an unequivocal initial response to treatment in 86% of these children in group 1 and in 79% in group 2. The event-free survival (EFS) was 30% at 252 months in group 1, while for group 2 the EFS was 67.6% at 63 months (P 0.002). Mortality from tumor activity was noted in 26 patients (70%) in group 1, while in group 2 mortality attributable to tumor progression was documented in 11 children (32%). We conclude that the use of adjuvant chemotherapy in these patients improves survival without any significant morbidity.

Is autologous bone marrow transplant (ABMT) and high-dose chemotherapy an approach that can rescue some children with advanced cancer disease?

The object was to determine the role of ABMT in children with advanced cancer. Those included had failed to respond to conventional treatment with 4 different ablative chemotherapy regimens. Bone marrow stem cells were identified with CD34. Cellular viability was determined after the bone marrow extraction and before the infusion. Fifteen patients were included, whose ages ranged from 1 to 13 years old with a median of 7. Six had acute leukemia, 6 with primitive neuroectodermic tumors, and 3 with other tumors. The median disease-free survival for the whole group was of 2 months, range of 1 to 29 months and SD of 10.1. A total of 6 children are alive (40%) and without evidence of tumor activity from 1 to 29 months. The disease-free survival rate for these group was of 19.1 months, with an SD of 7.9 months.

The burden of childhood cancer in Mexico: Implications for low- and middle-income countries: RIVERA-LUNA ET AL.

In Mexico, childhood cancer incidence and mortality have increased in the last decade. Through government actions since 2005, the Popular Medical Insurance (PMI) program for childhood cancer was created. The objective of PMI was to offer early cancer diagnosis, standardized treatment regimens, and numerous pediatric oncology residency programs. It has also accredited 55 national hospitals for the care of these children. Current problems still present under the PMI include shortage of pediatric oncologists and nurses and high rate of abandonment of treatment. Our aim is to describe the current scenario of childhood cancer care in Mexico, especially from the perspective of the PMI and how it has impacted human resources, infrastructure, and medical education.