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Background: Langerhans cell histiocytosis (LCH) is a rare neoplastic disease characterized by clonal proliferation of den-dritic cells. It is Mexico's ninth most frequent malignancy in patients under 18 years of age. The aim of the study was to determine the clinical characteristics, treatment, and survival of Mexican pediatric patients diagnosed with LCH treated from January 2010 to December 2018., Methods: We conducted a retrospective study of LCH using data from 19 accredited hospitals throughout the Mexican Republic. Patients < 18 years who were diagnosed with LCH between January 2010 and December 2018 were included (253 patients) in the study., Results: All patients had a histopathological diagnosis, and extension studies were performed at their treatment centers. The median age at diagnosis was 19 months. The most frequently affected sites included the bone (178 cases; 70%) and the skin (131 cases; 51.7%). Of the patients in Group 1, 48 (42%) had bone marrow involvement, 62 (53%) had splenomegaly, and 39 (34.8%) had liver involvement. Of the patients who underwent chemotherapy treatment, 61.2% exhibited a complete response, and 36 patients (14.2%) relapsed after complete remission. The most frequent sites of relapse were the skin, bone, lymph nodes, and liver. The overall survival rate was 91.3% and was lower for patients in Group 1 (77%) compared with those in Groups 2 (97%) and 3 (100%), p = 0.001., Conclusion: The current report aims to demonstrate the findings of a multicenter study conducted on Mexican children with LCH; consequently, these treatment results for a relatively infrequent disease merit further research., (Copyright: © 2024 Permanyer.)

Background: Pediatric cancer incidence in Mexico is ~160/million/year with leukemias making 49.8% of the cases. While survival rates have been reported in various Mexican studies, no data is available from the Telethon Pediatric Oncology Hospital-HITO, a nonprofit private institution specialized exclusively in comprehensive pediatric oncology care in the country that closely follows high-income countries' advanced standards of cancer care., Aim: To determine overall survival (OS) and relapse-free survival (RFS) in patients treated at HITO between December 2013 and February 2018., Methods and Results: Secondary analysis of data extracted from medical records. It included 286 children aged 0-17 years diagnosed with various cancers grouped into three categories based on location: (1) Acute lymphoblastic leukemia (ALL), (2) tumors within the central nervous system (TWCNS), and (3) tumors outside the CNS (TOCNS). OS and RFS rates for patients who completed 1 (n = 230) and 3 (n = 132) years of follow-up after admission were computed by sex, age, and cancer location, and separately for a subsample (1-year = 191, 3-years = 110) who fulfilled the HITO criteria (no prior treatment, underwent surgery/chemotherapy when indicated, and initiated therapy). TOCNS accounted for 45.1%, but ALL was the most frequent single diagnosis with 28%. Three-year OS for patients with ALL, TWCNS, and TOCNS who fulfilled the HITO criteria were 91.9%, 86.7%, and 79.3%, respectively; for 3-year RFS these were 89.2%, 60%, and 72.4%. Boys showed slightly higher OS and RFS, but no major differences or trends were seen by age group., Conclusion: This study sets a relevant reference in terms of survival and relapse for children with cancer in Mexico treated at a private oncology center that uses a comprehensive and integrated therapeutic model., (© 2022 The Authors. Cancer Reports published by Wiley Periodicals LLC.)

Rhodococcus is a pathogen that is known to cause infections in animals and humans, mainly in cases of immunocompromised patients. A case of a pediatric cancer patient suffering from a bloodstream infection caused by Rhodococcus corynebacterioides was described in this work. Gram positive rods were isolated from blood cultures. The target bacterium was identified using a combination of biochemical tests, the MALDI-TOF mass spectrometry technique, and the analysis of the 16S rRNA sequence. Moreover, an antimicrobial susceptibility test was performed using the E-test. The isolated bacterium was identified as R. corynebacterioides. The 3-year-old patient was successfully treated with vancomycin and meropenem. This is the first published report of R. corynebacterioides in a pediatric patient diagnosed with retinoblastoma that developed a bloodstream infection. R. corynebacterioides should be considered among the opportunistic infectious agents affecting pediatric cancer patients., (Copyright © 2022 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Ph-like subtypes with CRLF2 abnormalities are frequent among Hispano-Latino children with pre-B ALL. Therefore, there is solid ground to suggest that this subtype is frequent in Mexican patients. The genomic complexity of Ph-like subtype constitutes a challenge for diagnosis, as it requires diverse genomic methodologies that are not widely available in diagnostic centers in Mexico. Here, we propose a diagnostic strategy for Ph-like ALL in accordance with our local capacity. Pre-B ALL patients without recurrent gene fusions (104) were classified using a gene-expression profile based on Ph-like signature genes analyzed by qRT-PCR. The expressions of the CRLF2 transcript and protein were determined by qRT-PCR and flow cytometry. The P2RY8::CRLF2 , IGH::CRLF2, ABL1/2 rearrangements, and Ik6 isoform were screened using RT-PCR and FISH. Surrogate markers of Jak2-Stat5/Abl/Ras pathways were analyzed by phosphoflow. Mutations in relevant kinases/transcription factors genes in Ph-like were assessed by target-specific NGS. A total of 40 patients (38.5%) were classified as Ph-like; of these, 36 had abnormalities associated with Jak2-Stat5 and 4 had Abl. The rearrangements IGH::CRLF2, P2RY8::CRLF2 , and iAMP21 were particularly frequent. We propose a strategy for the detection of Ph-like patients, by analyzing the overexpression/genetic lesions of CRLF2 , the Abl phosphorylation of surrogate markers confirmed by gene rearrangements, and Sanger sequencing.

The P2RY8-CRLF2 and IGH-CRLF2 rearrangements induce the overexpression of cytokine receptor-like factor 2 (CRLF2) and have been associated with relapse and poor prognosis in B-cell acute lymphoblastic leukemia (B-ALL). Additionally, they are frequently documented in high-risk Hispanic populations. To better understand the potential causes of the adverse prognosis of childhood B-ALL in Mexico, we analyzed these rearrangements and the CRLF2 mRNA and protein levels in 133 Mexican children with B-ALL. We collected bone marrow samples at diagnosis and evaluated the CRLF2 gene expression by qRT-PCR and the total CRLF2 protein by flow cytometry. P2RY8-CRLF2 and IGH-CRLF2 were detected by RT-PCR and FISH, respectively. The median time of follow-up to determine the prognostic significance of the CRLF2 abnormalities was three years. In 82% of the participants, the mRNA levels correlated with the cell-surface and intracellular CRLF2 protein levels. The P2RY8-CRLF2 rearrangement was present in 31.5% (42/133) of the patients, while the IGH-CRLF2 rearrangement was detected in 13.5% (9/67) of patients with high expression of CRLF2 (6.8% of the total sample). CRLF2 copy number variations (gain) were also detected in 7.5% (5/67) of patients with high protein levels. The overall survival (OS) presented significantly lower rates in patients with high white blood cell count (≥50x10 9 /L) regardless of CRLF2 expression, but high levels of CRLF2 gene expression appears to contribute to the reduction of OS within this group of patients. In conclusion, in our cohort, a high occurrence of CRLF2 abnormalities was documented, particularly the P2RY8-CRLF2 rearrangement, which might represent a characteristic of the Mexican population. Targeted therapy to treat this group of patients could improve OS., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The aim of the study was to measure survival of children with acute lymphoblastic leukemia (ALL) under Mexico's public health insurance for the population treated under Seguro Popular . A retrospective cohort study using claims data from Mexico's Seguro Popular program, covering cancer treatment from 2005 to 2015 was conducted. Overall 5-year national and state-specific survival for children with ALL across Mexico who initiated cancer treatment under this program was estimated. From 2005 to 2015, 8,977 children with ALL initiated treatment under Seguro Popular . Under this financing scheme, the annual number of treated children doubled from 535 in 2005 to 1,070 in 2015. The estimates for 5-year overall survival of 61.8% (95%CI 60.8, 62.9) remained constant over time. We observed wide gaps in risk-standardized 5-year overall survival among states ranging from 74.7% to 43.7%. We found a higher risk of mortality for children who received treatment in a non-pediatric specialty hospital (Hazards Ratio, HR = 1.18; 95%CI 1.09, 1.26), facilities without a pediatric oncology/hematology specialist (HR = 2.17; 95%CI 1.62, 2.90), and hospitals with low patient volume (HR = 1.22; 95%CI 1.13, 1.32). In a decade Mexico's Seguro Popular doubled access to ALL treatment for covered children and by 2015 financed the vast majority of estimated ALL cases for that population. While some progress in ALL survival may have been achieved, nationwide 5-year overall survival did not improve over time and did not achieve levels found in comparable countries. Our results provide lessons for Mexico's evolving health system and for countries moving toward universal health coverage.

Background: The objective was to investigate factors associated with patient-related timing (PRT) to seek healthcare and health service-related timing (HSRT) to diagnose cancer and provide treatment to children without social security in Mexico., Procedure: A cross-sectional survey was conducted in 13 Ministry of Health hospitals in the states of Chihuahua, Jalisco, Mexico City, Morelos, Oaxaca, Puebla, Queretaro, State of Mexico, and Tlaxcala. Study participants were parents of recently diagnosed pediatric cancer patients (≤ 17 years of age). Three groups of factors were investigated: (1) patients (child and parent characteristics); (2) healthcare providers (HCPs) (first-contact HCP, institution, perceptions of barriers to healthcare, etc.); and (3) disease factors (cancer type/site, stage/risk at diagnosis). PRT and HSRT-associated factors were identified using multiple negative binomial regressions., Results: The study included 265 children; 49% sought care when symptoms first appeared. The median PRT was seven days, and the median HSRT was 40 days. Parents' perceptions of long wait times for appointments were associated with longer PRT and HSRT. Residing in the lowest or highest socioeconomic regions and persistent or worsening symptoms increased the probability of longer PRT. Older patient age, HCP requests for imaging tests or prescription for steroids, a higher number of doctors consulted, having a urinary tract cancer, and having an advanced stage or high-risk cancer increased the probability of longer HSRT., Conclusion: Strategies to shorten lag time from symptom onset to diagnosis and treatment are urgently needed for childhood cancers in Mexico., (© 2020 Wiley Periodicals, Inc.)

Methods: A qualitative study involving 72 in-person interviews and 4 focus groups was conducted using a semistructured interview guide. Key informants included family members, physicians, nurses, psychosocial providers, foundation leadership, volunteers, and communication professionals. The study sites included pediatric oncology centers in El Salvador, Guatemala, Mexico, and Panama. NVivo was used for thematic analysis., Results: Across all sites, parents had common questions and educational needs. Questions from families focused on their child's likelihood of dying from cancer and feelings of guilt that were based on their perception that they caused the disease. The origin of cancer, nutrition, and psychosocial support were the most important educational themes. However, the prioritization of different educational themes varied on the basis of cultural or social influences unique to each site. Some of these differences included a need for education surrounding amputations, sibling support, and alternative or traditional healers., Conclusion: This study demonstrates that although many educational needs were consistent across hospitals, some of the educational priorities differed by site despite geographic proximity and shared language. Developing an educational program in resource-limited settings can be challenging, but it is an important contributor to improving childhood cancer outcomes that should be tailored to the specific needs of a site. This study can be used as a guide for other programs with limited resources wanting to develop relevant educational materials for families.

Purpose Limited data describe the delivery of pediatric cancer care in Mexico. We report a nationwide survey of pediatric cancer units. Methods An electronic survey was distributed to 74 pediatric cancer units in Mexico to describe case volumes; organization of care; and availability of medical/surgical specialists, supportive care, complex therapies, and diagnostic services. Centers were classified as low (< 30 new patients/year), medium (30 to 59/year) and high (≥ 60/year). Results Sixty-two centers completed the survey (response rate, 84%). The median annual new case volume per center was 50 (interquartile range [IQR], 23 to 81). Thirty-four percent (n = 21), 26% (n = 16), and 40% (n = 25) of units were low-, medium-, and high-volume centers, respectively. Treatment units reported a median of two pediatric oncologists (IQR, 2) and one pediatric hematologist (IQR, 1 to 2). Availability of medical and surgical subspecialists varied by center size, with substantially more specialist support at higher-volume centers ( P < .01). Multidisciplinary tumor boards are available at 29% (six of 21), 56% (nine of 16), and 76% (19 of 25) of low- to high-volume centers, respectively ( P = .005). Radiation and palliative care services are available at 42% (n = 26) and 63% (n = 36) of all centers, which did not vary by center volume. Educational support for hospitalized children and school reintegration programs are available at 56% (n = 36) and 58% (n = 36) of centers, respectively. One third (38% [n = 23]) of centers reported that at least one half of patients were lost to follow-up during the transition from pediatric to adult programs. Conclusion A large variation exists in annual case volumes across Mexican pediatric cancer centers. Additional efforts to increase access to multidisciplinary, supportive, and palliative care across all pediatric cancer units in Mexico are required.

A total of 119 children (1990-95) with acute lymphoblastic leukemia (ALL) B-lineage either CD10+ or CD10- were registered into a single non-randomized chemotherapy protocol. Only untreated patients with standard risk were included in the study. Their ages ranged from 1.8-10 years with a mean of 5.1 years. There were 82 (68%) children with early pre B-All, 35 (29%) with pre B-ALL and 2(1.6%) with transitional pre B-ALL (p < 0.00001). The patients were divided according to CD10 reactivity, either + (94 children) or -(25 patients). The event-free survival (EFS) at 60 months for the CD10+ children was of 78% (alive 73/94), while for the CD10- was 71% (alive 18/25) (p = 0.6) and 74% for both groups. The factors that influenced favorably the survival in the CD10+ group were the age between 3 to 5.99 years (p < 0.00001), sex (either male or female), leukocyte count between 10-24.9 x 10(9)/l (p < 0.00001), LDH under 300 U/I (p < 0.00001) and L1 bone marrow cytomorphology (p < 0.00001). In the CD10- patients, the EFS was favorably influenced by the female sex (p = 0.04), leukocyte count under 10 x 10(9)/l (p = 0.05) and LDH < 300 U/l (p = 0.02). CNS infiltration was documented in 4.2% (5/119). Mortality secondary to chemotherapy was seen in 7%. In conclusion, this is the first large series in Mexican children with B-lineage ALL published. Because of the relatively small number of patients in each group (pre B and transitional pre B), all the patients in the current series were treated alike. When the 119 patients were divided only on the basis of CD10 reactivity, the EFS for both groups (CD10+ and-) was similar; therefore, the reactivity to CD10 has no prognostic value in this type of ALL.

Simultaneous exposure to cadmium and arsenic is highly probable in the urban area of San Luis Potosi, Mexico due to common localization of copper and zinc smelters. Therefore, in this work, rats were intraperitoneally exposed either to cadmium or arsenic alone, or simultaneously to both metals. The effects of these treatments on three different toxicological parameters were studied. Cadmium modified the LD50 of arsenic and conversely arsenic modified the LD50 for cadmium. At the histopathological level, arsenic appeared to protect against the cadmium effects, especially on testes. This protective effect seemed to be related to the glutathione levels found in this tissue: rats exposed to both arsenic and cadmium, presented glutathione values intermediate to those observed after exposure to either metal alone; arsenic had the highest value and cadmium the lowest. In liver, rats exposed to arsenic, cadmium or arsenic and cadmium, presented glutathione values below those in the saline group, with the lowest value corresponding to the arsenic and cadmium treatment. The results appear to support the proposed interaction between arsenic and cadmium and coexposure to both metals seems to alter certain effects produced by either metal alone.