Introduction: Pediatric acute leukemia is the most common childhood malignancy and one of the leading causes of cancer-related mortality worldwide, particularly, in low- and middle-income countries (LMICs), where treatment abandonment remains a major barrier to survival. Geographic accessibility and socioeconomic conditions are recognized determinants, but their combined influence in Mexico remains understudied. This study evaluated the association between geographic accessibility, socioeconomic factors, and treatment abandonment among children with acute leukemia in south-central Mexico. Methods: A prospective cohort study was conducted in Oaxaca, Puebla, and Tlaxcala from 2021 to 2023, including 574 children under 18 years diagnosed with acute lymphoblastic or myeloid leukemia. Geographic accessibility was estimated using travel distance and time from patients’ residences to referral hospitals, calculated with ORS Tools in QGIS. Socioeconomic variables included public health insurance affiliation, parental education and occupation, and number of siblings. Treatment abandonment was defined per SIOP criteria as failure to initiate or discontinuation of treatment for ≥4 consecutive weeks. Multivariable logistic regression, adjusted for child’s sex, age, year of diagnosis, and leukemia subtype, was used to assess associations. Results: Treatment abandonment occurred in 16.6% of patients. In multivariable analysis, lack of public health insurance (aOR = 2.83; 95% CI: 1.39-5.76; P < 0.01) and living ≥141 km from the hospital (aOR = 1.68; 95% CI: 1.02-2.74; P = 0.03) were significantly associated with abandonment. Other factors, including number of siblings, maternal education, and fathers’ occupation, were not statistically significant. Conclusion: Lack of public health insurance and greater distance to the hospital are key determinants of treatment abandonment in children with acute leukemia in south-central Mexico. Expanding insurance coverage, reducing indirect costs, and addressing geographic barriers are critical to improve treatment adherence and survival outcomes in this population.

Background/Objectives: B-cell precursor acute lymphoblastic leukemia (B-ALL), the most common pediatric acute leukemia (AL), is frequently characterized by aberrant antigen expression, which aids diagnosis and prognosis. The myeloid antigen CD66c is notably frequent in B-ALL and has been proposed as a marker of disease aggressiveness and treatment response. Evaluating CD66c in Mexican pediatric patients may provide insights into disease biology. Methods: A cohort of 128 pediatric patients was referred to the Laboratory of Oncoimmunology and Cytomics of Childhood Cancer (OCL) at Instituto Mexicano del Seguro Social (IMSS) for immunophenotyping tests between March 2022 and November 2023. Additionally, control bone marrow (BM) samples were assessed. Aberrant antigen expression in hematopoietic populations and BM microenvironment stroma phenotyping were performed. Results: In total, 84.38% of B-ALL patients exhibited aberrant expression of ≥1 myeloid antigen. Among CD66c-positive patients, 13.79% had detectable measurable residual disease (MRD) during follow-up and 20.69% died. Mesenchymal stromal cells (MSCs) from patients with positive or low CD66c expression displayed inflammatory profiles. ProB leukemias with low CD66c expression were more likely to exhibit detectable MRD, increased mortality, and reduced survival. Conclusions: Low CD66c expression induces molecular stealth that could favor immune evasion and niche persistence, thereby increasing the risk of relapse and therapeutic failure.

Background/Objectives: Acute leukemia, the most common childhood cancer, poses a significant public health challenge in low- and middle-income countries (LMICs) due to its high incidence and mortality rates. Survival rates in these regions are often lower, primarily due to delayed and inaccurate diagnoses, limited access to treatment, therapy abandonment, therapy-related toxicity, and inadequate healthcare infrastructure. In Mexico, a new initiative called OncoCREAN has been developed to address this urgent need by establishing local treatment centers near pediatric patients’ home cities, ensuring timely cancer detection and comprehensive disease treatment. Methods: A retrospective observational study was conducted on pediatric patients treated at the Mexican Social Security Institute (IMSS) between 18 May 2022 and 30 June 2025. Patients presenting clinical suspicion of acute leukemia were referred to OncoCREAN centers for sample collection and subsequent shipment to the Oncoimmunology and Cytomics Laboratory (OCL), where immunophenotyping confirmed the diagnoses. Results: The implementation of the OncoCREAN model significantly reduced diagnostic turnaround times, facilitating timely therapeutic decisions, minimized uncertainty, and optimized clinical management. The decentralized framework demonstrated feasibility across diverse geographic regions, ensuring access to advanced diagnostic technology for vulnerable populations and generating valuable data on disease incidence and molecular profiles. Conclusions: The OncoCREAN model highlights the critical importance of decentralizing high-technology diagnostic resources in modern pediatric oncology. This new approach to translational research that is accessible, inclusive, and relevant to society creates a paradigm shift in the management of childhood cancer and other diseases.