Methylene tetrahydrofolate reductase A1298C polymorphisms influence the adult sequelae of chemotherapy in childhood-leukemia survivors

Methotrexate resistance and its regulatory mechanisms in pediatric tumors and beyond

Methotrexate (MTX) is a critical antimetabolite drug in treating various pediatric diseases, including acute lymphoblastic leukemia (ALL), non-Hodgkin lymphoma (NHL), brain tumors, osteosarcoma, inflammatory myofibroblastic tumor (IMT), juvenile scleroderma (JS), and juvenile idiopathic arthritis (JIA). MTX acts as a folate antagonist by inhibiting dihydrofolate reductase (DHFR), an enzyme essential for the synthesis of tetrahydrofolate. This disruption impairs DNA synthesis, repair, and cellular replication, particularly affecting rapidly dividing cells. Despite its efficacy, MTX resistance poses significant challenges, particularly in pediatric oncology, where it undermines the ability to achieve sustained therapeutic effects, resulting in reduced therapeutic efficacy and poor prognosis. The mechanisms of MTX resistance encompassed reduced enzyme activity pivotal for MTX metabolism, enhanced expression of efflux transporters, genetic variations, and alterations in signaling pathways. Multifaceted strategies have been explored to overcome MTX resistance. Combination therapies with ginger extract, gold nanoparticles, and arsenic trioxide (ATO) have been investigated to augment MTX's cytotoxic effects. Synergies with mTOR inhibitors and MDM2 inhibitors have demonstrated enhanced outcomes in ALL. In JIA, targeting ATP-binding cassette (ABC) transporters and modulating transforming growth factor‑β (TGF-β) signaling pathways have emerged as promising approaches. For osteosarcoma, emphasis on autophagy pathways and non-coding RNAs influencing chemotherapy sensitivity could enhance MTX effectiveness. This review delineates MTX's therapeutic roles, elucidates its resistance mechanisms, and discusses current and potential strategies for managing MTX resistance to bolster treatment effectiveness in pediatric tumors and other diseases. This knowledge base could underpin further research and development of personalized treatments to optimize MTX's clinical benefits.

[Recent research on cognitive impairment in children with acute lymphoblastic leukemia]

Acute lymphoblastic leukemia (ALL) is the most common malignant neoplastic disease in children. With the continuous improvement in diagnosis and treatment, there has been an increasing number of ALL children who achieve long-term survival after complete remission; however, a considerable proportion of these children have cognitive impairment, which has a serious adverse impact on their learning, employment, and social life. This article reviews the latest research on cognitive impairment in children with ALL from the aspects of the influencing factors, detection techniques, and prevention/treatment methods for cognitive impairment.

Resistance Mechanisms in Pediatric B-Cell Acute Lymphoblastic Leukemia

Despite the rapid development of medicine, even nowadays, acute lymphoblastic leukemia (ALL) is still a problem for pediatric clinicians. Modern medicine has reached a limit of curability even though the recovery rate exceeds 90%. Relapse occurs in around 20% of treated patients and, regrettably, 10% of diagnosed ALL patients are still incurable. In this article, we would like to focus on the treatment resistance and disease relapse of patients with B-cell leukemia in the context of prognostic factors of ALL. We demonstrate the mechanisms of the resistance to steroid therapy and Tyrosine Kinase Inhibitors and assess the impact of genetic factors on the treatment resistance, especially TCF3::HLF translocation. We compare therapeutic protocols and decipher how cancer cells become resistant to innovative treatments—including CAR-T-cell therapies and monoclonal antibodies. The comparisons made in our article help to bring closer the main factors of resistance in hematologic malignancies in the context of ALL.