Nowadays, Pharmacogenomics tests, including Genome-wide association studies (GWAS), have a direct identification role in genetic alterations, treatment efficacy, cytotoxicity, prognosis, etc. However, the current knowledge gives little data about how genomic determinants can affect ALL susceptibility, chemotherapy, and chance of relapse (Wu and Li, 2018). Methotrexate (MTX) forms the backbone of maintenance cycles in childhood acute lymphoblastic leukemia (ALL) chemotherapy, including interim maintenance (Mandal et al., 2020). Major adversities include cytopenias, mucositis, liver toxicity, renal toxicity and skin toxicity. These toxicities enquire dose modification or omission (burn out) MTX-related toxicities may be determined by several factors like dose, duration, genetic susceptibility and risk factors (Vaishnavi et al ., 2018).