In a study looking at the effects of RFC1 polymorphisms (SNPs) and haplotypes on toxicities induced by HD-MTX in 88 pediatric patients with ALL, the authors found that the TT genotype in rs2838958 polymorphism was associated with a higher risk of mucositis in the patients compared to carriers who had at least one C allele in their genotype. The gene discussed is RFC1; the disease is acute lymphoblastic leukemia.