Genetic polymorphisms of genes involved in oxidative stress and inflammatory management in oncopediatric patients with chemo-induced oral mucositis

Oral mucositis (OM) is a painful inflammatory oral condition that affects children who undergo chemotherapy. Oxidative stress is a known OM mediator and pro-inflammatory cytokines contribute to the amplification of the immune response. OBJECTIVE: To investigate the possible associations of rs4880 (superoxide dismutase 2, SOD2 47 C/T), rs7943316 (catalase, CAT −21 A/T), rs1800629 (tumor necrosis factor α, TNF- α −308 G/A), and rs1800795 (interleukin 6, IL-6 −174 G/C) polymorphisms with chemo-induced OM occurrence and severity in oncopediatric patients. METHODOLOGY: We conducted a single-center, observational cross-sectional study with sample collection of oral epithelial cells from 95 children and adolescents with hematological cancers who underwent chemotherapy, followed by genomic DNA extraction. Single-nucleotide polymorphisms (SNPs) were assessed with PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism). Demographic data and information concerning OM occurrence were obtained from dental charts of the multidisciplinary oral care team. Information on OM severity was obtained from appropriately-filled Oral Assessment Guide records. Descriptive and inferential statistics were conducted with Student's T test, chi-squared test, and Fisher's exact test, with p≤0.05. RESULTS: The mean age was 10 years-old and most patients were male individuals (57.89%). Female sex was considered a protective factor for OM occurrence (OR=4.83; CI=[1.14; 16.57]). The AA genotype for CAT was the most frequent amongst individuals with severe OM (p=0.04). The GA genotype for TNF- α was the most frequent amongst individuals without severe OM (p=0.03). For SOD2 and IL-6 , the most frequent genotypes were CT and GG respectively for all groups (p>0.05). CONCLUSION: The AA genotype for CAT −21 A/T was a tendency among the group with severe OM. Data on TNF- α −308 G/A were inconclusive. No associations were detected for SOD2 47 C/T and IL-6 −174 G/C polymorphisms in oncopediatric patients with chemo-induced oral mucositis.