Polymorphic Variants in Oxidative Stress Genes and Acute Toxicity in Breast Cancer Patients Receiving Radiotherapy

CÓRDOBA EE; ABBA MC; LACUNZA E; FERNÁNDEZ E; GÜERCI AM

Cancer Research and Treatment

Korean Cancer Association

Año: 2016 vol. 48 p. 948 - 954

1598-2998

Purpose Reactive oxygen species (ROS) are generated as an indirect product of radiation therapy (RT). Genetic variation in genes related to ROS metabolism may influence the level of RT-induced adverse effects. We evaluated the potential association of single nucleotide polymorphism (SNP)-related response to radiotherapy injury in breast cancer patients undergoing RT. Materials and Methods Eighty patients receiving conventional RT were included. Acute effects were evaluated according to the Radiation Therapy Oncology Group (RTOG) scores. DNA was extracted from blood and buccal swab samples. SNPs were genotyped for GSTP1, GSTA1, SOD2, and NOS3 genes by polymerase chain reaction-based restriction-fragment-length-polymorphism (PCR-RFLP). Univariate analysis (ORs and 95% CI) and principal component analysis were used for correlation of SNPs and factors related to risk of developing ≥ grade 2 acute effects.ResultsSixty-five patients (81.2%) showed side effects, 32 (40%) presented moderate to severe acute skin toxicity, and 33 (41.2%) manifested minimal acute skin reactions by the end of treatment. In both univariate and multivariate analyses, nominally significant associations were found among body mass index (OR, 3.14; 95% CI, 8.5338- 1.1274; p= 0.022), breast size (OR, 5.11; 95% CI, 17.04- 1.54; p= 0.004), and grade ≥2 acute radiation skin toxicity. A significant association was also observed between NOS3 G894T polymorphism (OR, 9.8, 95% CI, 211.6- 0.45; p= 0.041) and grade ≥2 acute radiation skin toxicity in patients with neo-adjuvant chemotherapy treatment. ConclusionThe analysis of the factors involved in individual radiosensitivity contributed to the understanding of the mechanisms underlying this trait.