Single-Nucleotide Polymorphism (SNP) c.73G>A in the UBC9 (E2) SUMO Gene and Breast Cancer Risk in Polish Women

Introduction: Breast cancer is one of the major killers among malignant conditions worldwide, affecting one out of 10 women in industrialized countries and being the leading cause of cancer-related morbidity and mortality in women. The relationships between risk factors and breast cancer development are not exactly known. The selection of the UBC9 gene and its c.73G>A polymorphism (rs11553473) in breast cancer studies is justified by the gene’s critical role in sumoylation, its impact on DNA repair, and its association with aggressive tumor characteristics. UBC9 (SUMO-conjugating enzyme) is frequently overexpressed in breast cancer, often 5–8-fold higher than in normal tissues, where it promotes tumor proliferation, invasion, and metastasis, often in a sumoylation-independent manner. Aim: In the present work, the association of polymorphism in the UBC9 genes c.73G>A with breast cancer risk was investigated. Materials and Methods: In the reported study, paraffin-embedded tumor tissue was collected from women with lymph node-negative (n = 59) and lymph node-positive (n = 41) ductal breast carcinoma. Samples from age-matched, cancer-free women (n = 100) served as controls. The genotypes of the UBC9 c.73G>A polymorphism were determined by ASO-PCR methods. Results: In the present work, a significant positive association between the UBC9 c.73G>A G/A genotype and breast cancer is demonstrated. The variant A allele of UBC9 increased breast cancer risk. Some correlation was observed between the genotypes of UBC9 polymorphism and breast cancer invasiveness. A statistically significant increase was observed regarding G/A heterozygote frequency in stage II patients, according to Bloom–Richardson classification. There were no significant differences in genotype distribution among subgroups defined by TNM stage, histological grade, hormone receptor status, or HER-2 expression. Conclusions: In conclusion, the reported study indicates that the polymorphisms of the UBC9 gene may be positively associated with the incidence of breast cancer. However, further research is needed on larger study populations.