The emergence of breast cancer (BC) patients could be influenced by common polymorphisms in the ABCG2 gene which impact chemotherapeutic response. Reactive oxygen species (ROS) and altered redox conditions are two prevalent biochemical features that might be linked to cytological changes in breast cancer (BC) patients. This case-control study compares apoptosis, mitochondrial ROS levels, cytoplasmic ROS levels, and mitochondrial morphology with control for evaluating the relationship between mutations in the ABCG2 gene and the development of BC. It also evaluates oxidative stress in BC patients following diagnosis. The findings indicated that TT genotype was not linked to an elevated risk of BC (P more than 0.05) however, there has been a significant relationship between CT and CC and BC risk (P less than 0.05). A total of 11 new genetic mutations (SNPs) have been found; 6/11 (G71T), (T141C), (T148C), (G150C), (T169C), and (G172C) were non-synonymous mutations that altered the 3D protein's structure due to the amino acids in BC patients changing. Three of these mutations (G2559C), (G38A), and (G96428A) are synonymous mutations; two of these (163 G^Del), and (167 A^Del) are frameshift mutations that altered the 3D protein's structure. When put to comparison with normal tissue, the reaction to fluorescence dyes was more pronounced in BC tissue. According to our research, in addition to cytological changes, mutations and polymorphisms in the ABCG2 gene have been associated with the development of BC and its susceptibility to drugs. Additional validation of such results in a sizable population is required.