Investigation of microsatellite instability BAT25 and BAT26 in breast cancer patients by conventional polymerase chain reaction

Context: Breast cancer is the most common cancer among women worldwide, comprising 23% of the 1.1 million female cancers that newly diagnosed each year. Aims: The aim is to investigate the existence of microsatellite instability (MSI) in breast cancer of patients. Settings and Design: Fifty female patients with invasive ductal breast carcinoma collected. Inclusion criteria of patients include female patients with diagnostic feature of breast cancer and age range 26–42-year-old untreated with chemotherapy or hormonal therapy. Subjects and Methods: DNA had be extracted from frozen tissue samples of breast cancer. This protocol done according to the kit manufacture's manual of QIAamp DNA Mini Kit from Qiagen – USA. All samples tested for MSI by singleplex polymerase chain reactions (PCRs) using two microsatellite markers BAT25 and BAT26. PCR achieved in a final volume of 50 μl and after thermal cycles, gel visualization performed. Statistical Analysis Used: The significance of differences in proportions was analyzed using the Fisher's exact test with SPSS version 20 and values of P ≤ 0.001 considered statistically significant. Results: PCR demonstrating MSI in 13 (26%) of the 50 breast cancer sample. Eight (16%) of 50 breast cancer sample were BAT25 positive with a PCR product size of 124 bp, whereas 5 (10%) of 50 breast cancer sample were BAT26 positive with a PCR product size 121 bp. Conclusions: The result suggests strong evidence that MSI at the BAT25 and BAT26 and have involved in the pathogenesis of the great majority of breast cancers.