Plasma DNA as a potential biomarker for breast cancer detection
Breast cancer is a major malignancy among Indonesian women. It is often diagnosed in the later stages of cancer, which leads to poor prognosis and survival of the patients. This study investigated plasma DNA concentration as a potential biomarker for breast cancer. The benefit of using this detection is the cost-effectiveness and the samples can be collected from patients using non-invasive methods. Plasma samples were obtained from healthy controls (n=18) and cancer patients (n=22). Each sample was split into two equal portions for DNA isolation using two different methods for the NaI method and a commercially available kit (Qiagen/ QA) method. The DNA concentration was determined by using a GeneQuant spectrophotometer (Pharmacia). The t-test was used for statistical analysis, which was performed using the SPSS 17.0 software. Compared to the commercial method, extraction using NaI yielded higher DNA concentration, both from samples of healthy controls and cancer patients (p=0,008 and p=0.000, respectively). Furthermore, regardless of the isolation method used, the plasma DNA concentration was higher in healthy controls than in cancer cases (p=0,032 and p=0.005, for NaI and QA methods, respectively). In conclusion, isolation methods significantly affect DNA concentrations. The plasma DNA concentration of healthy controls is significantly higher than those of the cancer cases, suggesting that plasma DNA concentration might be a potential biomarker for breast cancer detection with less invasive sampling method than tissue biopsies.