Improved DNA Extraction Protocol from Frozen Blood of Patients Who Underwent Systemic Chemotherapy

The quality of the extracted genomic DNA is largely reduced in patients who are exposed to chemotherapeutic treatment, which is usually encountered in the commonly used DNA extraction methods that are not designed to isolate DNA from those patients. In this study, a special non-organic protocol was developed to overcome the negative effects of chemotherapeutic drugs on the quality of extracted DNA. Numerous modulations were applied in the washing, suspension, and lysis approaches to compensate for the harmful impacts of the chemotherapeutic drugs on the quality of genomic DNA. Obvious purity and adequate yields of the extracted DNA were demonstrated in the suggested protocol. The validity of this protocol for digestion with restriction endonucleases, conventional PCR, and real-time PCR was confirmed. This protocol proved satisfactory values of absorbance ratio (1.8 ± 0.02 and 2.1 ± 1.2, for A260/280 and A260/230, respectively) and adequate yields of DNA (10 ± 2.24) µg/100 µl. The validation experiments proved the efficacy of extracted DNA for downstream applications of molecular biology. The utilization of this method entails a useful approach for extracting molecular biology-grade DNA without having inhibitors against common enzymes used in molecular biology even after exposing patients to several sessions of chemotherapy.