Quantitative analysis of plasma cell-free DNA and its DNA integrity in patients with metastatic prostate cancer using ALU sequence

BACKGROUND: Prostate cancer (PC) is the most common cancer affecting men, it accounts for 29% of all male cancer and 11% of all male cancer related death. DNA is normally released from an apoptotic source which generates small fragments of cell-free DNA, whereas cancer patients have cell-free circulating DNA that originated from necrosis, autophagy, or mitotic catastrophe, which produce large fragments. AIM OF WORK: Differentiate the cell free DNA levels (cfDNA) and its integrity in prostate cancer patients and control group composed of benign prostate hyperplasia (BPH) and healthy persons. METHODOLOGY: cf-DNA levels were quantified by real-time PCR amplification in prostate cancer patients (n= 50), (BPH) benign prostate hyperplasia (n= 25) and healthy controls (n= 30) using two sets of ALU gene (product size of 115bp and 247-bp) and its integrity was calculated as a ratio of qPCR results of 247bp ALU over 115bp ALU. RESULTS: Highly significant levels of cf-DNA and its integrity in PC patients compared to BPH. Twenty-eight (56%) patients with prostate cancer had bone metastasis. ALU115 qpcr is superior to the other markers in discriminating metastatic patients with a sensitivity of 96.4% and a specificity of 86.4% and (AUC=0.981) CONCLUSION: ALU115 qpcr could be used as a valuable biomarker helping in identifying high risk patients, indicating early spread of tumor cells as a potential seed for future metastases.