The Importance of DNA Methylation to Breast Cancer Diagnosis

Abstract

According to the Egyptian National Cancer Registry Programme, breast cancer is the leading cancer among Egyptian females (Ibrahim A et al., 2014). At the time of initial diagnosis approximately 5% of patients are found to have advanced or metastatic disease. Although early diagnosis by screening mammography is believed to be responsible for the significant decline in breast cancer mortality, especially for women with premenopausal breast cancer. Thus, alternative approaches to breast cancer detection are clearly needed for improving diagnosis (Cho Y et al., 2010). Early in the formation and growth of a primary tumour (e.g., breast, colon, lung, or prostate cancer), cells are released into the bloodstream. These circulating tumour cells (CTC) can be enriched and detected via different technologies that take advantage of their physical and biologic properties. CTC analyses are considered a real-time “liquid biopsy” for patients with cancer (Pantel K and Alix-Panabieres C, 2010). The term “liquid biopsy” has also been adopted for the analysis of circulating cell-free tumour DNA (ctDNA) released from apoptotic or necrotic tumour cells. The development of sensitive molecular assays has allowed researchers to screen ctDNA in blood plasma for tumour-