Findings from a study recently published in Science Translational Medicine by researchers at Johns Hopkins (MD, USA) suggest that cell-free circulating tumor DNA (ctDNA) shed by tumors into the bloodstream have potential to act as cancer biomarkers.
The team analyzed blood samples from 640 patients with various cancer types using digital PCR-based technologies. ctDNA was detected in over 75% of patients with advanced pancreatic, ovarian, colorectal, bladder, gastroesophageal, breast, melanoma, hepatocellular and head and neck cancers, but in less than 50% of primary brain, renal, prostate or thyroid cancers. The researchers detected ctDNA in 55% of samples from 223 patients with localized tumors, including 73% of those with colorectal cancer and 57% of those with gastroesophageal cancer. In addition, they found that ctDNA was ore likely to be detected in patients at later stages of cancer.
Lead author of the study, Chetan Bettegowda, an Assistant Professor of oncology and neurological surgery, commented, “We are already very good at treating and curing cancer when it is localized, but we wanted to develop a non-invasive technology to enhance detection of cancer at an early stage, and we feel this is an exciting starting point for further work using this method.”
In addition to its use in early-stage cancer screening, the team also demonstrated the potential of ctDNA in monitoring responses to treatment and explaining mechanisms behind the resistance of some cancers to specific therapies. The authors wrote that their data suggest that “ctDNA is a broadly applicable, sensitive, and specific biomarker that can be used for a variety of clinical and research purposes in patients with multiple different types of cancer.”
Source: Bettegowda C, Sausen M, Leary RJ et al. Detection of circulating tumor DNA in early- and late-stage human malignancies. Sci. Transl. Med. 6(224), 224ra24 (2014); DNA shed by tumors shows promise for non-invasive screening and prognosis.