Circulating tumor DNA (ctDNA) is not a good proxy for liquid biopsies of tumor tissues for early detection.

The important conclusion that ctDNA is a mediocre proxy for liquid biopsies of tumor tissues for early detection was reached after new data were published recently in Nature Genetics. These data have shown that most mutations found in ctDNA are not related to tumor tissues but rather to the precancerous condition clonal hematopoiesis. Previously, our group has analyzed the sensitivity of the ctDNA test for early detection of cancer and concluded that the achievable sensitivity, especially for small tumors, is not enough to have clinical value. Now, the new data have shown a serious compromise in specificity. We believe that scientists who are interested in early cancer diagnostics should be aware of the limitations of this test, in both sensitivity and specificity. Our work may prompt further work aiming to alleviate these important issues in the cancer diagnostics field.