Analysis of tumor-derived DNA in plasma and bone marrow fluid in lung cancer patients

Liquid biopsies such as circulating tumor DNA in plasma and disseminated tumor cells in the bone marrow are currently available. However, it is unclear which types of samples are appropriate for detecting tumor DNA in these biopsies. Here, we collected primary tumors, pulmonary venous blood, peripheral blood, and rib bone marrow fluid from 10 lung cancer patients. Targeted deep sequencing was performed to identify mutations across 70 specimens. As a result, a total of 43 mutations were identified in the primary tumors. The mutation in the tumors was also identified in circulating tumor DNA in the pulmonary venous and peripheral blood in two patients. These patients showed poor prognosis, as compared to the other patients. However, no mutation was identified in the bone marrow in any of the patients. These results demonstrated that circulating tumor DNA in plasma is more sensitive and clinically useful as a biomarker as compared to DNA in bone marrow fluid.