Analysis of circulating cell-free DNA (cfDNA) in patients with malignant tumors is essential for clinical applications. Particularly in the field of lung cancer, examination of oncogene mutations in cfDNA is used in the clinic. However, it is unclear what kind of genomic alterations in DNA derived from tumor cells can be detected in cfDNA. The aim of this study was to analyze the characteristics of detectable genomic alterations in cfDNA.
Primary lesions, metastatic lesions, and plasma samples from six patients with primary lung cancer who underwent pathological autopsy were analyzed. CfDNA was extracted from 2 mL plasma collected less than 1 month before the patient’s death using a QIAamp Circulating Nucleic Acid Kit (Qiagen), according to the manufacturer’s instructions. Cancer-related target sequencing using a next-generation sequencer for somatic mutation analysis was performed with a Human Comprehensive Cancer Panel (Qiagen). Each tumor sample variant was analyzed in cloud analysis by Qiagen.
The results from one case were analyzed as follows. The numbers of highly confident and meaningful alterations were 1442 for lung tumors, 438 for adrenal glands, 46 for pelvic tumors, and 56 for cfDNA. We compared alterations detected in both DNA extracted from tumor samples and cfDNA and those detected in only DNA extracted from tumor samples.
The findings revealed that the former alterations had higher variant frequencies in DNA extracted from tumor samples than the latter alterations. We will present the data integrated from all six cases.
Clinical trial identification
Legal entity responsible for the study
Kazuo Kasahara, Prof.
All authors have declared no conflicts of interest.