The increased importance of cancer genotyping in guiding cancer treatment has created a need for efficient methods for genomic analysis of patients’ cancers. This increased dependence on DNA-based tumor genotyping assays (eg, sequencing, polymerase chain reaction [PCR], fluorescence in situ hybridization [FISH]) has triggered a growing interest in the analysis of free-floating DNA present in the blood of patients with cancer—plasma cell-free DNA (cfDNA). Sensitive PCR techniques together with high-throughput next-generation sequencing (NGS) technologies have evolved to a point where genetic analysis of cfDNA is possible.