ABSTRACT
BACKGROUND AND AIMS: Highly sensitive technologies are available for the molecular characterization of solid tumors, including digital PCR (dPCR). Liquid biopsy, based on the analysis of cell-free DNA (cfDNA), is often used to assess EGFR or RAS alterations in lung and colorectal cancers. Our study aimed to compare the results of two different dPCR platforms for the detection of mutations in cfDNA. METHODS: Plasma samples from lung and colorectal cancer patients collected as per routine procedures have been tested. cfDNA Was extracted from plasma, and samples were screened on the droplet digital PCR (ddPCR, BioRad) and solid dPCR QIAcuity (Qiagen). RESULTS: A total of 42 samples were analyzed, obtained from 20 Non-Small Cell Lung Cancer (NSCLC) patients carrying an EGFR or a KRAS mutation on tissue at diagnosis, and from 22 samples of colorectal cancer (CRC) patients, 10 of which presenting a KRAS mutation. EGFR mutation detection was 58.8% for ddPCR and 100% for dPCR (κ = 0.54; 95% CI, 0.37-0.71), compared to tissue results. The detection rate for RAS mutations was 72.7% for ddPCR and 86.4% for dPCR (κ = 0.34; 95% CI, 0.01-0.68), compared to tissue results. CONCLUSIONS: This study showed moderate agreement between dPCR and ddPCR. Sampling effect or threshold settings may potentially explain the differences in the cfDNA data between the two different platforms.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Cell-Free Nucleic Acids , Colorectal Neoplasms , Lung Neoplasms , Humans , Lung Neoplasms/diagnosis , Proto-Oncogene Proteins p21(ras)/genetics , Liquid Biopsy , Polymerase Chain Reaction/methods , Mutation , Lung/pathology , Colorectal Neoplasms/genetics , ErbB Receptors/geneticsABSTRACT
Imaging and tissue biopsies represent the current gold standard for breast cancer diagnosis and patient management. However, these practices are time-consuming, expensive and require invasive procedures. Moreover, tissue biopsies do not capture spatial and temporal tumor heterogeneity. Conversely, liquid biopsy, which includes circulating tumor cells, circulating free nucleic acids and extracellular vesicles, is minimally invasive, easy to perform and can be repeated during a patient's follow-up. Increasing evidence also suggests that liquid biopsy can be used to efficiently screen and diagnose tumors at an early stage, and to monitor changes in the tumor molecular profile. In the present review, clinical applications and prospects are discussed.
