title: KRAS G12V Mutation Detection by Droplet Digital PCR in Circulating Cell-Free DNA of Colorectal Cancer Patients.
abstract: KRAS mutations are responsible for resistance to anti-epidermal growth factor receptor (EGFR) therapy in colorectal cancer patients. These mutations sometimes appear once treatment has started. Detection of KRAS mutations in circulating cell-free DNA in plasma ("liquid biopsy") by droplet digital PCR (ddPCR) has emerged as a very sensitive and promising alternative to serial biopsies for disease monitoring. In this study, KRAS G12V mutation was analyzed by ddPCR in plasma DNA from 10 colorectal cancer patients and compared to six healthy donors. The percentage of KRAS G12V mutation relative to wild-type sequences in tumor-derived DNA was also determined. KRAS G12V mutation circulating in plasma was detected in 9 of 10 colorectal cancer patients whose tumors were also mutated. Colorectal cancer patients had 35.62 copies of mutated KRAS/mL plasma, whereas in healthy controls only residual copies were found (0.62 copies/mL, p = 0.0066). Interestingly, patients with metastatic disease showed a significantly higher number of mutant copies than M0 patients (126.25 versus 9.37 copies/mL, p = 0.0286). Wild-type KRAS was also significantly elevated in colorectal cancer patients compared to healthy controls (7718.8 versus 481.25 copies/mL, p = 0.0002). In conclusion, KRAS G12V mutation is detectable in plasma of colorectal cancer patients by ddPCR and could be used as a non-invasive biomarker.
authors.affiliation: Health Research Institute-Fundación Jiménez Díaz University Hospital (IIS-FJD), Madrid 28040, Spain. susana.olmedillas@fjd.es.
authors.forename: Susana
authors.initials: S
authors.lastname: Olmedillas López
authors.affiliation: Experimental Research Unit, General University Hospital of Albacete, Albacete 02006, Spain. doloresg@sescam.jccm.es.
authors.forename: Dolores C
authors.initials: DC
authors.lastname: García-Olmo
authors.affiliation: Health Research Institute-Fundación Jiménez Díaz University Hospital (IIS-FJD), Madrid 28040, Spain. mariano.garcia@fjd.es.|Department of Surgery, School of Medicine, Autónoma University of Madrid, Madrid 28029, Spain. mariano.garcia@fjd.es.
authors.forename: Mariano
authors.initials: M
authors.lastname: García-Arranz
authors.affiliation: Department of Surgery, School of Medicine, Autónoma University of Madrid, Madrid 28029, Spain. h.guadalajara@gmail.com.|Department of General Surgery, General Hospital of Villalba, Madrid 28400, Spain. h.guadalajara@gmail.com.
authors.forename: Héctor
authors.initials: H
authors.lastname: Guadalajara
authors.affiliation: Department of Surgery, Fundación Jiménez Díaz University Hospital, Madrid 28040, Spain. cpastorid@fjd.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Pastor
authors.affiliation: Health Research Institute-Fundación Jiménez Díaz University Hospital (IIS-FJD), Madrid 28040, Spain. damian.garcia@uam.es.|Department of Surgery, School of Medicine, Autónoma University of Madrid, Madrid 28029, Spain. damian.garcia@uam.es.|Department of Surgery, Fundación Jiménez Díaz University Hospital, Madrid 28040, Spain. damian.garcia@uam.es.
authors.forename: Damián
authors.initials: D
authors.lastname: García-Olmo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology*; D004273:DNA, Neoplasm / Q000097:blood*; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D018631:ras Proteins / Q000235:genetics*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D018631:ras Proteins
keywords: KRAS; circulating cell-free DNA; colorectal cancer; droplet digital PCR; plasma