title: Circulating cell-free DNA in plasma of melanoma patients: qualitative and quantitative considerations.
abstract: DNA integrity in blood is an emerging biomarker in cancer. Here we report a real time PCR approach for the absolute quantification of four amplicons of 67, 180, 306 and 476 bp in cutaneous melanoma. Three different integrity indexes (180/67, 306/67 and 476/67 ratios) were tested for their ability to reflect differences in plasma cell-free DNA (cfDNA) fragmentation in 79 patients affected by cutaneous melanoma and 34 healthy subjects. All the three integrity indexes showed higher values in melanoma patients in comparison with healthy subjects. According to ROC curve analysis, the ratio 180/67 is the most suitable index to be used in cancer patient selection, even if the combination of the 3 indexes gives the best performance in terms of clinical sensitivity. The most represented fragments in plasma of melanoma patients are those comprised between 181 and 307 bp, while in healthy subjects there is a prevalence of shorter fragments (67-180 bp). In conclusion, DNA integrity indexes can be considered suitable parameters for monitoring cfDNA fragmentation in melanoma patients.
authors.affiliation: Department of Clinical Physiopathology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy. p.pinzani@dfc.unifi.it
authors.forename: Pamela
authors.initials: P
authors.lastname: Pinzani
authors.forename: Francesca
authors.initials: F
authors.lastname: Salvianti
authors.forename: Sara
authors.initials: S
authors.lastname: Zaccara
authors.forename: Daniela
authors.initials: D
authors.lastname: Massi
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Giorgi
authors.forename: Mario
authors.initials: M
authors.lastname: Pazzagli
authors.forename: Claudio
authors.initials: C
authors.lastname: Orlando
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000097:blood*; D006801:Humans; D008545:Melanoma / Q000097:blood* / Q000235:genetics; D016133:Polymerase Chain Reaction; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000097:blood* / Q000235:genetics
chemical_list: D017931:DNA Primers; D004273:DNA, Neoplasm