Circulating cell-free DNA, SLC5A8 and SLC26A4 hypermethylation, BRAF(V600E): A non-invasive tool panel for early detection of thyroid cancer.
OBJECTIVE
In the latest years, high levels of circulating cell-free DNA (cf-DNA) have been found to be associated with cancer diagnosis and progression, and cf-DNA has become a potential candidate as biomarker for tumor detection. cf-DNA has been investigated in plasma or serum of many tumor patients affected by different malignancies, but not yet in thyroid cancer (TC). Furthermore, in TC cells the capability to metabolize iodine is frequently lost. SLC5A8 and SLC26A4 genes are both involved in the iodine metabolism, and SLC5A8 hypermethylation status is associated with the BRAF(V600E) mutation, which is the most frequent genetic event underlying the development of papillary TC. The aim of our study is the development of a new non-invasive tool for the diagnosis and prognosis of TC based on cf-DNA, SLC5A8 and SLC26A4 hypermethylation, and BRAF(V600E) analysis.


METHODS
cf-DNA was measured by quantitative real-time PCR in nine cases of anaplastic thyroid cancer (ATC), 58 medullary thyroid cancers (MTC), five of synchronous medullary and follicular thyroid cancers (SMFC), 23 follicular adenomas (FA), 86 papillary thyroid cancers (PTC). A control group of 19 healthy subjects was taken. Moreover, in the PTC group we analyze the state of hypermethylation of SLC5A8 and SLC26A4, BRAF(V600E) mutation, and their involvement in the loss of function of the thyroid.


RESULTS
cf-DNA showed a high ability to discriminate healthy individuals from cancer patients. cf-DNAALU83 and cf-DNAALU244 values were significantly correlated with the histological type of TC (P-value < 0.0001). A significant increase in the amount of cf-DNAALU83 and cf-DNAALU244 when methylation occurs was observed (P-value = 0.02). A correlation between BRAF(V600E) and cf-DNAALU244/ALU83 was also found (P-value = 0.02).


CONCLUSIONS
According to our experimental results, the panel including cf-DNA, SLC5A8 and SLC26A4 hypermethylation, and BRAF(V600E) analysis appears easy, reproducible, and non-invasive for the diagnosis on TC. Its possible implication in clinical setting remains to be elucidated.
Surgical clinic II, Department of Surgical, Oncological and Gastroenterological Sciences, University of Padova, Padova, Italy.
Mariangela
M
Zane
Marco
M
Agostini
Maria Vittoria
MV
Enzo
Eric
E
Casal Ide
Paola
P
Del Bianco
Francesca
F
Torresan
Isabella
I
Merante Boschin
Gianmaria
G
Pennelli
Andrea
A
Saccani
Domenico
D
Rubello
Donato
D
Nitti
Maria Rosa
MR
Pelizzo
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D027682:Cation Transport Proteins / Q000378:metabolism*; D004247:DNA / Q000097:blood*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008745:Methylation; D008875:Middle Aged; D027501:Monocarboxylic Acid Transporters; D010865:Pilot Projects; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012680:Sensitivity and Specificity; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D055815:Young Adult
D027682:Cation Transport Proteins; D027501:Monocarboxylic Acid Transporters; C476760:SLC5A8 protein, human; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D004247:DNA; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf
BRAF; Cell-free-DNA; Early diagnosis; Methylation; Thyroid cancers