GSTP1 methylation in cancer: a liquid biopsy biomarker?

The coding region of gene is preceded by a large CpG-rich region that is frequently affected by methylation. In many cancer types, is affected by hypermethylation and, as a consequence, it has a low expression. The aim of this review is to give an overview on methylation studies with a special focus on liquid biopsy, thus to summarize methods, results, sample types, different diseases, to have a complete information regarding this promising epigenetic biomarker. We used all the most valuable scientific search engines (PubMed, Medline, Scopus and Web of Science) searching the following keywords: , methylation, cancer, urine, serum, plasma and blood. is a largely investigated tissue biomarker in several malignancies such as prostate, breast, lung and hepatocellular carcinoma with good performances especially for diagnostic purposes. As a liquid biopsy biomarker, it has been mainly investigated in prostate cancer (PCa) where it showed a high specificity but a low sensitivity; thus, it is recommended in combination with other biomarkers. Despite the large number of published papers and the promising results, has not yet entered the clinical practice even for PCa diagnosis. For this reason, further large and prospective studies are needed to validate this assay.