Challenges of deciphering gastric cancer heterogeneity

Table 2 Selection of genes commonly detected in the peripheral blood of gastric cancer patients who displayed altered methylation patters

Gene	Function12	Specimen	Ref.
APC	Acts as an antagonist of the Wnt signalling pathway	Serum	[171]
BCL6B	Acts as a sequence-specific transcriptional repressor in association with BCL6	Plasma	[162]
CDH1	Cadherins are calcium-dependent cell adhesion proteins. They preferentially interact with themselves in a homophilic manner in connecting cells	Serum	[158]
DAPK1	Death-associated protein kinase 1 is a positive mediator of gamma-interferon induced programmed cell death	Serum	[161]
GSTP1	Mediates the voltage-dependent potassium ion permeability of excitable membranes	Serum	[161]
KCNA4	Plays an important role in detoxification by catalysing the conjugation of many hydrophobic and electrophilic compounds with reduced glutathione	Serum	[175]
MLH1	Involved in DNA mismatch repair	Serum	[171]
p15 (CDKN2B)	Functions as a cell growth regulator that inhibits cell cycle G1 progression	Serum	[158,161]
p16 (CDKN2A)	Plays an important role in cell cycle regulation by decelerating cell progression from G1 phase to S phase	Serum	[159,160,164,165]
RARB	Retinoic acid receptors bind as heterodimers to their target response elements in response to their ligands, all-trans or 9-cis retinoic acid, and regulate gene expression in various biological processes, such as embryonic morphogenesis, cell growth and differentiation	Serum	[158]
RASSF1A	Required for death receptor-dependent apoptosis	Serum	[174]
RUNX3	It functions as a tumour suppressor, and the gene is frequently deleted or transcriptionally silenced in cancer	Serum	[173,176]
SOX17	Involved in the regulation of embryonic development and in the determination of cell fate	Serum	[213]
TIMP3	Inhibitor of matrix metalloproteinases	Tissues, peritoneal washes, serum	[163,171]
TFPI2	May play a role in the regulation of plasmin-mediated matrix remodelling	Serum	[170]

¹http://www.genecards.org;

²Methylation-specific PCR.