TABLE 2.

Biomarkers underexpressed in H. pylori infected children in at least one study included in this review.

Biomarker	No. of studies with significant downregulation (references)	Biological function	Potential role in carcinogenesis
MUC5AC	1 (Park et al., 2015)	Extracellular secreted protein	Controversial
SLC5A8	2 (O’Ryan et al., 2015*, Orellana et al., 2016)	Transporter or enzyme	Anti-oncogenic
TIMP1	1 (Rautelin et al., 2010)	Extracellular secreted protein	Controversial

No.: Number. *Microarray results published by O’Ryan et al., are included as they were checked by qRT-PCR by Orellana et al.