TABLE 1.
Biomarkers overexpressed in H. pylori infected children in at least one study included in this review.
| Biomarker | No. of studies with significant upregulation (references) | Biological function | Potential role in carcinogenesis |
| β-catenin | 1 (Villarreal-Calderon et al., 2014) | Transcription factor | Oncogenic |
| BCL-2 | 1 (Ryszczuk et al., 2016) | Transporter or enzyme | Controversial |
| C-MYC | 1 (Nardone et al., 2001) | Transcription factor | Oncogenic |
| CCL18 | 1 (Ikuse et al., 2012) | Extracellular secreted protein | Controversial |
| CXCL9, 10, 11 | 1 (Ikuse et al., 2012) | Extracellular secreted protein | Controversial |
| CXCL13 | 2 (Ikuse et al., 2012; Obayashi et al., 2016) | Extracellular secreted protein | Oncogenic |
| COX2* | 1 (Kim et al., 2004) | Transporter or enzyme | Controversial |
| DC-SIGN | 1 (Wu et al., 2014) | Cell adhesion protein | Oncogenic |
| Gastrin** | 5 (Kato et al., 2004; Maciorkowska et al., 2006; Plonka et al., 2006; Czaja et al., 2008; Guariso et al., 2009) | Extracellular secreted protein | Oncogenic |
| EGFR | 2 (Maciorkowska et al., 2009; Ryszczuk et al., 2016) | Receptor | Oncogenic |
| Ki67 | 4 (Kim et al., 2004; Ozturk et al., 2005; Muñoz et al., 2007; Saf et al., 2015) | Not known | Not known |
| LCN2 | 2 (Ikuse et al., 2012; Obayashi et al., 2016) | Extracellular secreted protein | Controversial |
| p53*** | 2 (Ozturk et al., 2005; Saf et al., 2015) | Transcription factor | Anti-oncogenic |
| p21**** | 1 (Saf et al., 2015) | Signaling protein or kinases | Controversial |
| Pepsinogen I$ ***** | 8 (Fukuda et al., 2003; Rogers et al., 2003; Lopes et al., 2006; Roma et al., 2006; Guariso et al., 2009; Kassem et al., 2017; Nakayama et al., 2017; Kienesberger et al., 2018) | Extracellular secreted protein | GC biomarker |
| Pepsinogen II$ | 8 (Fukuda et al., 2003; Rogers et al., 2003; Lopes et al., 2006; De Angelis et al., 2007; Koivusalo et al., 2007; Guariso et al., 2009; Kassem et al., 2017; Nakayama et al., 2017) | Extracellular secreted protein | GC biomarker |
| PIM2 | 1 (Obayashi et al., 2016) | Signaling protein or kinases | Oncogenic |
| PPAR- Υ | 1 (Haruna et al., 2008) | Receptor | Controversial |
| REG3A | 1 (Obayashi et al., 2016) | Extracellular secreted protein | Controversial |
| miRNA-146a | 1 (Cortés-Márquez et al., 2018) | Post-transcriptional gene expression regulator | Controversial |
| miRNA-155 | 1 (Cortés-Márquez et al., 2018) | Post-transcriptional gene expression regulator | Controversial |
| VCAM-1 | 1 (Maciorkowska et al., 2005) | Cell adhesion protein | Oncogenic |
*1 study shows no significant mRNA upregulation in infected children. (Haruna et al., 2008). **2 studies show no significant change in expression (Nardone et al., 2001; Villarreal-Calderon et al., 2014). ***5 studies show no significant change in expression (Fukuda et al., 2003; Roma et al., 2006; Xie et al., 2006; De Angelis et al., 2007; Koivusalo et al., 2007), and 1 study show significant downregulation (Lopes et al., 2006); as most studies agree that gastrin is upregulated, it was not included in Table 2. ****1 study published before 1999 shows no significant change in expression (Jones et al., 1997). *****2 studies show no differences in serum levels compared to non-infected controls (De Angelis et al., 2007; Koivusalo et al., 2007). $1 study shows significant downregulation in gastric tissue (Ikuse et al., 2012). As most studies agree that pepsinogen is upregulated, it was not included in Table 2. No.: Number.