Page 137 - Helicobacter pylori and Gastric Cancer: From Tumor microenvironment to Immunotherapy

incidence and cancer[28]. In the present study we exploited this situation to study the relationship between selected virulence genes of H. pylori and the clinical status. Our results clearly support the notion that further studies aimed at establishing the negative predictive value of the presence of babA2 and babB alleles for GC development are warranted.
The cagE is a pathogenicity biomarker of H. pylori. A survey of previous studies suggested that the cagE prevalence is different around the world [29]. The general importance of cagE is best illustrated by its high frequency in GC patients as demonstrated by studies performed in patient populations derived from India (100%), Turkey (81.8%) and Thailand (93.8%)[30]. however, the prevalence of cagE gene in this study was only 55.9%, markedly different from the results obtained in the aforementioned countries [31]. In the present study cagE-positive isolates were slightly more detected in isolates from peptic ulcer dyspepsia patients PUD (68.4%) patients, but the potential significance of this finding, if any, remains to be established. The prevalence of cagA gene in our cohort is 70.6%, which resembles the situation in Western countries (Yamaoka et al., 2002), but is markedly lower than that observed in East Asian countries where cagA is present in more than 90% of cases (Uchida et al., 2009). Like cagE, cagA-positive isolates were enriched in samples obtained from peptic ulcer dyspepsia patients, albeit not in a statistically significant manner. Nevertheless, our findings support previous studies (Uchida et al., 2009, Wu et al., 2003) and should prove interesting to include our data in a meta-analysis of virulence genes in this respect. Our results show that the prevalence of iceA1 and iceA2 genes in isolates was 42.2% and 13.2%, respectively. These results are in agreement with previous studies showing that the iceA1 gene is prevalent in Japanese, Korean and The Dutch patients (Ito et al., 2000, Ko et al., 2008, Shiota et al., 2013) conversely the iceA2 allele was predominant in the United States and Colombia. In our cohort, the relation of the presence of iceA1 and the development of cases to gastric cancer was statistically significant (P=0.008). But our data showed that there was no significant association between iceA2 and GC compared with PUD or NUD. However, several studies have reported different results, as the iceA2 gene was detected to be predominant genotype in these studies (Aghdam et al., 2014, Biernat et al., 2014).
The babA is one of the mediators for the attachment to gastric cells by H. pylori[32]. More recent analysis of babA2 as a virulence marker has produced conflicting data on the usefulness of babA2 expression in predicting clinical outcome, which is most
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