Prevalence of multiple infections and the risk of gastric adenocarcinoma development at earlier age.

Helicobacter pylori and Epstein-Barr virus are well established infections for gastric cancer development. However, the role of cytomegalovirus alone or in combination with other infections is unclear. In this case-control study, the prevalence of different infections was evaluated, and their frequency was compared with clinicopathologic features among gastric cancer patients and normal volunteers from 2012 to 2017. Approximately two-thirds (61.9%) of the gastric cancer patients had at least 1 viral infection, while viral infection prevalence in normal volunteers was only 4.7% (P = 0.021). The higher infection frequency in gastric cancer patients was observed for EBV (49.2%). No CMV DNA was detected in normal volunteers. In contrast, one-fourth of the gastric cancer patients were infected with CMV. Furthermore, CMV frequency in tumoral tissues (68.75%) was significantly higher than in nontumoral tissues (12.5%) (P = 0.0311). Although H. pylori infection was significantly lower in tumoral tissues than in nontumoral tissues (P = 0.0136), all tumoral tissues had cagA, while only 61.5% of nontumoral tissues were cagA positive. CMV-infected patients were affected 14 years earlier than uninfected, and CMV-negative patients (mean age = 56 vs. 69 and 70 years; P= 7.6×10-3 and P = 2.7×10-4, respectively). Also, EBV viral load in earlier grades and stages was more than 100-fold higher than advanced grades and stages. Our results show a high level of infections in gastric cancer. The association of these infections especially with CMV contributes to gastric adenocarcinoma development at earlier age.