Gastrointestinal cancers are one of the most common cancers in humans and their pathogenesis is believed to be associated with different factors. Some viral infections are carcinogenic in nature and can cause gastrointestinal tract (GIT) neoplasms. However, there are insufficient evidences confirming this effect. Therefore, we aimed to investigate the relationship between Human Papillomavirus (HPV), Herpes Simplex virus (HSV), Epstein-Barr virus (EBV), Cytomegalovirus (CMV), John Cunningham Virus (JCV) and gastrointestinal cancer (GIT).

This case-control study was carried out at two educational centers of Qa'im Hospital and Imam Reza Hospital, Mashhad, Iran, from 2017 to 2018. Seventy-five patients with GIT cancers, including stomach (n=26), esophagus (n=27), and colorectal cancers (n=27), as the case group, and 81 subjects with gastrointestinal complaints that did not have GIT cancers as the control group, were enrolled. The Real Time-PCR was used to detect DNA of viruses. Data analysis was performed using SPSS 22 software.

The results showed that the JCV expression among colorectal and esophageal cancer patients was more frequent than that among control subjects (40.74% versus 7.69%; Odds Ratio (OR) = 6.75, 18.52% versus 0%; OR = 10.23, respectively). The frequency of EBV in gastric cancer patients was also higher than that of the control group (15.38% versus 0%, OR = 10.82). Besides, HPV-DNA expression in gastric and colorectal cancer patients was higher than that among control patients (15.38% versus 0%; OR =9.447, 22.22% versus 0%, OR =13.56 respectively).

Our data suggest that both JCV and HPV infections may be associated with colorectal and esophageal cancers risk, and EBV infection may be associated with an increased risk for gastric neoplasm.