Investigation on the presence, expression and pathogenesis of High-Risk Human papillomavirus in upper gastrointestinal tissue: a UK Based Study

Human papillomavirus (HPV) is one of the most prevalent sexually transmitted infections worldwide and is a well-established aetiological factor in several malignancies, particularly cervical and oropharyngeal cancers. Despite extensive investigation, the role of high-risk HPV (HR-HPV) in upper gastrointestinal (UGI) tissues, including the oesophagus and stomach, remains controversial due to inconsistent findings across different geographical regions. To our knowledge, no comprehensive study has evaluated the HR-HPV DNA presence, expression, associated histopathological features and host molecular differences in both cancerous and noncancerous upper gastrointestinal tissues from a United Kingdom population.

This study aimed to investigate the presence and expression of fourteen HR-HPV genotypes in cancerous and noncancerous oesophageal and gastric tissues. A total of 169 fresh UGI tissue specimens were collected, comprising 88 oesophageal and 81 gastric samples. HR-HPV DNA detection and genotyping were performed using real-time multiplex PCR, while HPV E7 and p16 protein immunoreactivity and koilocytotic changes were assessed in selected oesophageal specimens. Exploratory RNA sequencing was also performed on three HPV DNA positive and three HPV DNA negative noncancerous oesophageal specimens to investigate host gene expression differences associated with HPV DNA positivity.

HR-HPV DNA was detected in 5/88 oesophageal specimens (5.7%; 95% CI: 1.9–12.8%). All five positive specimens occurred in the noncancerous group (5/69; 7.2%; 95% CI: 2.4–16.1%), while no HR-HPV DNA was detected in the 19 cancerous oesophageal specimens (0%; 95% CI: 0.0–17.6%). HPV 56 was detected in all five positive specimens, with HPV 18 additionally detected in one specimen. HR-HPV 56 was detected as the most prevalent genotype in this cohort.

E7 immunoreactivity was observed in all five HPV DNA positive specimens and was absent from the HPV DNA negative samples, supporting viral protein expression and biological activity in the specimens examined. p16 immunoreactivity was present in three of the five HPV DNA positive specimens, and koilocytotic changes were observed in all four HPV DNA positive specimens available for histological assessment. Taken together, these findings indicate that HPV DNA detection was accompanied by viral protein expression and supportive cellular changes in the specimens examined. These findings are supportive but do not establish persistent infection, viral integration, transforming infection or causation. The exploratory transcriptomic analysis revealed differential gene expression between HPV DNA positive and HPV DNA negative noncancerous oesophageal tissues. Genes involved in cell cycle regulation and DNA replication pathways were upregulated in HPV DNA positive samples.

No HR-HPV DNA was detected in the 81 gastric specimens examined (0%; 95% CI: 0.04.5%). This finding shows no detectable HR-HPV DNA in this UK cohort using the assay applied, but it does not exclude a very low prevalence or viral burden below the assay detection limit. Overall, this study provides UK specific evidence of HR-HPV DNA and viral protein expression in a small group of noncancerous oesophageal specimens, but it does not establish HPV driven oesophageal disease or carcinogenesis.