Published online Mar 14, 2015. doi: 10.3748/wjg.v21.i10.2905
Peer-review started: May 9, 2014
First decision: June 10, 2014
Revised: June 27, 2014
Accepted: October 15, 2014
Article in press: October 15, 2014
Published online: March 14, 2015
Processing time: 311 Days and 23.2 Hours
AIM: To study the prevalence of human papillomavirus (HPV) in esophageal carcinoma in Tangshan, China, a high-incidence area.
METHODS: Formalin-fixed, paraffin-embedded tissue specimens from 198 patients who were pathologically diagnosed with esophageal squamous cell carcinoma from 2011 to 2013 were obtained from a pathology department in Tangshan. DNA was extracted from all 198 specimens to detect HPV by polymerase chain reaction (PCR). β-globin PCR was performed to check the quality of the DNA extraction procedure. PCR was performed to detect a wide range of HPV types, and type-specific PCR was performed to detect HPV types 16 and 18. Negative and positive controls were used for HPV 16 and 18 detection.
RESULTS: The DNA extraction method in this study appeared to be more effective than other previously reported methods. After DNA extraction, more than 98% of the tissue specimens had an acceptable result in the DNA qualification test (β-globin PCR). The overall prevalence of HPV in tumor tissues by GP6+/GP5+ PCR was 79.79%, and the prevalence of HPV types 16 and 18 was 40.40% and 47.47%, respectively. PCR demonstrated the presence of HPV, and direct sequencing confirmed the HPV genotypes. All HPV-positive PCR products were checked by DNA sequence analysis using DNAman and compared with the known HPV sequences listed in the Basic Local Alignment Search Tool database to evaluate the HPV types. This analysis confirmed the presence of HPV types 16 and 18.
CONCLUSION: DNA of high-risk HPV types 16 and 18 is present in esophageal tumors, implicating HPV as a possible etiologic factor for esophageal squamous cell carcinoma.
Core tip: China is considered to have a high incidence of esophageal cancer. Many etiologic factors for esophageal cancer have been described; in China, human papillomavirus (HPV) infection could be an important cause of esophageal cancer. Tangshan in Hebei, China has a high incidence of esophageal cancer. However, no large-sample analyses of the prevalence of HPV in this area have been performed. We analyzed the prevalence and types of HPV in 198 esophageal cancer specimens in this area of China. These findings have important significance for analysis of the various causes of local esophageal cancer.