Human papillomavirus type 16 is an important infectious factor in the high incidence of esophageal cancer in Anyang area of China

To investigate the potential role of human papillomavirus (HPV) infection in the pathogenesis of esophageal carcinomas in the Anyang area of China, we have evaluated specimens collected by balloon cytology examination from volunteers in two regions with significantly different incidences of esophageal carcinoma. 138 donors were from a village in a county with an esophageal carcinoma (EC) age-adjusted mortality rate of 132 x 10(5), the remaining 68 were resident in a second village from another county with an EC mortality rate of 52 x 10(5). Specimens were evaluated using both polymerase chain reaction (PCR) amplification and irt situ hybridization (ISH) protocols, PCR results showed that the prevalence of the human papillomavirus type 16 (HPV-16) Ed gene in the high incidence area was 1.9-fold higher than that of the low incidence area (72 and 37%, respectively, P < 0.01). Moreover, the positive rate corresponded with pathology grade. Similar results were obtained with the HPV-16 E7 gene. As the cells undergoing cytopathological progress, the HPV-16 E6 positive rate was increased, in both villages, In contrast to HPV-16 Ed and E7, detection of the HPV L1 gene was consistently lower, and its prevalence decreased with increasing dysplasia grades (P < 0.05), By ISH analyses, the expression rate of HPV-16 Ed in the specimens collected from the high incidence area was 2.2-fold higher than those from the low incidence area (49 versus 22%, respectively; P < 0.05), and transcription of the Ed gene paralleled cytopathology, HPV-18 was also detected in 17 and 15% of the specimens from the high and low incidence areas, respectively, but most of these samples were also simultaneously HVP-16 positive. These results suggest that HVP-16 plays a causative role in the high incidence of esophageal cancer in the Anyang region of China.