Detection of HPV16 in Esophageal Cancer in a High-Incidence Region of Malawi

Abstract

This study was designed to explore the role of human papillomavirus (HPV) in esophageal squamous cell carcinoma (ESCC). Fifty-five patients receiving diagnostic upper gastrointestinal endoscopy at Zomba Central Hospital or Queen Elizabeth Hospital in Blantyre (Malawi) in 2010, were included in our study. Formalin-fixed paraffin-embedded biopsies were collected for histopathological diagnosis. HPV DNA was detected using multiplex Quantitative PCR (qPCR) and in situ hybridization (ISH). p16INK4a staining served as a surrogate marker for HPV oncogene activity. Cell proliferation was determined by Ki-67 staining. Human immunodeficiency virus (HIV) status was evaluated by serology. Data on the consumption of alcohol and tobacco, and history of tuberculosis (TBC), oral thrush, and Herpes zoster, were obtained by questionnaire. Forty patients displayed ESCC, three displayed dysplastic epithelium, and 12 displayed normal epithelium. HPV16 was detected in six ESCC specimens and in one dysplastic lesion. Among HPV-positive patients, viral load varied from 0.001 to 2.5 copies per tumor cell. HPV DNA presence could not be confirmed by ISH. p16INK4a positivity correlated with the presence of HPV DNA (p = 0.03). Of particular note is that the Ki-67 proliferation index, in areas with diffuse nuclear or cytoplasmatic p16INK4a staining ≥50%, was significantly higher in HPV-positive tumors compared to the corresponding p16INK4a stained areas of HPV-negative tumors (p = 0.004). HPV infection in ESCC was not associated with the consumption of tobacco or alcohol, but there were significantly more patients drinking locally brewed alcohol among HPV-positive tumor patients compared to non-tumor patients (p = 0.02) and compared to HPV-negative tumor patients (p = 0.047). There was no association between HIV infection, history of TBC, Herpes zoster, oral thrush, or HPV infection, in ESCC patients. Our indirect evidence for viral oncogene activity is restricted to single tumor cell areas, indicative of the role of HPV16 in the development of ESCC. The inhomogeneous presence of the virus within the tumor is reminiscent of the “hit and run” mechanism discussed for β-HPV types, such as HPV38.

Esophageal squamous cell cancer susceptibility: Environmental and nutritional associations reveal a universally applicable pathogenesis scenario (Review)

“…Unlike the high prevalence of HPV in cancer of the cervix, the detection rate in ESCC is highly variable even within high-risk areas, averaging 19.8% in Africa and 27.7% worldwide. The major oncogenic strain, HPV16, has only been detected in 11.4% of ESCC cases (93,94). HPV viral genomes per cell are very low, if present at all, and the sequencing of viral-cellular DNA junctions has not been validated (93).…”

“…The major oncogenic strain, HPV16, has only been detected in 11.4% of ESCC cases (93,94). HPV viral genomes per cell are very low, if present at all, and the sequencing of viral-cellular DNA junctions has not been validated (93). Several other squamous cell cancers have a positive prognosis if found to be HPV-positive; however, this is not the case with ESCC (94,95).…”

Esophageal squamous cell carcinomas in a Malaysian cohort show a lack of association with human papillomavirus

“…deferred making their conclusions and instead advised further research to be undertaken to quantify HPV in ESCC and to conduct large population‐based case–control studies to provide a better understanding of the situation. Despite all the above, the uncertainty persists and to date reports have continued to surface associating HPV with esophageal cancers . Arguments that the difference in the stringency of measures used to control nucleic acid contamination during the HPV DNA analyses and disparities in the sensitivity of HPV detection methods may account for the variability in reported rates of HPV across the globe seem valid .…”

“…Despite all the above, the uncertainty persists and to date reports have continued to surface associating HPV with esophageal cancers. 13 Arguments that the difference in the stringency of measures used to control nucleic acid contamination during the HPV DNA analyses and disparities in the sensitivity of HPV detection methods may account for the variability in reported rates of HPV across the globe seem valid. 8,9 Yet other researchers are of the opinion that the different detection methods used do not necessarily result in the variability of HPV detection rates in esophageal cancer populations.…”

Human Polyomaviruses and Papillomaviruses

“…A study with 40 esophageal squamous cell carcinoma specimens from patients from Malawi demonstrates that six samples (15%) were positive for HPV16 [20]. One of three patients with dysplastic epithelium of the esophagus was also HPV16-positive, while none of the normal epithelium samples ( n = 12) contained HPV16 DNA.…”