Detection of human papillomavirus from archival tissues in cervical cancer patients in Mauritius

Abstract 

Background

Around half a million new cases of cervical cancer are diagnosed worldwide each year, accounting for almost 300,000 deaths. Development of cervical cancer can be multi-factorial, but high-risk human papillomaviruses (HPV) have been associated with the aetiology of cervical cancer. It is believed that HPV DNA integrates into the host DNA causing abnormal cell growth with cells becoming carcinogenic and spreading metastatically. In Mauritius, cervical cancer account for 65% of gynaecological cancers and 3.4% of the cervical cancers are diagnosed at the stage of carcinoma in situ.

Objectives

To determine the prevalence of HPV in histological samples from patients with cervical cancer in Mauritius.

Study design

DNA from archival cervical samples from a cohort of 65 patients suffering from cervical cancer and controls from Mauritius were tested for the presence of HPV using MY09/11 and GP5+/6+ primer sets.

Results

In a cohort of 65 patients from Mauritius, diagnosed with cervical cancer in the year 2000, 19% of cervical histology sections were found to be positive for the presence of high-grade HPV, exclusively HPV18 using MY09 and MY11 primers. Only 15% of the Mauritian population is over 50 years of age, whereas 66% (35) of the diagnosed cases of cervical cancer were seen in patients above 50 years with 50% (5) affected with HPV. These findings suggest that for an infection with HPV to develop into cancer may take years if not decades. Differences were noted using two different primer sets, MY09/11 and GP5+/6+. The latter produce a much smaller amplicon (150bp) compared to the former (∼450bp). Seven additional positive cases were detected with the GP5+/6+ primer set, resulting in an apparent prevalence of 32% as compared to the 19% seen with the MY09/11 primer set. This may indicate that some degradation of the target DNA has occurred during processing and storage of histological samples.

Conclusion

Using primer sets MY09/11 and GP5+/6+, only HPV type 18 was found in the Mauritian cohort with a prevalence of 32%.

Keywords: Cervical cancer, Human papillomavirus, Bioinformatics, Mauritius