Specific Human Papillomavirus Genotypes Isolated from Cervical Cancer Specimens in Calabar, Nigeria

Aim: To determine specific human papillomavirus genotypes isolated from cervical cancer specimens in Calabar, Nigeria.

Study Design: This is a cross-sectional study of archival paraffin-embedded tissue block of invasive cervical cancer specimen.

Study Place and Period: This study was done at the department of pathology, University of Calabar Teaching Hospital, Calabar for cervical cancer specimen between January 2006 and December 2014.

Methodology: Paraffin-embedded tissue block of invasive cervical cancer specimen from the study period (January 2006 to December 2014) were collected. Primary socio-demographic data were obtained from medical records in the department (such as surgical pathology register, histopathology request forms). Sections of the tissue were obtained from the blocks. The deoxyribonucleic acid (DNA) was extracted and a polymerase chain reaction was done. Then DNA enzyme immunoassay and reverse hybridisation line probe assay were performed for human papillomavirus DNA detection and specific HPV genotyping.

Results: Two hundred and forty-two cervical cancer specimens were analysed. The age range of the subjects is between 32 and 78 years with a mean age of 47.4 years. Two hundred and twenty-one (91.30%) of these samples were HPV DNA positive. Seven high-risk HPV (hrHPV) genotypes were isolated from these specimens which include types 16, 18, 31, 33, 35, 59 and 68/73.

The prevalence of the specific HPV genotype in invasive cervical cancer specimens are as follows: type 16 has the highest prevalence of 34%, followed by type 31 with a prevalence of 31.2%, type 18 with a prevalence of 16.3%, type 33(8.3%), Type 35(7.7%), Type 59(4.1%) and type 68/73 has the least prevalence of 1.8%. Multiple infections represented 4.10% of all the HPV DNA positive samples. Various infections with types 16 and 31 have a prevalence of 2.7% while multiple infections with types 16 and 35 have a prevalence of 1.4%.

Conclusion: The knowledge of the prevalent high-risk HPV in cervical cancer in our environment would enhance the development of a more appropriate and effective vaccine against HPV involved in the aetiology of cervical cancer.