Prevalence and distribution of high risk human papillomavirus subtypes in invasive cervical cancer in South-West Nigeria

Context: Despite the high incidence of cervical cancer in Nigeria, there are only a few large scale population based studies on HPV prevalence and genotype distribution. Aims: This study was carried out to determine the prevalence and distribution of human papillomavirus (HPV) types in invasive cervical cancer (ICC) in Nigeria. Settings and Design: Cross sectional period prevalence study. Methods and Material: Paraffin embedded tissue blocks of two hundred and thirty five archival cervical cancers diagnosed in three participating laboratories from South West Nigeria were analyzed for the presence of HPV DNA. Statistical Analysis: Data analysis was performed with the Statistical Package STATA 10. Results: Of the one hundred and eighty seven samples that were considered appropriate for HPV detection after histological evaluation 160 (85.6%) were positive for HPV DNA. The five most common types identified as single types among HPV positive cases were HPV16 (46.9%), HPV18 (19.4%), HPV45 (11.9%), HPV35 (5.0%), and HPV31 (3.1%). Others were HPV33, 39, 51, 52, 56, 58, 59, 66, and 68. HPV16 and 18 in single/multiple infections accounted for 69.4% of the samples. Multiple infections were detected in 4.4%. All the adenosquamous and neuroendocrine carcinomas tested positive for HPV, while 86.1% and 66.7% of the squamous cell and the adenocarcinomas were positive, respectively. Conclusion: These results are in consonance with reports from all other parts of the world that HPV16 and 18 accounts for almost 70% of cervical cancers, supporting data that effective vaccination against these two types will reduce the cervical burden in South West Nigeria.