Human Papillomavirus Genotypes Distribution in High-Grade Cervical Lesions and Invasive Cervical Carcinoma in Women Living in Mauritania: Implications for Cervical Cancer Prevention and HPV Prophylactic Vaccination

Abstract

Cervical cancer related to high-risk human papillomavirus (HR-HPV) is the second female cancer in Mauritania (Northwest Sahelian Africa). We assessed the distribution of HPV genotypes in Mauritanian women with high-grade cervical intraepithelial neoplasia (CIN2/3) or invasive cervical cancer (ICC). A prospective study was conducted in the Centre Hospitalier National, Nouakchott, Mauritania, to collect cervical biopsies among women suspected of CIN2/3 or cancer. HPV DNA detection and genotyping were carried out from formalin-fixed, paraffin-embedded biopsies using multiplex PCR (Human Papillomavirus Genotyping Real-Time PCR Kit, Bioperfectus Technologies Co., Taizhou, China). Fifty biopsies were included from women (mean age: 56.7 years) suffering from CIN2/3 (28.0%) and ICC (72.0%) which corresponded to 32 (64.0%) squamous cell carcinomas (SCC) and 4 (8.0%) adenocarcinomas (ADC). HPV DNA detection was successful in 47 (94.0%) samples. The most prevalent HR-HPV genotypes were HPV-45 (40.4%), HPV-16 (38.3%), HPV-39 and HPV-52 (23.4%), HPV-33 (17.0%), HPV-18 (14.9%), HPV-35 (4.2%), and HPV-56 (2.1%). The majority (93.6%) of HPV-positive biopsies contained at least one HPV type covered by the 9-valent Gardasil-9^® vaccine, and 40.9% were infected by multiple vaccine HPV genotypes. To eradicate cervical cancer in Mauritania, prophylactic HPV vaccination must be combined with primary molecular screening of cervical HR-HPV infection.

Keywords: HPV; HPV detection and genotyping; Mauritania; cervical cancer; cervical pathology; multiplex real-time PCR.

Figure 1

Geographical map of Mauritania. Mauritania, officially the Islamic Republic of Mauritania, is a sovereign country in northwest Africa. It is bordered by the Atlantic Ocean to the West, western Sahara to the north and the northwest, Algeria to the northeast, Mali to the east and the southeast, and Senegal to the southwest. Mauritania is the 11th largest country in Africa, and 90% of its territory is situated in the Sahara Desert. Most of its population of 4.73 million inhabitants live in the temperate south of the country, with roughly one-third concentrated in the capital and largest city, Nouakchott, located on the Atlantic coast. All study participants were included in the Centre Hospitalier National in Nouakchott.

Figure 2

Distribution of HPV types by histology. The samples were classified as high-grade cervical intraepithelial neoplasia (CIN2/3) or invasive cervical cancer, including adenocarcinoma (ADC) or squamous cell carcinoma (SCC). Nota bene: According to the manufacturer’s instructions and in accordance with the HPV classification nomenclature provided by the International Agency for Research on Cancer, the BMRT HPV Genotyping Real-Time PCR Kit distinguishes 21 HPV genotypes, including 14 genotypes (HPV-16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, and -68), 3 LR-HPV types (HPV-6, -11, and -81), and 4 genotypes classified as possibly oncogenic (HPV-26, -53, -73, and -82).

Figure 3

Distribution of HPV genotypes according to their inclusion in the 9-valent Gardasil-9^® vaccine: Percentage of low-risk (LR), high-risk (HR), and possibly carcinogenic HPV genotypes in 47 cervical samples positive for HPV DNA by molecular biology according to their possible prevention by Gardasil-9^® vaccine among adult women living in Mauritania. Nota bene: The 9-valent Gardasil-9^® vaccine (Merck & Co. Inc., Rahway, NJ, USA) targets the seven HR-HPV genotypes predominantly isolated in cervical cancer (HPV-16, -18, -31, -33, -45, -52, and -58) and two LR-HPV (HPV-6 and HPV-11).

Figure 4

Percentage of low-risk (LR), high-risk (HR), and possibly carcinogenic HPV genotypes in 47 cervical biopsies samples from adult women living in Mauritania, positive for HPV DNA not targeted by the 9-valent Gardasil-9^® vaccine by using the BMRT HPV Genotyping Real-Time PCR Kit. Nota bene: The 9-valent Gardasil-9^® vaccine (Merck & Co. Inc., Rahway, NJ, USA) targets the seven HR-HPV genotypes predominantly isolated in cervical cancer (HPV-16, -18, -31, -33, -45, -52, and -58) and two LR-HPV (HPV-6 and HPV-11).