RESUMEN
BACKGROUND: Cervical cancer is the third most common cancer among women worldwide, but particularly affects women living in sub-Saharan Africa. Screening and vaccination programs are two prevention approaches that can reduce cervical cancer incidence. However, effective vaccination campaigns require better knowledge of the prevalence of the main human papillomavirus (HPV) genotypes reported in high-grade neoplastic lesions and invasive carcinomas in women. METHODS: All samples collected in this study were processed using standard histopathological methods with haematoxylin and eosin staining of the sections. Areas with abnormal cells were then identified. The HPV genotype was determined on the DNA extracted from the same sections using nested PCR followed by amplicon sequencing and real-time PCR specific to five different HPV genotypes (16, 18, 33, 45 and 58). RESULTS: A total of 132 Gabonese patients with high-grade neoplastic lesions were included in this study; 81% were squamous cell carcinomas (SCC). At least one HPV was detected in 92.4% patients; HPV16 (75.4%) was the most frequent genotype, followed by HPV18, 58, 45, 33 and 35. Moreover, histological analysis showed that SCC samples had 50% and 58.2% stage III and IV tumor cells, respectively, according to the FIGO classification. Finally, 36.9% of these stage III and IV patients were less than 50 years old. CONCLUSIONS: Our results confirm the high prevalence of HPV16 and 18 genotypes among high-grade lesions in Gabonese women. This study confirms the need for a national strategy for early screening of precancerous lesions associated with a broad national vaccination program among non-sexually active women to significantly reduce the long-term cancer burden.
RESUMEN
BACKGROUND: The human papillomavirus (HPV) is the causative agent of cervical cancer, which is the leading cancer-related cause of death for women in Sub-Saharan Africa. In 2013, the Gabonese Ministry of Health and the Sylvia Bongo Ondimba Foundation implemented cervical cancer screening programs based on the detection of cancerous lesions by visual inspection with acetic acid and/or Lugol's iodine (VIA/VILI). This pilot study was set up to determine the HPV profile and analyze the nucleotide sequence variation of HPV16 circulating in patients with cervical abnormalities detected by VIA/VILI testing. METHODS: The cervical abnormalities observed upon VIA/VILI were confirmed by liquid-based cytology for all tested women. Nested PCR using the MY09/11 and GP5+/6+ primer sets was used to detect HPVs present in the extracted DNA. HPV genotypes were determined after sequencing of amplicons based on a high-throughput sequencing approach. For isolates of the HPV16 genotype, the E6 gene and the long control region (LCR) were directly sequenced using Sanger method. RESULTS: The study included 87 women who showed a positive VIA/VILI result. Cervical abnormalities were found in 40.23 % of women and 40 % were classified as high-grade lesions. The HPV detection rate was 82.9 % among women with abnormal cytology. Among all the identified high-risk HPV genotypes, HPV16, 18 and 33 were the most frequent. Multiple HPV infections were observed in 42.31 % of HPV-infected women. Analysis of the HPV16 sequence variation in the E6 gene and in the LCR showed that 85.3 and 14.7 % belonged to the African and European lineages, respectively. Among the African branch variants, Af2 was the most frequently identified in this study. CONCLUSION: This study offers the first report of the HPV detection rate and molecular epidemiology among Gabonese women with a positive result in a VIA/VILI screening test. Moreover, data on the HPV16 sequence variation confirm the predominance of African variants in high-grade lesions.