HPV genotype distribution among women with normal and abnormal cervical cytology presenting in a tertiary gynecology referral Clinic in Ethiopia

Abstract

Background: Cervical cancer is the second most prevalent cancer among women of child-bearing age in Ethiopia. The aim of this study was to determine human papilloma virus (HPV) genotype distribution among HIV-negative women with normal and abnormal cervical cytology results. Methods: We investigated a consecutive of 233 HIV-negative women between December 2008 and March 2009 presenting in a Tertiary Gynecology Referral Clinic in Ethiopia. Screening was done by Pap cytology and HPV detection and genotyping method was nested PCR (direct amplification with MY09/MY11 primers, followed by nested amplification with GP5/GP6 primers) and sequencing of the nested products. Sequencing of the non-purified nested PCR products was performed following re-amplification with Big dye terminator, using the GP6 primer. Results: Of the 233 study participants, 92 (39.5%) had abnormal cytology. All women with abnormal cervical cytology had positive HPV DNA compared to only 48.9% of those presenting with normal cytology. Of these women, the frequency of high-risk (HR)-HPV was 83.2% and its prevalence in women with abnormal cervical cytology was significantly higher than those with normal cytology (92.4% vs. 71%, p < 0.0001). The most frequent genotypes identified were HPV16 (44.1%), followed by HPV35 and HPV45 (each 6.2%), HPV31 (4.4%), HPV56 (3.7%), HPV18 and HPV59 (each 3.1%), HPV58 (2.5%) and HPV39 (1.9%). While the most common HR-HPV infections among women with normal cytology were HPV16 (20.3%), followed by HPV35 (8.7%), HPV56 and HPV58 (each 5.8%), HPV18, HPV31 and HPV39 (each 4.4%), HPV45 (2.9%) and HPV59 and HPV68 (each 1.5%), the most common HR-HPV infections in women with abnormal cytology included HPV16 (62%), followed by HPV45 (8.7%), HPV 31, HPV35 and HPV59 (each 4.4%), and HPV18, HPV52 and HPV56 (each 2.2%). We also noted low prevalence of multiple HPV infections in women with normal or abnormal cytology. Multivariable logistic analysis showed that residing in rural area (OR 3.24, 95% CI: 1.13-9.30), being multipara (OR 7.35, 95% CI: 1.78-30.38) and having abnormal cervical cytology results (OR 6.75, 95% CI: 1.78-25.57) were all independently associated with HPV16 genotype. Conclusions: Our study revealed a significant risk of infection with HR-HPV, in particular with HPV16 genotype, in women attending a referral center in Ethiopian women presenting with or without abnormal cervical cytology. Moreover, Pap smear cytology missed a significant proportion of women compared to those who were identified by PCR for HR-HPV infections. In addition, the PCR method we used was not suitable for sensitive detection of co-existent multiple infections. Data from the present study indicate that currently available HPV vaccines could prevent nearly 67% of all cervical cancer cases in women in Ethiopia.