A retrospective cohort study of human papillomavirus (HPV) genotypes in women with abnormal Pap smear cytology in Turkey

Abstract

Background/Aim: The most common genotypes of human papillomavirus (HPV) in patients with cervical cancer worldwide are HPV16 and HPV18. The persistence of these genotypes is associated with cervical cancer and detection, and HPV genotyping, particularly in women with abnormal Pap smears, has become a crucial tool for cervical cancer screening, diagnosis and management. We evaluated the overall prevalence of HPV in women with abnormal Pap smear cytology and also investigated age-specific HPV prevalence and HPV genotype distribution. Methods: We analyzed 716 cervical smear specimens in this retrospective cohort study. Cytological diagnoses of typical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesions (LSILs), and high-grade squamous intraepithelial lesions (HSILs) were made utilizing the Bethesda System. The Papanicolaou method was used for the staining of the Pap smears. The specimens were pre-screened for HPV DNA positivity using an HC2 assay (Qiagen, USA). After the pre-screening, a Cobas 4800 HPV test system (Roche Diagnostics GmBH, Germany) was used to genotype the HPV-positive samples. Results: Of the 716 cervical smear samples, 520 (72.6%) were found to be HPV-negative. Among the HPV-positive samples, 106 (23.2%), 57 (28.8%) and 33 (53.2%) were identified from 456 ASCUS, 198 LSIL and 62 HSIL cases, respectively. These findings revealed a gradual decrease in HPV prevalence with increased cytological grade (P<0.05). For high-risk, low-risk and high-risk/low-risk HPV types, 76 (38.8%), 78 (39.8%) and 42 (21.4) were positive according to the HC2 assay, respectively (P<0.05) Only 117 of the 196 HPV-positive samples were found to be HPV-positive with the Cobas 4800 HPV test system. HPV16 was the most prevalent type detected by the Cobas 4800 HPV test: 55 out of 117 HPV-positive smear samples across all age groups (47%). HPV16 was significantly more frequently detected in the HSIL samples than HPV18 (P<0.05). The prevalence of HPV was the highest in women with ages between 29 and 38 (71/196, 36.22%) and declined with age. Conclusion: We found that HPV16 and HPV18 were the most prevalent genotypes of HPV in a cohort of Turkish women; HPV16 was most frequently detected in HSIL samples from women with ages between 29 and 38. We conclude that investigating the incidence of HPV16 and HPV18 genotypes will be important for implementing new programs and protocols to reduce the incidence of cervical cancer. These data may contribute to the development of preventive strategies to reduce the cervical cancer burden in Turkey.