Uneven distribution of human papillomavirus 16 in cervical carcinoma and squamous cell carcinoma in older females: A retrospective database study.

Human papillomavirus (HPV) 16 is the dominant cofactor in cervical cancer development. The present report investigated the age-specific prevalence of HPV16 in cervical carcinoma (CIS) in females attending organised cervical cancer screening. A retrospective observational study was performed based on individual data from two databases. A total of 162 females aged between 20 and 65 years from Uppsala County, Sweden with CIS and an HPV test conducted between 2010 and 2011, preceding or concomitant to CIS diagnosis, were included. Females with cervical squamous cell carcinoma (SCC; n=35) were used for comparison. In total, 96% (n=156) of females with CIS were positive for high-risk HPV; HPV16 was the most prevalent (44.5%), followed by HPV33/52/58 (19.5%), HPV31 (13.1%) and HPV18/45 (9.5%). HPV16 was most frequently detected in females with CIS aged between 20 and 29 years (73.6%) and least frequently detected in those aged between 50 and 65 years (33.3%), with a statistically significant age-specific difference (P=0.001). Among the HPV16-positive females, multiple infections were most frequent in the younger age groups. The prevalence of HPV16 in females with CIS decreased with age, whereas a high prevalence of HPV16 remained in females with SCC. These results may indicate that HPV16 has increased oncogenic potential in older females.