Type-Specific Human Papillomavirus Distribution in Invasive Squamous Cervical Carcinomas in Tunisia and Vaccine Impact


Background: High risk human papillomaviruses (HPVs) are the leading cause of cervical cancer (CC) andPap smear screening has not been successful in preventing CC in Tunisia. HPV vaccination that targets HPV16and 18 offers a new efficient prevention tool. Identification of HPV types in CC is thus essential to determinethe impact of HPV vaccine implementation. The aim of this study is to provide specific data from Tunisia.Materials and
Methods: A total of 89 histological confirmed paraffin embedded samples isolated from patientswith CC diagnosed between 2001 and 2011 were collected from five medical centres from Northern and SouthernTunisia. HPV DNA was detected using a nested PCR (MY09/MY11-GP5+/GP6+) and genotyping was assessedusing a reverse blot line hybridisation assay that enables the detection of 32 HPV types.
Results: HPV DNA wasdetected in all samples. Twelve high risk types were detected; HPV16 and/or 18 were predominant, accountingtogether for 92.1% of all the CC cases (HPV16: 83.1%). Single infections accounted for 48.8% of the cases andwere mostly linked to HPV 16 (32.6%) and less frequently to HPV 18 (2.4%). The other high risk HPV singleinfections were linked to HPV 35 (4.6%), 45 (4.6%), 58 (2.3%) and 59 (2.3%). Multiple infections with mixingof 2 to 4 genotypes predominately featrued HPV16 and/or 18 with HPV 35 and 45 (96.6 %) and less frequentlywith HPV 59, 40, 66, 73 and 58. There was no statistically significant variation in the relative distribution ofHPV types with age.
Conclusions: These results strongly indicate that prophylactic HPV vaccines can have amajor impact in preventing CC in Tunisia