Objectives: Persistent infection with specific genotypes of human papillomaviruses (HPVs) is the main cause of invasive cervical cancer (ICC). Only a few of the various HPV types account for most of the cases worldwide, and geographical differences in their distribution are evident. Data from locally prevalent genotypes are essential in view of introduction of HPV type-specific prophylactic vaccines.
Methods: In this work, we have investigated HPV type distribution in samples of ICC cases that occurred in Uruguayan women. DNA extracted from ICC treated in Centro Hospitalario Pereira Rossell of Montevideo between 1999 and 2007 were analyzed. Search and typing were performed by polymerase chain reaction using generic GP5+/GP6+ primers and specific primers for HPV types 16, 18, 33, and 45. Positive GP5+/GP6+ samples, which were negative for all 4 high-risk HPV-specific types screened were further analyzed by sequencing.
Results: Human papillomavirus DNA sequences were found in 163 (92.6%) of 176 cases. The most prevalent genotypes were HPV16 (67.6%) and HPV18 (8.5%) followed by HPV45 (6.8%) and HPV33 (3.4%), as single or mixed infection. Other less frequent genotypes were HPV31, HPV35, HPV39, HPV51, HPV52, HPV58, HPV66, and HPV73. The viral type could not be determined (HPV X) in 1 case (0.6%) of the HPV DNA-positive cervical cancers and double infections were found in 1.7% of the cases. The higher percentage of most aggressive HPV (16/18/45) genotypes was detected in cases diagnosed at younger than 60 years old, whereas these genotypes were less frequent in older patients.
Conclusion: We conclude that HPV types 16, 18, and 45 have a very high prevalence in ICC of Uruguayan women. Results provide evidence that 16 of 18 infections are more aggressive, but most cancers could be vaccine preventable.