Genetic Diversity of HPV16 and HPV18 in BrazilianPatients With Invasive Cervical Cancer

Abstract

Cervical cancer is the fourth most common cancer among women, and 70–80% of these cancers are associated with two human papil lomavirus types: HPV16 and HPV18. Several studies have reported that intra-type diversity is associated with the progression of infec tion to invasive cancer. Herein, we report the genetic diversity of HPV16 and HPV18 in a cohort of 594 Brazilian women with invasive cervical cancer and describe the prevalence of lineages and intra-type diversity prior to the implementation of the public immuniza tion program in Brazil. HPV detection and genotyping were performed using PCR, PGMY/GP primers, and DNA extracted from fresh tumors. The HPV16 (378 women) and HPV18 (80 women) lineages were identified by PCR and sequencing of the LCR and E6 fragments, followed by SNV comparison and phylogenetic analysis. In our cohort, was found a higher frequency of the lineage A (in 217 women), followed by lineage D (in 97 women) and lineages B and C (in 10 women each) for HPV16; and a higher frequency of lineage A (in 56 women) followed by lineage B (in 15 women) in HPV18. The genetic diversity of HPV16 indicated a recent expan sion of specific variants or a selective advan tage that is associated with invasive cancer; this pattern was not observed for HPV18.