Abstract
BACKGROUND: Human papillomavirus (HPV) 33 belongs to the Alphapapillomavirus 9 (α-9 HPV) species group, which also contains types 16, 31, 35, 52, 58 and 67. The purpose of this study was to investigate the genetic variations of HPV33 and to explore its carcinogenicity among women in Taizhou, Southeast China. METHODS: Exfoliated cervical cells were collected for HPV genotyping. Only single HPV33 infection cases were selected, and their E6 and E7 genes were sequenced using the ABI 3730xl sequencer and then analysed using MEGA X. RESULTS: From 2014 to 2020, a total of 185 single HPV33-positive specimens were successfully amplified. We obtained 15 distinct HPV33 E6/E7 variants, which were published in GenBank under accession numbers OQ672665-OQ672679. Phylogenetic analysis revealed that all HPV33 E6/E7 variants belonged to lineage A, of which 75.7% belonged to lineage A1. Compared with CIN1, the proportion of sublineage A1 in CIN2/3 was higher, but there was no significant difference (76.5% vs. 80.6%, P > 0.05). Altogether, 20 single nucleotide substitutions were identified, of which 6 were novel substitutions, including T196G (C30G), A447T, G458T (R117L), G531A, A704A, and C740T. In addition, no significant trends were observed between the nucleotide substitutions of HPV33 E6/E7 variants and the risk of cervical lesions. CONCLUSION: This study provides the most comprehensive data on genetic variations, phylogenetics and carcinogenicity of HPV33 E6/E7 variants in Southeast China to date. The data confirmed that cervical lesions among women in Taizhou are attributable to HPV33, which may be due to the high infection rate of sublineage A1 in the population.