Human Papillomavirus Type 16 L2 Gene Sequence Variation Analysis in Indonesian Cervical Cancer Specimens

Human papillomavirus type 16 (HPV16) is the most prevalent etiology of cervical cancer in Indonesian women. The L2 minor capsid protein has considerable potential as a broad-protective antigen target of the cervical cancer vaccine strategies, yet the data on L2 gene variation is still minimal. In this research, we determined the variations of the HPV16 L2 gene sequences in Indonesian cervical cancer specimens.

We cross-sectionally observed 23 DNA isolates of HPV16 positive cervical cancer specimens stored in the laboratory of the Center for Diagnostic and Research on Infectious Diseases (PDRPI Lab), Faculty of Medicine, Universitas Andalas, Padang, Indonesia. We detected and amplified the HPV16 L2 gene sequences in the samples, followed by sequencing, DNA alignment, single nucleotide polymorphisms (SNPs) analysis, and phylogenetic tree reconstruction.

As many as 35 SNPs were found, consist of 18 synonymous SNPs (sSNPs) and 17 non-synonymous SNPs (nsSNPs). Amino acid variations were mostly detected at S269P (100%) and L330F (43.48%) with no variation in the immuno-protective region near L2 N-terminus. A total of 5 HPV16 phylogenetic sub-lineages were found closely related to A1 (n=5), A2 (n=12), A3 (n=2), A4 (n=3), and C (n=1).

The variations of HPV16 L2 gene sequences are mainly located in the central region of the L2 sequences, and the cross-protective region near the L2 N-terminus is remarkably conserved. This study should enhance the information about HPV16 L2 gene variation in Indonesia.