Genetic variability in E5, E6, E7 and L1 genes of human papillomavirus type 31.

Human papillomavirus (HPV) type 31 is an important pathogenic subtype associated with cervical cancer. The aims of the present study were to analyze E5, E6, E7 and L1 gene mutations of HPV‑31 among females, and to elucidate the evolutionary associations between them. In total, 87 positive samples were collected. The E5, E6, E7 and L1 genes were amplified by polymerase chain reaction and sequenced. Subsequently, two phylogenetic trees were constructed from the nucleotide sequences of the E5, E6 and E7 and the L1 variants of HPV‑31. In total, 31 mutation sites of E5, E6 and E7 genes were identified, of which 16 were non‑synonymous. T4053A (F80I), C285T (H60Y), C520T (A138V) and A743G (K62E) were the most common non‑synonymous mutations. A total of 30 mutation sites of L1 genes were identified, of which four were non‑synonymous. The most common non‑synonymous mutations of L1 genes were A6350G (T29A) and C6372A (T36N). By phylogenetic analysis, A and C variants were most frequently detected, while B variants were less frequently detected in this population. The sequence variation data obtained in the present study provides a foundation for future research regarding HPV‑induced oncogenesis, and may prove valuable for developing diagnostic probes and in the design of HPV vaccines for targeted populations.