The association of human papillomavirus type 16 E2 variations with cervical cancer in a Han Chinese population

Genetic variability of the HPV16 early genes and LCR. Present and future perspectives

Human papillomavirus 16 (HPV16) infection is the aetiologic factor for the development of cervical dysplasia and is regarded as highly carcinogen, because it is implicated in more than 50% of cervical cancer cases, worldwide. The tumourigenic potential of HPV16 has triggered the extensive sequence analysis of viral genome in order to identify nucleotide variations and amino acid substitutions that influence viral oncogenicity and subsequently the initiation and progression of cervical cancer. Nowadays, specific mutations of HPV16 DNA have been associated with an increased risk of high-grade squamous intraepithelial lesions and invasive cervical cancer (ICC) development, including E6: Q14H, H78Y, L83V, Ε7: N29S, S63F, E2: H35Q, P219S, T310K, E5: I65V, whereas highly conserved regions of viral DNA have been extensively characterised. In addition, numerous novel HPV16 mutations are observed among the studied populations from various geographic regions, hence advocating that different HPV16 strains seem to emerge with different tumourigenic capacities. The present review focuses on the variability of the early genes and the long control region, emphasising on the association of specific mutations with the development of severe dysplasia. Finally, it evaluates whether specific regions of HPV16 DNA are able to serve as valuable biomarkers for cervical cancer risk.

Analysis of genetic variation in human papillomavirus type 16 E1 and E2 in women with cervical infection in Xinjiang, China

BACKGROUND

Xinjiang is one of the regions with a high incidence of cervical cancer, and the genetic variation of human papillomavirus may increase its ability to infect the human body and enhance virus-mediated immune escape ability.

METHODS

Sanger sequencing of the HPV16 genome from 165 samples positive for HPV16 infection and phylogenetic analysis of the E1 and E2 genes revealed the gene polymorphism of HPV16 in Xinjiang.

RESULTS

The results showed that there were 109 samples with variations in HPV16 E1, 48 sites with nucleotide variations (19 missense variations and 29 synonymous variations), and 91 samples with variations in HPV16 E2, 25 sites with nucleotide variations (20 missense variations and five synonymous variations).

CONCLUSIONS

From the phylogenetic tree results, 149 samples were of the European variant and 16 samples were of the Asian variant. No African or North American/Asian variant types were found.

Comparison of Cervical Levels of Interleukins-6 and -8 in Patients with and without Cervical Intraepithelial Neoplasia

Introduction:

Interleukins-6 and -8 are two pro-inflammatory cytokines increasing in serum and local levels under malignant conditions. There are limited evidences on the association between cervical level of these two factors and cervical intraepithelial neoplasia (CIN). So, this study aimed to explore the association between cervical levels of IL-6 and IL-8 with cervical premalignant lesions.

Methods:

The present case-control study was conducted on married women undergone Pap smear for routine screening in two groups as the group with CIN (n=100) and the healthy control group (n=100). Cervical secretions were collected using sterile swab and the levels of IL-8 and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). The obtained data were analyzed by SPSS software.

Results:

The mean cervical IL-6 level was 568.66±594.62 pg/ml in the patients with CIN and 212.7±213.9 pg/ml in the controls (P <0.001). The cervical IL-8 levels in the case and control groups were measured to be 1320.43±876.5 pg/ml and 1053.59±747.64 pg/ml, respectively (p=0.02). By modifying the confounding size effect of the age and marital duration, it was determined that cervical levels of IL-6 and IL-8 were both associated with CIN.

Conclusion:

Our results showed that the cervical levels of IL-6 and IL-8 are associated with CIN independent of age and marital duration.

Association of Human Papillomavirus Type 16 Long Control Region Variations with Cervical Cancer in a Han Chinese Population

Objective: High-risk human papillomavirus (HPV) E6 and E7 proteins are the major oncoproteins involved in the tumorigenesis of cervical cancer. The long control region (LCR) in HPV plays an important role in regulating the expression of the E6 and E7 oncogenes. In the current study, we investigated the association of HPV16 LCR variations with cervical cancer. Methods: A total of 139 HPV16-positive cervical cancer patients (case group) and 116 HPV16-positive asymptomatic individuals (control group) were enrolled in the current study. Then, the HPV16 LCR was sequenced to determine the association between LCR variations and cervical cancer. Results: In the current study, HPV16 A1-A3 (19.4%), A4 (78.4%) and D3 (2.2%) variants were found in the case group. However, only A1-A3 (34.5%) and A4 variants (65.5%) were found in the control group. The distribution of the HPV16 variants between the case and control groups was significantly different (P=0.009). Moreover, a total of eleven variations (A7167G, A7173C, C7176T, C7200T, T7269C, C7286A, C7729A, C7763T, A7841G, G7867A and T24C) were significantly different between the case and control groups (P<0.05). For the sub-lineage analysis, only C7873G variations were significantly different between the case and control groups in the A4 (As) variant (P=0.039). Conclusion: Our results showed that specific variations in the HPV16 LCR were associated with cervical cancer. Our study will provide a good reference for further understanding of the relationship between HPV16 LCR variation and cervical cancer.

Human papillomavirus type 16 E6 and E7 gene variations associated with cervical cancer in a Han Chinese population

BACKGROUD

Human papillomavirus type 16 (HPV16) is a high-risk HPV subtype and a potent carcinogen. The HPV16 E6 and E7 genes are considered oncogenes that play a core role in the development of cervical cancer.

METHODS

In the current study, we enrolled 97 HPV16-positive cervical cancer patients (case group) and 136 HPV16-positive asymptomatic individuals (control group) in a study to analyse the association between HPV16 E6 and E7 gene variations and cervical cancer.

RESULTS

Our results showed that three HPV16 sub-lineages (A1-A3, A4 and D3) were present; the distribution of these variants between the case and control group was not significantly different (P = 0.178). When the distribution of the HPV16 E6 and E7 gene variations was compared, the distribution of only A131C (R10R) in the E6 gene showed a different trend between the case and control groups and C749T (S63F) in the E7 gene was significantly different between the case and control groups (P = 0.071 and P = 4.861 × 10^-10, respectively). Regarding the sub-lineages, no variations in the E6 gene were significantly different between the case and control group for the A4 (As) and A1-A3 (EUR) sub-lineages. However, the distribution of C749T (S63F) in the E7 gene was significantly different between the case and control groups for the A4 (As) and A1-A3 (EUR) sub-lineages (P = 1.815 × 10^-8 and P = 0.008). In the current study, we found that the C749T (S63F) variation in the HPV16 E7 gene was associated with cervical cancer not only in the A4 (As) sub-lineage but also in the A1-A3 (EUR) sub-lineage.

CONCLUSION

Our study will provide a good reference for further functional studies of the relationship between cervical cancer carcinogenesis and the HPV16 E6 and E7 genes.

Human Papillomavirus Type 16 E1 Mutations Associated with Cervical Cancer in a Han Chinese Population

Human papillomavirus type 16 (HPV16) is a high-risk HPV type and a potent carcinogen. HPV E1 is one of the most highly conserved proteins and it plays a central role in initiating HPV DNA replication. In current study, we enrolled 161 HPV16-positive cervical cancer patients (case group) and 171 HPV16-positive asymptomatic individuals (control group) in a study to analyse the association between HPV16 E1 genetic mutations and cervical cancer. The samples of case group were cervical cancer tissues and the samples of control group were cervical exfoliated cells. Three variants (A4, A1-A3 and D3) were found in the case group, 68.3% of the HPV16 E1 sequences belonged to the A4 (As) sub-lineage, 29.2% belonged to the A1-A3 (EUR) sub-lineage, and 2.5% belonged to the D3 (AA1) sub-lineage. Two variants (A4 and A1-A3) occurred in the control group. The A4 (As) sub-lineage was predominant in this group as well (66.1%), followed by the A1-A3 (EUR) sub-lineage (33.9%), but the D3 (AA1) sub-lineage was not found in the control group. The distribution of the HPV16 variants between the case and control groups was significantly different (P<0.05). When the distribution of the HPV16 E1 gene mutations was compared, the distribution of twenty-seven mutations was significantly different between the case and control groups (P<0.05), and twenty-two mutations occurred only in the D3 (AA1) sub-lineage, two were found only in the A4 (As) sub-lineage, one was found in the A1-A3 (EUR) sub-lineage, two was found in both the A4 (As) and A1-A3 (EUR) sub-lineages. In the sub-lineage analysis, the differences in the T933A (A23A), T1014G (D50E) and G2160A (R432R) mutations were statistically significant between the case and control groups for the A4 (As) sub-lineage (P<0.05), and the differences in the T2232C (F456F), G2337A (M491I) and A2547G (P561P) mutations were statistically significant between the case and control groups for the A1-A3 (EUR) sub-lineage (P<0.05). In the current study, we describe specific mutations in the HPV16 E1 gene associated with cervical cancer, and our study will provide a good reference for further functional studies of the relationship between cervical cancer carcinogenesis and HPV genes.