Susceptibility to human papillomavirus-associated cervical intra-epithelial neoplasia is determined by specific HLA DR-DQ alleles

Human Leucocyte Antigen Class II Risk and Protective Alleles in Women with Cervical Intraepithelial Neoplasia

Background

Persistent human papillomavirus (HPV) infection is a necessary cause for development of cervical precancerous lesions and cervical cancer, however, only a small percentage of women progress to cervical cancer. The local immune response, determined, among other factors, by Human Leucocyte Antigen (HLA) genes, is thought to be significant. Still the results of genome studies are inconsistent and differ between ethnical populations. The aim of the study was to assess an association between HLA-DQA1*; DQB1*; DRB1* allele's genetic variants between women with cervical precancerous lesions and healthy controls in Latvia.

Materials and methods

From January until April 2017 we enrolled 84 consecutive patients referred for colposcopy to Riga East University Hospital (Latvia) due to abnormal cervical cytology results. 57 women who came for a regular check-up and had normal cytology smears were included in the control group. Material from the cervix was taken for subsequent HLA genotyping of 13 DRB1*, 8 DQA1*, and 12 DQB1* alleles. Colposcopy was performed on all participants. In case of visual suspicion for CIN cervical biopsy was done.

Results

There were 57 "no CIN" patients, 23 histologically proven CIN 1 and 61 CIN2+ cases in the study population. CIN2+ was more often associated with DQA1*0401 (OR 6.68, 95% CI 1.47-30.29, p=0.014), DRB*15 (OR 2.99, 95% CI 1.22-7.39, p=0.017), DQB1*0401 (OR 2.91, 95%CI 1.11-7.68, p=0.03), DQA1*0103 (OR 2.72, 95% CI 1.02-7.21, p=0.045), DRB1*11 (OR 2.42, 95% CI 1.10-5.33, p=0.029) and DQB1*0301 (OR 1.94, 95% CI 1.12-3.38, p=0.018). Women with "no CIN" more often had DQB1*0501 (OR 0.17, 95% CI 0.04-0.81, p=0.026), DRB1*16 (OR 0.21, 95% CI 0.06-0.78, p=0.019), DQA1*0301 (OR 0.35, 95% CI 0.14-0.87, p=0.024) and DRB1*14 (OR 0.59, 95% CI 0.01-0.46, p=0.007).

Conclusions

In the current study we have demonstrated a strong association with risk and protective HLA class II alleles that are determined by the HLA-DRB1*; DQA1*; DQB1*.

Physiopathology and effectiveness of therapeutic vaccines against human papillomavirus

Human papillomavirus (HPV) is a well-known sexually transmitted disorder globally. Human papillomavirus (HPV) is the 3rd most common cancer that causes cervical carcinoma, and globally it accounts for 275,000 deaths every year. The load of HPV-associated abrasions can be lessened through vaccination. At present, three forms of prophylactic vaccines, Cervarix, Gadrasil, and Gardasil 9, are commercially accessible but all these prophylactic vaccines have not the ability to manage and control developed abrasions or infections. Therefore, a considerable amount of the population is not secured from HPV infectivity. Consequently, the development of therapeutic HPV vaccines is a crucial requirement of this era, for the treatment of persisting infections, and to stop the progression of HPV-associated cancers. Therapeutic vaccines are a developing trial approach. Because of the constitutive expression of E6 and E7 early genes in cancerous and pre-cancerous tissues, and their involvement in disturbance of the cell cycle, these are best targets for this therapeutic vaccine treatment. For the synthesis and development of therapeutic vaccines, various approaches have been examined comprising cell-based vaccines, peptide/protein-based vaccines, nucleic acid-based vaccines, and live-vector vaccines all proceeding towards clinical trials. This review emphasizes the development, progress, current status, and future perspective of several vaccines for the cure of HPV-related abrasions and cancers. This review also provides an insight to assess the effectiveness, safety, efficacy, and immunogenicity of therapeutic vaccines in the cure of patients infected with HPV-associated cervical cancer.

Epitope design of L1 protein for vaccine production against Human Papilloma Virus types 16 and 18

Cervical cancer accounts for about two-thirds of all cancer cases linked etiologically to Human Papilloma Virus (HPV). 15 oncogenic HPV types can cause cervical cancer, of which HPV16 and HPV18 combinedly account for about 70% of it. So, effective epitope design for the clinically relevant HPV types 16 and 18 would be of major medical benefit. Here, a comprehensive analysis is carried out to predict the epitopes against HPV types 16 and 18 through "reverse vaccinology" approach. We attempted to identify the evolutionarily conserved regions of major capsid protein (L1) as well as minor capsid protein (L2) of HPV and designed epitopes within these regions. In this study, we analyzed about 49 and 27 sequences of HPV L2 and L1 proteins respectively. Since we found that the intertype variability of L2 is higher than for L1 proteins, our analysis was emphasized on epitopes of L1 of HPV types 16 and 18. We had selected HLA-A*0201, DRB1*1501, DQB1*0602, DRB1*0401 and DQB1*0301 alleles for the prediction of T cell epitopes of L1 of HPV 16 and 18. Finally, we reported that predicted epitope sequences EEYDLQFIFQLCKITLTA, and RHGEEYDLQFIFQLCKITLTA of L1 protein of HPV 16, and LPDPNKF, PETQRLVWAC, PVPGQYDA, YNPETQRLVWAC, DTGYGAMD, PVPGQYDATK, KQDIPKVSAYQYRVFRV, RDNVSVDYKQTQLCI and YSRHVEEYDLQFIF of L1 protein of HPV 18 could be therapeutic tools for vaccine design against HPV.

Human Leukocyte Antigen Class I and II Alleles and Cervical Adenocarcinoma

BACKGROUND

Associations between human leukocyte antigens (HLA) alleles and cervical cancer are largely representative of squamous cell carcinoma (SCC), the major histologic subtype. We evaluated the association between HLA class I (A, B, and C) and class II (DRB1 and DQB1) loci and risk of cervical adenocarcinoma (ADC), a less common but aggressive histologic subtype.

METHODS

We pooled data from the Eastern and Western US Cervical Cancer studies, and evaluated the association between individual alleles and allele combinations and ADC (n = 630 ADC; n = 775 controls). Risk estimates were calculated for 11 a priori (based on known associations with cervical cancer regardless of histologic type) and 38 non a priori common alleles, as odds ratios (OR) and 95% confidence intervals (CI), adjusted for age and study. In exploratory analysis, we compared the risk associations between subgroups with HPV16 or HPV18 DNA in ADC tumor tissues in the Western US study cases and controls.

RESULTS

Three of the a priori alleles were significantly associated with decreased risk of ADC [DRB1*13:01 (OR = 0.61; 95% CI: 0.41-0.93), DRB1*13:02 (OR = 0.49; 95% CI: 0.31-0.77), and DQB1*06:03 (OR = 0.64; 95% CI: 0.42-0.95)]; one was associated with increased risk [B*07:02 (OR = 1.39; 95% CI: 1.07-1.79)]. Among alleles not previously reported, DQB1*06:04 (OR = 0.46; 95% CI: 0.27-0.78) was associated with decreased risk of ADC and remained significant after correction for multiple comparisons, and C*07:02 (OR = 1.41; 95% CI: 1.09-1.81) was associated with increased risk. We did not observe a difference by histologic subtype. ADC was most strongly associated with increased risk with B*07:02/C*07:02 alleles (OR = 1.33; 95% CI: 1.01-1.76) and decreased risk with DRB1*13:02/DQB1*06:04 (OR = 0.41; 95% CI: 0.21-0.80).

CONCLUSION

RESULTS suggest that HLA allele associations with cervical ADC are similar to those for cervical SCC. An intriguing finding was the difference in risk associated with several alleles restricted to HPV16 or HPV18-related tumors, consistent with the hypothesis that HLA recognition is HPV type-specific.

Human papillomavirus vaccines for the treatment of cervical cancer

Human papillomavirus (HPV) infection is a major cause of cervical cancer, the second most common cancer in women worldwide. Currently, a HPV L1-based virus-like particle has been approved as a prophylactic vaccine against HPV infection, which will probably lead to a reduction in cervical cancer incidence within a few decades. Therapeutic vaccines, however, are expected to have an impact on cervical cancer or its precursor lesions, by taking advantage of the fact that the regulatory proteins (E6 and E7) of HPV are expressed constantly in HPV-associated cervical cancer cells. Vaccine types targeting these regulatory proteins include the recombinant protein and DNA vaccines, peptide vaccines, dendritic-cell vaccines, and viral and bacterial vector deliveries of vaccines, and these may provide an opportunity to control cervical cancer. Further approaches incorporating these vaccine types with either conventional therapy modalities or the modulation of CD4(+) regulatory T cells appear to be more promising in achieving increased therapeutic efficacy. In this review, we summarize current and future therapeutic vaccine strategies against HPV-associated malignancies at the animal and clinical levels.

Association of KIR genes and HLA-C alleles with HPV-related uterine cervical disease in Korean women

This study investigated whether killer-cell immunoglobulin-like receptor (KIR) genes and human leukocyte antigen (HLA)-C alleles, receptors and ligands of natural killer cells are associated with the development of human papillomavirus (HPV)-related cervical disease in Korean women. Blood samples from 132 women with HPV-related cervical disease and 159 women without HPV infection were collected for genotyping of KIR genes and HLA-C alleles. Although no relationship was found between KIR genes and HPV-related cervical disease, a significant relationship was found between HLA-C alleles as ligands of KIR and HPV-related cervical disease. Women with HPV-related cervical disease were found to be significantly more likely to carry HLA-C*0303, particularly those with HPV 16 or 18 infection, and less likely to carry HLA-C*01 compared to women without HPV infection. HLA-C*0303 was found to confer susceptibility to HPV-related cervical disease, whereas HLA-C*01 was found to confer a protective effect against HPV-related cervical disease.

HLA-DRB1 Class II antigen level alleles are associated with persistent HPV infection in Mexican women; a pilot study

BACKGROUND

Persistent infection with high-risk human papillomavirus (HPV) is a major risk factor for malignant lesions and cervical cancer. A widely studied element in the search for genetic factors influencing risk HPV infection diseases is allelic variation of the human leukocyte antigen (HLA) locus. The study was designed to search for HLA susceptibility alleles contributing to the persistence of HPV infection in Mexican women.

METHODS

A total of 172 subjects were divided into three groups: 1) HPV-persistent patients; 2) HPV-cleared; and 3) HPV-reinfected patients. They were screened for HPV types using a polymerase chain reaction (PCR). PCR-sequence specific oligonucleotide probes (PCR-SSOP) was used for HLA DRB1 and DQB1 typing.

RESULTS

We observed that HLA-DQB1*0501 allele might be associated with susceptibility of reinfection with HPV (p = 0.01, OR = 4.9, CI 95% = 1.3 -18.7). Allele frequency of HLA-DRB1*14 was particularly reduced in patients with cancer when compared with the HPV-persistent group (p = 0.04), suggesting that this allele is a possible protective factor for the development of cervical cancer (OR = 2.98). HLA-DRB1*07 might be associated with viral clearance (p = 0.04).

CONCLUSIONS

Genetic markers for HPV infection susceptibility are different in each population, in Mexicans several HLA-DQB1 alleles might be associated with an enhanced risk for viral persistence. In contrast, DRB1*14, seems to confer protection against cervical cancer.

A comprehensive review on host genetic susceptibility to human papillomavirus infection and progression to cervical cancer

Cervical cancer is the second most common cancer in women worldwide. This is caused by oncogenic types of human papillomavirus (HPV) infection. Although large numbers of young sexually active women get HPV-infected, only a small fraction develop cervical cancer. This points to different co-factors for regression of HPV infection or progression to cervical cancer. Host genetic factors play an important role in the outcome of such complex or multifactor diseases such as cervical cancer and are also known to regulate the rate of disease progression. The aim of this review is to compile the advances in the field of host genetics of cervical cancer. MEDLINE database was searched using the terms, ‘HPV’, ‘cervical’, ‘CIN’, ‘polymorphism(s)’, ‘cervical’+ *the name of the gene* and ‘HPV’+ *the name of the gene*. This review focuses on the major host genes reported to affect the progression to cervical cancer in HPV infected individuals.

Interaction between polymorphisms of the human leukocyte antigen and HPV-16 variants on the risk of invasive cervical cancer

Background

Persistent infection with oncogenic types of human papillomavirus (HPV) is the major risk factor for invasive cervical cancer (ICC), and non-European variants of HPV-16 are associated with an increased risk of persistence and ICC. HLA class II polymorphisms are also associated with genetic susceptibility to ICC. Our aim is to verify if these associations are influenced by HPV-16 variability.

Methods

We characterized HPV-16 variants by PCR in 107 ICC cases, which were typed for HLA-DQA1, DRB1 and DQB1 genes and compared to 257 controls. We measured the magnitude of associations by logistic regression analysis.

Results

European (E), Asian-American (AA) and African (Af) variants were identified. Here we show that inverse association between DQB1*05 (adjusted odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.39–1.12]) and HPV-16 positive ICC in our previous report was mostly attributable to AA variant carriers (OR = 0.27; 95%CI: 0.10–0.75). We observed similar proportions of HLA DRB1*1302 carriers in E-P positive cases and controls, but interestingly, this allele was not found in AA cases (p = 0.03, Fisher exact test). A positive association with DRB1*15 was observed in both groups of women harboring either E (OR = 2.99; 95% CI: 1.13–7.86) or AA variants (OR = 2.34; 95% CI: 1.00–5.46). There was an inverse association between DRB1*04 and ICC among women with HPV-16 carrying the 350T [83L] single nucleotide polymorphism in the E6 gene (OR = 0.27; 95% CI: 0.08–0.96). An inverse association between DQB1*05 and cases carrying 350G (83V) variants was also found (OR = 0.37; 95% CI: 0.15–0.89).

Conclusion

Our results suggest that the association between HLA polymorphism and risk of ICC might be influenced by the distribution of HPV-16 variants.

Immunologic markers of cancer progression and prognosis

During the past decade, significant progress has been made in understanding the interactions between the immune system and cancer. The re-emergence of cancer immunosurveillance and immunoediting concepts has provided an understanding of several immunologic markers that are associated with cancer progression and prognosis. Recent studies have attempted to define the critical role of tumor infiltration by lymphocytes as a reflection of a tumor-related immune response. More recently, there has been an improved ability to demonstrate distinct subsets of tumor-infiltrating lymphocytes (TILs) in different tumor compartments. Several of these studies indicate that the presence of TILs may be associated with improved clinical outcome in several human cancers. However, this improved clinical outcome is dependent upon the intratumoral balance and quality of TILs, or infiltration of regulatory T cells or myeloid-derived suppressor cells. Immunologic markers have an important role in demonstrating intermediate end points of a therapeutic intervention and ultimately may be useful in predicting clinical outcomes. These markers are important to the development of successful immunotherapy strategies in cancer.

Human leukocyte antigen class II alleles and risk of cervical cancer in China

Human leukocyte antigen (HLA) class II alleles have been associated with an increased or decreased risk of developing cervical cancer through infection with oncogenic forms of human papillomavirus (HPV). To verify whether HLA class II allelic polymorphism is related to cervical cancer in China, 133 cervical cancers and 98 healthy controls were analyzed for HLA typing. Our results showed that DPB1*1301 allele frequency was significantly higher in the cervical cancers compared with healthy controls (OR, 3.793; p = 0.002; Pc = 0.04). A significant relationship was found between DRB1*150101-DQB1*0602 haplotype (OR, 0.180; p < 0.0001; Pc < 0.003), DRB1*070101-DQB1*0201 haplotype (OR, 0.110; p = 0.001; Pc = 0.03), and decreased risk for cervical cancer. Similar tendencies were observed for DRB1*150101-DQB1*0602 haplotype with HPV16 positive cervical cancers (OR, 0.182; p = 0.001; Pc = 0.021), and for DRB1*070101-DQB1*0201 haplotype (OR, 0.144; p =0.003; Pc = 0.063). These results indicate that HLA-DPB1*1301 may confer susceptibility to cervical cancer, and the haplotypes DRB1*150101-DQB1*0602 and DRB1*070101-DQB1*0201 may contribute to the resistance to the development of cervical cancer among Chinese women. The study suggests that specific HLA class II alleles and haplotypes may influence the immune response to specific HPV-encoded epitopes and affect the risk of cervical cancer in a Chinese population from an area with a high incidence of this neoplasia.

Association between HLA-DQB1 and cervical dysplasia in Vietnamese women

Host genetic background seems to play a key role in cervical carcinogenesis as only a small subset of women infected with high-risk human papillomaviruses (HPVs) develop cervical cancer. The rate of cervical cancer in Vietnamese women is notably high. To explore the association of human leukocyte antigen (HLA)-DQB1 alleles, HPV infection, and cervical dysplasia in this population, cervical smears were obtained from 101 women attending the obstetrics and gynecology clinic of Da Nang General Hospital in Vietnam. Besides the Papanicolaou test, HPV and HLA-DQB1 genotyping were performed using cervical smear DNA. Additionally, a subset of 30 blood samples was used as the gold standard for HLA genotyping. HLA-DQB1 alleles showed no association with HPV infection status. However, a positive association with cervical dysplasia was found for HLA-DQB1*0302 (P= 0.0229, relative risk (RR) = 4.737) and HLA-DQB1*0601 (P= 0.0370, RR = 4.038), whereas HLA-DQB1*0301 (P= 0.0152, RR = 0.221) was found negatively associated. The low diversity of HLA-DQB1 alleles, wide spectrum of HPV genotypes, and high prevalence of HPV 16 and HPV 18 observed in the study population suggest a permissive/susceptible genetic background that deserves further research. Total concordance of HLA-DQB1 genotyping results between blood and cervical cells confirms the potential value of cervical smears as an effective tool for the development of cervical cancer biomarkers.

HLA-DRB1 Alleles and Cervical Squamous Cell Carcinoma: Experimental Study and Meta-Analysis

Polymorphisms in human leukocyte antigen (HLA) genes have been implicated in the risk for cervical cancer. Association of certain class II HLA alleles with cervical cancer has been documented in various ethnic populations. The implications of such an association, however, are controversial. We analyzed 126 Chinese women with cervical squamous cell carcinoma (CSCC) and 289 healthy controls to test associations of certain HLA-DRB1 alleles. We then performed meta-analyses combining our own experimental data and data from nine other published studies. We found no significant differences in HLA-DRB1 allele frequencies in both CSCC and HPV-16-positive CSCC patients and control subjects. Meta-analysis provided evidence that four allele families (HLA-DRB1*04, *07, *11, and *15) and seven alleles (HLA-DRB1*0403, *0405, *0407, *0701, *1501, *1502, and *1503) were positively associated and two allele families (HLA-DRB1*09 and *13) and four alleles (HLA-DRB1*0901, *1301, *1302, and *1602) were negatively associated with CSCC in all studies or in Caucasian subgroups. In conclusion, our meta-analysis confirms the apparent association between certain HLA-DRB1 allele families and alleles and CSCC, suggesting that oncogenesis in this disease may be related to defects in immunoregulation. Larger studies may be needed, particularly in various ethnic groups, to further substantiate these associations.

Polymorphic amino acids at codons 9 and 37 of HLA-DQB1 alleles may confer susceptibility to cervical cancer among Chinese women

Cervical cancer is strongly associated with the infection by oncogenic forms of human papillomavirus (HPV). Although most women are able to clear HPV infection, some develop persistent infections that may lead to cancer, implying genetic susceptibility factors for malignant progression. To verify whether HLA class II DQB1 polymorphism is related to cervical cancer in Chinese population, HLA-DQB typing was carried out by PCR-SBT for 258 patients with cervical cancer and 284 healthy controls, and the allele frequencies were calculated. In this study, HLA-DQB1*060101 and DQB1*0602 alleles were significantly higher in the HPV16 infected patients with cervical cancer compared with healthy controls (chi(2) = 31.7452, p < 0.0001; chi(2) = 12.7838, p(c) = 0.0066), but DQB1*050201 allele was significantly lower (chi(2) = 26.2187, p < 0.0001). This result indicates that HLA-DQB1*060101 and DQB1*0602 may confer susceptibility to cervical cancer, and DQB1*050201 may contribute to the resistance to the development of cervical cancer among Chinese women. Sequence analysis reveals that DQB1*060101 allele encodes Leu at position 9 and Asp at position 37, unique to the susceptibility to cervical cancer, whereas the other DQB1 alleles encode Phe or Tyr and Ile or Tyr at the same two positions, respectively. This finding implies that polymorphic amino acids at the putative antigen binding residues 9 and 37 of HLA-DQB1 alleles may play an important role in the development of cervical cancer.

HLA Alleles and Risk of Cervical Intraepithelial Neoplasia Among Southwestern American Indian Women

An increase in cervical intraepithelial neoplasia (CIN) has been described in American Indian women in New Mexico. Differences in human leukocyte antigen (HLA) alleles have been reported in cervical intraepithelial neoplasia (CIN) compared with controls in other populations. We investigated HLA alleles and CIN in Southwest American Indian women. The case control study included 89 women with biopsy-proven CIN II/III (diagnosed November 1994 through October 1997) and 271 similar women with normal cervical epithelium from the same clinics. DRB1, DQB1, and DPB1 alleles were determined using DNA typing techniques. DQA1 and HLA-A allele typing was included for some subjects (randomly chosen n = 37 and n = 163 cases and controls, respectively). We found a decreased risk of CIN with DRB1*1402 (OR 0.5, 95% CI 0.3-0.9) and an increased risk with DRB1*1501 (OR 2.7, 95% CI 0.9-7.3). Additionally, DQA1*0102 was associated with increased risk (OR 4.5, 95% CI 1.3-5.3) and HLA-A*02 with decreased risk (OR 0.4, CI 0.2-0.9). Our findings are discussed along with studies in other populations.

HLA-DQB1 and cervical cancer in Venezuelan women

BACKGROUND

Cervical cancer represents a major health problem in Venezuela as well as in other Latin American countries. High-risk human papillomavirus (HR-HPV) infection is known as the major risk factor of cervical cancer. However, whether or not a HR-HPV-infected woman progresses to cervical cancer may depend on the immune system effectors induced by viral antigens presented by her specific human leukocyte antigens (HLA) alleles. The role of the HLA system in presenting peptides to antigen-specific T-cells may be critical for genetic susceptibility and genetic resistance to cervical carcinoma.

OBJECTIVE

We aimed to investigate the relationship between HLA-DQB1, HPV infection, and cervical cancer in Venezuelan women.

METHODS

Blood samples and cervical swabs were obtained from 36 patients and 79 healthy controls; additional cervical biopsies were obtained from all the patients. HPV DNA was detected by PCR and HLA-DQB1 genotyping was performed using a PCR-SSP protocol. RESULTS.: A positive association with cervical cancer was observed for HLA-DQB1*0201-0202 and *0402 alleles, however after Bonferroni correction only HLA-DQB1*0402 remained statistically significant (P value = 0.004, RR = 5.067).

CONCLUSION

This is the first report of HLA-DQB1 alleles associated with cervical carcinoma in Venezuelan women. Larger studies are needed to assess whether these HLA-DQB1*0201-0202 and *0402 alleles have a direct effect on disease susceptibility.

Regression of Low-Grade Cervical Intraepithelial Neoplasia in Patients With HLA-DRB1*13 Genotype

OBJECTIVE

The human leukocyte antigen (HLA)-DRB1*13 allele frequency is lower in women with cervical carcinoma than in the general population, suggesting that this allele could exert a protective effect against progression of cervical intraepithelial neoplasia (CIN) associated with human papillomaviruses (HPV). To test this hypothesis, we designed a prospective study of low-grade CIN (CIN1) and analyzed the probability of regression of these lesions according to HLA-DR and HPV status.

METHODS

The study sample was composed of 86 women with CIN1 who agreed to regular colposcopic follow-up and no immediate treatment. Biopsy specimens were taken under colposcopy for histology and for the determination of HPV and HLA status. Cases were classified into 3 groups: CIN1 regression, persistence for at least 12 months, or progression to CIN2 or 3.

RESULTS

The rate of spontaneous regression (95% confidence interval) at 24 months was 51.6% (39-61.6%) overall compared with 34.7% (13.4-50.8%) in HPV16/18 positive cases and 59.9% (43.7-71.4%) in HPV16/18-negative cases (P =.051). The rate of regression was 71.8% (40.8-86.5%) in patients with HLA-DRB1*13 and 45.9% (31.5-57.2%) in patients with other genotypes (P =.03). Regression reached 90.5% (38.9-98.5%) at 18 months in DRB1*13 patients with HPV16/18-negative-associated CIN (15.1% of the cases). In multivariable analysis, HLA-DRB1*13 allele and HPV16/18-negative status were independently associated with an increased probability for regression (adjusted hazard ratio 2.1 [1.0-4.1] and 2.5 [1.2-5.4], respectively).

CONCLUSION

A subset of approximately 15% of CIN1 highly likely to show spontaneous regression can be defined using 2 biologic parameters that characterize the viral causative agent and the host.

LEVEL OF EVIDENCE

II-2

Analysis of HLA-DRB1*0901-binding HPV-16 E7 helper T cell epitope

AIM

This study sought to determine the human papillomavirus (HPV)-16 E7 epitopes that would be presented by HLA-DR molecules to CD4-positive T cells in patients with cervical carcinoma.

METHODS

HLA-DR binding assays were performed using HPV-16 E7-derived synthetic peptides and, after incubation with these DR-binding peptides, helper T cell frequencies were analyzed in patients whose HLA and HPV genotypes were confirmed.

RESULTS

We determined that the E7d peptide, 61CDSTLRLCVQSTHVDIRTL80E, was bound by HLA-DRB1*0901. An increased frequency (0.3-2.4%) of type 2 helper T cell responses was found in HLA-DRB1*0901-positive patients with cervical dysplasia and carcinoma. We found that when IL-12 was combined with E7d-peptide stimulation in vitro, the frequency of type 1 helper T cell responses also increased in patients with carcinoma.

CONCLUSION

Thus HPV-16 E7d peptide as an HLA-DRB1*0901-restricted helper T cell epitope might usefully be incorporated into an understanding of the immunological mechanism and immunotherapy for this disease.

Loss of heterozygosity on chromosome 6 in HPV-16 positive cervical carcinomas carrying the DRB1*1501-DQB1*0602 haplotype

High-risk human papillomaviruses (HPVs), specifically HPV-16 and -18, have been associated with the development of carcinoma in situ (CIS) and of invasive cervical cancer (CC). However, only a small fraction of HPV-infected women will show signs of disease progression, suggesting that other factors in the carcinogenic pathway are needed. We previously demonstrated that human leukocyte antigen (HLA) DRB1*1501-DQB1*0602 (high risk) was associated with the development of CIS and CC tumors in HPV-16-positive patients. To characterize the molecular changes that could be relevant to tumor progression, we compared the extent of loss of heterozygosity (LOH) on chromosome 6 in HPV-16-positive CIS patients who were carriers of high-risk and neutral HLA haplotypes. CIS and CC cases demonstrated similar LOH patterns. A wide range of LOH frequencies was found at 6p (10-53%) and 6q (5-28%) in CIS cases, suggesting that LOH is an early event in the carcinogenic process. A comparative analysis of LOH frequencies in the high-risk versus the neutral HLA haplotypes showed a statistically significant difference in the extent of LOH at 6p24-p25 (58.6% versus 25.8%; P = 0.018) and at 6p21.3 (79.3% versus 35.5%; P = 0.001), a region that contains the HLA complex. LOH at this region could affect genes encoding HLA class I-II molecules, as well as factors responsible for the assembly, transport, and stable expression of HLA molecules. These losses may be a reflection of both an abnormal immune response and a general genome-wide instability resulting from virus persistence.

The Epidemiology of Cervical Cancer

Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined worldwide incidence of almost half a million new cases annually, second only to breast cancer. Basic and epidemiologic research conducted during the past 15-20 years have provided overwhelming evidence for an etiologic role for infection with certain types of sexually-transmitted human papillomavirus (HPV) as the primary cause of cervical cancer. The relative risks of cervical cancer following HPV infection as ascertained in case-control and cohort studies are among the highest in cancer epidemiology. The available evidence indicates that the HPV-cervical cancer association satisfies all relevant causal criteria for public health action. Other cervical cancer risk factors, such as smoking, parity, use of oral contraceptives, diet, other infections, and host susceptibility traits must be understood in the context of mediation of acquisition of HPV infection or in influencing events of the natural history of cervical neoplasia that occur following the establishment of a persistent HPV infection. Virtually all cervical carcinoma specimens contain HPV DNA, which suggests that HPV infection is a necessary cause of cervical neoplasia. This is the first instance in which a necessary cause has been demonstrated in cancer epidemiology--a realization that has obvious implications for primary and secondary prevention of this neoplastic disease.

Association between high-risk human papillomavirus DNA load and precursor lesions of cervical cancer in Mexican women

OBJECTIVE

Our objective was to determine the association between viral load of high risk human papilloma virus (HPV) using the Hybrid Capture II (HC II) system and cervical intraepithelial neoplasia (CIN) lesion stage.

METHODS

A total of 182 consecutive women with confirmed diagnoses of CIN 1-3 and 182 healthy women with negative Pap were included. All subjects underwent structured interviews focused on socioeconomic and reproductive factors. HC II testing was used to detect human papilloma virus (HPV) DNA. Viral load was measured by light measurements expressed as relative lights unit (RLU) ratio (specimens/control). Log(10)RLU ratios were categorized for analysis into four groups: negative (</=0); low viral load (0.01-1.0), middle viral load (1.01-2.0), and high viral load (2.0-3.6). Frequencies and association measurement odds ratio (OR) adjusted by unconditional multinomial regression (UMR) were used in analysis.

RESULTS

A total of 75 of 80 (93.7%) patients with CIN 2-3, 82 of 101 (79.4%) with CIN 1, and 36 of 182 (19.8%) controls were positive for HPV DNA. The higher the viral load of HPV DNA infection observed, the higher the probability of being associated with stage of CIN (P <0.001). Association between low viral load HPV and CIN 1 was 16.8 (7.2-39) compared with the highest association observed with high viral load and CIN 2-3 (OR(a) = 365.8, 94.7-1412). Both control and cases in the oldest women presented the highest viral load.

CONCLUSIONS

We found high frequencies of HPV DNA in CIN 1 and in CIN 2-3 patients. A clear association between viral load of HPV DNA was determined by HC II assay and CIN stage.

Host and viral genetics and risk of cervical cancer: a review

Infection with human papillomaviruses (HPV) is known to play a central role in the development of cervical cancer. Both host and viral genetic factors have been postulated to be important determinants of risk of HPV progression to neoplasia among infected individuals. In this report, we review epidemiological studies that have evaluated the role in cervical cancer pathogenesis of genetic variation in human leukocyte antigen (HLA) genes and in the HPV genome itself. A protective effect of HLA Class II DRB1*13/DBQ1*0603 alleles is the most consistent HLA finding in the published literature. A consistent association between HPV16 non-European variants and risk of disease is also evident from published work. These findings are discussed. Gaps in our understanding and future research needs are also discussed.

Immunity to oncogenic human papillomaviruses

The establishment of human papillomavirus (HPV) infection as a major cause of several human cancer forms, notably cervical cancer, has spurred development of prophylactic and/or therapeutic HPV vaccines for prevention of cervical neoplasia. Knowledge of the immunity to HPV forms the basis for such endeavors.

METHOD

A literature review of humoral and cellular immunity to HPV. The overview on human leukocyte antigen (HLA) and cervical cancer was expanded to a formal metaanalysis, where relevant articles were located by Medline search and citation analysis and graded by preassigned quality criteria on study design.

RESULTS

The antibody response to the HPV particle is dominated by a neutralizing antibody response to a typespecific, conformationally dependent immunodominant epitope. Vaccines based on viral particles lacking the viral genome (virus-like particles, VLPs) have been highly successful in preventing and treating HPV infection in several animal model systems. In humans, the serum antibody response to VLPs is stable over time, also after the HPV infection has been cleared, resulting in HPV serology being used as a marker of cumulative HPV exposure in spite of the fact that a significant proportion of HPV-exposed subjects fail to seroconvert. More than 90% of HPV infections will clear spontaneously. The factors that determine whether an HPV infection is cleared or persists and increases the risk for cancer are not known, but cellular immunity is implicated. Several HLA class II haplotypes are associated with cervical cancer: DQw3 increases and DR13 decreases the risk for cervical cancer in general (odds ratios (OR) and 95% confidence intervals (CI): 1.25(1.15-1.37) and 0.69 (0.56-0.85), respectively); DR15 increases the risk for HPV16-carrying cancer (OR: 1.47; CI: 1.20-1.81); and DR7 may be either protective or increase the risk. Most cervical cancers have downregulated the expression of at least one HLA class I antigen, whereas class II expression is increased in infected epithelium. A Th2 cytokine profile is associated with progression to cervical cancer. HPV-antigen-specific proliferative responses have been detected in many studies, although it is not entirely clear whether these responses are HPV type specific or may be cross-reactive between HPV types. Specific cytotoxic T lymphocyte (CTL) responses were originally reported in only a minority of infected subjects, typically cancer patients, but with advancing technology, specific CTLs can be stimulated from about half of the women with HPV-carrying disease. In animal model systems, CTL responses can mediate clearance.

CONCLUSION

The antibody response to HPV is a mediator of type-specific protective immunity, which forms the basis for prophylactic vaccine candidates. The cellular immunity to HPV is implicated as an important factor in cervical carcinogenesis, but the main targets and types of responses that mediate HPV clearance are not established.

HLA-DQBl alleles and susceptibility to cervical squamous cell carcinoma in Southern Iranian patients

The association of HLA class II with various autoimmune diseases has been extensively investigated. Despite the importance and functions of HLA genes in the evolution of cancer, the allele specific association of HLA molecules in cancer patients has not been well investigated. In this study the HLA-class II alleles frequency was investigated in Iranian patients with cervical squamous cell carcinoma. HLA typing was carried out by PCR amplification using sequence specific primers (PCR-SSP). DRB1, DQA1 and DQB1 typing was performed for 23 patients. The allele frequencies were calculated and compared with 36 healthy Iranian female controls. A positive association was observed between the existence of HLA-DQB1* 0601 and squamous cell carcinoma of the cervix (p<0.04, RR=1.94). Moreover, analysis of HLA-DRB1, DQA1 and DQB1 haplotypes indicated that none of the putative haplotypes were significantly associated with either patient or control group. Positive association of cervical carcinoma with a single allele of HLA-DQ provides evidence on the importance of HLA class II molecules and the immune response in squamous cell carcinoma of cervix.

HLA class II alleles associated with infection by HPV16 in cervical cancer in situ

HLA class II alleles have been associated with an increased risk of developing cervical cancer through infection with oncogenic forms of human papilloma virus (HPV). We have examined the association of variation at the DRB1 and DQB1 loci with HPV16 infection and risk of development of cervical cancer by analysis of 440 cases diagnosed with cervical cancer in situ and 476 age-matched controls in a retrospective case-control study. The infection history of a woman was studied by analysis of cervical smears taken at multiple times during a period of up to 27 years (1969-95). The frequency of a number of alleles are either increased (DRB1*0801, DRB1*1501, DQB1*0402 and DQB1*0602) or decreased (DRB1*0101, DRB1*1301, DQB1*0501 and DQB1*0603) in the cancer patients compared to the controls. After correction for multiple testing, only the DQB1*0602 and the DRB1*1501 alleles remain associated with cancer and only in HPV16-infected patients (DQB1*0602: 102/264 (39%) vs. 130/476 (28%), p = 0.028 and DRB1*1501: 104/259 (40%) vs. 132/469 (28%), p = 0.027). These alleles are associated primarily with infection by HPV and only indirectly affect the risk of developing cervical cancer in situ. To study the impact of these alleles on persistence of infection, women with short-term infections were compared to those with long-term infections. Carriers of DQB1*0602 and DRB1*1501 were more frequent in the group with long-term HPV infections, indicating that these class II alleles contribute to the inability to clear an HPV infection.

HLA-DQA1 allele typing by nonisotopic PCR-LIS-SSCP

In the present study we used a simple and reliable method for HLA-DQA1 allele typing based on the single-stranded conformation polymorphism (SSCP) properties of DNA molecules obtained by PCR. The technique consists of PCR amplification of a DNA fragment comprising the second exon of the HLA-DQA1 gene, amplicon denaturation using a low ionic strength solution (LIS), and electrophoresis on a small native polyacrylamide gel, followed by a rapid silver staining procedure. In order to validate the technique and to obtain the allele patterns for the DQA1 gene, 50 cervical samples were typed using this methodology and the commercial Amplitype HLA DQA1 Amplification and Typing kit. All the alleles detected with the kit were characterized by the LIS-SSCP approach. This procedure proved to be useful for population screening and typing of the DQA1 gene as well as for detecting new alleles or mutations in the donor-recipient molecular matching of HLA class II genes.

Human papillomavirus variants and squamous neoplasia of the cervix

Human papillomaviruses (HPVs) play a central role in the aetiology of cervical neoplasia. However, only a small proportion of cervical intraepithelial lesions infected with high-risk HPVs will progress to invasive cervical carcinoma, which indicates the involvement of additional factors. An important emerging viral factor is naturally occurring intratypic sequence variation. Such variation has been used to study the geographical spread of HPVs, but there is increasing evidence that it may be important in determining the risk of development of neoplastic disease. The collected data indicate that different HPV variants have altered biochemical and biological properties and represent an additional risk factor in the development of squamous intraepithelial lesions and invasive carcinoma of the cervix. This may be relevant not only to the biology of HPV infection and its association with squamous neoplasia, but also to the use of HPV typing in clinical practice.

Evaluation of the possible protective role of adeno-associated virus type 2 infection in HPV-associated premalignant disease of the cervix

OBJECTIVE

Our objective was to examine the prevalence of adeno-associated virus (AAV) infection in women with normal cervical smears and those with HPV-associated cervical intraepithelial neoplasia (CIN).

METHODS

HPV typing was performed on DNA from cervical smears of 211 women with CIN (CIN 1 = 83, CIN 3 = 128) and 433 healthy women who had a normal cervical smear. HPV typing was performed on all cases and controls using type-specific oligonucleotide primers (HPV 16, 18, 31, 33). AAV DNA was amplified by nested PCR from the same samples. The amplified DNA were separated on 2% agarose gels, blotted, and hybridized to AAV-2 DNA labeled by random priming with [alpha-(32)P]dCTP to confirm specificity of amplification.

RESULTS

A total of 131 cases of CIN were positive for one of the HPV types either alone or in combination. HPV 16 was present in 120 (57%) cases, HPV 18 in 15 (7%), HPV 31 in 27 (13%), and HPV 33 in 15 (7%) and there were multiple HPV types detected in 34 (16%) cases. All of the controls were selected to be negative for HPV. A total of 6/433 (1.4%) control cervical smears and 4/211 (1.9%) of CIN (CIN1 = 2; CIN3 = 2) contained AAV DNA. No correlation between AAV and any clinical feature was observed.

CONCLUSIONS

These results are different from some that have been previously published and suggest that AAV DNA is not frequently present in either normal control cervical samples or cervical intraepithelial neoplasia. This does not support the hypothesis that AAV may be protective against cervical cancer. Further research is necessary to understand the natural history of AAV infection and its role in human disease.

Viral load of human papilloma virus 16 as a determinant for development of cervical carcinoma in situ: a nested case-control study

BACKGROUND

Infection with certain types of human papillomavirus (HPV), which is common among young women, increases the risk of cervical cancer. However, less than 1% of young women positive for oncogenic types of HPV develop cervical cancer. We investigated whether the amount of HPV DNA is a useful predictor of progression to cervical carcinoma in situ.

METHODS

We estimated the amount of HPV 16 DNA by a PCR that uses the 5'-exonuclease (Taqman) method, in 478 women with cervical carcinoma in situ and 608 individually matched controls. To adjust for differences in the amount of genomic DNA between samples, we estimated the amount of a nuclear gene (beta-actin). We studied multiple smears (total 3835 archived samples) from each woman, taken over periods of up to 26 years, that covered normal cytology to development of cervical cancer.

FINDINGS

The risk of cervical carcinoma in situ increased with the amount of HPV 16 DNA. Analysis of the first smear from each woman, collected a mean of 7.8 years before cancer diagnosis, showed that women with the 20% highest amount of HPV 16 DNA were at a 60-fold higher risk of developing cervical carcinoma in situ than women negative for HPV 16. The first smear samples were classified as normal by squamous-cell cytology.

INTERPRETATION

Analysis of the amount of HPV DNA can predict cancer risk at a stage when current screening methods are uninformative. Testing for the amount of HPV 16 DNA during gynaecological health checks might strikingly improve our ability to distinguish between infections that have a high or low risk of progressing into cervical cancer.

Association between high-risk HPV types, HLA DRB1* and DQB1* alleles and cervical cancer in British women

Cervical scrapes from 116 British women referred with cervical cancer were tested for the presence of high oncogenic risk human papillomavirus (HPV) genotypes (HPV(hr)). Ninety-four per cent of the scrapes had one or more of these virus types and 66% were HPV16-positive. HPV18 was more frequent in adenocarcinoma. No evidence was found for an increased cancer risk associated with the HPV16 E6 350G variant. The HLA DRB1* and DQB1* alleles in these women and in 155 women with normal cytology and negative for HPV(hr) DNA were compared. DQB1*0301 alone (2P = 0.02) and in combination with DRB1*0401 (2P = 0.02) was found to be associated with cervical cancer. This was more marked in cancers positive for HPV types other than HPV16. In contrast, DRB1*1501 alone and in combination with DQB1*0602 was not significantly elevated in cancers overall, but did show some excess in HPV16-positive cancers (2P = 0.05), associated with HPV16-positive cervical cancers. Taking all cancers together, a marginally significant protective effect was found for DQB1*0501 (2P = 0.03) but no protective effect could be seen for DRB1*1301.

Genetic susceptibility to HPV infection and cervical cancer

Squamous cell carcinoma of the cervix (SCCC) is one of the leading causes of death in developing countries. Infection with high-risk human papillomavirus (HPV) is the major risk factor to develop malignant lesions in the cervix. Polymorphisms of the MHC and p53 genes seem to influence the outcome of HPV infection and progression to SCCC, although controversial data have been reported. MHC are highly polymorphic genes that encode molecules involved in antigen presentation, playing a key role in immune regulation, while p53 is a tumor suppressor gene that regulates cell proliferation. The HPV E6 protein from high-risk types binds p53 and mediates its degradation by the ubiquitin pathway. The role of these polymorphisms in genetic susceptibility to HPV infection and to SCCC remains under investigation.

Lack of association between HLA DQB1 alleles with HPV infection and histology findings in cervical cancer in Australian women

The association of human leukocyte antigen (HLA) types with cervical cancer and human papillomavirus (HPV) infection is controversial. In this study we examined 186 Australian women who had biopsy-confirmed cervical cancer and detected HLA DQB1 alleles and HPV DNA, using the polymerase chain reaction (PCR) amplification and sequence specific oligonucleotides probe (SSOP) hybridization methods. We analyzed the frequencies of 11 DQB1 alleles according to HPV DNA status (HPV positivity and HPV genotyping) and histology (tumor type, staging, grades, lymphocyte infiltration and nodal status). No significant differences among these 11 HLA DQB1 alleles were found with respect to HPV status and histology.

HPV 16 infection and progression of cervical intra-epithelial neoplasia: analysis of HLA polymorphism and HPV 16 E6 sequence variants

High-risk human papillomavirus (HPV) infection plays an important role in cervical intra-epithelial neoplasia (CIN), but HPV infection alone is not sufficient for progression to cervical cancer. Several lines of evidence suggest that cellular immune surveillance is important in the control of HPV infection and the development of CIN. The presentation to T cells of target viral peptides in the context of HLA molecules is influenced by the genetic polymorphisms of both HPV and HLA and thereby influences the host immune response and clinical outcome of HPV infection. HLA class I and II polymorphism in susceptibility for HPV 16 infection, development and progression of CIN was analyzed in a group of 118 patients participating in a prospective study of women with initial abnormal cytology. Patients were stratified according to HPV status and course of the disease. HLA-B*44 frequency was increased in the small group of patients with a lesion that showed clinical progression during follow-up [OR = 9.0 (4.6-17.5), p = 0.007]. HLA-DRB1*07 frequency was increased among HPV 16-positive patients compared with patients who were negative for all HPV types [OR = 5.9 (3.0-11.3), p = 0.02]. Our results are consistent with the immunogenetic factors associated with disease progression being different from those associated with susceptibility to HPV 16 infection. Sequencing of the HPV 16 E6 and E7 open reading frames of a subset of these patients (n = 40) showed the frequency of HPV 16 variants to be similar to other studies. However, there was no significant correlation between variant incidence and disease progression or viral persistence and no significant correlation with any HLA allele. It appears that multiple HLA types can influence HPV 16-associated cervical dysplasia but the role of HPV 16 variants in disease progression and susceptibility in relation to HLA polymorphism remains unclear.

Clinical models of chemoprevention for cervical cancer

Cervical carcinoma creates a worldwide, significant population burden that potentially could be reduced by new preventive strategies for cervical cancer such as chemoprevention. Given the vast array of clinical and molecular information available relating to cervical cancer and the precursor lesions along with a growing number of new molecular techniques, a model is needed to guide further investigation. Such a model would facilitate research design, guide hypothesis development and testing, and focus the use of molecular data collection and analysis. This article reviews the clinical and molecular data of cervical cancer and the precursor lesions in order to develop a model for chemoprevention research in cervical cancer.

An increased risk of cervical intra-epithelial neoplasia grade II-III among human papillomavirus positive patients with the HLA-DQA1*0102-DQB1*0602 haplotype: a population-based case-control study of Norwegian women

Several recent studies have reported different associations between HLA specificities and human papillomavirus (HPV)-associated disease of the cervix. We report the distribution of DQA1 and DQB1 genes and HPV infection in a population-based case-control study including 92 patients with histologically verified cervical intraepithelial neoplasia grade II-III (CIN II-III) (thus including moderate and severe dysplasia and carcinoma in situ) and 225 control subjects. We found an overrepresentation of the DQA1*0102-DQB1*0602 haplotype among HPV-positive cases compared with controls. The association was even stronger when comparing HPV-16-positive cases with HPV-16-positive controls. In addition, among HPV-16-positive individuals, we observed a decreased frequency of DQA1*0102-DQB1*0604 in cases compared with controls. We were not able to detect any association between CIN II-III and DQB1*03. Compared with previous findings in cervical cancer, our data indicate that carrying the DQA1*0102-DQB1*0602 haplotype gives an increased risk of developing CIN when infected with HPV-16, without influencing progression to cancer.

Analysis of E2 amino acid variants of human papillomavirus types 16 and 18 and their associations with lesion grade and HLA DR/DQ type

Human papillomavirus (HPV) 16 and HPV 18 E2 amino acid variants and host HLA DR/DQ haplotypes have been identified by direct nucleic acid sequencing from cervical scrapes. HPV16 E2 variants co-segregate with a nucleotide variant at nt350 (in E6), which previously has been associated with persistent infections. Both HPV16 and HPV18 E2 variants occur relatively more frequently in individuals with HLA DR/DQ haplotypes 0401/0301 and 1101/0301 but are not related to lesion grade.