Role In Cervical Carcinogenesis Research Articles

DNA methylation is not likely to be responsible for hTERT expression in premalignant cervical lesions.

Human telomerase reverse transcriptase (hTERT) mRNA expression seems to play an important role in cervical carcinogenesis. Analysis of the hTERT promoter region revealed the presence of a CpG island and a high overall GC content, suggesting a possible role for methylation in the regulation of hTERT gene expression. The present study was designed to evaluate the role of hTERT promoter methylation and E6/E7 human papilloma virus 16 (HPV-16) mRNA expression in hTERT regulation in premalignant cervical specimens. The methylation status of the hTERT promoter gene and hTERT mRNA quantification were investigated in 26 normal and 64 specimens of abnormal cytology using the MethyLight technique, Telo-TAGGG hTERT Quantification Kit and LightCycler technology. E6/E7 HPV-16 mRNA expression was also evaluated. No significant correlations were observed between hTERT mRNA expression and hTERT promoter methylation, as well as between telomerase activity and hTERT promoter methylation in normal and in premalignant cervical specimens. E6/E7 HPV-16 mRNA expression was observed in 72% of HPV-16-infected samples and was correlated with hTERT mRNA expression and telomerase activity (P < 0.05). This is the first study investigating the role of hTERT promoter methylation in hTERT mRNA expression and telomerase activity in premalignant lesions. The observed lack of correlation suggests that other mechanisms might be involved in the regulation of hTERT expression. The correlation between hTERT mRNA and E6/E7 mRNA expression confirms the role of HPV infection in hTERT regulation.

Hypermethylation and loss of heterozygosity of tumor suppressor genes on chromosome 3p in cervical cancer

We examined the promoter methylation status and LOH of the chromosome 3p genes, von Hippel-Lindau disease ( VHL), retinoic acid receptor β ( RAR-β), RAS association domain family 1A ( RASSF1A), and fragile histidine triad ( FHIT), in 37 samples of cervical squamous cell carcinoma and corresponding noncancerous tissues. We also analyzed the expression of RAR-β protein by immunohistochemistry. Promoter hypermethylation in RAR-β and FHIT was detected in 41% and 24% of tumors, respectively, whereas, no hypermethylation was detected in the corresponding noncancerous tissues. LOH in the regions of VHL, RAR-β, RASSF1A, and FHIT was observed in 3%, 30%, 22%, and 10% of informative cases, respectively. There were no correlations between LOH and promoter hypermethylation for all of these genes. Absent immunostaining of RAR-β protein correlated with hypermethylation and/or LOH of RAR-β gene. In addition, it correlated with higher level of SCC antigen and more frequent lymph node metastasis. Although biallelic inactivation by hypermethylation and concomitant LOH was infrequent, the high frequency of promoter hypermethylation and/or LOH of RAR-β and FHIT suggest that they play a role in cervical carcinogenesis independently. In addition, expression of RAR-β protein might be used as a prognostic factor in this disease.

Immune concept of human papillomaviruses and related antigens in local cancer milieu of human cervical neoplasia

It is presently the right time for clarifying human papillomavirus (HPV)-associated cellular immunity and clinical implications before global HPV vaccination programs begin. Infection with oncogenic HPV associates with the progression of cervical neoplasia. Both cellular and humoral immune responses are essential for the clearance of HPV-associated cervical lesions. There is increasing evidence that the immune system plays a pivotal role in determining the outcome of HPV infection. Viruses and associated neoplastic cells are proposed to have evolved mechanisms to avoid immune attack. T-cell-mediated immune responses against oncogenic HPV are believed to play a central role in cervical carcinogenesis. The presence of HPV-specific cytotoxic T lymphocytes (CTL) in a majority of human cervical cancer patients provides an approach for further study of their functional role in modulating this malignancy. Tumor-infiltrating lymphocytes (TIL) develop as manifestations of the recognition and defense against malignant cells by the host immune system. Cancer cells may overcome immune surveillance, either by downregulating the proliferation of HPV-specific CTL, or altering the effector compositions of immune cells against HPV infections. TIL in the tumor microenvironment can be functionally inhibited and lose the ability of clonal proliferation as a result of depressed expression of IL-2Ralpha. The upregulation of inhibitory signaling relates to the modulation of the virus- and/or tumor-specific immune responses. Alteration of host genetic susceptibility may also lead to abnormal immune response as a general genomic instability resulting from virus persistence. Induction of HPV-specific immune responses is anticipated as an intimate point for the treatment of cervical neoplasia.

Elevated Expression of the Oncogene c-fms and Its Ligand, the Macrophage Colony-Stimulating Factor-1, in Cervical Cancer and the Role of Transforming Growth Factor-β1 in Inducing c-fms Expression

Cervical cancer is the third most common gynecologic cancer in the United States. The presence and possible involvement of several cytokines have been studied in cervical cancer; however, very little data, if any, are available on whether cervical tumors are responsive to stimulation by the macrophage colony-stimulating factor-1 (CSF-1). Given the involvement of c-fms and its ligand CSF-1 in gynecologic cancers, such as that of the uterus and the ovaries, we have examined the expression of c-fms and CSF-1 in cervical tumor (n = 17) and normal cervix (n = 8) samples. The data show that c-fms and its ligand are significantly higher in cervical carcinomas compared with normal samples. Immunohistochemistry not only showed that tumor cells expressed significantly higher levels of c-fms but also c-fms levels were markedly higher in tumor cells than tumor-associated stromal cells. Blocking c-fms activity in cervical cancer cells, which express CSF-1 and c-fms, resulted in increased apoptosis and decreased motility compared with control, suggesting that CSF-1/c-fms signaling may be involved in enhanced survival and possibly invasion by cervical cancer cells via an autocrine mechanism. Combined, the data show for the first time the induction of CSF-1 and c-fms in cervical carcinomas and suggest that c-fms activation may play a role in cervical carcinogenesis. Additionally, our data suggest that transforming growth factor-beta1 may be a factor in inducing the expression of c-fms in cervical cancer cells. The data suggest that c-fms may be a valuable therapeutic target in cervical cancer.

Epidermal growth factor 61 A/G polymorphism and uterine cervical cancer

Cervical cancer, the second most common malignancy in women worldwide, is almost invariably associated with infection by human papillomavirus (HPV). However, although many women are infected with high-risk types of HPV, only a subset of infected women will ever develop cervical cancer. Therefore, host genetic factor may play a role in cervical carcinogenesis. Alterations in epidermal growth factor receptor (EGFR) are common events in cervical cancer. Therefore, we hypothesized that a functional polymorphism in the 5' untranslated region of the epidermal growth factor (EGF) gene, a natural ligand of the EGFR, may play a role in the cervical carcinogenesis and tumor invasiveness. We assessed the possible association between EGF +61 A/G polymorphism and cervical cancer risk in a hospital-based case-control study among 337 Korean women (168 cases, 169 age-matched controls). The frequencies of EGF +61 allele and genotype were not different between cases and controls. We observed increasing trend of lymph node metastasis from A/A homozygous genotype toward G/G homozygous genotype. We did not find any evidence that EGF +61 A/G polymorphism was associated with individual susceptibility of cervical cancer. However, although it was not statistically significant, the increasing trend of lymph node metastasis according to EGF genotype suggests the possibility that individual variance of EGF expression may be associated with cervical cancer invasiveness. We also confirmed that there exists striking ethnic heterogeneity of EGF genotype between Caucasian and East Asian population.

Interleukin-1 Beta -511 Polymorphism and Risk of Cervical Cancer

Cervical cancer is almost invariably associated with infection by human papillomavirus. It is believed that the host genetic factors such as inflammation-induced cytokines may play a role in cervical carcinogenesis. The IL1B gene, encoding IL-1β cytokine, contains several single nucleotide polymorphisms. One of them which is in the positions -511 (C-T) related with promoter region has been associated with increased IL-1β production and with increased risk of developing a number of inflammatory diseases and gastric carcinoma. We assessed the association between the IL1B -511 polymorphism and cervical cancer risk in a hospital-based case-control study among 546 Korean women (182 cases; 364 age-matched controls). The allele frequencies of the case subjects (C, 0.42; T, 0.58) were not significantly different from those of control subjects (C, 0.43; T, 0.57). Control subjects were in Hardy-Weinberg equilibrium. The carriers with -511 C/T or T/T genotypes were at higher risk of cervical cancer with odds ratio of 2.42 (95% CI 1.31-4.46, p<0.005). However, there was no difference of cervical cancer risk between C/T heterologous genotypes and T/T homologous genotypes. In conclusion, in Korean population, IL1B -511 C/C genotypes were significantly associated with a decreased risk of cervical cancer.

Promoter hypermethylation and loss of heterozygosity of FHIT genes in squamous cell carcinoma of uterine cervix

Objective : This study was to investigate the status of hypermethylation and loss of heterozygosity (LOH) in chromosome 3p tumor-suppressor gene for cervical carcinoma. Methods : We examined the promoter methylation status of the chromosome 3p gene, fragile histidine triad (FHIT), in 37 samples of cervical squamous cell carcinoma and corresponding noncancerous tissues using a methylation-specific polymerase chain reaction. We also analyzed the 37 paired samples for LOH at two loci on chromosome 3p. Results : Promoter hypermethylation in FHIT was detected in 24% of tumors, whereas no hypermethylation was detected in the corresponding noncancerous tissues. LOH in the regions of FHIT was observed in 10% of informative cases. There were no correlations between LOH and promoter hypermethylation for the gene. FHIT hypermethylation was associated with small tumors and, when adjusted for tumor size, correlated significantly with more frequent lymph node metastasis. Conclusion : Promoter hypermethylation and LOH of FHIT gene may play a role in cervical carcinogenesis. In addition, hypermethylation of FHIT may be associated with the status (aggressiveness) of cervical carcinoma.

Positive Association Between STAT3 and Ki-67 in Cervical Intraepithelial Neoplasia

Signal transducer and activator of transcription 3 (STAT3) has been regarded as an oncogene in many types of cancers. However, its role in cervical carcinogenesis is not well determined. The purpose of this study was to evaluate the expression patterns of STAT3 in cervical intraepithelial neoplasia (CIN), normal cervix (NC), and squamous cell carcinoma (SCC) to explore its possible role in cervical carcinogenesis. Paraffin-embedded sections from 83 patients including 20 CIN 1, 10 CIN 2, 26 CIN 3, and 27 comparative cases of 10 NC and 17 stage Ib SCC were collected in this study. Immunohistochemistry was performed to analyze the expression patterns of STAT3, and the results obtained were categorized by a semiquantitative method and were further correlated with the CIN histopathologic grade and the proliferation marker, Ki-67, using the chi2 test. Our results showed that nuclear STAT3 expression was predominantly in the squamous epithelial cells, and that high-grade CIN and stage Ib SCC lesions had a higher nuclear STAT3 expression when compared with NC and CIN 1. Furthermore, the nuclear STAT3 expression in CIN was significantly correlated with Ki-67 expression (p = 0.025), but not CIN lesion grade. In summary, our results indicate that an altered STAT3 expression in CIN is correlated with cell proliferation but may not have a direct contribution to cervical carcinogenesis.

Critical Roles for Non-pRb Targets of Human Papillomavirus Type 16 E7 in Cervical Carcinogenesis

High-risk human papillomaviruses (HPV) encode two oncogenes, E6 and E7, expressed in nearly all cervical cancers. In vivo, HPV-16 E7 has been shown to induce multiple phenotypes in the context of transgenic mice, including cervical cancer. E7 is a multifunctional protein known best for its ability to inactivate the tumor suppressor pRb. To determine the importance of pRb inactivation by E7 in cervical cancer, we pursued studies with genetically engineered mice. E7 expression in estrogen-treated murine cervix induced dysplasia and invasive cancers as reported previously, but targeted Rb inactivation in cervical epithelium was not sufficient to induce any cervical dysplasia or neoplasia. Furthermore, E7 induced cervical cancer formation even when the E7-pRb interaction was disrupted by the use of a knock-in mouse carrying an E7-resistant mutant Rb allele. pRb inactivation was necessary but not sufficient for E7 to overcome differentiation-induced or DNA damage-induced cell cycle arrest, and expression patterns of the E2F-responsive genes Mcm7 and cyclin E indicate that other E2F regulators besides pRb are important targets of E7. Together, these data indicate that non-pRb targets of E7 play critical roles in cervical carcinogenesis.

Distinct telomere length regulation in premalignant cervical and endometrial lesions: implications for the roles of telomeres in uterine carcinogenesis

Mouse models show that progressive shortening of telomeres with ageing causes chromosomal instability, which can lead to the initiation of cancer. However, it is unclear what roles telomere shortening plays in human carcinogenesis. The present study has investigated the involvement of telomere dynamics in uterine carcinogenesis. Using telomere-FISH (telo-FISH) assays, telomere lengths in premalignant and malignant cervical and endometrial lesions were measured and compared with chromosomal arm loss or gain. Telo-FISH signals were visualized with Cy3-labelled telomere-specific probes and presented as telomere intensity (TI). Early-stage cervical intraepithelial neoplasias (CINs), especially CIN2, had significantly shorter telomeres than corresponding normal squamous epithelia (p = 0.019), together with increased rates of chromosomal arm loss/gain (p < 0.001). Cervical cancers had relatively short telomeres, but they also showed greater heterogeneity than other sampled tissues, including those with long telomeres. In contrast, there was no significant difference between the telomere length of normal endometrium and of endometrial hyperplasia and endometrial cancer. There was no significant difference in the rate of chromosomal arm loss/gain between normal endometrium and endometrial hyperplasia. These findings suggest that progressive shortening of telomeres occurs in CIN, in association with chromosomal instability, which may play critical roles in cervical carcinogenesis. In contrast, endometrial hyperplasias have relatively stable telomeres without widespread chromosome alteration, implying that endometrial carcinogenesis involves mechanisms distinct from those of cervical carcinogenesis, possibly including microsatellite instability.

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.

Serum Phospholipid‐Fatty Acid Patterns and Antioxidant Status in Cervical Cancer Patients

This study was to examine the phospholipid-fatty acid (PL-FA) patterns, antioxidant status in patients with cervical intraepithelial neoplasia (CIN, n=32), invasive cervical cancer (ICC, n=23), and normal controls (n=41). While the EPA (C20:5ω3)+DHA (C22:6ω3)/linolenic acid (C18:3ω3, LNA) ratio (ω3 product/ω3 precursor) showed a significantly lower value at the stage of CIN (p<.0001), arachidonic acid (C20:4ω6, AA)/linoleic acid (C18:2ω6, LA) ratio (ω6 product/ω6 precursor) tended to be higher in patients (p=0.0682). In ω6 series fatty acids, there were consistent trends that desaturation indices were higher and elongation indices were lower in both CIN and ICC than in control. The level of malondialdehyde (MDA) was significantly higher in ICC than in control and CIN. The value of total antioxidant performance (TAP) was significantly lower in CIN. These findings may be related to the possibility of oxidative injury in patients. In conclusion, although these changes have limitations to define causal-effect relationship between the PL-FA patterns and disease outcomes, the significant changes in fatty acid patterns and antioxidant status observed in this study suggest that those may have roles in cervical carcinogenesis.

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.

Expression of the high-risk human papillomavirus type 18 and 45 E7 oncoproteins in cervical carcinoma biopsies

E7 proteins are major oncoproteins of high-risk human papillomaviruses (HPVs), which play a key role in cervical carcinogenesis. These proteins have been shown to immortalize primary human cells. Due to the absence of antibodies with suitable sensitivity and specificity, little is known about expression of the E7 oncoproteins in naturally infected tissues. Recently, high-level expression of the E7 protein of HPV-16, the most prevalent oncogenic HPV type, was demonstrated in cervical carcinomas by immunohistochemistry; however, approximately 15 additional high-risk HPV types are known to be associated with cervical carcinoma. It is unknown whether the E7 oncoproteins of HPV-18 and -45, the second and third most prevalent HPV types, are expressed in cervical cancers. Using antibodies against HPV-18 and -45 E7 proteins, it is shown here for the first time that the HPV-18 and -45 E7 proteins can be detected in cervical carcinoma biopsies. Together with anti-HPV-16 E7 antibodies, this could create the possibility of detecting E7 oncoproteins in approximately 80 % of all cervical cancers.

Association between the stages of cervical cancer and chromosome 1 aneusomy

The high-risk human papillomavirus is known to play a pivotal role in cervical carcinogenesis. Numerical and structural aberrations are known to be related to different behaviors of malignant cervical lesions. The aims of this study were (1) to assess the number of cervical cells with chromosome 1 aneusomy (monosomy, trisomy, and tetrasomy) in 20 women with cervical intraepithelial neoplasia (CIN 1, CIN 2, CIN 3, and invasive cancer) and three women without CIN by fluorescence in situ hybridization (FISH), (2) to determine the heterogeneity of aneusomy among women within each of the five groups studied, (3) to determine the association between the four progressive stages of cervical cancer and the number of cells with and without aneusomy, (4) to determine the association between number of cells with and without aneusomy and human papilloma virus (HPV) infection, and (5) to determine its usefulness as a biomarker of cancer risk. A hospital-based unmatched case–control study in a sample of 23 women grouped by disease stage and selected by histology from the Obstetrics and Gynecology Hospital of the Instituto Mexicano del Seguro Social (IMSS) in Mexico was conducted in 2002. Numerical aberrations of chromosome 1 in cervical smears were detected with FISH. HPV was detected with polymerase chain reaction (PCR) and typing was performed with restriction fragment length polymorphism (RFLPs). Analysis of chromosome 1 aneusomy revealed (1) homogeneity among women within each one of the five groups, (2) a positive linear trend between the aneusomy frequency and grade of lesion, and (3) an association between aneusomy and high-risk HPV infection. These findings suggest the usefulness of the number of cervical cells with chromosome 1 aneusomy as a biomarker. In order to validate this biomarker we suggest a larger prospective study of cytological samples of patients with a longer follow-up.

A region on human chromosome 4 (q35.1→qter) induces senescence in cell hybrids and is involved in cervical carcinogenesis

Human papillomavirus (HPV) types 16 and 18 are known to play a major role in cervical carcinogenesis. Additional genetic alterations are required for the development and progression of cervical cancer. Previously, we showed that the introduction of an entire human chromosome 4 into HPV-immortalized cells by microcell-mediated chromosome transfer (MMCT) can induce senescence in cell hybrids. In the present study, we established eight new murine donor cell lines harboring different fragments of the human chromosome 4. These were tested for their ability to induce senescence by MMCT into HPV16-immortalized keratinocytes (HPK II) and cervical carcinoma cells (HeLa). By exclusion, we could identify a region for a putative senescence gene or genes at 4q35.1-->qter. Further evidence that this locus may be involved in cervical carcinogenesis was obtained by studying sections of high-grade cervical intraepithelial neoplasias (CIN2/3) and cervical cancers from 87 women using a combination of interphase fluorescence in situ hybridization (I-FISH) and microsatellite PCR. I-FISH indicated copy number loss at 4q34-->qter. Microsatellite analysis showed that loss of one or more alleles at chromosome 4 was more frequent in the cervical carcinomas than in the CINs. Loss of heterozygosity (LOH) affected four areas, D4S412 (4p16.3), D4S2394 (4q28.2), D4S3041 (4q32.3), and D4S408 (4q35.1), and was highest at D4S408. LOH at terminal 4q has been reported previously for cervical carcinomas and other human malignancies. This is the first report associating allelic loss at 4q34-->qter with high-grade intraepithelial neoplasia and cervical carcinoma, and the first experimental evidence that this locus or these loci can induce senescence in cervical carcinoma cells and HPV16-immortalized cells.

Immunization with adenoviral vectors carrying recombinant IL-12 and E7 enhanced the antitumor immunity to human papillomavirus 16-associated tumor

Objective Human papillomavirus (HPV) infection play a significant role in cervical carcinogenesis, and HPV oncoprotein E7 has important functions in the formation and maintenance of cervical cancers. Interleukin-12 (IL-12) has been reported to induce cellular immune responses, and has also been demonstrated to suppress the growth of tumors and the expression of E7. Here, we investigate the utility of adenovirus E7 (AdE7) and adenovirus IL-12 (AdIL-12) for protection against TC-1 tumor using an animal model. Methods The antitumor effects induced by AdIL-12 and/or E7 were assessed by measurements of tumor size. E7-specific antibody and INF-γ production in sera were measured, as were T-helper cell proliferative responses. Cytotoxic T-lymphocytes (CTL) and T cell subset depletion studies were also performed. Results Infection of tumor sites with a combination of AdIL-12 and AdE7 resulted in an antitumor effect which was significantly more profound than that which resulted from singular infections with either AdIL-12 or AdE7. Combined infection resulted in regression of 9-mm-sized tumors in ∼80% of our experimental animals as compared to the PBS group. Serum levels of E7-specific antibody and INF-γ production, as well as T-helper cell proliferative responses, were found to be significantly higher in coinfected with AdIL-12 and AdE7 group than in single infection with either AdIL-12 or AdE7 group. CTL responses only exhibited by the AdIL-12 and AdE7 coinjected group suggested that these tumor suppression effects were mediated primarily by CD8+ and, to a lesser degree, by CD4+ T cells. Conclusion Combined injection with adenovirus carrying IL-12 and E7 induced significant antitumor immunity against TC-1 tumors. They may prove useful in clinical applications for the treatment of HPV-associated tumors.

Epstein-Barr virus plays little role in cervical carcinogenesis in Korean women

We examined whether Epstein-Barr virus (EBV) infection plays a role in cervical carcinogenesis in Korean women. EBV infection was examined using polymerase chain reaction (PCR) with two different primer pairs flanking the BamHI "W" fragment of EBV and by EBV-encoded small RNAs (EBER) in situ hybridization in various histologic types of cervical cancer, including 17 cases of squamous cell carcinoma, 36 cases of adenocarcinoma, and 3 cases of small-cell carcinoma. We also evaluated 20 cases of cervical intraepithelial neoplasia and 20 cases of normal uterine cervix. One case of squamous cell carcinoma and three cases of cervical intraepithelial neoplasia were positive for EBV DNA using PCR, but EBER in situ hybridization analysis showed that none of the PCR-positive cases expressed EBER. EBV DNA was not found using PCR in any of the 20 normal uterine cervices. From our results, EBV infection does not seem to play a role in cervical carcinogenesis in Korean women.

Epstein–Barr virus plays little role in cervical carcinogenesis in Korean women

We examined whether Epstein–Barr virus (EBV) infection plays a role in cervical carcinogenesis in Korean women. EBV infection was examined using polymerase chain reaction (PCR) with two different primer pairs flanking theBamHI “W” fragment of EBV and by EBV-encoded small RNAs (EBER)in situhybridization in various histologic types of cervical cancer, including 17 cases of squamous cell carcinoma, 36 cases of adenocarcinoma, and 3 cases of small-cell carcinoma. We also evaluated 20 cases of cervical intraepithelial neoplasia and 20 cases of normal uterine cervix. One case of squamous cell carcinoma and three cases of cervical intraepithelial neoplasia were positive for EBV DNA using PCR, but EBERin situhybridization analysis showed that none of the PCR-positive cases expressed EBER. EBV DNA was not found using PCR in any of the 20 normal uterine cervices. From our results, EBV infection does not seem to play a role in cervical carcinogenesis in Korean women.

Immunization with Adenoviral Vectors Carrying Recombinant IL-12 and E7 Enhanced the Antitumor Immunity against Human Papillomavirus 16-associated Tumor

Human papillomavirus (HPV) infection has a significant role in cervical carcinogenesis, and HPV oncoprotein E7 plays an important part in the formation and maintenance of cervical cancer. Interleukin-12 (IL-12) has been reported to induce a cellular immune response, and to suppress the tumor growth and the E7 production. Here we describe the use of adenoviral delivery of the HPV 16 E7 subunit (AdE7) along with adenoviral delivery of IL-12 (AdIL-12) in mice with HPV-associated tumors. Mice were injected with TC-1 cells to establish TC-1 tumor, and then they were immunized with AdIL-12 and/or AdE7 intratumorally. The anti tumor effects induced by AdIL-12 and/or E7 were evaluated by measuring the size of the tumor. E7-specific antibody and INF-gamma production in sera, and the T-helper cell proliferative responses were then measured. Cytotoxic T-lymphocyte (CTL) and T cell subset depletion studies were also performed. Combined AdIL-12 and AdE7 infection at the tumor sites significantly enhanced the antitumor effects more than that of AdIL-12 or AdE7 single infection. This combined infection resulted in regression of the 9 mm sized tumors in 80% of animals as compare to the PBS group. E7-specific antibody and INF-gamma production in the sera, and the T-helper cell proliferative responses were significantly higher with coinfection of AdIL-12 and AdE7 than with AdIL-12 or AdE7 alone. CTL response induced by AdIL-12 and AdE7 in the coinjected group suggested that tumor suppression was mediated by mostly CD8+ and only a little by the CD4+ T cells. IL-12 and E7 application using adenovirus vector showed antitumor immunity effects against TC-1 tumor, and this system could be use in clinical applications for HPV-associated cancer.