Lack of serum antibodies to the major HSV-2 specified DNA-binding protein before diagnosis of cervical neoplasia

Association between human herpesvirus infection and cervical carcinoma: a systematic review and meta-analysis

BACKGROUND

Cervical cancer (CC) is one of the most common gynecologic tumors among women around the world. Although the etiological role of human papillomavirus (HPV) in CC is well established, other factors in CC carcinogenesis remains unclear. Here, we performed a systematic review and meta-analysis to explore the association between infections of human herpesvirus (HHVs) and CC risk.

METHODS

Embase and PubMed databases were utilized to search the relevant studies. The revised JBI Critical Appraisal Tool was used to assess the quality of the included studies. Prevalence and odds ratios (ORs) with 95% confidence intervals (CI) were calculated to evaluate the association between viral infection and CC or precancerous cervical lesions (PCL).

RESULTS

Totally 67 eligible studies involving 7 different HHVs were included in meta-analysis. We found an increased risk of CC or PCL that was associated with the overall infection of HHVs (CC, OR = 2.74, 95% CI 2.13-3.53; PCL, OR = 1.95, 95% CI 1.58-2.41). Subgroup analysis showed a trend towards positive correlations between herpes simplex virus type 2 (HSV-2) infection and CC (OR = 3.01, 95% CI 2.24 to 4.04) or PCL (OR = 2.14, 95% CI 1.55 to 2.96), and the same is true between Epstein-Barr virus (EBV) infection and CC (OR = 4.89, 95% CI 2.18 to 10.96) or PCL (OR = 3.55, 95% CI 2.52 to 5.00). However, for HSV-1 and cytomegalovirus (HCMV), there was no association between viral infection and CC or PCL. By contrast, the roles of HHV-6, HHV-7, and Kaposi sarcoma-associated herpesvirus (KSHV) in cervical lesions were unclear due to the limited number of studies.

CONCLUSIONS

This study provided evidence that HHVs infection as a whole increase the risk of CC incidence. In addition, some types of HHVs such as EBV and HSV-2 may serve as potential targets in the development of new interventions or therapeutic strategies for cervical lesions.

Herpes simplex virus type 2 and the risk of cervical cancer: a meta-analysis of observational studies

OBJECTIVES

To assess whether herpes simplex virus type 2 (HSV-2) infection has an effect on the risk of cervical cancer.

METHODS

A systematic literature search of PubMed, Embase, Web of Science, and Scopus from their inception through July 2013 was conducted and reference lists of retrieved articles were reviewed. Information on the characteristics of the included studies, risk estimates, and control for possible confounding factors was extracted independently by two investigators. A random effects model was used to calculate the pooled risk estimates.

MAIN RESULTS

Sixteen articles with 20 studies (14 case control and 6 longitudinal) involving 3,337 patients with cervical cancer were included. Compared with individuals who did not experience HSV-2 infection, the pooled ORs of cervical cancer for individuals with HSV-2 infection were 1.37 (95 % CI 1.12-1.69) for traditional case-control studies and 1.04 (95 % CI 0.82-1.31) for prospective or retrospective nested case-control studies.

CONCLUSIONS

Given that a longitudinal study gives a higher level of evidence than a traditional case-control study, the existing observational epidemiological evidence do not support a harmful effect of HSV-2 infection on cervical cancer.

Nordic biological specimen bank cohorts as basis for studies of cancer causes and control: quality control tools for study cohorts with more than two million sample donors and 130,000 prospective cancers

The Nordic countries have a long tradition of large-scale biobanking and comprehensive, population-based health data registries linkable on unique personal identifiers, enabling follow-up studies spanning many decades. Joint Nordic biobank-based studies provide unique opportunities for longitudinal molecular epidemiological research. The Nordic Biological Specimen Banks working group on Cancer Causes and Control (NBSBCCC) has worked out very precise quality assurance principles for handling of the samples, based on the tradition in biobank culture. The aim of this paper is to demonstrate how high standards of quality assurance can also be developed for the data related to the subjects and samples in the biobanks. Some of the practices adopted from the strong Nordic cohort study experience evidently improve quality of nested case-control studies nested in biobank cohorts. The data quality requirements for the standardised incidence ratio calculation offer a good way to check and improve accuracy of person identifiers and completeness of follow-up for vital status, which are crucial in case-control studies for picking up right controls for the cases. The nested case-control design applying incidence-density sampling is recommended as an optimal design for most biobank-based studies. It is demonstrated how some types of biobanks have a period immediately after sampling, when the cancer risk is not comparable with the cancer risk in the base population, and how many of the biobanks never represent the normal average population of the region. The estimates on the population-representativeness of the biobanks assist in interpretation of generalisability of results of the studies based on these samples, and the systematic tabulations of numbers of cancer cases will serve in study power estimations. The well over 130,000 prospective cancer cases registered among subjects in the NBSBCCC biobank cohorts have already offered unique possibilities for tens of strong studies, but for rare exposure-outcome combinations predictions on future numbers of cases improve the chance to select the right moment when the study will have accurate statistical power.

Nordic biological specimen banks as basis for studies of cancer causes and control--more than 2 million sample donors, 25 million person years and 100,000 prospective cancers

The Nordic countries have a long tradition of large-scale biobanking and comprehensive, population-based health data registries linkable on unique personal identifiers, enabling follow-up studies spanning many decades. Joint Nordic biobank-based studies provide unique opportunities for longitudinal molecular epidemiological research. The purpose of the present paper is to describe the possibilities for such joint studies, by describing some of the major Nordic biobank cohorts with a standardised calculation of the cancer incidence in these cohorts. Altogether two million donors have since 1966 donated more than four million biological samples, stored at -20 degrees C to -135 degrees C, to 17 biobank cohorts in Finland, Iceland, Norway and Sweden. As a result of joint database handling principles, the accuracy of personal identifiers and completeness of follow-up for vital status in all participating biobanks was improved. Thereafter, the cancer incidence was determined using follow-up through the national cancer registries. Biobanks based on random samples of population typically showed slightly lower cancer incidence rates than the general population, presumably due to better participation rates among health-conscious subjects. On the other hand, biobanks including samples for viral screening or clinical testing showed 1.5 to 2.1 fold increased incidence of cancer. This excess was very high immediately after sampling, but for some cancer sites remained elevated for years after clinical sampling. So far, more than 100 000 malignant neoplasms have occurred after sample donation, and the annual increase of the cancer cases in these cohorts is about 10 000. The estimates on the population-representativity of the biobanks will assist in interpretation of generalizability of results of future studies based on these samples, and the systematic tabulations of numbers of cancer cases will serve in study power estimations. The present paper summarizes optimal study designs of biobank-based studies of cancer.

Serological evidence of an association between chlamydial infections and malignant lymphomas

Chronic infections may predispose to malignant growth. Recently, serological markers of chronic Chlamydia pneumoniae infection have been associated with lung cancer. Our aim was to study the possible association between chronic chlamydial infections and malignant lymphomas. The present case-control study involved 72 patients with lymphoma (31 females and 41 males) and matched controls. 53 patients had non-Hodgkin's lymphoma (NHL) and 19 had Hodgkin's disease. The sera, collected at the time of diagnosis, were tested for IgG antibodies and immune complexes to C. pneumoniae and C. trachomatis by a microimmunofluorescence method and ELISA and for IgG antibodies and immune complexes to Helicobacter pylori by ELISA. The serological markers suggesting chronic chlamydial infection were associated with malignant lymphoma. The association was most evident for the presence of C. pneumoniae-specific immune complexes in NHL (OR = 7.3, 95% CI 2.2-25) and appeared to be limited to men. No association between H. pylori antibodies or immune complexes and malignant lymphomas could be demonstrated. Our study provides seroepidemiological evidence of an association between chronic chlamydial infections and lymphomas.

Herpes simplex virus type 2 infection and cervical cancer: a prospective study of 12 years of follow-up in Finland

This study was initiated to investigate the role of past herpes simplex virus type 2 (HSV-2) infection, as determined by serum antibody analysis, in the etiology of cervical neoplasia. Two Finnish registers, the registry of the Social Insurance Institution's Mobile Clinic Survey and the Finnish Cancer Registry, were linked. About 40,000 blood samples were drawn in 1968-72 and stored by the Social Insurance Institution. According to the Cancer Registry, 32 cases of cervical carcinoma or carcinoma in situ for which serum samples were available were diagnosed in this cohort during a follow-up of 12 years (1968-81). The serum samples of these individuals and age matched controls (2:1) from the cohort were analyzed for HSV-2 antibodies. HSV-2 infection as determined by the best available HSV-2 type-specific antibody assay, glycoprotein gG2-ELISA, was not related to cervical neoplasia, i.e., the risk of cervical neoplasia among the HSV-2 positive women was not higher than that among the negative ones (smoking-adjusted relative risk = 0.5, 95 percent confidence interval = 0.2-1.6). The results do not support the hypothesis that HSV-2 is an etiologic agent for cervical neoplasia.

Pre- and posttreatment serum antibody responses to HPV 16 E2 and HSV 2 ICP8 proteins in women with cervical carcinoma

Serum antibodies to early proteins of human papillomavirus type 16 (HPV 16 E2 protein) and herpes simplex virus type 2 (HSV 2 ICP8) can be measured by ELISA. In the serum of 122 newly diagnosed cervical carcinoma patients and age-matched controls, enhanced IgA antibody levels to an HPV-16 E2 protein derived peptide no. 245 indicated a 9.5-fold (95% confidence limits 2.8-57.2) relative risk of cervical carcinoma. No significant risk was found with a corresponding HPV 6 E2 peptide or HSV 2 ICP8. To evaluate the HPV 16 E2 peptide as a possible tumor marker for cervical carcinoma serial postoperative serum samples were tested from 27 women with cervical carcinoma. Antibody responses to the HPV 16 E2 peptide depended on the clinical stage. Stage I and II patients showed decreasing posttreatment IgA and/or IgG antipeptide antibody levels. Stage III and IV patients initially showed decreasing antipeptide antibody levels followed by increasing levels. These patients also showed increasing IgG antibody levels to the HSV 2 ICP8. However, increasing antibody levels to the HPV 16 E2 peptide indicated significantly (P less than 0.05) worse 2-year disease free survival (recurring disease) than did stable or decreasing antibody levels. The results suggest that serum antipeptide antibodies to the HPV 16 E2 peptide no. 245 can be used for the monitoring of cervical carcinoma.