Are smoking and chlamydial infection risk factors for CIN? Different results after adjustment for HPV DNA and antibodies

Age, period, and birth cohort-specific effects on cervical cancer mortality rates in Japanese women and projections for mortality rates over 20-year period (2012-2031)

OBJECTIVES

We aimed to determine the effects of age, period, and birth cohort on cervical cancer mortality rate trends in Japanese women, by age-period-cohort (APC) analysis. Additionally, we analyzed projected mortality rates.

METHODS

We obtained data on the number of cervical cancer deaths in Japanese women from 1975-2011 from the national vital statistics and census population data. A cohort table of mortality rate data was analyzed on the basis of a Bayesian APC model. We also projected the mortality rates for the 2012-2031 period.

RESULTS

The period effect was relatively limited, compared with the age and cohort effects. The age effect increased suddenly from 25-29 to 45-49 years of age and gently increased thereafter. An analysis of the cohort effect on mortality rate trends revealed a steep decreasing slope for birth cohorts born from 1908-1940 and a subsequent sudden increase after 1945. The mortality rate projections indicated increasing trends from 40 to 74 years of age until the year 2031.

CONCLUSIONS

The age effect increased from 25-29 years of age. This could be attributable to the high human papilloma virus (HPV) infection risk and the low cervical cancer screening rate. The cohort effect changed from decreasing to increasing after the early 1940s. This might be attributable to the spread of cervical cancer screening and treatment before 1940 and the high HPV infection risk and reduced cervical cancer screening rate after 1945. The projected mortality rate indicated an increasing trend until the year 2031.

Tripolar mitosis in human cells and embryos: occurrence, pathophysiology and medical implications

Tripolar mitosis is a specific case of cell division driven by typical molecular mechanisms of mitosis, but resulting in three daughter cells instead of the usual count of two. Other variants of multipolar mitosis show even more mitotic poles and are relatively rare. In nature, this phenomenon was frequently observed or suspected in multiple common cancers, infected cells, the placenta, and in early human embryos with impaired pregnancy-yielding potential. Artificial causes include radiation and various toxins. Here we combine several pieces of the most recent evidence for the existence of different types of multipolar mitosis in preimplantation embryos together with a detailed review of the literature. The related molecular and cellular mechanisms are discussed, including the regulation of centriole duplication, mitotic spindle biology, centromere functions, cell cycle checkpoints, mitotic autocorrection mechanisms, and the related complicating factors in healthy and affected cells, including post-mitotic cell-cell fusion often associated with multipolar cell division. Clinical relevance for oncology and embryo selection in assisted reproduction is also briefly discussed in this context.

Multinucleation during C. trachomatis infections is caused by the contribution of two effector pathways

Chlamydia trachomatis is an obligate intracellular bacterial pathogen and the second leading cause of sexually transmitted infections in the US. Infections cause significant morbidity and can lead to serious reproductive sequelae, including an epidemiological link to increased rates of reproductive cancers. One of the overt changes that infected cells exhibit is the development of genomic instability leading to multinucleation. Here we demonstrate that the induction of multinucleation is not conserved equally across chlamydial species; C. trachomatis L2 caused high levels of multinucleation, C. muridarum intermediate levels, and C. caviae had very modest effects on multinucleation. Our data show that at least two effector pathways together cause genomic instability during infection leading to multinucleation. We find that the highly conserved chlamydial protease CPAF is a key effector for one of these pathways. CPAF secretion is required for the loss of centrosome duplication regulation as well as inducing early mitotic exit. The second effector pathway involves the induction of centrosome position errors. This function is not conserved in three chlamydial species tested. Together these two pathways contribute to the induction of high levels of genomic instability and multinucleation seen in C. trachomatis infections.

Chlamydia trachomatis infection: implications for HPV status and cervical cancer

Genital Chlamydia trachomatis (CT) infections have been identified as a major health problem concern. CT is associated with adverse effect on women reproduction and also associated with cervical hypertrophy and induction of squamous metaplasia, providing a possible relationship with human papillomavirus (HPV) infection. Infection by high-risk HPV types is crucial to the pathogenesis of invasive cervical cancer (ICC), but other co-variants/cofactors must be present for the development of malignancy. CT biological effect may damage the mucosal barrier, improving HPV infection, or may interfere in immune response and viral clearance supporting the persistence of HPV infection. Moreover, CT-related chronic cervical inflammation, decrease of lower genital tract antigen-presenting cells, inhibition of cell-mediated immunity, and anti-apoptotic capacity may influence the natural history of HPV infection, namely persistence progression or resolution. Although several epidemiological studies have stated a positive association involving CT and HPV-related cervical neoplastic lesions and/or cervical cancer (CC), the specific role of this bacterium in the pathogenesis of cervical neoplasia has not been completely clarified. The present review summarizes several studies on CT role in cervical cancer and suggests future research directions on HPV and CT interaction.

Alcohol consumption and viral load are synergistically associated with CIN1

Purpose

We investigated the association between alcohol consumption and risk of cervical intraepithelial neoplasia (CIN) and cervical cancer, and determined whether these associations were modified by human papillomavirus (HPV) viral load in high-risk HPV-positive women participating in the Korean HPV cohort study (KHPV).

Methods

Among the women recruited in the KHPV (n = 1,243) from March 2006 to December 2009, we analyzed normal cytology (n = 581) as control group, CIN1 (n = 299), CIN2/3 (n = 161), or cervical cancer (n = 202). Multinomial logistic analysis was performed to estimate multivariate-adjusted odds ratios (OR).

Results

Alcohol drinkers had an increased risk of CIN1 (OR = 2.18, 95% CI 1.22–3.89) compared with non-drinkers after adjusting for potential confounders. Subjects with more frequent alcohol consumption had a higher risk of CIN1 (p for linear trend <0.0001). Higher ethanol consumption was associated with an increased risk of CIN1 (p for linear trend = 0.0001). We also observed a synergistic effect between HPV viral load and alcohol consumption: drinkers with a high HPV viral load (≥100 RLU/PC) were associated with a significantly increased risk of CIN1 (OR = 19.1; 95% CI, 6.60–55.3, interaction p<0.001). There were no associations between alcohol drinking and CIN2/3 or cervical cancer.

Conclusions

HPV viral load and alcohol was associated with the risk of CIN1 among high-risk HPV-positive women. This is the first demonstration that alcohol is an independent and combined risk factor of CIN1.

Evaluation of the polyclonal ELISA HPV serology assay as a biomarker for human papillomavirus exposure

BACKGROUND

Seropositivity to human papillomavirus (HPV)16 and 18 antibodies is used as a measure of cumulative HPV exposure and as a stratifier of HPV exposure for vaccine efficacy analyses. Overall performance of these assays, as a measure of HPV exposure, has not been evaluated.

METHODS

Using data from the enrollment phase of the HPV16/18 vaccine trial in Costa Rica, we evaluated the performance of the polyclonal enzyme-linked immunosorbent assay (ELISA) HPV16 and 18 serological assays as a measure of HPV exposure. Biologic (e.g., HPV infection at the cervix) and behavioral characteristics (e.g., lifetime number of sexual partners) with known associations with current and past HPV infection were used to define cases and controls (HPV exposed vs. not exposed). Prevaccination serum was measured for antibodies against HPV16 and 18 by ELISA; cervical samples were tested for HPV DNA using PCR SPF10/LiPA25. ELISA results were analyzed using receiver-operator characteristic curves; performance was evaluated at the manufacturer set cut point (HPV16 = 8, HPV18 = 7) and at cut points chosen to optimize sensitivity and specificity (HPV16 = 34, HPV18 = 60).

RESULTS

Defining cases as type-specific HPV DNA positive with high-grade abnormal cytology (i.e., combined molecular and microscopic markers of infection), HPV16-ELISA gave sensitivity that was lower at the optimal cut point than the manufacturer cut point (62.2 compared with 75.7, respectively; P = 0.44). However, specificity was higher (85.3 compared with 70.4, respectively; P < 0.0001). Similarly, HPV18-ELISA gave sensitivity that was lower at the optimal cut point than the manufacturer cut point (34.5 compared with 51.7, respectively; P = 0.40), with higher specificities (94.9 compared with 72.6, respectively; P < 0.0001).

CONCLUSIONS

Modifying cut points did not improve the low sensitivity. The low sensitivity of this assay does not support its use for risk stratification or clinical settings.

Chlamydia induces anchorage independence in 3T3 cells and detrimental cytological defects in an infection model

Chlamydia are gram negative, obligate intracellular bacterial organisms with different species causing a multitude of infections in both humans and animals. Chlamydia trachomatis is the causative agent of the sexually transmitted infection (STI) Chlamydia, the most commonly acquired bacterial STI in the United States. Chlamydial infections have also been epidemiologically linked to cervical cancer in women co-infected with the human papillomavirus (HPV). We have previously shown chlamydial infection results in centrosome amplification and multipolar spindle formation leading to chromosomal instability. Many studies indicate that centrosome abnormalities, spindle defects, and chromosome segregation errors can lead to cell transformation. We hypothesize that the presence of these defects within infected dividing cells identifies a possible mechanism for Chlamydia as a cofactor in cervical cancer formation. Here we demonstrate that infection with Chlamydia trachomatis is able to transform 3T3 cells in soft agar resulting in anchorage independence and increased colony formation. Additionally, we show for the first time Chlamydia infects actively replicating cells in vivo. Infection of mice with Chlamydia results in significantly increased cell proliferation within the cervix, and in evidence of cervical dysplasia. Confocal examination of these infected tissues also revealed elements of chlamydial induced chromosome instability. These results contribute to a growing body of data implicating a role for Chlamydia in cervical cancer development and suggest a possible molecular mechanism for this effect.

Association of HPV infection and Chlamydia trachomatis seropositivity in cases of cervical neoplasia in Midwest Brazil

High-risk human papillomavirus (HPV) is considered the main etiological agent for cervical neoplasia. However, the presence of a single type HPV infection alone is unlikely to be sufficient to cause cervical cancer. There is epidemiologic evidence suggesting that HPV and Chlamydia trachomatis play a central role in the etiology of cervical intraepithelial neoplasia and subsequent cervical cancer. To evaluate the HPV prevalence and the seropositivity for C. trachomatis in women referred to the colposcopy clinic due to an abnormal cervical smear and to examine the effect of this association on the severity of cervical neoplasia. Following enrollment, 131 patients underwent colposcopy and biopsies when necessary. HPV DNA was detected by the polymerase chain reaction (PCR) and genotyping was performed by reverse line-blot hybridization assay. C. trachomatis seropositivity was tested by ELISA for the detection of IgG antibodies. The prevalence of HPV infection was 86.3%. Seropositivity for C. trachomatis was 26%. Thirty-one women (27.4%) were positive for C. trachomatis antibodies and HPV-DNA. The most prevalent HPV type in C. trachomatis-seropositive women were HPV 16 (51.6%) and this HPV type was present mainly in neoplasia cases. Positivity for HPV, particularly HPV types 16 and 18, and C. trachomatis seropositivity was significantly associated with a diagnosis of high grade neoplasia. Borderline significance was observed after adjustment for HPV. C. trachomatis seropositivity is associated with high grade neoplasia in women infected with HPV, mainly when the types 16 and 18 were involved.

Human papillomavirus infection and the risk of cervical cancer in Japan

Infection with a high-risk human papillomavirus (HPV) is established as a major risk factor for cervical cancer. In Japan, eight HPV genotypes (16, 18, 31, 33, 35, 45, 52 and 58) confer a much higher risk of cervical cancer and its immediate premalignant lesions (cervical intraepithelial neoplasia grade 3 [CIN 3]) than do other high-risk and the low-risk HPV types. However, only a small fraction of infected women develop CIN 3 or invasive cervical cancer, suggesting the involvement of additional cofactors in cervical carcinogenesis. A multicenter prospective cohort study of Japanese women with low-grade cervical abnormalities has demonstrated that tobacco smoking is significantly associated with an increased risk of persistent low-grade cervical lesions, while the presence of human leukocyte antigen Class II DRB1*1302 protects against progression to CIN 3. Understanding the epidemiology of HPV infections and cervical cancer may improve prevention and lead to novel clinical management strategies for cervical precursor lesions. Viral and host factors that affect the risk of cervical cancer are discussed in this review.

Chlamydia trachomatis infection causes mitotic spindle pole defects independently from its effects on centrosome amplification

Chlamydiae are Gram negative, obligate intracellular bacteria, and Chlamydia trachomatis is the etiologic agent of the most commonly reported sexually transmitted disease in the United States. Chlamydiae undergo a biphasic life cycle that takes place inside a parasitophorous vacuole termed an inclusion. Chlamydial infections have been epidemiologically linked to cervical cancer in patients previously infected by human papillomavirus (HPV). The inclusion associates very closely with host cell centrosomes, and this association is dependent upon the host motor protein dynein. We have previously reported that this interaction induces supernumerary centrosomes in infected cells, leading to multipolar mitotic spindles and inhibiting accurate chromosome segregation. Our findings demonstrate that chlamydial infection causes mitotic spindle defects independently of its effects on centrosome amplification. We show that chlamydial infection increases centrosome spread and inhibits the spindle assembly checkpoint delay to disrupt centrosome clustering. These data suggest that chlamydial infection exacerbates the consequences of centrosome amplification by inhibiting the cells' ability to suppress the effects of these defects on mitotic spindle organization. We hypothesize that these combined effects on mitotic spindle architecture identifies a possible mechanism for Chlamydia as a cofactor in cervical cancer formation.

Chlamydia trachomatis and risk of prevalent and incident cervical premalignancy in a population-based cohort

BACKGROUND

Cofactors might affect the risk of the rare progression from infection with carcinogenic human papillomavirus (HPV) to cervical premalignancy to invasive cancer. Some studies have observed that Chlamydia trachomatis infection is associated with increased risk for cervical cancer. In a large prospective cohort, we assessed the role of C trachomatis in cervical premalignancy and addressed confounding by HPV.

METHODS

We identified 182 women with prevalent and 132 women with incident histological cervical intraepithelial neoplasia grade 2 (CIN2), grade 3 (CIN3), or cervical cancer (CIN2+) in the Costa Rica HPV Natural History Study. Control subjects were 995 (approximately 10% of the 10 049) subjects who were randomly selected from the same study. Cervical HPV status at enrollment was determined by MY09/MY11 polymerase chain reaction amplification and dot-blot hybridization. The presence of C trachomatis DNA in cervical exfoliated cells at enrollment was determined by a novel serovar-specific polymerase chain reaction-based C trachomatis detection and genotyping assay. Plasma drawn at enrollment from each subject was used to determine C trachomatis immunoglobulin G (IgG) status. Logistic regression was used to examine the association between C trachomatis and CIN2+, taking into account possible confounding by HPV.

RESULTS

C trachomatis positivity at enrollment was associated with CIN2+ and concurrent and subsequent carcinogenic HPV infection. To account for confounding by HPV status, we restricted the analysis to women positive for carcinogenic HPV DNA at enrollment and found no association between C trachomatis status (as assessed by DNA or IgG) at enrollment and combined prevalent and/or incident CIN2+ (for C trachomatis DNA positivity, odds ratio = 0.77, 95% confidence interval = 0.42 to 1.41; for C trachomatis seropositivity, odds ratio = 1.09, 95% confidence interval = 0.85 to 1.41).

CONCLUSIONS

We found no association between C trachomatis status, as assessed by DNA or IgG, and risk of cervical premalignancy, after controlling for carcinogenic HPV-positive status. Previous positive associations between C trachomatis and cervical premalignancy could have been caused, in part, by an increased susceptibility to HPV infection.

Prevalence of micronuclei in exfoliated uterine cervical cells from patients with risk factors for cervical cancer

CONTEXT AND OBJECTIVE

Pap smears are the most common and inexpensive screening method for cervical cancer. We analyzed micronucleus prevalence in exfoliated cervical mucosa cells, to investigate associations between increased numbers of micronuclei and risk factors for cervical cancer.

DESIGN AND SETTING

Analytical cross-sectional study, at Instituto de Pesquisa em Oncologia (IPON).

METHODS

Exfoliated cervical cells were obtained from 101 patients between September 2004 and November 2005. Patients' ages, habits (passive or active smoking, alcoholism and numbers of sexual partners), age at first sexual intercourse, contraceptive methods used, histories of sexually transmitted diseases, use of hormone replacement therapy, numbers of pregnancies and abortions, inflammatory cytology and cervical intraepithelial neoplasia (CIN) were obtained. Cells were collected using Ayre spatulas, transferred to vials containing 0.9% saline solution for micronucleus tests and analyzed at 1000x magnification. The number of micronuclei in 1,000 epithelial cells per patient sample was counted.

RESULTS

Comparisons between groups with active (7.9 +/- 7.8) and passive (7.2 +/- 10.6) smoking versus no smoking (3.7 +/- 5.1); with/without alcoholism (7.8 +/- 1.4 and 6.9 +/- 10.1); with/without inflammatory cytology (10.7 +/- 10.5 and 1.3 +/- 1.7); and with CIN I, II and III and no CIN (respectively 4.3 +/- 4.3, 10.6 +/- 5.3, 22.7 +/- 11.9 and 1.3 +/- 1.4) found elevated micronucleus prevalence (P < 0.05).

CONCLUSIONS

We concluded that the prevalence of micronuclei in exfoliated uterine cervical cells was greater in patients with one or more risk factors for uterine cervical cancer than in patients without risk factors.

The effect of lifestyle factors on gynaecological cancer

Several lifestyle factors affect a woman's risk of gynaecological cancer and-potentially-can be modified to reduce risk. This chapter summarises the evidence for the effect of lifestyle factors on the incidence of gynaecological malignancy. The incidence of obesity is increasing in the developed world such that it now contributes as much as smoking to overall cancer deaths. Women with a body mass index (BMI)>40 have a 60% higher risk of dying from all cancers than women of normal weight. They are also at increased risk from gynaecological cancer. Dietary factors significantly influence the risk of gynaecological cancer: fruit, vegetables and antioxidants reduce risk whereas high animal fat and energy intakes increase risk. Alcohol intake adversely affects breast cancer risk, possibly accounting for 4% of all breast cancers. Physical activity protects against ovarian, endometrial and postmenopausal breast cancer, independently of BMI. The oral contraceptive pill has a substantial and long-lasting effect on the prevention of ovarian and endometrial cancer and is one of the best examples of large-scale chemoprevention in the developed world. Childbearing is protective against ovarian, endometrial and breast cancer but increases the risk of cervical cancer. Smoking acts as a cofactor in cervical carcinogenesis and increases the risk of ovarian cancer, particularly mucinous tumours.

Chlamydia trachomatis Causes Centrosomal Defects Resulting in Chromosomal Segregation Abnormalities

Chlamydiae traffic along microtubules to the microtubule organizing center (MTOC) to establish an intracellular niche within the host cell. Trafficking to the MTOC is dynein dependent although the activating and cargo-linking function of the dynactin complex is supplanted by unknown chlamydial protein(s). We demonstrate that once localized to the MTOC, the chlamydial inclusion maintains a tight association with cellular centrosomes. This association is sustained through mitosis and leads to a significant increase in supernumerary centrosomes, abnormal spindle poles, and chromosomal segregation defects. Chlamydial infection thus can lead to chromosome instability in cells that recover from infection.

IgG antibodies to HPV16, 52, 58 and 6 L1-capsids and spontaneous regression of cervical intraepithelial neoplasia

To identify the predictive markers for spontaneous regression of cervical intraepithelial neoplasia (CIN), we examined whether IgG antibody responses to common human papillomavirus (HPV) L1-capsids correlate with CIN regression. In a cohort study, a total of 116 Japanese women with CIN grade I/II were tested for cervical HPV DNA and serum IgG antibodies to HPV16/52/58/6 L1-capsids. Our data suggest that baseline IgG reactivities to HPV L1-capsids do not serve as a predictive marker of CIN regression, in contrast to histological CIN grades and HPV DNA status.