Cigarette smoking and cervical cancer: Part I: a meta-analysis

Systematic replication of smoking disease associations using survey responses and EHR data in the All of Us Research Program

OBJECTIVE

The All of Us Research Program (All of Us) aims to recruit over a million participants to further precision medicine. Essential to the verification of biobanks is a replication of known associations to establish validity. Here, we evaluated how well All of Us data replicated known cigarette smoking associations.

MATERIALS AND METHODS

We defined smoking exposure as follows: (1) an EHR Smoking exposure that used International Classification of Disease codes; (2) participant provided information (PPI) Ever Smoking; and, (3) PPI Current Smoking, both from the lifestyle survey. We performed a phenome-wide association study (PheWAS) for each smoking exposure measurement type. For each, we compared the effect sizes derived from the PheWAS to published meta-analyses that studied cigarette smoking from PubMed. We defined two levels of replication of meta-analyses: (1) nominally replicated: which required agreement of direction of effect size, and (2) fully replicated: which required overlap of confidence intervals.

RESULTS

PheWASes with EHR Smoking, PPI Ever Smoking, and PPI Current Smoking revealed 736, 492, and 639 phenome-wide significant associations, respectively. We identified 165 meta-analyses representing 99 distinct phenotypes that could be matched to EHR phenotypes. At P < .05, 74 were nominally replicated and 55 were fully replicated. At P < 2.68 × 10-5 (Bonferroni threshold), 58 were nominally replicated and 40 were fully replicated.

DISCUSSION

Most phenotypes found in published meta-analyses associated with smoking were nominally replicated in All of Us. Both survey and EHR definitions for smoking produced similar results.

CONCLUSION

This study demonstrated the feasibility of studying common exposures using All of Us data.

Risk factors for human papillomavirus infection, cervical intraepithelial neoplasia and cervical cancer: an umbrella review and follow-up Mendelian randomisation studies

BACKGROUND

Persistent infection by oncogenic human papillomavirus (HPV) is necessary although not sufficient for development of cervical cancer. Behavioural, environmental, or comorbid exposures may promote or protect against malignant transformation. Randomised evidence is limited and the validity of observational studies describing these associations remains unclear.

METHODS

In this umbrella review, we searched electronic databases to identify meta-analyses of observational studies that evaluated risk or protective factors and the incidence of HPV infection, cervical intra-epithelial neoplasia (CIN), cervical cancer incidence and mortality. Following re-analysis, evidence was classified and graded based on a pre-defined set of statistical criteria. Quality was assessed with AMSTAR-2. For all associations graded as weak evidence or above, with available genetic instruments, we also performed Mendelian randomisation to examine the potential causal effect of modifiable exposures with risk of cervical cancer. The protocol for this study was registered on PROSPERO (CRD42020189995).

RESULTS

We included 171 meta-analyses of different exposure contrasts from 50 studies. Systemic immunosuppression including HIV infection (RR = 2.20 (95% CI = 1.89-2.54)) and immunosuppressive medications for inflammatory bowel disease (RR = 1.33 (95% CI = 1.27-1.39)), as well as an altered vaginal microbiome (RR = 1.59 (95% CI = 1.40-1.81)), were supported by strong and highly suggestive evidence for an association with HPV persistence, CIN or cervical cancer. Smoking, number of sexual partners and young age at first pregnancy were supported by highly suggestive evidence and confirmed by Mendelian randomisation.

CONCLUSIONS

Our main analysis supported the association of systemic (HIV infection, immunosuppressive medications) and local immunosuppression (altered vaginal microbiota) with increased risk for worse HPV and cervical disease outcomes. Mendelian randomisation confirmed the link for genetically predicted lifetime smoking index, and young age at first pregnancy with cervical cancer, highlighting also that observational evidence can hide different inherent biases. This evidence strengthens the need for more frequent HPV screening in people with immunosuppression, further investigation of the vaginal microbiome and access to sexual health services.

Non-Genetic Factors and Risk of Cervical Cancer: An Umbrella Review of Systematic Reviews and Meta-Analyses of Observational Studies

Objectives: The association between non-genetic risk factors and cervical cancer (CC) remains controversial and unclear. This umbrella review was conducted to evaluate and synthesize previously published systematic reviews and meta-analyses related to non-genetic factors and CC risk.

Methods: We searched PubMed, Web of Science, and EMBASE to identify studies investigating the association between extragenetic factors and CC risk. For each article, we calculated the summary effect size and the 95% confidence interval. Specific criteria were used to classify the association into four levels: strong, highly suggestive, suggestive, or weak.

Results: A total of 18 meta-analyses of different risk factors for CC were examined; these studies covered risk factors related to diet, lifestyle, reproduction, disease, viral infection, microorganisms, and parasites. Oral contraceptive use and Chlamydia trachomatis infection were shown to increase CC risk, and this was supported by strong evidence. Additionally, there were four risk factors supported by highly suggestive evidence and six risk factors supported by suggestive evidence.

Conclusion: In conclusion, there is a strong association between oral contraceptive use, Chlamydia trachomatis infection, and increased CC risk.

Dose-risk relationships between cigarette smoking and cervical cancer: a systematic review and meta-analysis

OBJECTIVE

Cervical cancer (CC) is the fourth most frequent cancer worldwide. Cigarette smoking has been shown to influence CC risk in conjunction with human papillomavirus (HPV) infection. The aim of this study is to provide the most accurate and updated estimate of this association and its dose-response relationship.

METHODS

Using an innovative approach for the identification of original publications, we conducted a systematic review and meta-analysis of studies published up to January 2021. Random effects models were used to provide pooled relative risks (RRs) of CC for smoking status. Dose-response relationships were evaluated using one-stage random effects models with linear or restricted cubic splines models.

RESULTS

We included 109 studies providing a pooled RR of invasive CC and preinvasive lesions, respectively, of 1.70 [95% confidence interval (CI), 1.53-1.88] and 2.11 (95% CI, 1.85-2.39) for current versus never smokers, and, respectively, 1.13 (95% CI, 1.02-1.24) and 1.29 (95% CI, 1.15-1.46) for former versus never smokers. Considering HPV does not alter the positive association or its magnitude. Risks of CC sharply increased with few cigarettes (for 10 cigarettes/day, RR = 1.72; 95% CI, 1.34-2.20 for invasive CC and RR = 2.13; 95% CI, 1.86-2.44 for precancerous lesions). The risk of CC increased with pack-years and smoking duration and decreased linearly with time since quitting, reaching that of never smokers about 15 years after quitting.

CONCLUSION

This comprehensive review and meta-analysis confirmed the association of smoking with CC, independently from HPV infection. Such association rose sharply with smoking intensity and decreased after smoking cessation.

Effect of Alpha-Lipoic Acid Supplementation on Low-Grade Squamous Intraepithelial Lesions-Double-Blind, Randomized, Placebo-Controlled Trial

Low-grade squamous intraepithelial lesion (SIL) is a cytologic diagnosis etiologically related to human papilloma virus (HPV) infection that leads to the release of inflammation mediators, the formation of reactive oxygen species (ROS) and decreased levels of antioxidants in tissues, which is why antioxidants might be considered effective against SIL progression. This randomized double-blind placebo-controlled study aimed to investigate the effectiveness of alpha-lipoic acid (ALA) supplementation (600 mg/day) on the regression of low-grade SIL in 100 patients. Low-grade SIL was determined after the cytological screening, colposcopic examination and targeted biopsy and histological confirmation of cytological−colposcopic diagnosis. Inflammation parameters and the presence of HPV were determined by standard laboratory methods. Dietary and lifestyle habits were investigated using a standardized and validated semi-quantitative food questionnaire (FFQ). ALA supplementation significantly reduced the proportion of patients with low-grade cytological abnormalities, in comparison to placebo. Given the obtained level of significance (p < 0.001), the presented results indicate that short-term ALA supplementation shows a clinically significant effect on cervical cytology. Future studies should focus on the use of innovative formulations of ALA that might induce bioavailability and therapeutic efficiency against HPV infection and the investigation of synergistic effects of concurrent dietary/lifestyle modification and ALA supplementation in both low-grade and high-grade SIL.

Association between involuntary smoking and risk of cervical cancer in Chinese female never smokers: A prospective cohort study

Involuntary smoking was a major public health problem for women in China. Previous studies mainly focused on secondhand smoke (SHS), which referred to direct exposure to smoke from burning cigarettes. Little evidence existed about the relationship between thirdhand smoke (THS), the residual tobacco smoke remaining in the environment after tobacco had been smoked, and cervical cancer. The China Kadoorie Biobank (CKB) study recruited 0.3 million female participants from 10 areas across China during 2004-2008. After an 11.2-year median follow-up, we documented 1094 cervical cancer cases. Multivariable Cox regression yielded adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of SHS and THS with cervical cancer incidence, respectively and jointly. Overall, 60.3% reported weekly SHS exposure, and 83.2% had been exposed to THS. Daily SHS exposure and THS exposure at the enrollment were associated with elevated risks of cervical cancer incidence, with adjusted HRs (95% CI) of 1.22 (1.06,1.42) and 1.24 (1.03,1.49), respectively. The longer the exposure duration, the higher the risks (P for trend = 0.006, 0.035, respectively). Compared with those who were neither exposed to SHS nor THS, those exposed to both SHS and THS had the highest risk, with adjusted HRs (95% CI) of 1.29 (1.05,1.58). Area of residence, breastfeeding duration and heating fuel types are potential effect modifiers. Among Chinese females, both SHS and THS were associated with higher risks of cervical cancer incidence, and a dose-response relationship was found between the exposure duration and cervical cancer risk. Our findings reinforce the need for proactive strategies for tobacco control, to protect women health.

A cluster randomized controlled trial for a multi-level, clinic-based smoking cessation program with women in Appalachian communities: study protocol for the "Break Free" program

BACKGROUND

The cervical cancer burden is high among women living in Appalachia. Cigarette smoking, a cervical cancer risk factor, is also highly prevalent in this population. This project aims to increase smoking cessation among women living in Appalachia by embedding a smoking cessation program within a larger, integrated cervical cancer prevention program.

METHODS

The broader program, the Take CARE study, is a multi-site research collaborative designed to address three risk factors for cervical cancer incidence and mortality: tobacco use, human papillomavirus (HPV) infection, and cervical cancer screening. Break Free is a primary care clinic-based implementation program that aims to promote smoking cessation among female smokers in Appalachia by standardizing clinical practice protocols. Break Free includes: (1) implementation of a tobacco user identification system in the Electronic Health Record, (2) clinic staff and provider training on the Ask, Advise and Refer (AAR) model, (3) provider implementation of AAR to identify and treat women who want to quit smoking within the next 6 months, (4) facilitated access to cessation phone counseling plus pharmacotherapy, and (5) the bundling of Break Free tobacco cessation with HPV vaccination and cervical cancer screening interventions in an integrated approach to cervical cancer prevention. The study spans 35 Appalachian health clinics across 10 healthcare systems. We aim to enroll 51 adult female smokers per health system (total N = 510). Baseline and follow-up data will be obtained from participant (provider and patient) surveys. The primary outcome is self-reported 12-month point prevalence abstinence among enrolled patients. All randomized patients are asked to complete follow-up surveys, regardless of whether they participated in tobacco treatment. Data analysis of the primary aims will follow intent-to-treat methodology. Secondary outcomes will assess program implementation and cost effectiveness.

DISCUSSION

Addressing high tobacco use rates is critical for reducing cervical cancer morbidity and mortality among women living in Appalachia. This study evaluates the implementation and effectiveness of a smoking cessation program in increasing smoking cessation among female smokers. If results demonstrate effectiveness and sustainability, implementation of this program into other health care clinics could reduce both rates of smoking and cervical cancer. Trial registration NCT04340531 (April 9, 2020).

Use of electronic nicotine delivery systems (ENDS) among U.S. women of reproductive age: Prevalence, reported reasons for use, and toxin exposure

Given the rapidly expanding marketplace for Electronic Nicotine Delivery Systems (ENDS), it is important to monitor patterns of use, particularly among vulnerable populations. This study examined ENDS prevalence, reasons for use (i.e., to help quit smoking and for appealing flavors), and toxin exposure among U.S. women of reproductive age using data from the Population Assessment of Tobacco and Health (PATH) Study (2013-17). Exclusive ENDS users, dual users of ENDS and cigarettes, and exclusive cigarette smokers were compared within and between pregnant and not-pregnant women. Among pregnant women, prevalence of exclusive ENDS and dual use was similar (0.8%; 95%CI = 0.4-1.2% vs. 1.4%; 95%CI = 0.9-2.0%, respectively), but exclusive ENDS use was less prevalent than dual use among not-pregnant women (1.1%; 95%CI = 0.9-1.4% vs. 3.7%; 95%CI = 3.3-4.0%, respectively). Most women reported ENDs were used to help quit smoking (66.5-90.0%) and for appealing flavors (57.6-87.4%), and endorsement rates did not differ by use pattern or pregnancy status. Except for metals, toxin exposure was substantially lower for exclusive ENDS users relative to dual users and exclusive cigarette smokers regardless of pregnancy status. Pregnant and not-pregnant U.S. women regularly report using ENDS for help with quitting smoking and for appealing flavors. Although no type or pattern of tobacco/nicotine use is safe, especially during pregnancy, using ENDS exclusively is consistent with lower overall toxin exposure for pregnant and not-pregnant women. This study advances understanding of ENDS use and toxin exposure in women of reproductive age, a population highly vulnerable to the effects of nicotine/tobacco consumption.

Oxidative stress markers in patient-derived non-cancerous cervical tissues and cells

High-risk human papillomaviruses (HPV) are the causative agents of cervical cancer. However, not all infected women develop cervical cancer. Cervical tumorigenesis is characterized by a multifactorial etiology, with oxidative stress (OS) likely playing a major role. In addition to exogenous sources, metabolic processes also contribute to OS. In principle, variability in levels of cervical OS has the potential to influence the likelihood of conversion to cervical cancer. To ask whether such variability indeed existed, we assessed the levels of ROS and the oxidative DNA damage biomarker 8-oxodG in normal non-cancerous cervical tissues and cells obtained from women with uterovaginal pelvic organ prolapse following vaginal hysterectomy. We demonstrated five and ten-fold variability between tissues isolated from the transformation zone (TZ) and ectocervix (EC) of different women, respectively. Despite the greater variability (likely due to differences in tissue composition), the overall pattern of ROS levels in EC tissues mirrored those obtained in their corresponding TZ tissues. Our results also show that the levels of ROS in TZ tissues were always higher than or equal to those found in the respective EC tissues, providing a possible explanation for TZ tissue being the primary target for HPV infection and cervical carcinogenesis. Interestingly, primary keratinocytes isolated and cultured from these cervical specimens also displayed high variability in ROS levels, with some strongly mirroring the levels of ROS observed in their corresponding tissues, while others were less closely associated. Finally, we demonstrated that the levels of DNA damage mirrored the levels of ROS in the cultured primary cells. Understanding the factors and mechanisms that dispose certain individuals to develop cervical cancer has the potential to enable the development of approaches that make the conversion of HPV infection to cancer development even more rare.

Cofactors and Their Association with Cancer of the Uterine Cervix in Women Infected with High-Risk Human Papillomavirus in South India

Background:

Human papilloma viruses (HPVs) are recognized as the major etiological agents of most pre invasive and invasive cancer of the uterine cervix. Many cofactors in association with high-risk HPV (HR-HPV) trigger infection which leads to cervical carcinogenesis. The aim was to study various cofactors and their association with cervical cancer in women infected with HR-HPV.

Methods:

The present study screened a total of 156 subjects for the presence of HPV infection. Association of various cofactors with cervical cancer was estimated using binary logistic regression analysis.

Results:

The HR-HPV infection showed a very significant risk factor for cervical cancer. Among the cofactors, the education level, early sexual exposure and age at pregnancy had no significant association while low socioeconomic status (SES) and high parity showed significant association as risk factors for cervical cancer. Tobacco chewing with betel quid was not significantly associated with cervical cancer.

Conclusions:

The present study indicates that low SES is a major risk factor associated with cervical cancer. Bringing awareness about HPV infection and intensifying routine screening programs for cervical cancer will help reduce the risk of cervical cancer among women with low SES in this region.

Co-carcinogenesis: Human Papillomaviruses, Coal Tar Derivatives, and Squamous Cell Cervical Cancer

Cervical cancer (CC) is the fourth most common cancers among women worldwide. Human papillomaviruses (HPVs) play a major role in the etiology of CC, with several lines of epidemiologic and experimental evidence supporting a role for non-viral (co-carcinogens) and host genetic factors in controlling the risk for progression to neoplasia among HPV-infected individuals. The role of co-carcinogens in the development of CC is significant in the developing world where poor sanitation and other socio-economic conditions increase the infectious cancer burden. Here, we discuss how exposure to environmental factors such as coal tar derivatives from cigarette smoking, tar-based sanitary products, and inhaled smoke from biomass-burning stoves, could activate host pathways involved in development of HPV-associated squamous cell cancers in resource-limited settings. Understanding interactions between these pathways with certain oncogenic HPV genotypes may guide implementation of strategies for control and treatment of HPV-associated cancers that develop in populations at high risk of exposure to various co-carcinogens.

Incidence Trends of Cervical Cancer in Adolescents and Young Adults: Brazilian Population Based Data

PURPOSE

High incidence rates for cervical cancer in adolescents and young adults (AYAs: 15-29 years) make this the most common carcinoma in Brazil. Our aim was to analyze the incidence trends for cervical cancer (CC) and in situ neoplasia (IsN) among this age group.

METHODS

Incidence data were extracted from 21 Brazilian population-based cancer registries (PBCRs). Tumors with behavior code/3 (malignant) were classified as CC. Tumors with behavior code/2 were classified as IsN. Age-adjusted and age-specific incidence rates were calculated for individuals aged 15-19 years, 20-24 years, and 25-29 years. Incidence trends were evaluated by joinpoint regression analyses.

RESULTS

The median incidence rate of CC for AYA in Brazil was 3.63 per 100,000, with the highest rate observed in Recife (27.50 per 100,000). Significant increase in incidence for CC was identified in two PBCRs, with decreased rates for three PBCRs. The median incidence rate of IsN was 16.78 per 100,000 and was highest in Roraima (93.37 per 100,000). Increased incidence rates for IsN were identified in six PBCRs, with significant decreases in two PBCRs.

CONCLUSION

The incidence rate for CC among AYA in Brazil is high and warrants intervention in terms of both prevention and control.

Prevalence, Age Distribution, and Risk Factors of Visual Inspection With Acetic Acid-Positive From 2007 to 2011 in Jakarta

Background

Cervical cancer is still the second most frequent cancer among Indonesian women, thus screening program is still critically important to prevent it. Visual inspection with acetic acid (VIA) was introduced as a method which is most suitable with Indonesia’s condition compared with the other screening methods. The Female Cancer Program from Jakarta Regional collaborated with Leiden University in 2007 to 2011 has done cervical cancer screening using VIA method, involving 25,406 women spreading across several primary health centers in Jakarta. By using these data, we found out the prevalence, age distribution, and risk factor of VIA positive in Jakarta as a basis to predict the budget and logistics for the next cervical cancer screening and to do an advocating to the Jakarta’s government.

Methods

A secondary data analysis was conducted from several areas in Jakarta from 2007 to 2011. VIA test was used as the screening method, and performed by doctors and midwives with technical supervision by gynecologists.

Results

From 25,406 women, there were 1,192 cases (4.7%) of VIA test positive. The risk factors that can significantly influence the result of VIA positive were number of marriage, parity, smoking habits, and the use of hormonal contraception with OR 1.51, 1.85, 1.95, and 0.68, respectively.

Conclusions

Prevalence of VIA test-positive is 4.7% in Jakarta population. The findings of precancerous lesions and cervical cancers are not only between thirty and fifty years old, but also below the thirty years old and after fifty years old. We suggest that VIA test should be performed to all reproductive age and elder women who are not screened yet.

Impact of exposure to tobacco smoke, arsenic, and phthalates on locally advanced cervical cancer treatment-preliminary results

BACKGROUND

Cancer research is a national and international priority, with the efficiency and effectiveness of current anti-tumor therapies being one of the major challenges with which physicians are faced.

OBJECTIVE

To assess the impact of exposure to tobacco smoke, arsenic, and phthalates on cervical cancer treatment.

METHODS

We investigated 37 patients with locally advanced cervical carcinoma who underwent chemotherapy and radiotherapy. We determined cotinine and five phthalate metabolites in urine samples collected prior to cancer treatment, by gas chromatography coupled to mass spectrometry, and urinary total arsenic by atomic absorption spectrometry with hydride generation. We used linear regression to evaluate the effects of cotinine, arsenic, and phthalates on the change in tumor size after treatment, adjusted for confounding variables.

RESULTS

We detected no significant associations between urinary cotinine, arsenic, or phthalate monoesters on change in tumor size after treatment, adjusted for urine creatinine, age, baseline tumor size, and cotinine (for arsenic and phthalates). However, higher %mono-ethylhexyl phthalate (%MEHP), a putative indicator of phthalate diester metabolism, was associated with a larger change in tumor size (β = 0.015, 95% CI [0.003-0.03], P = 0.019).

CONCLUSION

We found no statistically significant association between the urinary levels of arsenic, cotinine, and phthalates metabolites and the response to cervical cancer treatment as measured by the change in tumor size. Still, our results suggested that phthalates metabolism may be associated with response to treatment for locally advanced cervical cancer. However, these observations are preliminary and will require confirmation in a larger, more definitive investigation.

Genetic susceptibility to cervical cancer: role of common polymorphisms in apoptosis-related genes

Cervical cancer is a common malignancy which poses a significant health burden among women, especially those living in the developing countries. Although human papillomavirus (HPV) infection has been unequivocally implicated in the etiopathogenesis of the cancer, it alone is not adequate to contribute to the malignant transformation of cervical cells. Most HPV infections regress spontaneously, and only a small proportion of women have persistent infections which eventually lead to malignancy. This suggests that interplays between HPV infection and other cofactors certainly exist during the process of cervical carcinogenesis, which synergistically contribute to the differential susceptibility of an individual to the malignancy. Undoubtedly, host genetic factors represent a major element involved in such a synergistic interaction, and accumulating evidence suggests that polymorphisms in apoptosis-related genes play an important role in the genetic susceptibility to cervical cancer. This review consolidates the recent literatures on the role of common polymorphisms in apoptosis-related genes in genetic susceptibility to cervical cancer.

Comparison of crude and age-specific incidence rates of breast, ovary, endometrium and cervix cancers in Iran, 2005

BACKGROUND

Cancer accounts for 12.6% of total deaths in the world (just after heart disease).

MATERIALS AND METHODS

Frequency and age-specific incidence rates of breast and gynecologic cancers in Iran are calculated based on the dataset of the National Cancer Registry of Iran in 2005.

RESULTS

Gynecologic and breast cancer accounted for 7.6% and 25.6% of total cancer cases, respectively. Ovarian cancer was the most frequent gynecologic cancer followed by endometrium. Endometrial cancer revealed the highest age specific incidence rate followed by ovary (after 59 years).

CONCLUSIONS

Regarding disease burden, breast and gynecologic cases account for 33.4% of total cancer patients. The age specific incidence rate is a useful guide in epidemiologic and future plans.

[Operative risk related to tobacco in gynecology]

If tobacco has been recognized for many years as a major risk factor for cardiovascular, lung diseases and cancer in the general population, women are insufficiently aware of the consequences and the specific gynecological operative risks related to this intoxication. Thus, a regular tobacco consumption increases the risk for many gynecological conditions may require surgical treatment with in addition a significant negative impact on the healing process and the risk of postoperative complications. The operative risk must be explained by surgeons in daily practice gynecological, pelvic surgery or breast screening. The issue of smoking cessation should precede surgery has been established by a consensus conference of experts on perioperative smoking held in 2005. The implementation of these recommendations during the preoperative period requires improvement of staff training and better practices to allow smoking cessation effective and sustainable. It is lawful in this context to delay scheduled surgery of 6 to 8 weeks to allow an optimal smoking cessation and to continue smoking cessation for the time necessary for healing to reduce the excess operative risk associated with smoking.

Age-group differences in human papillomavirus types and cofactors for cervical intraepithelial neoplasia 3 among women referred to colposcopy

BACKGROUND

Recommendations for high-risk human papillomavirus (HR-HPV) testing as an adjunct to cytology for cervical cancer screening differ by age group, because HR-HPV tests lack adequate specificity in women aged <30. Here, we assess age-group differences in HPV types and other risk factors for cervical intraepithelial neoplasia (CIN) grade 3 or worse (CIN3+) versus CIN0-2 in women from four colposcopy clinics.

METHODS

Women ages 18 to 69 (n = 1,658) were enrolled and completed structured interviews to elicit data on behavioral risk factors prior to their examinations. HPV genotyping was done on exfoliated cervical cell samples. We estimated relative risks (RR) for HPV types and cofactors for CIN3+, overall and stratified by age group.

RESULTS

After 2 years of follow-up, we identified 178 CIN3+, 1,305 CIN0-2, and 175 indeterminate outcomes. Nonvaccine HR-HPV types were only associated with CIN3+ among women ≥ 30 (RR = 2.3, 95% CI: 1.5-3.4; <30: RR = 0.9). Among all HR-HPV-positive women, adjusting for age, significant cofactors for CIN3+ included current smoking (RR = 1.5), former smoking (RR = 1.8), regular Pap screening (RR = 0.7), current regular condom use (RR = 0.5), and parity ≥ 5 (RR = 1.6, P(trend) for increasing parity = 0.07). However, the parity association differed by age group (≥ 30: RR = 1.8, P(trend) = 0.008; <30: RR = 0.9; P(trend) =.55).

CONCLUSION

Subgroup variation by age in the risk of CIN3+ points to the importance of the timing of exposures in relation to CIN3+ detection.

IMPACT

Future screening strategies need to consider natural history and secular trends in cofactor prevalence in the pursuit of appropriately sensitive and specific screening tools applied to appropriate age groups.

Pattern Discovery from Biological Data

Extracting useful information from structured and unstructured biological data is crucial in the health industry. Some examples include medical practitioner’s need to identify breast cancer patient in the early stage, estimate survival time of a heart disease patient, or recognize uncommon disease characteristics which suddenly appear. Currently there is an explosion in biological data available in the data bases. But information extraction and true open access to data are require time to resolve issues such as ethical clearance. The emergence of novel IT technologies allows health practitioners to facilitate the comprehensive analyses of medical images, genomes, transcriptomes, and proteomes in health and disease. The information that is extracted from such technologies may soon exert a dramatic change in the pace of medical research and impact considerably on the care of patients. The current research will review the existing technologies being used in heart and cancer research. Finally this research will provide some possible solutions to overcome the limitations of existing technologies. In summary the primary objective of this research is to investigate how existing modern machine learning techniques (with their strength and limitations) are being used in the indent of heartbeat related disease and the early detection of cancer in patients. After an extensive literature review these are the objectives chosen: to develop a new approach to find the association between diseases such as high blood pressure, stroke and heartbeat, to propose an improved feature selection method to analyze huge images and microarray databases for machine learning algorithms in cancer research, to find an automatic distance function selection method for clustering tasks, to discover the most significant risk factors for specific cancers, and to determine the preventive factors for specific cancers that are aligned with the most significant risk factors. Therefore we propose a research plan to attain these objectives within this chapter. The possible solutions of the above objectives are: new heartbeat identification techniques show promising association with the heartbeat patterns and diseases, sensitivity based feature selection methods will be applied to early cancer patient classification, meta learning approaches will be adopted in clustering algorithms to select an automatic distance function, and Apriori algorithm will be applied to discover the significant risks and preventive factors for specific cancers. We expect this research will add significant contributions to the medical professional to enable more accurate diagnosis and better patient care. It will also contribute in other area such as biomedical modeling, medical image analysis and early diseases warning.

Cigarette smoke condensate-induced oxidative DNA damage and its removal in human cervical cancer cells

Exposure to cigarette smoke is well documented to increase oxidative stress and could account for higher risk of cervical cancer in smokers. Cervical pre-cancerous lesions that are initiated by human papillomavirus (HPV) infection generally regress in the absence of known risk factors such as smoking. 8-oxodeoxyguanosine (8-oxodG) is a highly mutagenic oxidative DNA lesion that is formed by the oxidation of deoxyguanosine. In the present study, we examined: a) the effect of cigarette smoke condensate (CSC) on 8-oxodG formation in and its removal from HPV-transfected (ECT1/E6 E7), HPV-positive (CaSki) and HPV-negative (C33A) human cervical cancer cells, and b) the cell cycle progression and apoptosis in CSC-treated ECT1/E6 E7 cells. CSC induced 8-oxodG in a dose- (p=0.03) and time (p=0.002)-dependent fashion in ECT1/E6 E7 cells as determined by flow cytometry. A 2.4-fold higher level of 8-oxodG was observed in HPV-positive compared with HPV-negative cells. However, 8-oxodG lesions were almost completely removed 72 h post-exposure in all cell lines as determined by ImageStream analysis. This observation correlates with the 2- and 5-fold increase in the p53 levels in ECT1/E6 E7 and CaSki cells with no significant change in C33A cells. We conclude that: a) cigarette smoke constituents induce oxidative stress with higher burden in HPV-positive cervical cancer cells and b) the significant increase observed in p53 levels in wild-type cervical cells (ECT1/E6 E7 and CaSki) may be attributed to the p53-dependent DNA repair pathway while a p53-independent pathway in C33A cells cannot be ruled out.

Null genotypes of GSTM1 and GSTT1 contribute to risk of cervical neoplasia: an evidence-based meta-analysis

Background and Objectives

Glutathione S-transferases (GSTs) are multifunctional enzymes that play a key role in the detoxification of varieties of both endogenous products of oxidative stress and exogenous carcinogens.

Methods

In this meta-analysis, twenty-five studies were identified by searching PubMed, EMBASE, ISI Web of Science and CBM databases: 23 evaluated GSTM1 and 19 evaluated GSTT1. Crude odds ratios with corresponding 95% confidence intervals were used to estimate the association between GSTM1 and GSTT1 polymorphisms and risk of cervical neoplasia. Subgroup analyses were conducted by pathological history, ethnicity, source of DNA for genotyping, quality score, and matching variable.

Results

The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk of cervical neoplasia (for GSTM1: OR = 1.40; 95%CI, 1.19–1.65; for GSTT1: OR = 1.30; 95%CI, 1.05–1.62, respectively). Subgroup analyses showed that the null genotype of GSTM1 increased the risk of cervical neoplasia in Asians, studies with DNA isolation from white blood cells and tissue samples, both high and low quality studies, and matched studies. In GSTM1-GSTT1 interaction analysis, individuals with dual null genotype were associated with a significantly increased risk of cervical neoplasia (OR = 1.72; 95%CI, 1.18–2.51).

Conclusion

These findings indicate that GSTM1 and GSTT1 polymorphisms, particularly GSTM1-GSTT1 interaction, may play critical roles in the development of cervical neoplasia. A conservative manner should be adopted to interpret these results because of obvious heterogeneity between-study, unadjusted data, and relatively small sample size in this meta-analysis. Well designed studies with larger sample size are of great value to confirm these results.

Passive smoke exposure and abnormal cervical cytology in a predominantly Hispanic population

OBJECTIVE

We sought to evaluate the association between passive cigarette smoke exposure and cervical cytological abnormalities in a predominantly Hispanic sample.

STUDY DESIGN

Data were collected as part of a larger, ongoing randomized clinical trial. Inclusion criteria were met by 4403 Hispanic (73%) and non-Hispanic (27%) women between 18-55 years of age (mean = 30.14 ± 8.7). Analysis of variance and multivariate logistic regression determined the association between passive smoke exposure and Pap abnormality.

RESULTS

Passive smoke exposure was positively associated with having an abnormal Pap smear (odds ratio, 1.70; 95% confidence interval, 1.14-2.52) as was current active smoking (odds ratio 1.45; 95% confidence interval, 1.03-2.04). Neither effect was modified by ethnicity. Increasing hours per week of passive smoke exposure was associated with low-grade squamous intraepithelial lesion (P < .05).

CONCLUSION

Passive smoke exposure is an important independent risk factor for cytological abnormalities in Hispanic and non-Hispanic women. This study adds to the growing body of evidence of the dangers of passive smoke exposure.

Prevalence of abnormal cervical cytology among subfertile Saudi women

BACKGROUND AND OBJECTIVES

Since cervical cancer is reportedly the seventh most frequent cancer in women in Saudi Arabia and the eighth most frequent cancer among women aged between 15 and 44 years, we wanted to determine the prevalence of abnormal cervical cytology among subfertile women attending the reproductive medicine unit of a tertiary care center in Saudi Arabia.

METHODS

This was a retrospective, cross-sectional, hospital-based study. A Pap smear was done for 241 of 493 (48.9%) subfertile women from January 2008 through February 2009.

RESULTS

The Pap smear was normal in 166 of 241 patients (67.9%), abnormal in 71 (29.5%), and unsatisfactory for evaluation in 4 (1.7%). According to the revised Bethesda system, epithelial cell abnormality was found in 7 (2.9%), inflammation in 55 (22.8%), and infection in 9 (3.7%) patients. Epithelial cell abnormalities were further classified as atypical squamous cells of undetermined significance (ASC-US) (n=3, 42.8%), atypical squamous cells of high grade (ASC-H) (n=1, 14.3%), low-grade squamous intraepithelial lesion (LSIL) (n=2, 28.5%), and glandular cell abnormalities (AGS) (n=1, 14.3%).

CONCLUSION

The high prevalence of abnormal cervical cytology in our subfertile women accentuates the need for screening in patients eligible for in vitro fertilization. In addition, a well-organized screening program for cervical cell abnormalities at the national level should be implemented to allow identification of subfertile women at risk so that potentially life-saving measures can be undertaken early.

Cigarette smoke-induced DNA damage and repair detected by the comet assay in HPV-transformed cervical cells

Human papillomavirus (HPV) is the causative factor in the development and progression of cervical cancers in >97% of the cases, although insufficient. Epidemiological studies suggest an elevated risk of cervical cancer for cigarette smokers; therefore, we examined cigarette smoke-induced DNA damage and repair in HPV16-transformed human ectocervical cells (ECT1/E6 E7). Cells were treated with cigarette smoke condensate (CSC) for 72 h to assess the formation of single- and double-strand DNA breaks, measured by alkaline and neutral single cell gel electrophoresis assays, respectively. The mean tail length of cells with single-strand breaks was increased by 1.8-, 2.7- and 3.7-fold (p<0.001) after treatment with 4, 8 and 12 microg/ml CSC, respectively. The tail length with double-strand breaks was also increased dose-dependently. These results were further supported by measurement of the mean tail moment: the increase in both single- and double-strand breaks were much more pronounced with increasing concentration of CSC, by up to 23.5-fold (p<0.0001 for both assays). To examine the DNA repair, cells were treated with CSC for 72 h, followed by CSC withdrawal and re-incubation of the cells with fresh medium for 24, 48, or 72 h. Both single- and double-strand DNA breaks were removed during the initial 24 h but no further removal of the damage was observed. Up to 80% of residual single- and double-strand DNA breaks (p<0.05) were found to persist at all CSC concentrations examined. Ellagic acid, a known antioxidant and free-radical scavenger, was found to significantly inhibit DNA breaks induced by CSC. Thus, free radicals may be a plausible source of CSC-induced DNA damage. These data show that CSC-mediated DNA strand breaks are highly persistent, and suggest that persistence of cigarette smoke-associated DNA damage in the presence of HPV infection may lead to increased mutations in cervical cells and ultimately higher cancer risk.

[Human papillomavirus and cervical neoplasia]

Human papillomavirus (HPV) has been established as an important etiological factor for the development of cervical cancer. This DNA virus primarily infects the epithelium and can induce benign and malignant lesions of the mucous membranes and skin. Some HPVs are considered high risk due to their role in malignant progression of cervical tumors. Genital HPV infections are common and usually transient among young sexually active women. Only a small fraction of infected women develop cervical cancer, implying the involvement of environmental and genetic cofactors in cervical carcinogenesis. Classification, virology, pathology, natural history, epidemiological features of genital HPV infection, and future prospects for cervical cancer prevention with HPV vaccines will be reviewed here.

Acceptance of the HPV vaccine for adolescent girls: analysis of state-added questions from the BRFSS

PURPOSE

Previous research regarding human papillomavirus (HPV) awareness and vaccine acceptance has relied on convenience or other selected samples of the population. To assess the prevalence of HPV awareness and vaccine acceptance in Kentucky we added questions to the 2006 Kentucky Behavioral Risk Factor Survey System (BRFSS), a population-based survey of health behaviors.

METHODS

Women who participated in the statewide BRFSS were asked two HPV-related questions: one assessed previous awareness of HPV, and another assessed vaccine acceptance for girls 10 to 15 years old. We used crosstabulations and multivariate logistic regression to determine which factors were associated with HPV awareness and vaccine acceptance. Because the HPV vaccine Gardasil was approved in June 2006, we conducted an analysis of pre- and postapproval HPV awareness and vaccine acceptance. We also compared results across Appalachian and non-Appalachian counties, two distinct regions of Kentucky.

RESULTS

Overall, 57.6% of women had heard of HPV, and 70.2% accepted vaccination for girls. HPV awareness increased after Gardasil's approval, but the increase was much smaller among Appalachian women. Prevalence of vaccine acceptance was unchanged in both regions. Awareness of HPV was not associated with vaccine acceptance, and factors significantly associated with vaccine acceptance in multivariate analysis differed by Appalachian status.

CONCLUSIONS

This population-based survey of Kentucky women found relatively high vaccine acceptance for girls. Also, many respondents reported not knowing whether they accept vaccination, and factors associated with vaccine acceptance varied by Appalachian status. These findings suggest that acceptance of the HPV vaccine for girls may improve with targeted interventions.

Inequalities in the incidence of cervical cancer in South East England 2001-2005: an investigation of population risk factors

BACKGROUND

The incidence of cervical cancer varies dramatically, both globally and within individual countries. The age-standardised incidence of cervical cancer was compared across primary care trusts (PCTs) in South East England, taking into account the prevalence of known behavioural risk factors, screening coverage and the deprivation of the area.

METHODS

Data on 2,231 cases diagnosed between 2001 and 2005 were extracted from the Thames Cancer Registry, and data on risk factors and screening coverage were collated from publicly available sources. Age-standardised incidence rates were calculated for each PCT using cases of squamous cell carcinoma in the screening age group (25-64 years).

RESULTS

The age-standardised incidence rate for cervical cancer in South East England was 6.7 per 100,000 population (European standard) but varied 3.1 fold between individual PCTs. Correlations between the age-standardised incidence rate and smoking prevalence, teenage conception rates, and deprivation were highly significant at the PCT level (p < 0.001). However, screening coverage was not associated with the incidence of cervical cancer at the PCT level. Poisson regression indicated that these variables were all highly correlated and could not determine the level of independent contribution at a population level.

CONCLUSION

There is excess disease burden within South East England. Significant public health gains can be made by reducing exposure to known risk factors at a population level.

Is smoking an independent risk factor for invasive cervical cancer? A nested case-control study within Nordic biobanks

The strong correlation between smoking and exposure to oncogenic human papillomaviruses (HPVs) has made it difficult to verify the independent role of smoking in cervical carcinogenesis. Thus, the authors evaluated this role. Five large Nordic serum banks containing samples from more than 1,000,000 subjects were linked with nationwide cancer registries (1973-2003). Serum samples were retrieved from 588 women who developed invasive cervical cancer and 2,861 matched controls. The samples were analyzed for cotinine (a biomarker of tobacco exposure) and antibodies to HPV types 16 and 18, herpes simplex virus type 2, and Chlamydia trachomatis. Smoking was associated with the risk of squamous cell carcinoma (SCC) among HPV16- and/or HPV18-seropositive heavy smokers (odds ratio=2.7, 95% confidence interval: 1.7, 4.3). A similar risk of SCC (odds ratio=3.2, 95% confidence interval: 2.6, 4.0) was found in heavy smokers after adjustment for HPV16/18 antibodies. The point estimates increased with increasing age at diagnosis and increasing cotinine level. This study confirms that smoking is an independent risk factor for cervical cancer/SCC in women infected with oncogenic HPVs. These findings emphasize the importance of cervical cancer prevention among women exposed to tobacco smoke.

Tobacco smoking and chewing as risk factors for multiple human papillomavirus infections and cervical squamous intraepithelial lesions in two countries (Côte d'Ivoire and Finland) with different tobacco exposure

Our objective was to compare the association between tobacco smoking and chewing and the risk of multiple human papillomavirus (HPV) infections and cervical squamous intraepithelial lesions (SILs) in two populations with different tobacco exposure. We studied 2,162 women from Côte d'Ivoire, West Africa, and 419 women from Finland, Northern Europe, with baseline data on cervical screening, HPV DNA status and smoking and chewing habits. The proportion of women who smoked and/or chewed tobacco was higher in Finland (36.8%) than in Côte d'Ivoire (3.7%), where tobacco chewing (2.6%) was more common than tobacco smoking (1.4%). Having multiple HPV infections was common in HPV16 and/or 18-infected women (60.4% in Finland and 47.2% in Côte d'Ivoire). There was no increased risk of multiple HPV infections among tobacco consumers. We found that women >or=30 years of age exposed to tobacco through smoking in Finland (OR: 2.2, 95% CI: 0.5-8.7) and chewing in Côte d'Ivoire (OR: 5.5, 95% CI: 2.1-14) had a moderately or highly increased risk of high-grade SIL, respectively. In the latter, the risk was statistically significant. Our findings emphasize the need for health initiatives targeted to prevent tobacco smoking or chewing among women especially in less industrialized countries.

Glutathione-S-transferase M1 and T1 and cytochrome P1A1 genetic polymorphisms and susceptibility to cervical intraepithelial neoplasia in Greek women

The aim of the study was to determine the importance of genetic polymorphisms of glutathione-S-transferase T1 and M1 and cytochrome P1A1 genes in the development of cervical intraepithelial neoplasia in Greek women. This was a prospective, case-control study conducted by the Cervical Pathology and Colposcopy Unit of a University Ob/Gyn Department from 1999 to 2003. Cervical smears from 114 controls without any cytological and/or colposcopical evidence of cervical pathology and from 166 women with history of cervical intraepithelial neoplasia (56 CIN I, 54 CIN II and 56 CIN III) were examined with polymerase chain reaction for the above-mentioned genetic polymorphisms, taking also in mind their smoking attitudes. Statistical analysis was performed to detect any association between the null genotype of GSTM1 and GSTT1 genes and the CYP1A1 m1 polymorphism and the severity of cervical intraepithelial neoplasia. The distributions of the GSTT1 and GSTM1 wild-type genotypes were 57.48 and 39.75%, respectively. No woman with homozygous GSTT1 and GSTM1 null/null genotype was identified. CYP1A1 m1 polymorphism frequency was 24.49%. No woman with homozygous CYP1A1 m1/m1 genotype was detected as well. No significant difference in the frequencies of the GSTM1 and GSTT1 null alleles, and the CYP1A1 m1 polymorphism, was found between cases and controls. After application of Mantel-Haenszel chi procedure, there was no linear severity of the lesion and the frequency of these polymorphisms. According to our results, glutathione-S-transferase T1 and M1 and cytochrome P1A1 genetic polymporphisms do not appear to be a risk factor for cervical disease irrespective of smoking habits.

Acquisition of new infection and clearance of type-specific human papillomavirus infections in female students in Busan, South Korea: a follow-up study

Background

Little is known about the natural history of human papillomavirus (HPV) infection in Asian women.

Methods

A follow-up study was conducted, with exfoliated cervicovaginal cells self-collected from, and questionnaires administered to 197 female students, aged 17–26 years, who had been already examined one and half years before. The presence of 25 HPV types was evaluated by a polymerase chain reaction-based assay.

Results

The acquisition of new infection for any HPV type among 171 female students at risk who were negative at baseline, 60% of whom had remained as virgins, was 17.5% (95% confidence interval [CI]: 11.8–23.2). Among individual types, HPV16, 18 and 35 showed the highest rate of new infection. Women who had had first sexual intercourse (OR = 2.9; 95% CI: 1.0–8.8), or had changed sexual partners (OR = 2.9; 95% CI: 0.9–9.3) during the follow-up period showed a higher risk of new HPV infection than women who had remained virgins since baseline. The rate of new infection also tended to be higher in those who started, or continued smoking during the follow-up period, than in nonsmokers. Clearance of HPV infections since baseline examination was 80.6% (95% CI: 67.6–93.5), and did not differ between high-risk and low-risk HPV types or between single- and multiple-type infections.

Conclusion

This study shows that the acquisition of new HPV infection among young women in the Republic of Korea is high and also the clearance is frequent. Self-collection of cervicovaginal cells is applicable to follow-up studies that include virgins.

Smoking is an independent risk factor for oncogenic human papillomavirus (HPV) infections but not for high-grade CIN

BACKGROUND

Recent evidence implicates smoking as a risk factor for cervical cancer (CC), but the confounding from high-risk human papillomavirus (HPV) infections is not clear.

OBJECTIVES

To analyse the role of smoking as an independent predictor of CIN2+ and HR-HPV infections in a population-based prospective (NIS, New Independent States of former Soviet Union) cohort study.

STUDY DESIGN AND METHODS

A cohort of 3,187 women was stratified into three groups according to their smoking status: (i) women who never smoked; (ii) those smoking in the past; and (iii) women who are current smokers. These groups were analysed for predictors of (a) HR-HPV; (b) high-grade CIN, and (c) outcome of HR-HPV infections and cytological abnormalities during prospective follow-up (n = 854).

RESULTS

The three groups were significantly different in all major indicators or risk sexual behaviour (or history) implicating strong confounding. There was no increase in HSIL/LSIL/ASC-US cytology or CIN1+/CIN2+/CIN3+ among current smokers. Only few predictors of HR-HPV and CIN2+ were common to all three groups, indicating strong interference of the smoking status. There was no difference in outcomes of cervical disease or HR-HPV infections between the three groups. In multivariate model, being current smoker was one of the five independent predictors of HR-HPV (P = 0.014), with adjusted OR = 1.52 (95%CI 1.09-2.14). In addition to age, HR-HPV was the only independent predictor of CIN2+ in multivariate model (OR = 14.8; 95%CI 1.72-127.31).

CONCLUSIONS

These data indicate that cigarette smoking is not an independent risk factor of CIN2+, but the increased risk ascribed to smoking is mediated by acquisition of HR-HPV, of which current smoking was an independent predictor in multivariate model.

Prognostic value of histopathology and trends in cervical cancer: a SEER population study

BACKGROUND

Histopathology is a cornerstone in the diagnosis of cervical cancer but the prognostic value is controversial.

METHODS

Women under active follow-up for histologically confirmed primary invasive cervical cancer were selected from the United States Surveillance, Epidemiology, and End Results (SEER) 9-registries public use data 1973-2002. Only histologies with at least 100 cases were retained. Registry area, age, marital status, race, year of diagnosis, tumor histology, grade, stage, tumor size, number of positive nodes, number of examined nodes, odds of nodal involvement, extent of surgery, and radiotherapy were evaluated in Cox models by stepwise selection using the Akaike Information Criteria.

RESULTS

There were 30,989 records evaluable. From 1973 to 2002, number of cases dropped from 1,100 new cases/year to 900/year, but adenocarcinomas and adenosquamous carcinoma increased from 100/year to 235/year. Median age was 48 years. Statistically significant variables for both overall and cause-specific mortality were: age, year of diagnosis, race, stage, histology, grade, hysterectomy, radiotherapy, tumor size and nodal ratio. The histological types were jointly significant, P < 0.001. Cause-specific mortality hazard ratios by histological type relatively to non-microinvasive squamous cell carcinoma were: microinvasive squamous cell carcinoma 0.28 (95% confidence interval: 0.20-0.39), carcinoma not otherwise specified 0.91 (0.79-1.04), non-mucinous adenocarcinoma 1.06 (0.98-1.15), adenosquamous carcinoma 1.35 (1.20-1.51), mucinous adenocarcinoma 1.52 (1.23-1.88), small cell carcinoma 1.94 (1.58-2.39).

CONCLUSION

Small cell carcinoma and adenocarcinomas were associated with poorer survival. The incidental observation of increasing numbers of adenocarcinomas despite a general decline suggests the inefficiency of conventional screening for these tumors. Increased incidence of adenocarcinomas, their adverse prognosis, and the young age at diagnosis indicate the need to identify women who are at risk.

Human papillomavirus vaccine: knowledge and attitudes in two Appalachian Kentucky counties

OBJECTIVE

A vaccine against common high-risk types of human papillomavirus (HPV) associated with cervical cancer risk was recently approved. We assessed women's acceptance of HPV vaccination for themselves and for adolescent girls, in an Appalachian population with cervical cancer incidence and mortality rates among the highest in the United States.

METHODS

We conducted a population-based, random-digit telephone survey of over 600 adult women residing in two Appalachian Kentucky counties. The analysis focused on questions of HPV vaccine acceptance, and their relationship to several factors.

RESULTS

The majority of women indicated an interest in HPV vaccination for themselves (85.2%), but they were less accepting of a vaccine being administrated to girls of ages 10-15 (67.6%). Women who were younger, lower-income and smokers were more likely to support vaccination.

CONCLUSIONS

Although a relatively high percentage of women found the HPV vaccination acceptable for their own use, there was less enthusiasm for supporting vaccination to girls. This finding is of concern since the vaccine is being recommended for adolescent girls and young women, prior to sexual initiation. Educational campaigns will be needed for a successful vaccine implementation.

Hypermethylation of two consecutive tumor suppressor genes, BLU and RASSF1A, located at 3p21.3 in cervical neoplasias

OBJECTIVES

Although initiated by human papillomavirus (HPV), cervical carcinogenesis demands other cofactors to shape its natural course. Epigenetic effects such as DNA methylation, are considered to contribute to carcinogenesis process.

METHODS

The methylation status of BLU and RASSF1A, as well as the HPV infection status, were assessed in a full spectrum of cervical neoplasia, including 45 low-grade squamous intraepithelial lesions (LSIL), 63 high-grade squamous intraepithelial lesions (HSIL), 107 squamous cell carcinomas (SCC), 23 adenocarcinomas (AC), and 44 normal control tissues.

RESULTS

The BLU was methylated in 76.9% of SCC, 57.4% of HSIL, 20.0% of LSIL and 12.5% of normal tissues (P<0.001). The RASSF1A was methylated in 15% of SCC, 17.5% of HSIL, but not in LSIL or normal tissues (P<0.001). In AC, 43.5% of patients showed BLU methylation and 26.1% RASSF1A methylation, significantly higher than the corresponding control frequencies of 12.5% (P=0.005) and 0% (P=0.001), respectively. There was an insignificant trend toward loss of BLU methylation with advancing clinical stages of SCC (84.8%, 67.7%, and 63.6% in stages I, II, and III/IV, respectively; P=0.08). Patients with LSIL infected with high-risk HPV showed a higher rate of BLU methylation than those without HPV (38.8% vs 9.1%, respectively; P=0.057). The methylation of RASSF1A was inversely related to HPV infection in patients with HSIL/SCC (P=0.003).

CONCLUSIONS

These results suggest that the methylation of BLU and RASSF1A genes is associated with cervical carcinogenesis, which could be clinically important in the future molecular screening of cervical neoplasia.

Synergy between Cigarette Smoking and Human Papillomavirus Type 16 in Cervical Cancer In situ Development

BACKGROUND

A majority of studies have implicated the involvement of cigarette smoking in cervical cancer development, although its mechanism of action remains unclear. We conducted a large population-based case-control study to address the potential interaction between smoking and human papillomavirus type 16 (HPV-16) in development of cervical cancer in situ (CIS).

METHODS

Information on risk factors for CIS was collected via interview, and archival cervical smears were tested for HPV-16 DNA presence in cases (n = 375) and controls (n = 363). Adjusted odds ratios (OR) for the effects of smoking, HPV-16 presence/absence, and load at first smear (taken, on average, 9 years before diagnosis) were calculated.

RESULTS

The risk for CIS among current smokers who were HPV-16 positive at time of first smear was >14-fold [adjusted OR, 14.4; confidence interval (95% CI), 5.6-36.8] compared with HPV-16-negative current smokers. In contrast, the risk for CIS among HPV-16-positive nonsmokers was only 6-fold (adjusted OR, 5.6; 95% CI, 2.7-11.5), compared with HPV-16-negative nonsmokers. HPV-16-positive smokers with high viral load at time of first smear exhibited a high risk for CIS (adjusted OR, 27.0; 95% CI, 6.5-114.2) compared with HPV-16-negative smokers. Within nonsmokers, however, high HPV-16 load contributed only a 6-fold increased risk compared with HPV-16-negative nonsmokers (adjusted OR, 5.9; 95% CI, 2.4-14.6). Interaction was observed (P = 0.03) between duration of smoking and HPV-16 presence in CIS development.

CONCLUSION

Results suggest a synergistic effect between smoking and both HPV-16 status and HPV-16 viral load, which may occur almost a decade before CIS detection.

Health behaviors of cancer survivors: examining opportunities for cancer control intervention

PURPOSE

A population-based investigation was conducted to examine the prevalence of health behaviors (smoking, alcohol use, physical activity, and cancer screening) of cancer survivors by age, time since diagnosis, and cancer site. Understanding health behaviors of survivors is imperative, as many survivors are living longer and are at risk for cancer recurrence, second cancers, and complications from treatment.

METHODS

Using the National Health Interview Survey, this study examined the prevalence of smoking and alcohol use as well as whether cancer survivors (n = 7,384) are meeting current recommendations for physical activity and cancer screening compared with noncancer controls (n = 121,347).

RESULTS

Cancer survivors are similar to controls with respect to smoking status and alcohol consumption after adjusting for group differences. However, younger survivors (18 to 40 years) are at greater risk for continued smoking than controls. Survivors are 9% more likely to meet physical activity recommendations compared with controls. chi2 tests indicate no significant differences in smoking, alcohol consumption, and physical activity by time since diagnosis, but differences by cancer site exist. Female cancer survivors are 34% and 36% more likely to meet mammogram and Papanicolaou smear screening recommendations, respectively, compared with controls. Similar screening patterns were found for prostate-specific antigen screening in men.

CONCLUSION

This study provides benchmark approximations of the prevalence of risky health behaviors of survivors by time since diagnosis and cancer site. As part of the collective effort to reduce late effects of cancer treatment, oncologists may be in the best position to offer initial guidance for promoting healthy lifestyle behaviors among cancer survivors.

Genetic polymorphisms of FAS and FASL (CD95/CD95L) genes in cervical carcinogenesis: An analysis of haplotype and gene-gene interaction

OBJECTIVE

Whereas human papillomavirus (HPV) infection is necessary but not sufficient for cervical carcinogenesis, host genetic variations may confer individual susceptibility. Resistance to apoptosis is a hallmark of cancer in which FAS/FAS ligand signaling plays an important role. The present study examines the hypothesis that genetic polymorphisms in FAS and FAS ligand genes, alone or in combination, are associated with cervical carcinogenesis.

METHODS

The genotypes of FAS -670A/G, FAS -1377G/A, and FASL -844C/T were assessed in 143 patients with high-grade squamous intraepithelial lesions (HSIL), 175 patients with invasive squamous cell carcinomas (SCC), and in age-matched controls by real-time PCR with allele-specific TaqMan probes. The status of cervical high-risk HPV infection was determined and adjusted to test the independence of genotype in the risk assessment.

RESULTS

The A-allele and AA-genotype frequencies of FASA -670G were significantly higher in HSIL/SCC than in controls (60% vs. 54%, P = 0.04, OR 1.26 [95% CI 1.01-1.57]; 38.0% vs. 28.6%, P = 0.02, OR 1.70 [95% CI 1.07-2.70]). No association between FAS -1377 or FASL -844 polymorphisms and HSIL/SCC could be identified. The FAS -1377A/-670A haplotype conferred a higher risk for HSIL/SCC (OR 3.05, 95% CI 1.28-7.30) than FAS -670A alone (OR 1.26, 95% CI 1.28-7.30). The interaction between FAS -670AA and FASL -844CC genotypes was associated with a risk of HSIL/SCC (OR 2.13, 95% CI 1.06-4.29) higher than that of the FAS -670AA genotype alone (OR 1.70, 95% CI 1.07-2.70).

CONCLUSIONS

The FAS -1377A/-670A haplotype in combination with FASL -844C is associated with cervical carcinogenesis.

Comparative analysis of invasive cervical cancer incidence rates in three Appalachian states

BACKGROUND

Invasive cervical cancer (ICC) rates remain elevated in the Appalachian region of the United States. We investigated patterns of invasive cervical cancer incidence rates in three Appalachian states (Kentucky, West Virginia, Pennsylvania) to uncover specific high-risk subgroups within this large and heterogeneous region.

METHODS

The analysis was conducted for the three states combined and individually. Invasive cervical cancer rates were characterized by individual and county-level sociodemographic variables, including age, race, poverty, education, Appalachian status, and rural/urban status. Bivariate analyses and multivariable Poisson regression models were conducted to address the relative contributions of each variable to the risk of invasive cervical cancer.

RESULTS

The three states differed in the contribution of each factor to the risk of invasive cervical cancer. The overall invasive cervical cancer incidence rates for Kentucky, West Virginia, and Pennsylvania were 13.4, 13.9, and 10.2 per 100,000/yr, respectively. After controlling for other demographic variables, the effect of Appalachian status on invasive cervical cancer was weaker, while rural status, education, and race were stronger, significant predictors.

CONCLUSIONS

This study illustrates the heterogeneity of population demographics and invasive cervical cancer risk, and the need to identify subregions and subgroups within Appalachia at highest risk for this disease.

The Fragile Histidine Triad Gene: A Molecular Link Between Cigarette Smoking and Cervical Cancer

PURPOSE

Smoking is an epidemiologic risk factor for cervical cancer. The fragile histidine triad (FHIT) gene is a tumor suppressor gene that is altered in 80% of tobacco-associated lung cancers. We hypothesized that reduced FHIT protein expression, homozygous deletions (HD) or hemizygous deletions (HemiD) and microsatellite alterations (MA) at the FHIT/FRA3B locus occur more commonly in cervical cancers of smokers than nonsmokers.

EXPERIMENTAL DESIGN

Archival tissues of 58 patients with stage IA1 to IB2 squamous cell carcinoma of the cervix were identified. FHIT protein expression was studied with immunohistochemistry. Laser capture microdissection was used to isolate tumor and normal DNA. HD/HemiD of FHIT exons 4 and 5 were analyzed by monoplex real-time PCR. MA at FHIT/FRA3B were studied with multiplex nested PCR with three fluorescently labeled microsatellite markers (D3S1300, D3S1312, and D3S1480).

RESULTS

Eighteen of 26 tumors from smokers (69%) and 13 of 32 nonsmokers (41%; P < 0.05) showed loss of FHIT protein expression. Thirty-seven stage IB tumors yielded sufficient DNA for analyses. HD or HemiD of both exons tested occurred in 8 of 17 smokers (47%) and 2 of 20 nonsmokers (10%; P < 0.05). MA at more than two sites were found in 11 of 17 tumors of smokers (65%) and 6 of 20 nonsmokers (30%; P < 0.05). Mean composite genomic FHIT alteration scores were significantly higher for tumors of smokers versus nonsmokers (0.67 versus 0.40; P < 0.02).

CONCLUSION

Loss of FHIT expression, HD, HemiD, and MA at the FHIT/FRA3B locus occur significantly more commonly in cervical cancers of smokers. These findings suggest that the tumor suppressor gene FHIT may represent a molecular target in cigarette smoking-associated cervical carcinogenesis.

Integration of human papillomavirus type 11 in recurrent respiratory papilloma-associated cancer

OBJECTIVES/HYPOTHESIS

The main objective was to demonstrate that human papillomavirus (HPV) type 11 is an aggressive virus that plays a significant role in the development of laryngeal cancer in patients with a history of recurrent respiratory papillomatosis (RRP). We have done so by preliminary investigation into the molecular mechanism underlying the malignant transformation of RRP to invasive squamous cell carcinoma.

STUDY DESIGN

An experimental, nonrandomized, retrospective study using tissue specimens from nine patients with a history of RRP that progressed to laryngeal or bronchogenic cancer was performed.

METHODS

DNA and RNA were extracted from 20 formalin-fixed, paraffin-embedded specimens from six patients with a history of early onset RRP and laryngeal cancer and from three patients with early onset RRP and bronchogenic cancer. Polymerase chain reaction (PCR) was performed on DNA to determine the HPV type in each specimen. Reverse-transcriptase PCR specific for virus transcripts was performed on RNA to determine whether the viral genome was integrated into the host genome.

RESULTS

HPV-11 but not HPV-6, 16, or 18 was found in all of the laryngeal and bronchogenic cancers in patients with a history of early onset RRP in this study. RNA, sufficiently intact for examination, was obtained from seven patients. Analysis of HPV 11 transcripts revealed integration of the viral genome in three of seven patients.

CONCLUSIONS

HPV type 6 and 11 are considered "low-risk" viruses and are not associated with genital cancers, as are HPV types 16 and 18. However, our data suggests that HPV type 11 is an aggressive virus in laryngeal papilloma that should be monitored in patients with RRP.

Viruses, chemicals and co-carcinogenesis

The etiology of cancers appears to be complex and multifactorial. Peyton Rous and others demonstrated the process of co-carcinogenesis by exposing rabbits to a virus and tars. Epidemiologists have proposed virus-chemical interactions to cause several cancers. For example, one might propose that the etiology of cervical cancer results from a complex interplay between oncogenic viruses and cervical tar exposures through tar-based vaginal douching, cigarette smoking, and/or long-term cooking over wood-burning stoves in poorly ventilated kitchens. Hepatocellular carcinoma may result from the joint effects of viruses and hepatotoxic chemical carcinogens. Kaposi's sarcoma might happen following reciprocal actions of human herpes virus-8 infection, immunosuppression, and chemical exposures, such as nitrite radicals and alumino-silicates. Use of Koch's postulates will not help one prove or disprove a multifactorial causation of disease; new criteria are needed. Delineating the web of causation may lead to additional strategies for prevention and treatment of several cancers.