The interaction between HPV infection and estrogen metabolism in cervical carcinogenesis

β-Estradiol Induces Mitochondrial Apoptosis in Cervical Cancer Through the Suppression of AKT/NF-κB Signaling Pathway

BACKGROUND

Cervical cancer is the fourth most prevalent gynecological cancer worldwide, which threatens women's health and causes cancer-related mortality. In the search for effective anticervical cancer drugs, we discovered that β-estradiol (E2), a patent drug for estrogen deficiency syndrome treatment, displays the most potent cytotoxicity against HeLa cells.

OBJECTIVE

This study aims to evaluate the growth inhibitory effect of β-estradiol on HeLa cells and explore its underlying mechanisms.

METHODS

CCK-8 assay was used to evaluate the cytotoxicity of 6 compounds against HeLa cells. Flow cytometric analysis and Hoechst 33258 staining assay were performed to detect cell cycle arrest and apoptosis induction. The collapse of the mitochondrial potential was observed by the JC-1 staining assay. The expression levels of proteins were examined by western blotting.

RESULTS

β-Estradiol, at high concentration, displays potent cytotoxicity against HeLa cells with an IC50 value of 18.71 ± 1.57 μM for 72 h treatment. β-Estradiol induces G2/M cell cycle arrest through downregulating Cyclin B1 and p-CDK1. In addition, β-estradiol-induced apoptosis is accompanied by the loss of mitochondrial potential, activation of the Caspase family, and altered Bax/Bcl-2 ratio. β-Estradiol markedly decreased the expression level of p-AKT and p-NF-κB.

CONCLUSION

This study demonstrated that β-estradiol induces mitochondrial apoptosis in cervical cancer through the suppression of the AKT/NF-κB signaling pathway, indicating that β-estradiol may serve as a potential agent for cervical cancer treatment.

The Relationship between Estrogen-Related Signaling and Human Papillomavirus Positive Cancers

High risk-human papillomaviruses (HPVs) are known carcinogens. Numerous reports have linked the steroid hormone estrogen, and the expression of estrogen receptors (ERs), to HPV-related cancers, although the exact nature of the interactions remains to be fully elucidated. Here we will focus on estrogen signaling and describe both pro and potentially anti-cancer effects of this hormone in HPV-positive cancers. This review will summarize: (1) cell culture-related evidence, (2) animal model evidence, and (3) clinical evidence demonstrating an interaction between estrogen and HPV-positive cancers. This comprehensive review provides insights into the potential relationship between estrogen and HPV. We suggest that estrogen may provide a potential therapeutic for HPV-related cancers, however additional studies are necessary.

Cervical cancer and potential pharmacological treatment with snake venoms

Cervical cancer is the fourth most common cancer worldwide in women. Apoptosis reactivation has become the main strategy for decreasing cancer proliferation. There is a need to extend the search for new drugs to implement more effective and less toxic strategies for cervical cancer treatment. Research has been carried out to find new drugs that have minimal side effects and that focus on the tumor microenvironment, particularly in the induction of cellular apoptosis and cell migration and the inhibition of angiogenesis. Potent toxins from snake venoms have shown potential as sources for the synthesis of new drugs with such characteristics. The present work aimed to describe cervical cancer characteristics, associated risk factors, current treatments and to highlight the effects of toxins isolated from the venom of snakes of the Viperidae family on cervical cancer cell lines.

Significance of HPV16 Viral Load Testing in Anal Cancer

Human papilloma virus (HPV) is highly frequent among patients with anal squamous cell carcinoma, but the viral load (VL) differs between patients. This study aimed to compare the rate of HPV positivity, HPV16VL, p16^INK4A and p53 expression between treatment naive and recurrent anal cancer patients. HPV was genotyped via AmpliSens® HPV HCR-genotype-titre-FRT kit. HPV16 VL was determined via quantitative polymerase chain reaction-based in-house test. p16^INK4A and p53 expression was tested via immunohistochemistry. The cohort comprised 13 treatment-naive and 17 recurrent anal SCC patients. High-risk HPV was detected in 87% of cases, and HPV16 (73%) was the predominant genotype. The rate of HPV positivity was higher among women and nonsmokers, and majority of HPV-positive cases were also p16^INK4A-positive. All p53-negative tumors were HPV16-positive. The most predominant p53 staining pattern in the HPV-positive group was scattered type, whereas it was diffuse type in the HPV-negative group. The HPV16 VL was higher in the treatment-naive group. Further, in the treatment-naive group, cases with scattered staining pattern of p53 had higher HPV16 VL than cases with diffuse staining pattern. The opposite result was noted in the recurrent cancer group. Moreover, p16-positive cases with scattered p53 staining pattern in the treatment naive group had higher HPV16 VL than their counterparts in the recurrent cancer group. In conclusion, the HPV VL, as is the association between VL and p16^INK4A /p53, is in an inversed trend in treatment naive and recurrent cancer patients, highlighting the importance of HPV VL measurement in anal SCC.

GPER Overexpression in Cervical Cancer Versus Premalignant Lesions: Its Activation Induces Different Forms of Cell Death

BACKGROUND

The effect of estrogen has been traditionally studied through the modulation of its alpha and beta nuclear receptors; however, the G Protein-Coupled Estrogen Receptor (GPER) has been recently involved in the pathology of numerous tumors. Although the study of GPER in cervical cancer has begun, its contribution still remains to be completely evaluated.

OBJECTIVE

The purpose of this work was to determine the expression of this receptor in different degrees of cervical lesions and whether the stimulation with its specific agonist (G-1) modulated mechanisms of cell survival or cell death in cervical cancer cells.

METHODS

Sections of 44 formalin-fixed paraffin-embedded blocks from patients were analyzed by automated immunohistochemistry. After the stimulation with G-1, proliferation was evaluated by the xCELLigence technology, the integrity of the mitochondrial membrane permeability by MitoCaptureTM fluorescence staining, apoptosis by flow cytometry, and senescence by the senescence-associated β-galactosidase kit.

RESULTS

GPER was widely expressed in cervical cancer but not in its precursor lesions. The staining was predominantly cytoplasmic, although it was also important in the nucleus of the epithelial cells. G-1 inhibited proliferation, decreased the mitochondrial permeability, and increased the percentage of apoptosis in SiHa, HeLa, and C-33A. Only in C-33A, an increase of the cells in necrosis was observed, whereas SiHa was the only cell line in which senescence was evidenced.

CONCLUSION

GPER is a receptor associated with cervical cancer that inhibits the growth and induces different mechanisms of death in cells derived from uterine cervical cancer. It suggests that GPER can be considered a pharmacological target that prevents the development of cervical carcinogenesis.

Human papillomavirus infection increases the risk of breast carcinoma: a large-scale systemic review and meta-analysis of case-control studies

Background

Breast carcinoma (BC) is a cancer with a high morbidity rate, but the mechanisms by which it develops are never clear. There has been speculation regarding the potential relationships between breast cancer and local HPV infections for some time, and although much clinical research supports this hypothesis, some research results disprove the association. Therefore, the association is still inconclusive.

Methods

We performed the data collection by searching the database PubMed, Embase, Cochrane Library and Web of science. In addition, 22 sites were added manually. After carefully selection, the pooled odds rate of 37 included case control studies was calculated. Subgroup analysis, publication bias and trim & fill analysis were conducted to make the result more reliable.

Results

The analysis of 37 case control studies containing 3,607 BC cases and 1,728 controls showed obviously increase of BC risk with human papillomavirus (HPV) positive [summary odds ratio (SOR) =6.22, 95% confidence interval 4.25 to 9.12; P=0.0002]. Subgroup analysis proved three high risk HPV types (HPV16, 18 and 33) were positively correlated to BC.

Conclusions

This systemic review and meta-analysis provide the evidence for HPV infection as a potential risk factor in BC, while the mechanism of this hypothesis still needs further evaluation.

Association of estradiol and HPV/HPV16 infection with the occurrence of cervical squamous cell carcinoma

The associations between human papillomavirus (HPV) infection or hormonal exposure and cervical cancer risk are well established. However, to the best of our knowledge, the association between high endogenous estradiol levels in conjunction with HPV/HPV16 infection and the risk of cervical squamous cell carcinoma remains unknown. To investigate this, the current study conducted a matched case-control study in Shanxi Province, China, in which clinical samples were obtained from 74 females with newly diagnosed uterine cervix squamous cell carcinoma and 74 matched healthy females who were selected from 582 healthy females according to age, place of residence, marital status and menopausal status. From all participants, DNA was extracted from cells obtained from a cervical smear and serum was separated from venous blood withdrawn during days 5-8 of the menstrual cycle. HPV/HPV16 DNA and estradiol expression levels in the serum were measured by general polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Significant differences were identified in the positive HPV and HPV16 DNA expression rates between patients and controls, with odds ratios (95% confidence interval) of 3.74 (1.84-7.59) and 4.04 (1.97-8.28), respectively. Expression levels of estradiol in patients were significantly higher compared with the controls (P<0.001), however, this was only identified when the HPV16 E2 or E6 oncogene status was negative. Considering 40 ng/ml as the cut-off estradiol level, 78.38% of patients exhibited high estradiol levels, which was significantly higher than the percentage of controls (P<0.001). An additive interaction pattern was revealed between estradiol expression levels and HPV/HPV16 infection. The results suggest that among the various types of HPV, HPV16 may be most likely to cause uterine cervix squamous cell carcinoma and an abnormally high level of endogenous estradiol may further increase this risk. Therefore, estradiol therapy may represent a new treatment strategy for cases of cervical cancer associated with HPV infection.

WITHDRAWN: The anti-cancer properties in parallel with toxic effects of indole-3-carbinol derivatives

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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.

Oral contraceptive and progestin-only use correlates to tissue tumor marker expression in women with cervical intraepithelial neoplasia

BACKGROUND

The study was conducted to investigate correlations between combined oral contraceptive (COC), any progestin-only contraceptive, medicated intrauterine device (MID) or systemic progestin-only (Syst-P) use and tumor marker expression in cervical intraepithelial neoplasia compared to nonusers.

STUDY DESIGN

One-hundred ninety-five women of fertile age with cervical biopsies ranging histologically from normal epithelium to carcinoma in situ were recruited consecutively. Combined oral contraceptive, Syst-P and MID users were investigated according to the expression of 11 tumor markers.

RESULTS

Overexpression of cyclooxygenase-2 (Cox-2) was observed in COC users, while interleukin 10 was underexpressed. When users of progestogen-only contraceptives were analyzed, there was a lower expression of cytokeratin 10 and interleukin 10. When only MID users were analyzed, a high expression of p53 was found. Expression of Cox-2, p53 and retinoblastoma protein differed between COC and MID users.

CONCLUSION

The study showed molecular alterations, which, in general, have not been studied previously in COC users and have never been studied in progestogen-only users. These biological events might be involved in epidemiological correlations found between hormonal contraceptive use and cervical neoplasms.

Results from a dose-response study using 3,3'-diindolylmethane in the K14-HPV16 transgenic mouse model: cervical histology

The human papilloma virus is the major cause of cervical cancer. Viral infection initiates cervical intraepithelial neoplasia, which progresses through several stages to cervical cancer. The objective of this study is to identify the minimum effective dose of diindolylmethane that prevents the progression from cervical dysplasia to carcinoma in situ. We document cervical histology in K14-HPV16 mice receiving different doses of diindolylmethane. Urinary diindolylmethane concentrations are reported. Diindolylmethane could enhance the efficacy of human papilloma virus vaccines, creating a new therapeutic use for these vaccines in women already infected with the virus. Five doses (0-2,500 ppm) of diindolylmethane were incorporated into each mouse diet. The reproductive tract was serially sectioned and urine was obtained for analysis of urinary diindolylmethane. The results indicate that 62% of mice receiving 1,000 ppm diindolylmethane remained dysplasia-free after 20 weeks compared with 16% of mice receiving no diindolylmethane and 18% receiving 500 ppm; 1,000 ppm of 3,3'-diindolylmethane in the diet completely suppressed the development of cervical cancer. Urinary diindolylmethane levels increased significantly as diindolylmethane in food increased. These findings imply usefulness for diindolylmethane in the search to prevent cervical cancer when used in combination with prophylactic or therapeutic vaccines.

The role of retinoid deficiency and estrogens as cofactors in cervical cancer

Persistent infection with high-risk human papillomaviruses (HR-HPVs) is involved in cervical cancer (CC), a major cause of cancer mortality worldwide. Infection occurs primarily at the transformation zone (TZ), the most estrogen- and retinoid-sensitive region of the cervix. Development of CC affects a small percentage of HR-HPV-infected women and often takes decades after infection, suggesting that HR-HPV is a necessary but not sufficient cause of CC. Thus, other cofactors are necessary for progression from cervical HR-HPV infection to cancer such as long-term use of hormonal contraceptives, multiparity, smoking, as well as micronutrient depletion and in particular retinoid deficiency, which alters epithelial differentiation, cellular growth and apoptosis of malignant cells. Therefore, early detection of HR-HPV and management of precancerous lesions together with a profound understanding of additional risk factors could be a strategy to avoid this disease. In this review we focus on the synergic effect of estrogens, retinoid deficiency and HR-HPVs in the development of CC. These risk factors may act in concert to induce neoplastic transformation in squamous epithelium of the cervix, setting the stage for secondary genetic or epigenetic events leading to cervical cancer.

TP53 genetic polymorphisms and environmental risk factors associated with cervical carcinogenesis in a cohort of Brazilian women with cervical lesions

The purpose of this study was to determine the prevalence of TP53 polymorphism at codon 72 and its association with environmental risk factors in a sample of women in Rio de Janeiro, Brazil. A cross-sectional study was conducted with 304 women with histological diagnoses of negative, precancerous, and cancerous lesions between October 2004 and May 2006. Antecedents of exposure to environmental risk factors were ascertained through an interview-administered questionnaire, and whenever indicated, colposcopy tests and lesion excisions were performed. Genomic DNA was extracted from leukocytes of peripheral blood subjects, and genotyping of TP53 polymorphism was conducted using polymerase chain reaction and restriction fragment-length polymorphism methods. Crude and adjusted odds ratios (OR) and their 95% confidence intervals (CI) were ascertained for selected risk factors and allelic groups among control, low-grade squamous intraepithelial lesion (LSIL), and high-grade squamous intraepithelial lesion (HSIL)/cancer strata, using logistic regression analysis. The TP53 polymorphism distribution in this population was 64 (21.1%) Arg/Arg, 55 (18.1%) Pro/Pro, and 185 (60.9%) Arg/Pro. Women who were heterozygous (Arg/Pro) showed an independent risk for cervical HSIL/cancer (adjusted OR: 1.92, 95%CI: 1.03-1.59, controlled for age, ethnicity, and age at menarche) compared to Pro/Pro genotypic women. Age at sexual onset up to 16 yr old (adjusted OR: 1.97, 95%CI: 1.18-3.3), lifelong 3-4 sexual partners (adjusted OR: 2.38, 95%CI: 1.32-4.28), current smoking (adjusted OR: 2.32, 95%CI: 1.31-4.13), and smoking more than 10 yr (adjusted OR: 2.52, 95%CI: 1.042-6.09) were found to be independent risk factors for cervical HSIL/cancer. Women possessing the Arg/Pro genotype presented a higher risk for HSIL/cancer development compared to Pro/Pro genotypic women in the sample studied after control for selected confounders. Early sexual onset, multiple sexual partners, and current and past tobacco smoking were independent risk factors for HSIL/cancer development.

Are estradiol metabolites involved in gynaecological carcinogenesis?

Certain estradiol metabolites are biologically active, sometimes several times more potent than their parent substance. Highly sophisticated laboratory methods allow us to understand oestrogenic effects as a net effect of the corresponding metabolite pattern. Currently, research is focused on the anticancerogenic effects of 2-hydroxyestrone and particularly 2-methoxyestradiol, as well as the possible carcinogenic properties of 4-hydroxyoestrogens and 16α-hydroxyestrone. The clinical relevance of these activities, demonstrated in in-vitro and animal experiments, remains unclear - it is proven, however, that the metabolite production can be altered in certain malignancies such as endometrial-, breast- and cervical carcinoma. Clinical studies, including our studies, have demonstrated a negative correlation between the ratio of 2-hydroxyestrone to 16α-hydroxyestrone and breast cancer risk. However, the design and interpretation of such studies should consider factors influencing metabolic pattern such as diet, physical activity, smoking, as well as internal diseases and certain drugs.

Hormone replacement after gynaecological cancer

Treatment of gynaecological cancer frequently results in the loss of ovarian function and menopausal symptoms. Symptoms of iatrogenic menopause are usually significantly more intense than those of natural menopause due to sudden onset of symptoms, younger age and its effects on common physical and psychological problems of cancer therapy like body image concerns and sexual dysfunction. The most effective treatment for menopausal symptoms is hormone replacement therapy (HRT). However, it is very controversial if HRT is safe in patients after a gynaecological malignancy. The main concerns are the potential stimulation of residual cancer and the induction of new hormone-dependent disease. However, the majority of the most common gynaecological malignancies like squamous cell carcinomas of the cervix, serous papillary epithelial ovarian carcinomas and squamous cell carcinomas of the vulva are not oestrogen dependent. Furthermore, current scientific evidence does not show HRT to adversely affect the outcome in patients after treatment for hormone sensitive cancers like early stage endometrioid adenocarcinomas of the endometrium. There are only a small number of gynaecological malignancies like low grade endometrial stromal sarcomas in which HRT is an absolute contraindication. Therefore, as maintaining quality of life and minimising the physical and psychological impact of treatment side effects is one of the most important factors in cancer care, it is imperative to give patients unbiased information about their individual cancer which in most cases will allow them to use HRT without any detrimental effect on their survival.

Diindolylmethane inhibits cervical dysplasia, alters estrogen metabolism, and enhances immune response in the K14-HPV16 transgenic mouse model

This study was designed to establish whether 3,3'-diindolylmethane (DIM) can inhibit cervical lesions, alter estrogen metabolism in favor of C-2 hydroxylation, and enhance immune function in the K14-HPV16 transgenic mouse model. Mice were bred, genotyped, implanted with E(2) pellets (0.25 mg/90-day release) under anesthesia, and divided into groups. Wild-type and transgenic mice were given either AIN76A diet alone or with 2,000 ppm DIM for 12 weeks. Blood and reproductive tracts were obtained. Blood was analyzed for estrogen metabolites and IFN-gamma. The cervical transformation zone was sectioned and stained for histology. Estradiol C-2 hydroxylation and serum IFN-gamma levels were significantly increased over controls in wild-type and transgenic mice receiving DIM. In wild-type mice without DIM, hyperplasia of the squamous epithelium was observed. Wild-type mice fed DIM displayed a normal thin epithelium. In transgenic mice without DIM, epithelial cell projections into the stroma (papillae) were present. An additional degree of nuclear anaplasia in the stratum espinosum was observed. Dysplastic cells were present. Transgenic mice fed DIM displayed some mild hyperplasia of the squamous epithelium. DIM increases estrogen C-2 hydroxylation in this model. Serum INF-gamma was increased, indicating increased immune response in the DIM-fed animals. Histopathology showed a marked decrease in cervical dsyplasia in both wild-type and transgenic mice, indicating that DIM delays or inhibits the progression from cervical dysplasia to cervical cancer. Using the K14-HPV16 transgenic mouse model, we have shown that DIM inhibits the development of E6/E7 oncogene-induced cervical lesions.

Elevated aromatase expression correlates with cervical carcinoma progression

OBJECTIVES

We have previously demonstrated that aromatase mRNA is induced in cervical carcinomas compared to normal tissue, suggesting that in situ aromatase expression leading to elevated local estrogen production may contribute to cervical carcinogensis. Our objectives are to examine 1) whether aromatase protein and activity are induced in cervical carcinomas, 2) aromatase expression correlates with disease stage, and 3) inflammatory cytokines (e.g., IL-6 and TNFalpha) may correlate with aromatase expression.

METHODS

RNA and protein were isolated from human cervical carcinomas and normal cervical biopsies to examine aromatase expression, using real-time RT-PCR, Western blot analysis, and immunohistochemistry. Aromatase activity in tissue was measured using the tritiated water release method. IL-6 and TNFalpha expression was also examined.

RESULTS

Aromatase protein and activity levels were increased in cervical carcinomas compared to normal tissue. RNA levels correlated significantly with disease progression, with highest aromatase expression detected in stage IV tumors (p<0.001, R(2)=0.77). Aromatase promoters 1.3 and 1.4 were elevated in cervical carcinomas and in cervical cancer cells. The expression of inflammatory cytokines IL-6 and TNFalpha, known to induce aromatase, significantly correlated with aromatase expression (R(2)>0.9). TNFalpha treatment induced aromatase expression in cervical cancer cells.

CONCLUSION

Increased aromatase protein and activity in cervical carcinomas and the correlation of its expression with disease stage implicates it in cervical carcinogenesis. The correlation of IL-6 and TNFalpha expression with aromatase suggests that these inflammatory cytokines may induce aromatase expression, which is confirmed by induction of aromatase expression due to TNFalpha treatment of cervical cancer cells.

Tumor Morphology and Immunohistochemical Expression of Estrogen Receptor, Progesterone Receptor, p53, and Ki67 in Urogenital Carcinomas of California Sea Lions (Zalophus californianus)

Metastatic carcinoma of urogenital origin is a common cause of mortality in free-ranging California sea lions (Zalophus californianus). The etiology of this cancer is likely multifactorial, with viral infection, genetic factors, and exposure to environmental organochlorine contaminants possible contributing factors. In this study, expression of estrogen receptor α (ER α), progesterone receptor (PR), p53, and Ki67 were evaluated by immunohistochemistry in 12 sea lions with metastatic carcinoma, genital epithelial dysplasia, and intraepithelial neoplasia; 4 with genital epithelial dysplasia and intraepithelial neoplasia without metastases; and 6 control animals. Dysplastic and neoplastic lesions were identified in multiple areas of the cervix, vagina, penis, prepuce, and urethra in affected animals, suggesting multicentric development. Lesions were graded according to degree of epithelial dysplasia and infiltration and lesions of different grades were evaluated separately. Estrogen receptor expression was lower in intraepithelial lesions compared with normal genital epithelium, and expression in metastatic lesions was completely absent. There was progesterone receptor expression in neoplastic cells in intraepithelial lesions of all grades and in metastases, with no significant difference between lesion grades or between control and affected epithelium. Ki67 index and p53 expression increased with lesion grade and were higher in lesions than normal epithelium. Metastatic tumors exhibited highly variable morphology; however, proliferation index, ER α, PR, and p53 expression were similar in tumors with different patterns of growth. These results suggest that endogenous hormones, environmental contaminants that interact with steroid hormone receptors, and alterations in p53 may play a role in urogenital carcinogenesis in California sea lions.

Role of hormone cofactors in the human papillomavirus-induced carcinogenesis of the uterine cervix

If human papillomavirus (HPV) is necessary for the development of (pre)neoplastic lesions of the uterine cervix, it is not sufficient. Among the cofactors involved in the malignant transformation of cells infected by HPV, sex hormones may facilitate the cervical carcinogenesis by different mechanisms, including the induction of squamous metaplasia in the transformation zone of the cervix, interactions between steroid hormones and HPV gene expression and alterations of the local immune microenvironment.

Induction of aromatase expression in cervical carcinomas: effects of endogenous estrogen on cervical cancer cell proliferation

Epidemiologic studies have implicated estrogenic exposure as well as human papilloma virus (HPV) infection in cervical carcinogenesis, and some studies have suggested that estrogen and HPV may play synergistic roles in cervical tumorigenesis. In this study, we report a novel finding that approximately 35% of cervical carcinomas tested (n = 19) express aromatase, the enzyme responsible for converting androgen to estrogen, the rate-limiting and final step in estrogen biosynthesis. On the other hand, no aromatase expression was detected in precancerous (n = 42) or normal cervical (n = 17) tissue samples. Increased aromatase was associated with increases in estrogen receptors (ER-alpha and ER-beta) and a decrease in progesterone receptor levels, suggesting that in situ estrogen signaling via ER may be involved in tumor growth. Stable overexpression of aromatase in HPV+ cervical cancer cells resulted in increased cellular proliferation, anchorage-independent growth, and ER expression and activity. In contrast, little change in ER was observed in HPV- cells. Steroid hormone receptor expression observed in vitro paralleled that seen in cervical carcinomas expressing aromatase. Aromatase overexpression also induced the expression of cyclin D1, proliferating cell nuclear antigen, and the HPV oncogenes, E6 and E7. Furthermore, the data underscores the importance of steroid receptor (estrogen and progesterone receptors) regulation in cervical carcinogenesis. To our knowledge, this is the first report demonstrating the induction of aromatase expression in cervical carcinomas, and opens the possibility that aromatase inhibitors may be potential therapeutic agents in cervical carcinomas expressing aromatase.

Reports: plasma and dietary phytoestrogens and risk of premalignant lesions of the cervix

A number of epidemiological studies have observed an inverse association between phytoestrogens and risk of certain hormonally dependent cancers. We undertook an exploratory analysis of the relationship between specific phytoestrogens and premalignant cervical lesions. A case-control study of 122 women with histologically confirmed cervical squamous intraepithelial lesions (SILs) of the cervix and 183 cytologically normal controls was conducted from 1992 to 1996 in Honolulu, Hawaii. A cervical cell sample was obtained for human papillomavirus (HPV) testing. Dietary information was collected using a structured survey, and a fasting blood sample was taken for measurement of five isoflavonoids (genistein, glycitein, daidzein, O-desmethylangolensin, and equol), two flavonoids (hesperetin and naringenin), and two lignans (enterodiol and enterolactone). Plasma levels of equol and enterodiol were positively associated with cervical SIL risk: odds ratio, OR = 6.5; 95% confidence interval, CI = 1.4-29.2; P for trend = 0.02 and OR = 2.7; 95% CI = 1.1-6.3; P for trend = 0.01, respectively, for the highest relative to the lowest quartile level after adjustment for age, race/ethnicity, HPV infection, cigarette smoking, alcohol drinking, and lifetime number of sexual partners. A nonsignificant positive association with cervical SIL risk was observed for plasma enterolactone. Consistent with the relationships observed for the plasma lignans, dietary sources of lignans, including garlic and taro leaves/ong choy/marunggay, were positively associated with cervical SIL risk. A positive association was also suggested for other lignan sources such as seaweed, onions, grapefruit, and seeds. This is the first study to observe a positive association between specific phytoestrogens and premalignancies of the cervix. The results of this investigation should be considered preliminary and need to be verified in larger, prospective studies.

Human ADA3 binds to estrogen receptor (ER) and functions as a coactivator for ER-mediated transactivation

We have recently identified the hADA3 protein, the human homologue of yeast transcriptional coactivator yADA3, as a novel HPV16 E6 target. Using ectopic expression approaches, we further demonstrated that hADA3 directly binds to the 9-cis retinoic acid receptors alpha and beta, and functions as a coactivator for retinoid receptor-mediated transcriptional activation. Here, we examined the role of endogenous hADA3 as a coactivator for estrogen receptor (ER), an important member of the nuclear hormone receptor superfamily. We show that ADA3 directly interacts with ER alpha and ER beta. Using the chromatin immunoprecipitation assay, we also show that hADA3 is a component of the activator complexes bound to the native ER response element within the promoter of the estrogen-responsive gene pS2. Furthermore, using an ER response element-luciferase reporter, we show that overexpression of ADA3 enhances the ER alpha- and ER beta-mediated sequence-specific transactivation. Reverse transcription-PCR analysis showed an ADA3-mediated increase in estrogen-induced expression of the endogenous pS2 gene. More importantly, using RNA interference against hADA3, we demonstrate that inhibition of endogenous hADA3 inhibited ER-mediated transactivation and the estrogen-induced increase in the expression of pS2, cathepsin D, and progesterone receptor, three widely known ER-responsive genes. The HPV E6 protein, by targeting hADA3 for degradation, inhibited the ER alpha-mediated transactivation and the protein expression of ER target genes. Thus, our results demonstrate that ADA3 directly binds to human estrogen receptor and enhances the transcription of ER-responsive genes, suggesting a broader role of mammalian hADA3 as a coactivator of nuclear hormone receptors and the potential role of these pathways in HPV oncogenesis.

Altered urinary profiles of polyamines and endogenous steroids in patients with benign cervical disease and cervical cancer

The risk of cancer of the cervix is linked with sexual behavior. Although infectious agents, such as human papillomaviruses (HPVs) are implicated, these alone may be insufficient to induce the disease. We investigated the potential role of estrogen, androgen, and polyamine metabolism as co-factors in the development of cervical cancer. We obtained urine samples from patients with benign cervical disease (n=18) and cervical cancer (n=18) and from age-matched normal female subjects (n=25). For 11 polyamine determination, an improved and sensitive gas-chromatographic with nitrogen/phosphorus-detection (GC/NPD) procedure was used. The urinary levels of 25 androgens and corticoids and 16 estrogens were quantitatively determined by gas chromatography-mass spectrometry-selected ion-monitoring (GC/MS/SIM). In the patients with cervical cancer, the ratio of 16alpha-hydroxy estrone (16alpha-OH E1)/2-hydroxy estrone (2-OH E1), putrescine (Put)/N(1)-acetylspermidine (N(1)-acSpd) and 5beta-tetrahydrocortisol (THF)/5alpha-tetrahydrocortisol (5alpha-THF) were significantly increased in comparison to the values of the normal controls. These data suggest: (1) an increase of 16alpha-hydroxylation in estrogen metabolism; (2) the high activity of polyamine oxidase (PAO) in polyamine metabolism; and (3) the low activity of 5alpha-reductase in androgen metabolism may play a significant role in the development of cervical cancer. Although additional research is necessary, the combination of 16alpha-OH E1/2-OH E1 and THF/5alpha-THF may provide a dual marker for the discrimination of benign cervical disease and cervical cancer.

Neoplastic change of squamo-columnar junction in uterine cervix and vaginal epithelium by exogenous estrogen in hpv-18 URR E6/E7 transgenic mice

OBJECTIVE

The goal of this study was to study whether estrogen could induce progression of cervical neoplasia by the influence of direct hormonal transactivation of the viral genes.

METHODS

We examined the in vivo effect of estrogen on HPV-18 URR E6/E7 transgenic mice. We analyzed the growth stimulation of epithelial cells at squamo-columnar junction and vagina and the expression of HPV E6/E7 in transgenic mice. The promoter activity of HPV-18 URR after treatment of estrogen was also evaluated by in vitro transient transfection assay.

RESULTS

The dysplastic lesions of lower genital tract were more frequently seen in the HPV-18 URR E6/E7 transgenic mice and estrogen-treated mice, when compared to those of control group (P < 0.05). The majority of cells in whole epithelial layer of cervix and vagina were proliferating cell nuclear antigen-positive (PCNA) by immunohistochemical staining in the estrogen-treated transgenic mice. Hyperplastic glandular lesions were also identified in estrogen-treated HPV-18 URR E6/E7 transgenic mice (5 of 21) and estrogen-treated nontransgenic mice (2 of 10). The level of E6/E7 transcripts in transgenic mouse was increased in the presence of estradiol. Treatment with 0.5 x 10(-6) M estradiol in the presence of cotransfection with the estrogen receptor expression vector and URR-CAT showed an additive effect of CAT activity (4.8-fold increase).

CONCLUSION

The HPV E6 and E7 oncogenes implicated in cervical cancer are indeed capable of potentiating tumor formation in animal model. Continual estrogen-induced proliferation might be viewed by in vivo and in vitro mechanisms by which squamous cells as well as glandular cells in cervix and vagina became permissive for neoplastic progression in HPV-18 URR E6/E7 transgenic mice and their molecular systems.

Relationship between steroid hormone contraceptives and HPV, cervical intraepithelial neoplasia and cervical carcinoma

Available data demonstrate an increase in the transcription of high-risk papillomaviruses by the 16alpha-hydroxylation of estrogens, which is in line with the epidemiologic data showing an increased cervical carcinogenesis risk for long-term contraceptive-using, HPV-infected women. No evidence exists for an increase in HPV-negative contraceptive users.

Diindolylmethane alters gene expression in human keratinocytes in vitro

Indole-3-carbinol (I3C) and its dimer 3,3'-diindolylmethane (DIM), obtained from dietary consumption of cruciferous vegetables, have multiple biochemical activities. Both compounds have been effective clinically in treating precancerous lesions of the cervix and laryngeal papillomas, pathologies with a human papillomavirus (HPV) component. Using cDNA microarrays, we examined early changes in gene expression after treatment with 100 micro mol/L DIM in C33A and CaSki cervical cancer cells and in an immortalized human epithelial cell line (HaCat), as well as in normal human foreskin keratinocytes (HFK). Multiple analyses were done after treating C33A cells for 6 h; other analyses included 4- and 12-h treatments of C33A and 6-h treatments of CaSki, HaCat and HFK cells. DIM consistently altered the expression of >100 genes at least twofold. Many of the stimulated genes encode transcription factors and proteins involved in signaling, stress response and growth. Results were comparable between transformed cells with and without integrated HPV sequences, and many of the same genes were induced in these cancer-derived cells and in noncancer cells. Eight genes encoding bZip proteins were among the most consistently and robustly induced, including the stress-associated immediate early gene GADD153 (>50 fold in C33A) and nuclear factor-interleukin 6 (NF-IL6), also known as c/EBPbeta, (>5 fold in C33A), which has been shown to reduce expression of HPV oncogenes. Induction of GADD153, NF-IL6 and ATF3 was confirmed by Western analysis. In functional analyses, DIM not only suppressed transcription of a luciferase gene driven by the HPV11 upstream regulatory region (URR) in C33A, CaSki, HaCat and HFK cells from >2-fold to 37-fold depending on the type of cells, but also reduced endogenous transcription of HPV16 oncogenes to undetectable levels in CaSki cells as determined by an RNase protection assay. Ectopic expression of GADD153 or NF-IL6 suppressed transcription in a dose-dependent manner driven by the HPV11 URR in C33A, CaSki, HaCat and HFK cells. These results identify unexpected ways in which dietary I3C and DIM invoke cellular responses and are consistent with a potential antiviral effect of DIM on keratinocytes, but they do not explain the differential sensitivity of transformed keratinocytes to apoptosis by DIM.

Estradiol metabolism and malignant disease

Endogenous estradiol metabolism results in metabolic products that are still capable of exerting various biological, partially estrogen-antagonistic actions. This indicates that the effects of estradiol in carcinogenesis may depend on individual variations of metabolic breakdown of estradiol. The aim of this paper is to review and discuss the available data relating to stimulatory and inhibitory properties of estradiol metabolites on carcinogenesis. Results of main D-ring metabolites and main A-ring metabolites are presented. There are indications that the endogenous production of growth influencing estradiol metabolites may be elevated in neoplasias. Some results in this respect are available for stimulating tumor growth for the D-ring metabolite 16-hydroxyestrone and the A-ring metabolites 4-hydroxyestrone and 4-hydroxyestradiol. Inhibitory effects exist for the A-ring metabolite 2-methoxyestradiol (2-ME). So far, only a few metabolites have been studied closely for their influence on carcinogenesis. There is also a dearth of data on the intracellular metabolism of estradiol in neoplastic tissues. Knowledge of the metabolites may reveal new approaches to diagnosis and treatment of malignant diseases. 2-ME has already shown actions in pharmacological dosages which led already to a first trial to prove its suitability for treating human breast cancer.

Interactions of the female hormonal environment, susceptibility to viral infections, and disease progression

Sex hormones influence susceptibility and disease predisposition for many genital tract infections. This review describes the mechanisms by which sex steroids affect mucosal immunity, with particular reference to human immunodeficiency virus (HIV) and genital herpes, and the stage-specific effects of hormonal contraception on human papillomavirus (HPV) infection. Estrogen's role is important in the early stages of several infections as it stimulates antibody- and cell-mediated immune responses. There is increased expression of some cytokines in peripheral blood and vaginal fluids during the follicular phase of the menstrual cycle and with use of hormonal contraception. Whether estrogen exerts a protective or deleterious influence depends on the infecting organism and stage of infection or disease. Estrogen apparently reduces susceptibility to primary HPV infection but in the event of persistent HPV infection, sex steroid hormones (estrogen and/or progesterone) are associated with progression to cervical cancer. It is important that these stage-specific effects are better described because most vaccines will try to prevent either infection or disease. Clinicians with patients at high risk of sexually transmitted infections, especially HIV, require better information on the risks associated with different hormonal contraceptive regimes.

Therapy for Recurrent Respiratory Papillomatosis

Human papillomaviruses types 6 or 11 are aetiological agents of recurrent respiratory papillomatosis, a disease characterized by benign exophytic tumours usually on the vocal cords. Surgery debulks the tumours, but these growths generally recur at regular intervals. Adjunct medical treatments, aimed at containing the virus and growth of tumours, include indole-3-carbinol or its dimer diindolylmethane, interferon, photodynamic therapy and others. Preventive and therapeutic vaccines hold promise for eliminating the virus.

Indole-3-carbinol and diindolylmethane induce apoptosis of human cervical cancer cells and in murine HPV16-transgenic preneoplastic cervical epithelium

Dietary indole-3-carbinol (I3C) has clinical benefits for both cervical cancer and laryngeal papillomatosis, and causes apoptosis of breast cancer cells in vitro. We asked whether I3C and its major acid-catalyzed condensation product diindolylmethane (DIM), which is produced in the stomach after consumption of cruciferous vegetables, could induce apoptosis of cervical cancer cell lines. We also asked whether this effect could be observed in vivo. In vitro, both I3C and DIM caused accumulation of DNA strand breaks in three cervical cancer cell lines. Induction of apoptosis was confirmed by nuclear morphology, nucleosome leakage, altered cytoplasmic membrane permeability and caspase 3 activation. Neither I3C nor DIM caused apoptotic changes in normal human keratinocytes. In C33A cervical cancer cells, DIM was more potent than I3C [dose at which the number of viable cells was 50% of that in untreated cultures (LD(50)) = 50-60 micromol/L for DIM and 200 micromol/L for I3C in a mitochondrial function assay] and faster acting. Furthermore, I3C reduced Bcl-2 protein in a time- and dose-dependent manner. In HPV16-transgenic mice, which develop cervical cancer after chronic estradiol exposure, apoptotic cells were detected in cervical epithelium by TdT-mediated dUTP nick-end labeling staining and by immunohistochemical staining of active caspase 3 only in mice exposed to 17beta-estradiol (E2) and fed I3C. Rare apoptotic cells were also observed by hematoxylin and eosin staining in the spinous layer of the cervical epithelium in both control and transgenic mice. Estradiol reduced the percentage of these late-stage apoptotic cells in the cervical epithelium of transgenic, E2-treated mice, but this reduction was prevented by I3C. These data confirm the proapoptotic action of I3C on transformed cells in vitro, extend the observations to cervical cancer cells and to DIM and show for the first time that dietary I3C results in increased apoptosis in target tissues in vivo.

Oestrogen and progesterone increase the levels of apoptosis induced by the human papillomavirus type 16 E2 and E7 proteins

Human papillomavirus (HPV) type 16 infects the genital tract and is generally acknowledged to be a causative agent of cervical cancer. HPV infection alone is not sufficient to induce cervical cancer and other factors such as steroid hormones are thought to play a role in the establishment and/or progression of this disease. The HPV-16 E2 protein is required for virus replication and modulates viral gene expression whereas the HPV-16 E7 protein is required for cell transformation. We and others have shown that both the E2 and E7 proteins can induce apoptotic cell death in HPV-transformed and non-HPV transformed cell lines. Here we show that the steroid hormones oestrogen and progesterone can both increase the levels of E2- and E7-induced apoptosis. The oestrogen metabolite 16 alpha-hydroxyoestrone also increases E2- and E7-induced cell death and the dietary component indole-3-carbinol, which reduces the formation of 16alpha-hydroxyoestrone from oestrogen, blocks the effects of oestrogen. Thus the metabolism of oestrogen to 16 alpha-hydroxyoestrone appears to be required for the effects of this hormone on E2- and E7-induced cell death. We also show that the oestrogen receptor antagonist 3-hydroxytamoxifen blocks the effects of oestrogen on E2- and E7-induced cell death, whereas the anti-progesterone RU486 blocks the effects of both progesterone and oestrogen. We discuss these results in terms of the origin and progression of cervical cancer.

Contraceptive and reproductive risk factors for cervical intraepithelial neoplasia in American Indian women

OBJECTIVES

To evaluate contraceptive and reproductive risk factors for cervical intraepithelial neoplasia (CIN) in southwestern American Indian women.

METHODS

We conducted a clinic-based case-control study. Cases were American Indian women with biopsy-proven CIN I, CIN II or CIN III. Controls were from the same clinics and had normal cervical epithelium. All subjects underwent structured interviews focused on contraceptive and reproductive factors. Laboratory assays included polymerase chain reaction (PCR)-based tests for cervical human papillomavirus (HPV) infection.

RESULTS

We enrolled 628 women in the study. The strongest risk factors for CIN II/III included HPV infection (adjusted odds ratio [OR] = 7.9, 95% CI : 4.7-13.2), and low income (OR = 3.1, 95% CI : 1.7-5.7). The use of an intrauterine device (IUD) ever (OR = 3.0, 95% CI : 1.4-6.1) and currently (OR = 4.1, 95% CI : 1.1-14.6), and > or = 3 vaginal deliveries (OR = 5.2, 95% CI : 2.4-11.1) were associated with CIN II/III. History of infertility was also associated with CIN II/III (OR = 2.1, 95% CI : 1.0-4.2).

CONCLUSIONS

The data suggest that history of infertility, IUD use and vaginal deliveries were associated with CIN among American Indian women.

Connective tissue activating peptide III expression disappears progressively with increased dysplasia in human cervical epithelium

OBJECTIVE

The aim of this study was to explore the possible involvement of CTAP-III in the development of cervical cancer as it progresses through several cervical intraepithelial neoplasia (CIN) stages.

MATERIAL AND METHODS

Twenty-four cervical specimens were obtained by direct punch biopsy, conization, or hysterectomy. Diagnosis of CIN I to CIN III was based on standard morphological criteria in 12 specimens. Tissue specimens were also obtained from 4 normal uteri and 8 cases of invasive squamous cell cervical carcinoma. RT-PCR, using CTAP-III-specific primers, was used to identify CTAP-III mRNA and polyclonal antibodies, directed against the N-terminus of CTAP-III, for immunostaining of the CTAP-III protein.

RESULTS

RT-PCR yielded amplified fragments in RNA derived from normal cervical tissue, while no PCR product was detected in the invasive cervical carcinoma tissue. The PCR product corresponded to a CTAP-III plasmid PCR product. Both tissues expressed the same amounts of GAPDH mRNA as the control for the integrity and equal amounts of the isolated RNA. In each of the 16 specimens of normal cervices and of CIN tissues, epithelial cells were stained with the anti-CTAP-III antibodies. In normal epithelium, CTAP-III staining was homogeneously distributed in all epithelial layers, except in the highly active and proliferating basal cells. CTAP-III was localized at the epithelial cell membrane or between adjacent epithelial cells in a granular, chain-like pattern of staining. In the CIN specimens, CTAP-III staining was no longer seen in the deep epithelial layers, consistent with the dysplastic appearance of the cells, and remained in the seemingly normal superficial epithelial layers. Cells of invasive cervical carcinoma did not stain for CTAP-III and were detected in endothelial cells of capillary blood vessels.

CONCLUSION

The specific localization of CTAP-III between adjacent epithelial cells suggests a possible role of this chemokine in maintaining the normal architecture of epithelial tissues. Its progressive disappearance in increasingly severe CIN may be applied to distinguish between specific stages in the progression of cervical carcinoma.

Innervated island flaps in morphofunctional vulvar reconstruction

In this article, the authors present their own experience in vulvar reconstruction following vulvectomy using two different innervated island flaps according to the size and site of the defect. Island-flap mobilization is possible thanks to the rich blood supply of the perineal region. The methods described are a "V-Y amplified sliding flap from the pubis" and a "fasciocutaneous island flap" raised from one or both gluteal folds. The V-Y amplified sliding flap from the pubis is indicated when the defect is symmetric and located anteriorly. This flap is harvested from the pubis and vascularized by the deep arterial network of the pubis. Sensory innervation is provided by branches of the ileo-inguinal nerve. The fasciocutaneous island flap, raised from one or both gluteal folds, can be used following hemivulvectomy or radical vulvectomy, respectively, to cover posteriorly located defects. Vascularization is provided by the musculocutaneous perforating branches of the pudendal artery, whereas sensory innervation is maintained through the perineal branches of the pudendal nerve. Twenty-two patients have undergone reconstructive surgery of the vulvar region from 1989 to date. On 14 patients, a V-Y amplified sliding flap was used; on 7 patients, reconstruction was carried out by island flaps raised from the gluteal fold. Both techniques are compatible with inguino-femoral lymphadenectomy, and they allow for a correct morphofunctional reconstruction and provide good local sensibility. The final result is aesthetically satisfactory, as all final scars are hidden in natural folds.

Smoking and oral contraceptives as risk factors for cervical carcinoma in situ

Human papillomavirus (HPV) is probably a necessary but definitely not a sufficient cause of cervical carcinoma. However, it remains unclear which factors, in addition to HPV, are important for the development of cervical carcinoma and its precursor lesions. To address this issue, we conducted a case-control study nested in a population-based cohort consisting of women participating in cytological screening in one Swedish county, any time during 1969 through 1995. Detailed information on sexual practice, smoking habits and oral contraceptive (OC) use were collected through telephone interviews with 422 case patients diagnosed with cervical carcinoma in situ and 422 control subjects. All cytological smears were analyzed for presence of HPV 16/18 by a polymerase chain reaction (PCR)-based method. Odds ratios (OR) were used as measures of relative risk. After multivariate adjustment, a 2-fold higher risk was observed among current smokers compared with never smokers [OR 1.94; 95% confidence interval (CI 1.32-2.85)], an association apparently confined to women younger than 45 years. Current use of OCs was associated with a 4-fold increased risk overall (OR 3.64; 95% CI 1.91-6.93) with a monotonic increase with increasing duration of use (p for trend < 0.001). The number of sexual partners was significantly, positively associated with risk among HPV 16/18-negative (p for trend < 0.005) but not among HPV 16/18-positive women. Our data confirm the association between smoking and cervical carcinoma in situ, which might be age-dependent. Our results further indicate a relation with OC use and the risk for cervical carcinoma in situ.

Influence of ovarian hormones on urogenital infection

Numerous studies have examined the influence of hormones on infectious diseases and there is now a wealth of data relating to the more specific effect of the sex hormones, oestrogen and progesterone, on urogenital infections. The interaction between these hormones and the immune system is complex and the variation of hormonal effect between species further complicates the true picture as related to humans. Although it is difficult therefore to draw general conclusions regarding predominant effects of specific hormones, there is the suggestion that oestrogen enhances the pathogenicity of many urogenital micro-organisms. Our understanding of the influential role played by sex hormones in disease pathogenesis is at an early stage and illustrates well the importance of drawing together and interpreting as a whole both epidemiological and molecular studies.

Relatively high expression ratio of sex hormone-binding globulin exon VII splicing variant to wild-type mRNA in human uterine cervical cancers

We have demonstrated the intracellular expression of sex hormone-binding globulin (SHBG) exon VII splicing variant mRNA in human uterine cervical cancer using reverse transcription-polymerase chain reaction-Southern blot and DNA sequencing analyses. Analysis of the missing base pairs proved they corresponded to the entire exon VII, which is considered to encode a portion of the steroid-binding site, suggesting that the steroid-binding affinity of the variant protein might be different from that of the wild-type SHBG. In uterine cervical cancers, the wild-type mRNA levels were lower (P<0.01) and the ratio of the SHBG variant to wild-type mRNA levels was higher (P<0.01) than in the normal cervix. In cervical adenocarcinomas, the wild-type mRNA levels were higher (P<0.05) and the ratio of the SHBG variant to wild-type mRNA levels was lower (P<0.05) than in cervical keratinizing squamous cell carcinomas. There was no difference in expression among the clinical stages of cervical cancers. These results suggest that a relative increase of intracellular variant SHBG protein in human uterine cervical cancers might be involved in the disruption of the normal estrogen dependence.

Invasive cancer of the vulva

This study comprised 328 patients with histologically confirmed primary invasive vulvar cancer, treated between 1948 and 1994. It retrospectively analyzes survival rates in relation to various prognostic factors. Mean and median age at diagnosis was 69 years (n = 328). The patients had experienced various symptoms on an average of 16.3 months prior to diagnosis (median, 6 months). Common presenting symptoms were pruritus, smarting pain, and vulvar tumor. Three hundred patients (91.5%) had squamous cell carcinomas and they were classified according to stage and tumor differentiation as follows: Stage I, 106 (35%); Stage II, 111 (37%); Stage III, 44 (15%); and Stage IV, 39 (13%); well differentiated, 107 (36%); moderately differentiated, 129 (43%); poorly or undifferentiated, 45 (15%); and in 19 cases (6%), tumor differentiation was not available. In 277 (92%) patients the primary treatment was surgical; 189 (63%) patients additionally received radiotherapy and 13 (4%) patients were also given chemotherapy. In 18 patients (6%), the primary treatment was radiotherapy and 5 of these also received chemotherapy. Two patients were given primary chemotherapy and three patients received no treatment. Median survival rate was not reached during the observation time for Stage I. At 10 years observation time survival rate was 85% in this stage. Median survival times for Stages II, III, and IV were reached at 128, 20, and 8 months observation time, respectively. The median survival time in patients with well-differentiated tumors was 152 months; corresponding figures for moderately differentiated and poorly differentiated tumors were 114 and 74 months, respectively. The most important prognostic factors in this study were tumor stage (P < 0.00001), patient age (P < 0.01), and tumor differentiation (P = 0.02).

Chronic estrogen-induced cervical and vaginal squamous carcinogenesis in human papillomavirus type 16 transgenic mice

High-risk human papillomaviruses (HPVs), including type 16, have been identified as factors in cervical carcinogenesis. However, the presence and expression of the virus per se appear to be insufficient for carcinogenesis. Rather, cofactors most likely are necessary in addition to viral gene expression to initiate neoplasia. One candidate cofactor is prolonged exposure to sex hormones. To examine the possible effects of estrogen on HPV-associated neoplasia, we treated transgenic mice expressing the oncogenes of HPV16 under control of the human keratin-14 promoter (K14-HPV16 transgenic mice) and nontransgenic control mice with slow release pellets of 17beta-estradiol. Squamous carcinomas developed in a multistage pathway exclusively in the vagina and cervix of K14-HPV16 transgenic mice. Estrogen-induced carcinogenesis was accompanied by an incremental increase in the incidence and distribution of proliferating cells solely within the cervical and vaginal squamous epithelium of K14-HPV16 mice. Expression of the HPV transgenes in untreated transgenic mice was detectable only during estrus; estrogen treatment resulted in transgene expression that was persistent but not further upregulated, remaining at low levels at all stages of carcinogenesis. The data demonstrate a novel mechanism of synergistic cooperation between chronic estrogen exposure and the oncogenes of HPV16 that coordinates squamous carcinogenesis in the female reproductive tract of K14-HPV16 transgenic mice.

Oral contraceptives and cancer. A review of the evidence

The following review considers epidemiological data published from 1990 onwards on oral contraceptives (OCs) and the risk of cancers of the breast, cervix uteri, endometrium, ovary, liver and skin. In several studies, breast cancer risk was seen to be elevated among women who were current users of an OC, or had recently stopped using an OC, whereas there was no residual risk 5 or more years after stopping OC use. No interaction was observed between type of OC, or with any recognised risk factor for breast cancer, or time-factor, except for some potential excess risk for women who started OC use at a young age. Most studies have confirmed that OCs moderately increase the risk of cervical cancer, particularly in human papilloma virus (HPV)-positive women, thus suggesting that OCs may act as a promoter for HPV-induced carcinogenesis. Recent epidemiological studies have confirmed that combined OCs provide substantial protection against endometrial and ovarian cancers, and results suggest that such protection is long-lasting, and may persist for 15 years or more after stopping OC use. Most case-control studies have shown a relationship between OC use and hepatocellular carcinoma. However, data from cohort studies or analysis of vital statistics indicate that the public health impact of such an association is modest, if not negligible. No association was observed between combined OC use and the incidence of skin melanoma, or any other common skin neoplasm. In terms of clinical and public health implications, the most relevant points regarding OC use are: (i) recent data confirm that OCs confer presistent protection against ovarian cancer; and (ii) any increased risk of breast cancer in OC users is moderate and is restricted to current/recent users. This is reassuring for younger women, whose baseline risk of this disease is extremely low.

Contraceptive use and reproductive history in women with cervical human papillomavirus infection

The study was conducted to investigate whether cervical human papillomavirus infections (CHPI) are associated with contraceptive use and reproductive history. The contraceptive and reproductive histories in 972 women seeking contraceptive advice were noted and screening conducted for human papillomavirus infection. The interview included number of pregnancies and childbirths, legal and spontaneous abortions, and menstrual pattern. Information about current use of contraceptive methods, about casual sex, and history of combined oral contraceptive pill (OC) use was obtained. Women with a history of spontaneous abortion showed a significant correlation with CHPI, as did women who used high-dose OCs when compared with the remaining study population (odds ratio 3.0). There was no association between use of low-dose OCs and CHPI. In multifactorial analyses with adjustment for age, number of lifetime sexual partners, number of partners during the preceding six months and age at first intercourse, the significant correlation between use of high-dose OCs and CHPI remained (adjusted odds ratio 2.8). The results indicate a relationship between female steroid hormones and the occurrence of CHPI. An association with high-dose OCs could not be excluded.

The epidemiology of cervical carcinogenesis

Epidemiologic and laboratory data suggest that cervical cancer typically arises from a series of causal steps. Each step can be studied separately in the hope of better etiologic understanding and improved cancer prevention. The earliest identified etiologic step is infection of young women with specific types of venereally transmissible human papillomaviruses (HPVs). Cervical HPV infections often lead to low grade squamous intraepithelial lesions (mildly abnormal Pap smears). Human papillomavirus infections and their associated lesions are extremely common among young, sexually active women. The infections typically resolve spontaneously even at the molecular level within months to a few years. Uncommonly, HPV infections and/or low grade lesions persist and progress to high grade lesions. The risk factors for progression are mainly unknown but include HPV type and intensity, cell-mediated immunity, and reproductive factors. Nutritional factors or co-infection with other pathogens may also be involved at this apparently critical etiologic step between common low grade and uncommon high grade intraepithelial lesions. Except for advancing age, no epidemiologic risk factors have been found for the next step between high grade intraepithelial lesions and invasive cancer. At the molecular level, invasion is associated with integration of viral DNA. Based on worldwide research, the steps in cervical carcinogenesis appear to be fundamentally the same everywhere, with a central role for HPV infection. The importance of etiologic cofactors like smoking, however, may vary by region.

Indole-3-carbinol. A novel approach to breast cancer prevention

The results show that all of the carcinogens, oncogenes, and tumor-associated viruses that we have studied profoundly affect the extent of 2- and 16 alpha-hydroxylation in a prorisk direction. All of the dietary and biological responses associated with increased cancer risk decrease 2-hydroxylation and increase 16 alpha-hydroxylation. Remarkably, although PAHs are reported to induce P450-1A1, we have found them to decrease 2-hydroxylation. Finally, using indole-3-carbinol to induce 2-hydroxylation results in the chemoprevention of mammary tumors in rodents and recurrences of laryngeal papillomas in humans. Also correlating with these studies in HPV is the decrease in the C-2/C-16 alpha metabolite ratio observed in women with CIN relative to control subjects. The greatest decrease was observed in women with the most severe form, CIN3 (Figure 23). These findings are under further investigation.