Spontaneous malignant transformation of human ovarian surface epithelial cells in vitro.

PURPOSE: Epithelial ovarian cancer has no reliable marker for early detection and no known specific premalignant changes. Human ovarian surface epithelial (HOSE) cells expressing human papillomavirus type 16 (HPV-16) E6/E7 genes undergo crisis, and surviving cells exhibit an immortalized phenotype. Cells show an increasingly invasive phenotype on collagen rafts over time. To ascertain the nature of this aberrant growth, we characterized this spontaneous progression of HOSE cells from a benign to an invasive phenotype using histopathology, immunophenotyping, and tumorigenesis assays. EXPERIMENTAL DESIGN: At various passages, cells were monitored for growth on collagen, response to tumor necrosis factor alpha and daunorubicin, immunohistochemistry and Western blot analysis of E-cadherin and beta-catenin, growth in soft agar, and tumor formation in immunodeficient mice. RESULTS: As passage number increased, cells became increasingly aggressive on collagen, with more pronounced focal stratification and invasion. Furthermore, late-passage cells were more resistant to the apoptotic effects of TNF-alpha and daunorubicin than earlier-passage cells. E-cadherin expression was limited to early-passage cells, whereas beta-catenin was expressed regardless of passage. Cells invading collagen formed colonies in soft agar at low efficiency but were not tumorigenic in immunodeficient mice. Some cultures recovered from colonies grew in soft agar at high efficiencies, and one was tumorigenic. CONCLUSIONS: HOSE cells expressing E6/E7, over time, develop characteristics of malignant cells and produce tumors consistent with an ovarian surface epithelium lineage. Progression of HOSE cells from a benign to an invasive phenotype in vitro may provide a model to dissect the progression of ovarian cancer.

Nonrandom chromosomal imbalances in human ovarian surface epithelial cells immortalized by HPV16-E6E7 viral oncogenes.

We had previously immortalized human ovarian surface epithelial (HOSE) cells using HPV16E6E7 ORFs. In order to identify crucial genetic events involved during cell immortalization, the genomic profile of immortalization of five HOSE cell lines was analyzed by comparative genomic hybridization. Our results showed that chromosomal imbalance was common in HOSE cells after immortalization. The common chromosomal imbalances identified in immortal HOSE cells are: +19q13.1 (5/5 lines), -13q12 approximately qter (4/5 lines), +5q15 approximately q33 (3/5 lines), +20q11.2 approximately q13.2 (3/5 lines) and -22q11.2 approximately qter (3/5 lines). Other chromosomal imbalances, which were detected in two of the five immortal HOSE cell lines, included gains on chromosome 1 and 11q12 approximately q13, and losses on 2p, 4q, 8p, 10p and 11q14 approximately qter. The chromosomal imbalances observed in HOSE cells before immortalization include -8pter approximately p11.2, -11q23 approximately qter, -13q12 approximately qter and +19 which may represent early genetic events during cell immortalization. The genomic profile was examined in one HOSE cell line (HOSE 6-3) at various stages of immortalization. The genomic profiles of HOSE 6-3 cells after crisis were largely stable. A few additional chromosomal imbalances were detected in the immortalized HOSE cells after an extensive culture period including +11pter approximately q23, -15q23 approximately qter, and +17q12 approximately qter. Identification of nonrandom chromosomal imbalance in immortalized HOSE cells may facilitate the identification of specific chromosomes harboring genes involved in the immortalization of human ovarian surface epithelial cells.

Human papillomavirus-11-associated recurrent respiratory papillomatosis is more aggressive than human papillomavirus-6-associated disease.

The aim of this study was to determine whether viral type (HPV-6 vs. HPV-11) could predict the clinical course of recurrent respiratory papillomatosis in children. Viral typing, using the polymerase chain reaction, was performed on laryngeal biopsies of 61 patients treated at Children's Hospital of Michigan. HPV-6 was detected in 29 of the patients' biopsies and HPV-11 in 32 biopsies. HPV-11 was more common among the African-American patients than among Caucasians (P = 0.001). Patients with HPV-11 were diagnosed at a younger age (36.2 vs. 48.2 months; P = 0.04) and were more likely to have active disease (P = 0.0311) at the time of this study. They tended to have longer periods of disease activity (8 years vs. 5 years; P = 0.026), required more surgical procedures (42 procedures/patient vs. 13.6; P = 0.02), and more procedures per patient, per year (2.9 vs. 5.3; P = 0.0164). Three of the patients infected with HPV-11 developed invasive papillomatosis and bronchogenic squamous cell carcinoma, and two of these patients died of disease. Our findings suggest that HPV-11 infection confers a more aggressive course to recurrent respiratory papillomatosis.

Human papillomavirus infection in "young" versus "old" patients with squamous cell carcinoma of the head and neck.

BACKGROUND: Human papillomavirus (HPV) represents a potential risk factor for squamous cell cancer of the head and neck (SCCHN). We evaluated the prevalence of HPV DNA in patients with SCCHN diagnosed at the University of Michigan from 1994-1996. METHODS: Patients were stratified by age at diagnosis as "young" (<50 years; median, 39) or "old" (>50 years; median, 66). Fourteen "young" and 14 "old" were matched for tumor site, and 4 additional "old" patients were included. Specimens were analyzed by polymerase chain reaction for HPV DNA using 2 sets of consensus primers. HPV sequences were confirmed by Southern blot hybridization and typed with type-specific probes. RESULTS: Overall, 15 of 32 (46.9%) samples contained HPV sequences. HPV 16 was detected in 9 of 15 (60%), HPV-18 in 1 of 15 (6.6%), and 5 of 15 (33.3%) remained untyped by multiple methods. When stratified, 7 of 14 (50%) "young" were HPV-positive compared with 8 of 18 (44.4%) "old" (p =.76). Survival in patients with HPV-positive SCCHN was significantly longer than that for HPV-negative patients. CONCLUSIONS: The incidence of HPV in "young" versus "old" is not significantly different, suggesting similar roles for both groups. Patients with HPV-positive tumors may have a survival advantage relative to patients with HPV-negative tumors.

Human papillomavirus type, proliferative activity, and p53: potential markers of aggressive papillomatosis.

CONTEXT: The predictive value of nuclear proliferation antigen (Ki-67), tumor suppressor gene product p53, and human papillomavirus type has not been evaluated for outcome of laryngeal papilloma. OBJECTIVE: This study was designed to determine whether immunohistochemical analysis of Ki-67 and p53 and human papillomavirus typing by polymerase chain reaction are able to identify patients with a more aggressive course of laryngeal papillomatosis. DESIGN: Immunohistochemistry and polymerase chain reaction were performed on archival, paraffin-embedded, laryngeal papillomatosis biopsy specimens at the time of diagnosis, at an intermediate time during treatment, and at the last procedure available. Staining indexes for Ki-67 and p53 were determined, and human papillomavirus type was analyzed for all biopsies. PATIENTS: Twelve patients with recurrent laryngeal papillomatosis for at least 5 years were selected from patients treated at our institution during the last 20 years. MAIN OUTCOME MEASURES: Separate analyses were conducted comparing average Ki-67 and p53 indexes against disease outcome, viral type, or average number of procedures per year. Associations were analyzed between virus type, average number of procedures per year, outcome, and histology. RESULTS: No statistically significant associations were noted in Ki-67 or p53 indexes and outcome. Weak associations were noted for p53 indexes and procedures per year and virus type. Weak associations also were noted between virus type and development of neoplasia. CONCLUSIONS: Our observations suggest that human papillomavirus typing may be helpful in identifying patients with aggressive recurrent laryngeal papillomatosis. The weak association between p53 indexes and procedures per year and virus type may have some predictive value in identifying aggressive lesions.

Model for the fetal recruitment of simian gamma-globin genes based on findings from two New World monkeys Cebus apella and Callithrix jacchus (Platyrrhini, Primates).

The originally embryonic gamma-globin locus duplicated and acquired a novel (fetal) pattern of expression in a defined time period (55-40 million years ago) during primate phylogeny. The objective of this study was to determine some of the factors that led to first the emergence of fetal gamma specificity and then the maintenance of different fetal gamma expression patterns in extant simian primates (e.g., human, capuchin monkey). Analyses focused on two platyrrhine (New World monkey) species: the common marmoset (Callithrix jacchus) and the brown capuchin monkey (Cebus apella), each of which has paired, non-allelic gamma loci (5'-gamma 1-gamma 2-3'). Quantitation of beta-type globin mRNAs expressed in a 4.5 week old embryo of Callithrix jacchus revealed that in addition to its primary epsilon-globin message, considerable amounts of gamma 1 message and just trace levels of gamma 2 message are present. In contrast, analyses of gamma-globin messenger RNAs expressed in a Cebus apella fetal liver indicated that gamma 2 expression is at least 120 times greater than gamma 1 expression. Using a luciferase reporter and a transient assay system, the strengths of gamma 1 and gamma 2 promoter fragments of Cebus apella were compared in erythroid (K562) and non-erythroid (HeLa) cell lines. Due to the lack of chromatin repression in a transient expression system, the results do not fully recapitulate globin expression. However, the results suggest that sequences contained within the Cebus gamma 1 and gamma 2 proximal promoter regions (-200 to +1 bp) can direct gamma transcription in both cell lines. In K562 and, to a lesser extent, in HeLa cells Cebus gamma 2 promoter fragments were significantly stronger (P < 0.01) than gamma 1 promoter fragments. This is consistent with the fact that the Cebus gamma 1 promoter contains several mutations, including a proximal CCAAT box mutation (CCAAT-->CCAAc). The epsilon-gamma 1 intergenic distances in these platyrrhines (5.4 kb in Cebus apella and 6.9 kb in Callithrix jacchus) are short, supporting the inference that it was also short in the stem simian primates. The results suggest that immediately following the gamma duplication, the gamma 1 gene of the stem simians was still embryonic and the downstream gamma 2 gene was largely silent. A further inference is that once gamma 2 accumulated regulatory mutations that disrupted binding of fetal repressors, gamma 2 was expressed fetally and, through gene conversion, passed these characteristics to the gamma 1 gene. The fetal expression of gamma 1 is most evident in catarrhines (Old World monkeys and hominoids), which preferentially express the gamma 1 locus during fetal life.

Organotypic culture of human ovarian surface epithelial cells: a potential model for ovarian carcinogenesis.

The objective of this work was to establish an in vitro multidimensional culture system for human ovarian surface epithelial (HOSE) cells as a model for ovarian carcinogenesis. The epithelial origin of cell outgrowth from cells obtained from the ovarian surface was confirmed by keratin staining. Two cultures from two different patients were established, HOSE-A and HOSE-B. Cultures were infected with a retrovirus expressing human papillomavirus genes E6 and E7 to extend their life span. HOSE cells were seeded onto collagen gels containing NIH3T3-J2 fibroblasts as feeder cells and grown to confluence submerged in growth medium. The collagen bed was then raised to the air-medium interface for 7 d (organotypic culture). Microscopically, fixed cultures revealed a single layer of flat cells growing on the collagen surface, reminiscent of HOSE cells in vivo. Infected HOSE-A and HOSE-B cells exhibited aberrant growth because they stratified. In addition, established ovarian cancer lines grown in this fashion stratified and showed malignant phenotypes. Thus, cells grown in organotypic culture resemble their in vivo counterparts, providing a basis for establishing a system to study growth, proliferation, differential gene expression, and perhaps malignant transformation of HOSE cells.

Low false-negative rate of PCR analysis for detecting human papillomavirus-related cervical lesions.

Although PCR analysis is a sensitive test for detection of human papillomavirus (HPV) in the cervix, the proportion of cases of cervical dysplasia missed, or the false-negative rate, has been unknown. We determined the accuracy of PCR analysis for HPV DNA as a predictor of HPV-related cervical lesions in a cross-sectional study of sexually active women, aged 18 to 50 years, from the University of Michigan Family Medicine HPV study. Of 133 eligible participants, 41 underwent colposcopy because of a positive result for HPV of the cervix by the PCR method and 92 underwent screening colposcopy with biopsy prior to knowing the HPV PCR results. Twenty-four of those screened were subsequently found to also be HPV DNA positive. In those found to be HPV positive, histological studies revealed the presence of condyloma or cervical intraepithelial neoplasia in 16 women (24.6%) and changes suggestive of condyloma in 5 (7.6%). No HPV-negative woman had an abnormal biopsy or cytology report (P = 0. 000001). The false-negative rate (1 - sensitivity) for HPV PCR analysis for detection of the presence of a cervical HPV-related lesion was 0% (95% confidence interval, 0 to 0.047), and the specificity was 60.7%. In summary, PCR analysis for HPV DNA had a very low false-negative rate for predicting HPV-related lesions of the cervix in a community-based population. This supports the validity of using the absence of HPV at the cervix, as determined by PCR testing, as an inclusion criterion for patients in control groups in studies dealing with low-grade cervical lesions.

Basaloid squamous cell carcinoma: a distinctive human papilloma virus-related penile neoplasm: a report of 20 cases.

Most penile neoplasms are squamous cell carcinomas (SCC), but there are subtypes that show morphologic and possibly etiologic differences. Clinicopathologic features of 20 patients with basaloid carcinoma (BC), an unusual variant of squamous cell carcinoma, are presented. Median age was 52 years, and all tumors were located in the glans, three confined to the perimeatal region. Average tumor size was 3.8 cm. Microscopically, nests of small, basophilic cells with numerous mitosis were present. Human papillomavirus DNA sequences (type 16), using the polymerase chain reaction (PCR), were found in 9 of 11 cases. Differential diagnosis included urethral transitional cell, basal cell, small cell neuroendocrine, and metastatic carcinoma. Factors more significantly associated with regional metastasis and mortality were tumor thickness greater than 10 mm and infiltration of the corpus cavernosum. A comparison with typical squamous cell carcinoma showed basaloid carcinoma to have a higher histologic grade, a deeper invasion of penile anatomic levels, and a higher mortality rate. Of 17 patients observed, 10 were dead of disease (average time, 34 months), one was alive with disease 6 months after diagnosis, and 5 were alive and free of disease (average time, 71 months); the remaining patient died of other causes. Basaloid carcinoma is a distinctive morphologic subtype of squamous cell carcinoma frequently associated with the human papilloma virus.

Bradykinin blocks angiotensin II-induced hypertrophy in the presence of endothelial cells.

Angiotensin-converting enzyme inhibitors block left ventricular hypertrophy in vivo. A component of this effect has been attributed to tissue accumulation of bradykinin. Little is known regarding the effect of bradykinin on cardiomyocytes. The objectives of the present study were to define the effects of bradykinin on isolated ventricular cardiomyocytes (from adult and neonatal rat hearts) and to determine the extent to which bradykinin blocks hypertrophy in vitro. Bradykinin was found to be a hypertrophic agonist, as defined by increased protein synthesis and atrial natriuretic peptide secretion and expression. Bradykinin (10 micromol/L) increased [3H]phenylalanine incorporation by 23+/-3% in adult and by 36+/-10% in neonatal cardiomyocytes. Constitutive atrial natriuretic peptide secretion by neonatal myocytes was increased 357+/-103%. All effects of bradykinin were abolished by the B2-kinin receptor antagonist Hoe 140. These increases were similar in magnitude to those observed with phenylephrine (20 micromol/L) and angiotensin II (1 micromol/L). However, in cardiomyocytes cocultured with endothelial cells, bradykinin did not increase protein synthesis. Angiotensin II increased [3H]phenylalanine incorporation by 24+/-3% in adult cardiomyocytes in monoculture and by 22+/-2% in adult rat cardiomyocytes cocultured with endothelial cells. Bradykinin abolished this angiotensin II-induced hypertrophy in myocytes cultured with endothelial cells but not in myocytes studied in the absence of endothelial cells. In conclusion, bradykinin has a direct hypertrophic effect on ventricular myocytes. The presence of endothelial cells is required for the antihypertrophic effects of bradykinin. The results suggest that the increase in local concentration of bradykinin associated with angiotensin-converting enzyme inhibition is an important mechanism by which hypertrophy can be blocked. Manifestation of this mechanism appears to require bradykinin-stimulated release of paracrine factor(s) from endothelial cells, which are also able to block the hypertrophic effects of Ang II.

Clinical models of chemoprevention for cervical cancer.

Cervical carcinoma creates a worldwide, significant population burden that potentially could be reduced by new preventive strategies for cervical cancer such as chemoprevention. Given the vast array of clinical and molecular information available relating to cervical cancer and the precursor lesions along with a growing number of new molecular techniques, a model is needed to guide further investigation. Such a model would facilitate research design, guide hypothesis development and testing, and focus the use of molecular data collection and analysis. This article reviews the clinical and molecular data of cervical cancer and the precursor lesions in order to develop a model for chemoprevention research in cervical cancer.

Preferential association of human papillomavirus with high-grade histologic variants of penile-invasive squamous cell carcinoma.

BACKGROUND: Human papillomavirus (HPV) is causally associated with cervical squamous cell carcinoma (SCC) and its precursor lesions. By analogy, HPV is believed to play a role in penile cancer through progression of HPV-associated penile squamous intraepithelial lesions (SIL). HPV DNA has been reported to be present in 100% of high-grade penile SIL, but the percentage of invasive or infiltrating penile SCC that was positive for HPV DNA has varied from study to study (positivity values ranging from 32% to 82%). PURPOSE: To ascertain whether HPV is associated with penile cancer, we used a polymerase chain reaction (PCR)-based assay to test specimens of penile SCC for the presence of HPV DNA. METHODS: A total of 117 formalin-fixed, paraffin-embedded specimens of penile cancer from an equal number of patients who had been diagnosed either at the Memorial Sloan-Kettering Cancer Research Center in New York City between 1964 and 1992 or the Universidad Nacional de Asunción in Paraguay between 1980 and 1992 were analyzed. Specimens were examined without prior knowledge of the histology of the lesions. Methods were used that minimized sample contamination, thus avoiding false-positive results. PCR and Southern blot analyses were used to determine HPV type. The presence of HPV DNA was studied for association with the tumor properties histopathology, growth pattern, tumor grade, regional lymph node status, and anatomic location. Two-sided statistical tests were used to determine P values. RESULTS: HPV DNA was detected in 26 (22.2%) of 117 specimens. In 23 (88.5%) of the 26 HPV-positive specimens, HPV type 16 (only) was identified. HPV DNA was frequently associated with SCC in areas showing basaloid and/or warty changes (nine [47.4%] of 19 specimens were HPV positive; P = .0125). More highly significant was the association of virus with basaloid SCC (nine [75%] of 12 specimens were HPV positive; P = .0005). However, HPV was not found to be associated with typical SCC of the penis (five [11.1%] of 45 specimens were HPV positive). Virus DNA was more often associated with high-grade tumors (P = .0278) exhibiting aggressive growth (P = .0382) localized to the glans penis (P = .0324). Stepwise logistic regression analysis revealed that only tumor histopathology was a significant predictor of an HPV association. CONCLUSIONS: The presence of HPV DNA was found to be significantly associated only with those penile SCC exhibiting basaloid changes. Furthermore, HPV DNA sequences tended to be associated with higher grade and more aggressive tumor localized to the glans penis. The low frequency of HPV in penile SCC implies that only a small proportion of these cancers arise from HPV-associated penile SIL.

Surrogate endpoint biomarkers for cervical cancer chemopreventive trials.

Cervical intraepithelial neoplasia (CIN) represents a spectrum of epithelial changes that provide an excellent model for developing chemopreventive interventions for cervical cancer. Possible drug effect surrogate endpoint biomarkers are dependent on the agent under investigation. Published and preliminary clinical reports suggest retinoids and carotenoids are effective chemopreventive agents for CIN. Determination of plasma and tissue pharmacology of these agents and their metabolites could serve as drug effect intermediate endpoints. In addition, retinoic acid receptors could serve a both drug and biological effect intermediate endpoints. Possible biological effect surrogate endpoint biomarkers include cytomorphological parameters, proliferation markers, genomic markers, regulatory markers, and differentiation. Given the demonstrated causality of human papillomavirus (HPV) for cervical cancer, establishing the relationship to HPV will be an essential component of any biological intermediate endpoint biomarker. The pathologic effect surrogate endpoint biomarker for cervical cancer is CIN, used clinically for years. The desired effect for chemopreventive trials is complete regression or prevention progression. In planning chemoprevention trials, investigators need to consider spontaneous regression rates, the subjective nature of detecting CIN, and the impact of biopsy on regression. If intermediate endpoint biomarkers that met the above criteria were available for cervical cancer, then new chemopreventive agents could be rapidly explored. The efficacy of these new agents could be determined with a moderate number of subjects exposed to minimal risk over an acceptable amount of time. The impacts on health care for women would be significant.

Association between HLA-DQB1 alleles and risk for cervical cancer in African-American women.

Squamous-cell carcinoma of the cervix and its precursor lesions are associated with human papillomavirus (HPV) infection. Epidemiological studies indicate that HPV infection in itself is not sufficient for cervical-cancer induction, suggesting that other factors contribute to carcinogenesis. We have investigated the potential role of host genetic background as one such factor. We screened a series of squamous-cell carcinomas of the cervix for HLA-class-II DQB1* alleles by the polymerase chain reaction and site-specific oligonucleotide probe hybridization and for HPV type from African-American women using a local, ethnically matched control panel. Statistically significant associations for increase in relative risk for cervical cancer were seen for DQB1*0303 and DQB1*0604. DQB1*0201 and the heterozygote DQB1*0301/*0501 showed a decrease in relative risk for cervical cancer. HPV typing revealed no association between virus type and DQB1 alleles. Our results confirm other studies showing an increase in relative risk for cervical cancer associated with HLA-DQ3 alleles in Caucasians.

Factors associated with human papillomavirus infection in women encountered in community-based offices.

OBJECTIVE: To assess risk factors for cervical human papillomavirus (HPV) infection in women presenting to community-based offices because of vaginal symptoms or for preventive screening. DESIGN: Cross-sectional analysis of history, physical examination, and microbiological infection variables. SETTING: Two community-based family practice offices in southeastern Michigan. PATIENTS: Two hundred seventy-three women, 18 to 50 years of age, presenting to the study sites because of vaginal symptoms or for a pelvic examination for preventive screening. MAIN OUTCOME MEASURE: Human papillomavirus infection of the uterine cervix as determined by polymerase chain reaction testing. RESULTS: Human papillomavirus infection was detected in 21.2% of the women (24.9% and 13.1% of women with and without vaginal symptoms, respectively); 34% of these infections were HPV types 16 or 18. Fifty-four percent of the women with HPV infection who underwent colposcopy had condyloma or cervical intraepithelial neoplasia verified on biopsy. Independent associations were found between HPV infection and the following female risk factors: the presence of vaginal itching, odor, or swelling; knowing the current sexual partner less than 24 months; age less than 40 years; household income of $14,000 or less; and ever having had six or more sexual partners. CONCLUSIONS: In addition to three previously described risk factors for genital HPV infection, two previously unrecognized risk factors were identified in this lower-risk population. These risk factors included the presence of vaginal symptoms of itching, odor, or swelling and having known the current sexual partner less than 24 months. Nevertheless, using risk factors alone, two thirds of the women infected with HPV in this population were not identified as being at high risk of infection. No subset of sexually active women was identified who were at no risk of HPV infection.

Presence of human papillomavirus infection of the uterine cervix as determined by different detection methods in a low-risk community-based population.

OBJECTIVE: To evaluate the effectiveness of various screening tests for detecting genital human papillomavirus (HPV) in a community-based population and to determine the prevalence of cervical lesions on colposcopically directed biopsies in patients found to have HPV by any screening test. DESIGN: Cross-sectional analysis of 208 female patients screened for HPV by clinical examination, Papanicolaou test, dot blot hybridization test (ViraPap, Digene Inc, Silver Spring, Md), and polymerase chain reaction (PCR) analysis. All persons with abnormal or positive results by any method were offered colposcopic evaluation. SETTING: Two community-based family practice offices in southeastern Michigan. MAIN OUTCOME MEASURES: The presence of HPV as determined by each test and results of colposcopic biopsies (gold standard) in patients who had HPV identified by any test. RESULTS: The prevalence of HPV infection was 20.3% by PCR analysis, 3.1% by ViraPap, 3.0% by the Papanicolaou test, and 0% by clinical examination. Symptomatic patients (those with complaints of vaginal odor, swelling, or itching) were more likely to harbor HPV as determined by PCR analysis than were asymptomatic women (P = .03, odds ratio = 2.65). Human papillomavirus type 16 or 18 was found in 41% of patients with positive PCR analyses and in all patients with positive ViraPap tests that were typed. Colposcopy with biopsy (gold standard for the presence of HPV disease) was performed on 34 of the 41 patients who tested positive for HPV by PCR analysis. Histologic results revealed that 79.4% of these patients had cervical disease: 14.6% had cervical intraepithelial neoplasia, 38.3% had condyloma, and 26.5% had cervicitis. CONCLUSIONS: Human papillomavirus as detected by PCR analysis was present in 20.3% of women in our population and was often one of the higher-risk types (16 or 18). A positive PCR analysis was predictive of cervical disease on colposcopic biopsy. The ViraPap test, Papanicolaou test, and clinical examination were insensitive measures for detecting HPV-related lesions in this population.

Viral role in cervical and liver cancer.

Hepatitis B virus (HBV) and certain human papillomaviruses (HPV) have been suspected of playing a role in human malignancy. The long latency period (decades) and the fact that only a small proportion of infected individuals subsequently have cancer suggests that these viruses probably contribute in an indirect manner to the development of cancer. Analysis of viral gene function at the molecular level supports this conclusion. More studies are needed to understand the subtle interactions between host cell and viral functions and the genetic and environmental factors that may contribute to malignancy.

A spectrum of bilateral squamous conjunctival tumors associated with human papillomavirus type 16.

Three patients with bilateral tumors presenting as multiple keratinizing and verrucous lesions of the bulbar and tarsal conjunctiva were determined by DNA amplification and hybridization studies to harbor human papillomavirus type 16 (HPV-16). Results of biopsy in two patients showed infiltrating squamous cell carcinoma in one eye and dysplasia or carcinoma in situ in the fellow eye. In the third patient, focal, inflamed, hypertrophic, papillary lesions with pseudoglandular invaginations of the surface epithelium were found in the tarsal conjunctivae of both eyes. These are the first documented cases of bilateral conjunctival tumors associated with human papillomavirus.

Tissue effects of and host response to human papillomavirus infection.

Human papillomaviruses are a heterogeneous group of DNA tumor viruses associated with hyperplastic (warts, condylomata), dysplastic (CIN and VIN), and malignant lesions (carcinomas) of squamous epithelium. Each HPV type is preferentially associated with specific clinical lesions and has an anatomic site preference for either cutaneous or mucosal squamous epithelium. Infection appears to begin in the basal cells. Early gene expression is associated with acanthosis, and late gene expression is associated with appearance of structural antigens and virions in nuclei of cells of the granular layer, usually koilocytotic cells. Malignant transformation of warts and papillomas appears to be related to a variety of factors: (1) infection by certain HPV types (HPV-5, HPV-8, HPV-16, HPV-18, HPV-31); (2) decreased cellular immunity to HPV-associated antigens; and (3) interaction with cofactors such as other microorganisms or sunlight. Spontaneous regression or successful treatment of the benign lesions appears to depend on either naturally acquired or iatrogenically related stimulation of HPV type-specific immunity. The humoral antibody response to HPV particles may be important in preventing infection. In contrast, the local events surrounding regression of warts and condylomata are primarily associated with specific cell-mediated immunity. Local cell-mediated immune responses, particularly cell-associated soluble mediators and stationary macrophage-like cells, may be especially important in the host's immune response to mucosal infections.

Human papillomavirus infection and neoplasia. Speculations for the future.

Human papillomavirus infections of the skin and anogenital tract are common. The association of these viruses with neoplasia, particularly of the anogenital tract, has stimulated efforts to devise practical methods of detection and typing of HPV. Although experimental diagnostic tests are available, they are, for the most part, complex and time consuming and are limited to medical centers researching HPV. New methods for preparing probes with higher sensitivities for hybridization tests will allow use of in situ methods on formalin-fixed tissues and will probably be the method of choice. Antigen detection systems are not available, except for antisera directed against the common structural antigens. The most useful immunologic test will be directed toward detection of nonstructural antigens in fixed tissues; such a system could also be useful for virus typing. Therapies based on use of these antigens to stimulate the immune system may be applicable as an alternative to current therapies. Most intriguing are the prospects for a vaccine based on either structural or nonstructural viral antigens. It has been estimated that as many as 20% of cancer deaths in women worldwide are associated with HPV. Thus, use of an effective vaccine would relieve considerable human suffering. Until the host immune response to HPV infection is better defined, however, much of the effort dedicated to developing a vaccine may be futile.