Human papillomavirus type 18 DNA and E6-E7 mRNA are detected in squamous cell carcinoma and adenocarcinoma of the lung

Detection of Human Papillomavirus DNA, E6/E7 Messenger RNA, and p16INK4a in Lung Cancer: A Systematic Review and Meta-analysis

BACKGROUND

The etiologic link between human papillomavirus (HPV) and lung cancer is still controversial.

METHODS

PubMed and Cochrane databases were searched from inception to December 2020 to identify studies on the infection of HPV in lung cancer. We calculated the attributable proportion of HPV in lung cancer by pooling the infection of cases positive for both HPV DNA and biomarkers of carcinogenesis that may be induced by HPV (E6/E7 messenger RNA or p16INK4a).

RESULTS

A total of 117 studies, comprising data of 12 616 lung cancer cases from 22 countries across 5 continents, were included. The overall HPV DNA positivity in primary lung cancer cases worldwide was 16.4% (95% confidence interval, 12.7%-20.5%). HPV DNA positivity of lung cancer varied significantly by pathological type and geographic region. Notably, the expression rate of p16INK4a is significantly higher than the positivity of HPV DNA and of HPV E6/E7 mRNA (P < .05). The estimate of HPV attributable proportion defined by expression of E6/E7 mRNA was 0 and of p16INK4a was 7.3%.

CONCLUSIONS

The data in this systematic review is robust enough to contradict the possible participation of HPV in lung cancer carcinogenesis. Prophylactic vaccines targeting HPV cannot have the potential to prevent lung cancer.

Prevalence of HPV-DNA and E6 mRNA in lung cancer of HIV-infected patients

HIV-infected individuals could be at a greater risk for developing lung cancer than the general population due to the higher prevalence in the former of human papillomavirus (HPV) in the oral cavity and higher smoking rates. Our aim was to assess HPV prevalence and E6 viral oncogene transcription in lung cancer samples from HIV-infected individuals. This was a single-center, retrospective study of a cohort of HIV-1-infected patients diagnosed with and treated for lung cancer. Pathological lung samples archived as smears or formalin-fixed paraffin-embedded blocks were subjected to HPV genotyping, detection of human p16 protein and assessment for HPV E6 mRNA expression. Lung cancer samples from 41 patients were studied, including squamous cell carcinoma (32%), adenocarcinoma (34%), non-small cell cancer (27%), and small cell cancer (7%). HPV DNA was detected in 23 out of 41 (56%, 95% CI 41–70%) of samples and high-risk (HR)-HPV types were detected in 16 out of 41 (39%, 95% CI 26–54%), HPV-16 being the most prevalent [13/16 (81.3%, 95% CI 57.0–93%]. In samples with sufficient material left: expression of p16 was detected in 3 out of 10 (30%) of HR-HPV DNA-positive tumors and in 3 out of 7 (43%) of the negative ones; and E6 mRNA was detected in 2 out of 10 (20%) of HPV-16-positive samples (squamous lung cancers). These two patients had a background of a previous HPV-related neoplasia and smoking. HR-HPV DNA detection was prevalent in lung cancers in HIV-infected patients. However, viral oncogene expression was limited to patients with previous HPV-related cancers.

HPV and lung cancer: A systematic review and meta-analysis

BACKGROUND

Lung cancer has emerged as a global public health problem and is the most common cause of cancer deaths by absolute cases globally. Besides tobacco, smoke infectious diseases such as human papillomavirus (HPV) might be involved in the pathogenesis of lung cancer. However, data are inconsistent due to differences in study design and HPV detection methods.

AIM

A systematic meta-analysis was performed to examine the presence of HPV-infection with lung cancer.

METHODS AND RESULTS

All studies in all languages were considered for the search concepts "lung cancer" and "HPV" if data specific to HPV prevalence in lung cancer tissue were given. This included Journal articles as well as abstracts and conference reports. As detection method, only HPV PCR results from fresh frozen and paraffin-embedded tissue were included. Five bibliographic databases and three registers of clinical trials including MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov were searched through February 2020. A total 4298 publications were identified, and 78 publications were selected, resulting in 9385 included lung cancer patients. A meta-analysis of 15 case-control studies with n = 2504 patients showed a weighted overall prevalence difference of 22% (95% CI: 12%-33%; P < .001) and a weighted overall 4.7-fold (95% CI: 2.7-8.4; P < .001) increase of HPV prevalence in lung cancer patients compared to controls. Overall, HPV prevalence amounted to 13.5% being highest in Asia (16.6%), followed by America (12.8%), and Europe (7.0%). A higher HPV prevalence was found in squamous cell carcinoma (17.9%) compared to adenocarcinoma (P < .01) with significant differences in geographic patterns. HPV genotypes 16 and 18 were the most prevalent high-risk genotypes identified.

CONCLUSION

In conclusion, our review provides convincing evidence that HPV infection increases the risk of developing lung cancer.

Human papillomavirus and lung cancer: an overview and a meta-analysis

PURPOSE

This review is devoted to assessing the prevalence of human papillomavirus (HPV) in lung cancer (LC) in the world. HPV is recognized as the etiological factor of cervical cancer, however, there is widespread evidence that this virus is detected not only in gynecological carcinomas, but also in tumors of other organs, in particular the upper respiratory tract and digestive tract.

MATERIALS AND METHODS

 A search was conducted to a depth of 29 years in the PubMed, Web of Science, Scopus, databases. The review includes 95 articles.

RESULTS

Of all the analyzed studies (9195 patients), 12 works showed a complete absence of HPV in the biological material in patients with LC. The absence of a virus among lung cancer patients has been established for Canada, the Netherlands and Singapore. The highest average percent of occurrence of this virus is shown for such countries as: Brazil, Korea, Greece and Taiwan (more than 40%). But the highest percentage of HPV occurrence by region is observed in Latin America (33.5%), followed by the Asian countries (31%), in European countries the frequency is 18%. Interestingly, the highest occurrence of high oncogenic types (16 and 18) is observed in Asia (40.3%), then in Latin America (33.6%), Europe (25.6%) and North America (15.4%). Low-oncogenic types (6 and 11) are also predominantly observed in Asia (39.9%), while in Europe and North America 30% and 12.8%, respectively. A meta-analysis of the prevalence of HPV was conducted using Comprehensive Meta-Analysis 3.0. Program, which included 26 studies, the results of which revealed: the prevalence of HPV infection in tumor lung tissue was compared with normal lung tissue OR (95% CI) = 5.38 (3.21-9.00) p < 0.0001, significance was also found for Chinese studies OR = 6.3, 95% CI 3.42-11.53, p < 0.0001, I2 = 71.8% and for nine studies in Europe OR = 6.3, 95% CI 1.8-22.18, p = 0.004, I2 = 51.0%. However, given the fact that the frequency of occurrence of HPV in lung tumor tissue varies greatly, a question may arise about the real role of HPV in LC carcinogenesis, which makes further research relevant and promising.

The Association between Human Papillomavirus Infection and Smoking, Age, Gender in Lung Cancer Patients: A Meta-Analysis

BACKGROUND

The aim of our study was to identify the association between Human papillomavirus (HPV) positive rate and smoking in lung cancer (LC) patients. Meanwhile, to analyze differences among gender, age differences on HPV infection rate in LC patients.

METHODS

We performed a systematic literature search through PubMed, Wan Fang, China National Knowledge Infrastructure (CNKI), MEDLINE, EMBASE (OVID), and Web of Science databases from 1991-2017, and we searched these keywords such as "lung cancer", "HPV", "smoking", and "human papillomavirus". Review Manager 5.3 software was used to analyze. An estimate of the odds ratio (OR) with 95% confidence intervals (CI) was calculated.

RESULTS

In China, a statistical significance was observed between HPV positive rate and smoking in LC patients (OR=2.34, 95%CI: 1.76-3.09, P<0.001; I² =25%). However, after stratified by region, no significance was observed in other regions, gender, and age.

CONCLUSION

HPV infections are associated with smoking in LC patients. The association between HPV infection and smoking in LC patients may relate to different regions. There were no differences between gender and age among HPV infection rates in LC patients. To identify the etiology of smoking, HPV, and LC, a further experimental research needs to be conducted.

Risk factors of Lung Cancer in nonsmoker

Generally, the cause of lung cancer is attributed to tobacco smoking. But many of the new lung cancer cases have been reported in nonsmokers. Apart from smoking; air pollution, environmental exposure, mutations, and single-nucleotide polymorphisms are known to be associated with lung cancer. Improper diet, alcohol consumption, marijuana smoking, estrogen, infections with human papillomavirus (HPV), HIV, and Epstein-Barr virus are suggested to be linked with lung cancer but clear evidences to ascertain their relation is not available. This article provides a comprehensive review of various risk factors and the underlying molecular mechanisms responsible for increasing the incidence of lung cancer. The pathologic, histologic, and genetic differences exist with lung cancer among smokers and nonsmokers. A better understanding of the risk factors, differences in pathology and molecular features of lung cancer in smokers and nonsmokers and the mode of action of various carcinogens will facilitate the prevention and management of lung cancer.

Investigating the role of human papillomavirus in lung cancer

Lung cancer is the leading cancer worldwide among men and women with morbidity reaching 1.6 million. Human Papillomavirus is the causal factor of cervical cancer while its association with others is still under investigation. The purpose of our study is to examine the presence of HPV DNA as well as high-risk E6/E7 mRNA in patients with lung cancer.

Lung tissues were collected during bronchoscopy and tested for HPV DNA and E6/E7 mRNA.

67 lung tissue samples were analysed. The age range was 49–85 years old (y.o) with a mean age of 67.6 y.o. 9 patients were female and 58 were male. The study included 12 Small Cell Lung Cancers (SCLC) and 55 Non Small Cell Lung Cancer (NSCLC). HPV DNA was detected in 3.0% (2/67) of lung cancer cases, while no E6/E7 mRNA of five high-risk HPV types was found in tissue samples examined. The two positive patients had no prior history of an HPV related disease.

Using the mRNA test as a gold standard for the association of HPV with malignant transformation, the present results showed no association of HPV status with lung cancer. Further investigation of more lung cancer tissues is required to reach safe conclusions.

Human papillomavirus and lung cancinogenesis: an overview

Lung cancer is the most common cause of cancer deaths worldwide. Although tobacco smoking is considered to be the main risk factor and the most well-established risk factor for lung cancer, a number of patients who do not smoke have developed this disease. This number varies between 15 % to over one-half of lung cancer cases, and the deaths from lung cancer in non-smokers are increasing every year. There are many other agents that are thought to be etiological, including diesel exhaust exposure, metals, radiation, radon, hormonal factors, cooking oil, air pollution and infectious diseases, such as human papillomavirus (HPV). Studies in various parts of the world have detected HPV DNA at different rates in lung tumors. However, the role of HPV in lung cancer is still unclear. Thus, in this review, we investigated some molecular mechanisms of HPV protein activity in host cells, the entry of HPV into lung tissue and the possible route used by the virus to reach the lung cells.

The association between human papillomavirus infection and female lung cancer: A population-based cohort study

Lung cancer is the leading cause of cancer deaths among Taiwanese women. Human papillomavirus (HPV) has been detected in lung cancer tissues. The aim of this study was to investigate the association between HPV infection and lung cancer among the Taiwanese women. The analytical data were collected from the longitudinal health insurance databases (LHID 2005 and 2010) of the National Health Insurance Research Database (NHIRD). The study participants were 30 years and older and included 24,162 individuals who were identified with HPV infection from 2001 to 2004 and 1,026,986 uninfected individuals. Lung cancer incidence among infected and uninfected individuals was compared using the univariate and multivariate regression models. Among the total participants, 24,162 individuals were diagnosed with HPV. After adjusting for age, gender, low income, residential area, and comorbidity, the risk of lung cancer was higher in women (hazard ratio [HR] 1.263, 95% CI 1.015-1.571), while all cancer risks were high in both men and women with corresponding hazard ratios (HR) of 1.161 (95% CI 1.083-1.245) and HR 1.240 (95% CI 1.154-1.331), respectively. This study showed a significant increase in lung cancer risk among Taiwanese women who were exposed to HPV infection.

Metastatic HPV-related head and neck squamous cell carcinoma to the lung and mediastinal lymph nodes in aspirated cytology material: A diagnostic pitfall

BACKGROUND

Although HPV-related head and neck squamous cell carcinoma (HNSCC) has good prognosis, a small proportion of patients develop distant metastases and have worse outcomes. Such metastases can be particularly difficult to diagnose in the lung and mediastinum, where they show extensive morphologic overlap with primary pulmonary neoplasms. This case series discusses metastatic HPV-related HNSCC in lung and mediastinal fine needle aspiration (FNA) cytology.

METHODS

The cytopathology archives were searched for lung and mediastinal FNA specimens of patients with HNSCC. Specimens were included if either the index FNA or the patient's original HNSCC was positive for HPV by DNA in-situ hybridization (ISH). Ten such cases were identified. Patient demographics and primary tumor details were tabulated from the electronic medical record. All FNA slides and stains were reviewed.

RESULTS

The ten patients (mean age of 58.2 years) included 4 smokers. Smears from all cases were hypercellular and hyperchromatic, with focal keratinization in 6/10 (60%). Core biopsies and cell blocks showed basaloid morphology with variable amounts of necrosis. All ten FNAs were diffusely positive for p16 (100%) and 7/9 cases stained (77.8%) were positive for HPV DNA ISH.

CONCLUSIONS

Metastatic HPV-related HNSCC to the lung and mediastinal lymph nodes share the characteristic basaloid, minimally keratinizing morphology seen in Primary HNSCC cytology. Poorly differentiated pulmonary squamous cell carcinoma and neuroendocrine carcinomas are the primary differentials. Although primary lung neoplasms are not HPV-related, p16 positivity can be seen in both squamous cell and small cell lung carcinomas. HPV ISH allows definitive diagnosis of metastatic HPV-related HNSCC.

Detection of human papillomavirus in non-small cell carcinoma of the lung

High-risk human papillomavirus (hrHPV) is an etiologic agent in squamous cell carcinoma (SqCC) arising in the oropharynx and cervix, and a proven prognostic factor in oropharyngeal SqCC. Many studies have found HPV in non-small cell lung carcinoma (NSCLC). Recent studies advocate the detection of messenger RNA transcripts of E6/E7 as more reliable evidence of transcriptively active HPV in tumor cells. The clinical significance of finding HPV remains unclear in NSCLC. This study sought to determine the prevalence of biologically active HPV infection in NSCLC comparing different methodologies. Surgical pathology material from resected primary lung adenocarcinoma (ADC; n=100) and SqCC (n=96) were retrieved to construct tissue microarrays. In situ hybridization (ISH) for hrHPV DNA (DNA-ISH), hrHPV E6/E7 RNA (RNA-ISH), and p16 immunohistochemistry were performed. Cases of oropharyngeal SqCC with known HPV infection were used as positive controls. Expression of p16 was scored as positive if at least 70% of tumor cells showed diffuse and strong nuclear and cytoplasmic staining. Punctate nuclear hybridization signals by DNA-ISH in the malignant cells defined an HPV-positive carcinoma. Of the 196 patients (range, 33-87 years; 108 men), p16 was positive in 19 ADCs and 9 SqCCs, but HPV DNA-ISH and RNA-ISH were negative in all cases. Our study did not detect HPV infection by DNA-ISH or RNA-ISH in any cases of primary NSCLC despite positive p16 expression in a portion of ADC and SqCC. p16 should therefore not be used as a surrogate marker for HPV infection in NSCLC.

HPV-associated lung cancers: an international pooled analysis

Human papillomavirus (HPV) is the etiologic risk factor for cervical cancer. Some studies have suggested an association with a subset of lung tumors, but the etiologic link has not been firmly established. We performed an international pooled analysis of cross-sectional studies (27 datasets, n = 3249 patients) to evaluate HPV DNA prevalence in lung cancer and to investigate viral presence according to clinical and demographic characteristics. HPV16/18 were the most commonly detected, but with substantial variation in viral prevalence between geographic regions. The highest prevalence of HPV16/18 was observed in South and Central America, followed by Asia, North America and Europe (adjusted prevalence rates = 22, 5, 4 and 3%, respectively). Higher HPV16 prevalence was noted in each geographic region compared with HPV18, except in North America. HPV16/18-positive lung cancer was less likely observed among White race (adjusted odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.12-0.90), whereas no associations were observed with gender, smoking history, age, histology or stage. Comparisons between tumor and normal lung tissue show that HPV was more likely to be present in lung cancer rather than normal lung tissues (OR = 3.86, 95% CI = 2.87-5.19). Among a subset of patients with HPV16-positive tumors, integration was primarily among female patients (93%, 13/14), while the physical status in male cases (N = 14) was inconsistent. Our findings confirm that HPV DNA is present in a small fraction of lung tumors, with large geographic variations. Further comprehensive analysis is needed to assess whether this association reflects a causal relationship.

HPV analysis in distinguishing second primary tumors from lung metastases in patients with head and neck squamous cell carcinoma

For patients with head and neck squamous cell carcinoma (HNSqCC), the development of squamous cell carcinoma (SqCC) in the lung may signal a new primary or the onset of metastatic dissemination. Although the distinction influences prognosis and therapy, it may not be straightforward on histologic or clinical grounds. The human papillomavirus (HPV) is an etiologic agent for SqCCs arising from the oropharynx but not for SqCCs arising from other head and neck sites. For patients with HNSqCC who develop a lung SqCC, HPV analysis could be useful in establishing tumor relationships. High-risk HPV in situ hybridization was performed on 54 lung SqCCs from patients with a previously diagnosed HNSqCC and on 166 primary lung carcinomas from patients without a prior HNSqCC. HPV was detected in 11 of 220 (5%) cases. All HPV-positive cases were from patients with a prior oropharyngeal SqCC. For the paired oropharyngeal and lung SqCCs, HPV status was concordant in 95% of cases. Time from treatment of HPV-positive oropharyngeal carcinomas to detection of lung carcinoma ranged from 1 to 97 months (mean, 36 mo). Two HPV-positive cancers were detected in the lung 8 years after treatment of the oropharyngeal primary. Despite the long interval, E6 sequencing analysis of 1 of these paired samples confirmed that the tumors harbored the same HPV-16 variant. HPV does not seem to play a role in the development of primary lung cancer. For patients with oropharyngeal SqCC who develop lung SqCC, HPV analysis may be helpful in clarifying tumor relationships. These relationships may not be obvious on clinical grounds, as HPV-related HNSqCC may metastasize long after treatment of the primary tumor.

Lung Cancer and Human Papilloma Viruses (HPVs): Examining the Molecular Evidence

Human papilloma virus (HPV), known to be an etiological agent for genital cancers, has been suggested also to be a possible contributory agent for lung cancer. Alternatively, lung cancer, formerly considered to be solely a smoker's disease, may now be more appropriately categorised into never smoker's and smoker's lung cancer. Through this paper we attempt to bring forth the current knowledge regarding mechanisms of HPV gaining access into the lung tissue, various strategies involved in HPV-associated tumorigenesis in lung tissue.

Prevalence of human papillomavirus 16/18/33 infection and p53 mutation in lung adenocarcinoma

Human papillomavirus (HPV) infection is a causative event for the development of uterine cervical carcinoma. Human papillomavirus (HPV) 16, 18, and 33 DNA has been also detected frequently in lung adenocarcinomas (AdCs) in East Asian countries; however, its prevalence in Japan remains unclear. We therefore screened for HPV 16/18/33 DNA in 297 lung AdCs in a Japanese population by multiplex PCR with type-specific primers. As reported previously, HPV 16 DNA was detected in two cervical cancer cell lines, CaSki and SiHa, while HPV 18 DNA was detected in HeLa cells, and 0.1-1.0 copies of HPV-DNA per cell were detectable by this method. However, with this method, none of the 297 lung AdCs showed positive signals for HPV 16/18/33 DNA, indicating that HPV-DNA is not or is very rarely integrated in lung AdC genomes in the Japanese. Furthermore, none of the lung AdCs showed positive signals by nested PCR with HPV 16/18 type-specific primers. Therefore, we further attempted to detect HPV 16/18/33 DNA in 91 lung cancer cell lines, including 40 AdC cell lines. Among them, 30 have been established in Japan and the remaining 61 in the USA. No HPV signals were obtained in any of the 91 cell lines by either multiplex or nested PCR, while the p53 gene was mutated in 81 of them including 35 of the 40 AdC cell lines. These results indicate that HPV 16/18/33 infection does not play a major role in the development of lung AdC in Japan nor in the USA.

Vaccination against human papilloma virus (HPV): epidemiological evidence of HPV in non-genital cancers

Recently, the vaccine against human papillomavirus (HPV) was introduced in the national vaccination programmes of several countries worldwide. The established association between HPV and the progression of cervical neoplasia provides evidence of the expected protection of the vaccine against cervical cancer. During the last two decades several studies have also examined the possible involvement of HPV in non-genital cancers and have proposed the presence of HPV in oesophageal, laryngeal, oropharyngeal, lung, urothelial, breast and colon cancers. The possible involvement of HPV in these types of cancer would necessitate the introduction of the vaccine in both boys and girls. However, the role of HPV in the pathogenesis of these types of cancer has yet to be proven. Moreover, the controversial evidence of the possible impact of the vaccination against HPV in the prevention of non-genital cancers needs to be further evaluated. In this review, we present an overview of the existing epidemiological evidence regarding the detection of HPV in non-genital cancers.

Human papilloma virus and female lung adenocarcinoma

Lung cancer is the leading cause of cancer among women worldwide, and adenocarcinoma is the most common histological subtype among non-smoking women. Previous studies showed that human papillomavirus (HPV) infection may relate to the tumorigenesis of pulmonary adenocarcinoma. Women with anogenital malignancy have a higher risk of lung cancer, which raises the possibility of HPV transmission from the cervix to the lung. Two postulated pathways are discussed in this work. First, HPV may infect the female cervix and then move to the lung by blood circulation. The second transmission route is the HPV infection of oral cavity resulting from dangerous sexual contacts, and subsequently transmitted to the lung. This chapter also reviews the techniques for detecting the existence, subtypes, and viral load of HPV. Future studies are needed to demonstrate the causal inference between HPV infection and the risk of female lung adenocarcinoma.

Human papillomavirus type 16 and 18 in primary lung cancers--a meta-analysis

Lung cancer is the leading cause of cancer mortality worldwide. A possible carcinogenic role of human papillomavirus (HPV) has been investigated for >20 years and has major clinical and public health implications. We performed a meta-analysis to assess the prevalence of HPV16 and HPV18 in primary lung cancers (2435 subjects from 37 published studies). The overall HPV prevalence ranged from 0.0 to 78.3% with large heterogeneity across geographic regions and histological tissue types. A higher proportion, 50% (7/14), of the European studies reported low or no HPV prevalence (0-10%) compared with the Asian studies, 22% (4/18). When the analysis was limited to HPV16 and HPV18 prevalence, a higher prevalence in Asia (HPV16 = 11.6% and HPV18 = 8.8%) than in Europe (HPV16 = 3.5% and HPV18 = 3.6%) was observed. Studies using HPV-specific primers resulted in higher prevalence rates than consensus HPV primers (HPV16: Asia = 13% and Europe = 6%; HPV18: Asia = 13% and Europe = 5%). Further studies are needed to elucidate the role of HPV in lung carcinogenesis with careful thought given to study design and laboratory detection methods for a more accurate assessment of HPV status in lung tumors.

HPV infection and p53 inactivation in pterygium

PURPOSE

Our recent report indicated that tumor suppressor gene (p53) mutations and protein aberrant expression were detected in pterygium. Inactivation of p53 by Human papillomavirus (HPV) 16/18 E6 plays a crucial role in cervical tumorigenesis. In this study, we further speculate that p53 inactivation may be linked with HPV infection in pterygium pathogenesis. To investigate the involvement of HPV 16/18 E6 in p53 inactivation in pterygium, the association between HPV 16 or HPV 18 infection, the HPV E6 oncoprotein, and p53 protein expression was analyzed in this study.

METHODS

HPV 16/18 infection was detected by nested-polymerase chain reaction (nested-PCR), the p53 mutation was detected by direct sequencing, and the p53 and the HPV 16/18 E6 proteins were studied using immunohistochemistry on 129 pterygial specimens and 20 normal conjunctivas.

RESULTS

The HPV 16/18 was detected in 24% of the pterygium tissues (31 of 129) but not in the normal conjunctiva, and the HPV16/18 E6 oncoprotein was detected in 48.3% of HPV 16/18 DNA-positive pterygium tissues (15 of 31). In addition, p53 protein negative expression in pterygium was correlated with HPV16/18 E6 oncoprotein expression but not with a p53 mutation.

CONCLUSIONS

HPV 16/18 E6 contributes to HPV-mediated pterygium pathogenesis as it is partly involved in p53 inactivation and is expressed in HPV DNA-positive pterygium.

Incidence of human papilloma virus in lung cancer

HPV has been identified not only in gynaecological carcinomas but also in tumors of other organs, especially of the oropharynx and upper aero-digestive tract. In this study we focused on the available literature on HPV in lung carcinomas. In total, 53 publications reporting on 4508 cases were reviewed and assessed for the following parameters: continent and region of the study, number of cases, detection method, material type, HPV type, histological subtype and number of the HPV-positive cases. Overall, the mean incidence of HPV in lung cancer was 24.5%. While in Europe and the America the average reported frequencies were 17% and 15%, respectively, the mean number of HPV in asian lung cancer samples was 35.7%. There was a considerable heterogeneity between certain countries and regions. Particular high frequencies of up to 80% were seen in Okinawa (Japan) and Taichung (Taiwan). However, there were also discrepant results within the same region pointing to methodological differences and the need for validation. All lung cancer subtypes were affected and especially the high risk types 16, 18, 31 and 33 as well as the low risk types 6 and 11 were found, the later mainly in association with squamous cell carcinomas. The data suggest that HPV is the second most important cause of lung cancer after cigarette smoking and strongly argues for additional research on this issue.

Sequence variants of Toll-like receptor 4 and susceptibility to prostate cancer

Chronic inflammation has been hypothesized to be a risk factor for prostate cancer. The Toll-like receptor 4 (TLR4) presents the bacterial lipopolysaccharide (LPS), which interacts with ligand-binding protein and CD14 (LPS receptor) and activates expression of inflammatory genes through nuclear factor-kappaB and mitogen-activated protein kinase signaling. A previous case-control study found a modest association of a polymorphism in the TLR4 gene [11381G/C, GG versus GC/CC: odds ratio (OR), 1.26] with risk of prostate cancer. We assessed if sequence variants of TLR4 were associated with the risk of prostate cancer. In a nested case-control design within the Health Professionals Follow-up Study, we identified 700 participants with prostate cancer diagnosed after they had provided a blood specimen in 1993 and before January 2000. Controls were 700 age-matched men without prostate cancer who had had a prostate-specific antigen test after providing a blood specimen. We genotyped 16 common (>5%) single nucleotide polymorphisms (SNP) discovered in a resequencing study spanning TLR4 to test for association between sequence variation in TLR4 and prostate cancer. Homozygosity for the variant alleles of eight SNPs was associated with a statistically significantly lower risk of prostate cancer (TLR4_1893, TLR4_2032, TLR4_2437, TLR4_7764, TLR4_11912, TLR4_16649, TLR4_17050, and TLR4_17923), but the TLR4_15844 polymorphism corresponding to 11381G/C was not associated with prostate cancer (GG versus CG/CC: OR, 1.01; 95% confidence interval, 0.79-1.29). Six common haplotypes (cumulative frequency, 81%) were observed; the global test for association between haplotypes and prostate cancer was statistically significant (chi(2) = 14.8 on 6 degrees of freedom; P = 0.02). Two common haplotypes were statistically significantly associated with altered risk of prostate cancer. Inherited polymorphisms of the innate immune gene TLR4 are associated with risk of prostate cancer.

Infection of human papillomavirus type 18 and p53 codon 72 polymorphism in lung cancer patients from India

STUDY OBJECTIVES

Infection with specific high-risk HPV types 16 and 18 and polymorphism of p53 codon 72 has been strongly associated with the genesis of various neoplasms in humans, but such study in lung cancer is limited and the results are controversial. In India, the role of these two factors has been strongly implicated in cervical and other cancers, but the occurrence of HPV or p53 codon 72 polymorphism has not been examined in lung cancer, which is the most common cause of cancer-related death in India.

DESIGN AND PATIENTS

A total of 40 tumor biopsy specimens from advanced lung cancer patients and blood samples from 40 matching control subjects were obtained for the analysis of high-risk HPV types 16 and 18 infection and p53 codon 72 polymorphism by polymerase chain reaction.

RESULTS

Only HPV type 18 was detected in 5% (2 of 40 lung cancer patients), but no other HPV could be detected. A significantly increased frequency of Arg/Arg homozygotes was observed in patients with advanced lung cancer when compared to that of control subjects (p = 0.004; odds ratio, 5.13; 95% confidence interval, 1.59 to 17.26). However, no significant correlation could be made between p53 polymorphism and different clinical stages, except for advanced stage IV patients, who showed a higher proportion of Arg/Pro heterozygous genotype.

CONCLUSIONS

HPV detected in a small proportion of lung cancer patients in India demonstrated an exclusive prevalence of HPV type 18, and there was a significantly higher frequency of p53 Arg/Arg genotype when compared to that of control subjects. Observation of a shorter duration of symptoms (< or = 4 months) in as many as 78% (seven of nine stage IV patients) with Arg/Pro genotype may be an indication that lung cancer patients with the heterozygous p53 genotype are more susceptible to early progression.

Prevalence of human papillomaviruses in lung carcinomas: a study of 218 cases

High-risk human papillomaviruses (HPV) are largely implicated in the carcinogenesis of cervical carcinomas. Their role in bronchopulmonary carcinomas is still unclear. In the present study, we have explored 218 fresh frozen lung tumours for the presence of HPV with the Roche line blot assay and for the expression of mRNAs encoding E6 oncoprotein in HPV positive tumours. Only four samples were positive for HPV detection, one poorly differentiated squamous cell carcinoma and three large cell carcinomas. E6 mRNA was undetectable in these four samples. Our data confirm the low prevalence of HPV in lung carcinomas in Western European countries and do not plead in favour of a carcinogenic role for HPV in these carcinomas.

Lung adenocarcinoma and human papillomavirus infection

Over the past three decades, the incidence of lung adenocarcinoma has increased worldwide. Most individuals with lung adenocarcinoma (especially women) are nonsmokers. Reported risk factors for the development of lung adenocarcinoma include cigarette smoking; exposure to cooking fumes, air pollution, second-hand smoke, asbestos, and radon; nutritional status; genetic susceptibility; immunologic dysfunction; tuberculosis infection; and asthma. Human papillomavirus (HPV) infection is a known risk factor for the development of squamous cell carcinoma (SCC), but it has not been thoroughly assessed as a potential risk factor for the development of pulmonary adenocarcinoma. More than 50% of people are infected with HPV during their lifetimes, either via intrauterine or postnatal infection. Recent studies involving Taiwanese patients have demonstrated a possible association between HPV infection and the risk of developing pulmonary adenocarcinoma. HPV transmission pathways have not yet been conclusively identified. The observation of certain types of HPV in association with cervical and oral SCC raises the possibility of sexual transmission of HPV from the cervix to the oral cavity, with subsequent transmission to the larynx and then to the lung. HPV infection and metaplasia in lung tissue may increase an individual's susceptibility to the tumorigenesis of pulmonary adenocarcinoma. Further epidemiologic and pathologic investigations will be necessary to establish a causal relation.

An AP-1 binding site mutation in HPV-16 LCR enhances E6/E7 promoter activity in human oral epithelial cells

Expression of the human papillomavirus (HPV) E6 and E7 oncoproteins is responsible for the transforming ability of the virus. The HPV long control region (LCR) and E6/E7 promoter regulate transcription of the E6 and E7 viral oncogenes. However, factors involved in the stimulation of E6/E7 promoter activity in carcinogenesis are unclear. We previously identified a point mutation in an HPV-16 immortalized human oral keratinocyte cell line subsequently exposed to a tobacco-specific carcinogen. This mutation was located in the LCR at nucleotide 7633 and contains binding sites for the transcription activator, AP-1, overlapping with putative binding regions for the transcription factor, C/EBP, which represses the E6/E7 promoter. In this study, this mutation was analyzed by both electrophoretic mobility shift analysis and luciferase assays. We found that the point mutation enhanced the binding affinity of AP-1 to the LCR, thus stimulating the E6/E7 promoter activity. Our results suggest that mutations in binding sites for crucial regulators may be the result of exposure to carcinogens and could induce expression of the E6 and E7 oncogenes.

HPV infections and lung cancer

Because of the major clinical impact of bronchial cancer worldwide, the possibility that human papillomavirus (HPV) contributes to its pathogenesis as a co-carcinogen is an intriguing one. Bronchial squamous cell carcinoma develops through well defined precursor lesions, often at the sites of squamous metaplasia. Benign squamous cell papillomas are rare but HPV DNA has been found in almost half of those studied, implicating a causal association. In invasive bronchial cancer, morphological changes seen in HPV lesions elsewhere are often seen. HPV DNA has been detected in 21.7% of the 2,468 bronchial carcinomas analysed to date and the same high risk types implicated in other squamous cell cancers have been identified. Clearly, more effort should be focused on assessing the role of HPV in bronchial carcinogenesis, by analysing the synergistic effects of carcinogenic agents (cigarette smoke, radiation, asbestos, etc) and HPV in different experimental settings.

HPV infections and lung cancer

Because of the major clinical impact of bronchial cancer worldwide, the possibility that human papillomavirus (HPV) contributes to its pathogenesis as a co-carcinogen is an intriguing one. Bronchial squamous cell carcinoma develops through well defined precursor lesions, often at the sites of squamous metaplasia. Benign squamous cell papillomas are rare but HPV DNA has been found in almost half of those studied, implicating a causal association. In invasive bronchial cancer, morphological changes seen in HPV lesions elsewhere are often seen. HPV DNA has been detected in 21.7% of the 2,468 bronchial carcinomas analysed to date and the same high risk types implicated in other squamous cell cancers have been identified. Clearly, more effort should be focused on assessing the role of HPV in bronchial carcinogenesis, by analysing the synergistic effects of carcinogenic agents (cigarette smoke, radiation, asbestos, etc) and HPV in different experimental settings.

Association of p53 codon 72 polymorphism with advanced lung cancer: the Arg allele is preferentially retained in tumours arising in Arg/Pro germline heterozygotes

The association of p53 codon 72 polymorphism with cancer has been investigated by several scientific groups with controversial results. In the present study, we examined the genotypic frequency of this polymorphism in 54 patients with advanced lung cancer and 99 normal controls from the geographical region of Greece. Sputum and bronchial washing samples from each patient were assayed for the presence of human papillomavirus. Codon 72 heterozygous (Arg/Pro) patients were also analysed for loss of heterozygosity at the TP53 locus, in order to determine the lost p53 allele (Arg or Pro). p53 Arg/Arg genotype was significantly increased in lung cancer patients compared to normal controls (50% vs 24.2%, P<0.002). Human papillomavirus was detected only in two patients (3.7%). Loss of heterozygosity at the TP53 locus was found in 14 out of 27 Arg/Pro patients (51.85%). The Pro allele was lost in 11 cases (78.6%), while the Arg allele was lost in three (21.4%). Our results suggest that p53 codon 72 Arg homozygosity is associated with advanced lung cancer, and that the Arg allele is preferentially retained in patients heterozygous for this polymorphism. On the other hand, human papillomavirus infection does not seem to play an important role in lung carcinogenesis.

Recent striking changes in histological differentiation and rate of human papillomavirus infection in squamous cell carcinoma of the lung in Okinawa, a subtropical island in southern Japan

AIMS

The incidence of lung cancer in Okinawa has been the highest in Japan since 1975, and squamous cell carcinoma (SCC), especially the well differentiated form, is the most prevalent form in Okinawa, although well differentiated SCC is relatively rare in mainland Japan. Furthermore, a high proportion of SCC of the lung in Okinawa was positive for human papillomavirus (HPV). In this study, we report recent striking changes in histological features and in the incidence of HPV infection.

METHODS

In Okinawa between 1986 and 1998, 1109 surgically resected lung tumours were examined histopathologically. In addition, human papillomavirus infection was detected by the polymerase chain reaction and Southern blot analysis in SCC cases reported in 1993 and 1995-8. Non-isotopic in situ hybridisation of HPV DNA was also carried out.

RESULTS

Up until 1994 SCC, especially the well differentiated form, was the most prevalent type of tumour. However, since 1995 the number of such cases has diminished steadily, accompanied by a slight rise in the incidence of adenocarcinoma. Although most present and past patients are heavy smokers, the incidence of SCC, especially the well differentiated form, continues to decrease steadily. Furthermore, in 1993, HPV was detected in 79% of all cases, and was particularly prevalent in the well differentiated form, but the rate fell to 68% in 1995, 35% in 1996, 23% in 1997, and 24% in 1998. The age distribution of patients, the male to female ratio, and the number of tumours overexpressing p53 protein did not change significantly over the study period, and thus did not correlate with changes in the differentiation of SCC.

CONCLUSIONS

The decreasing incidence of viral infection correlates strongly with the falling numbers of SCC cases, especially well differentiated cases. These findings suggest that HPV might be involved in the development of SCC of the lung, affecting the histological differentiation of SCC in particular, at least in Okinawa, a subtropical island in southern Japan.

Prognostic implication of human papillomavirus infection in squamous cell carcinoma of the lung

On the subtropical island of Okinawa, squamous cell carcinoma (SCC), particularly the well-differentiated form, is the most frequent type of lung cancer, while this form is relatively rare on the Japanese mainland and in other countries. Furthermore, in Okinawa, in 1993, 80% of SCC cases of the lung were found to be infected with human papillomavirus (HPV). We studied the prognosis of SCC of the lung with HPV infection (n = 25) and compared it with non-HPV-infected SCC (n = 16). Using the Kaplan-Meier method (Wilcoxon analysis), the prognosis of HPV-infected cases was found to be better than that of the non-infected cases. In the virus-infected cases, apoptosis and infiltration of a large number of Langerhans cells were demonstrated. In addition to these findings, the virus-infected tumors were demonstrated to be histologically well-differentiated, perhaps contributing to the favorable prognosis. However, among the virus-infected cases, the type 16 virus-infected cases showed a poorer prognosis, compared to those infected with other HPV types. p53 gene mutation was also examined, and was considered to be an unfavorable prognostic factor, as reported elsewhere. However, in Okinawa, HPV-positive cases with p53 mutations showed a slightly better prognosis than did non-viral infected cases with p53 mutations. The TNM staging system was also useful for categorizing the virus-infected cases. The prognosis of stage III (A and B) cases was poor. All of our present cases received surgical treatment. Chemotherapy and radiation therapy were not performed. Such treatment, however, might be effective, because virus-infected uterine cervical carcinomas have been routinely treated with chemotherapy and radiation. Furthermore, if the immunological basis of increased Langerhans cell infiltration in HPV-infected cases is elucidated, a clinical trial with immunotherapy may be favorable for the clinical outcome.

Detection of human papillomavirus DNA in bronchopulmonary carcinomas by hybrid capture II: a study of 185 tumors

BACKGROUND

Some human papillomaviruses (HPVs) are oncogenic in the cervix and are also associated with benign and malignant proliferations in other organs. Currently, the association of HPV with tumors of the lower respiratory tract is not so clearly defined because the studies are difficult to compare; series of cases reported from different geographic regions have used frozen or formalin fixed samples and a variety of techniques of HPV detection.

METHODS

The authors studied the prevalence of HPV in a large series of 185 frozen bronchopulmonary tumor samples with a new solution hybridization technique, Hybrid Capture II assay. This test is largely applied in cervical pathology. Its sensitivity is very close to the sensitivity of PCR. It allows the detection of 18 mucosal HPV types, divided into 1 oncogenic and 1 nononcogenic group.

RESULTS

Oncogenic HPV DNA was detected by the Hybrid Capture II assay in 5 cases (2.7%) of 185 (3 males and 2 females). In the rare positive cases detected, the authors could not find any consistent morphologic changes classically associated with HPV infection in anogenital lesions, such as koilocytosis.

CONCLUSIONS

Oncogenic HPV DNA is detected in a small proportion of cases of bronchopulmonary carcinoma, and thus HPV infection appears to play a limited role in the tumorigenesis of most lung carcinomas.

Ultrastructural study of intranuclear inclusion bodies of pulmonary adenocarcinoma

Intranuclear inclusion bodies are sometimes observed in pulmonary adenocarcinoma by light microscopy. Electron microscopic characteristics of lung cancer cells with intranuclear inclusion bodies were studied. In addition, polymerase chain reaction (PCR) was performed using primers coding for human papillomavirus (HPV) types 16, 18, and 33. Eosinophilic intranuclear inclusion bodies were observed in 22 out of 285 cases by light microscopy. Immunohistochemically, cancer cell nuclei stained with PE-10. Three types of intranuclear inclusion bodies were classified electron microscopically. Type A showed aggregation of electron dense particles (30-40 nm) with an electron-dense core and was most frequently observed. Type B consisted of a mass of branching and whirling tubular structures. Type B intranuclear inclusions had a relationship with inner nuclear membrane. In type C, several spherical inclusions were observed in one nucleus. HPV DNA was detected using PCR and type-specific probes in a case with type A inclusion bodies. This study suggests that intranuclear inclusion bodies in pulmonary adenocarcinoma are formed by several different mechanisms.

Infection, immunity, and cancer

A significant percentage of human cancers worldwide are associated with infections due to known viruses, including human papillomaviruses (cervical cancer and other skin cancers), human T-lymphotropic viruses (adult T-cell leukemias and lymphomas in endemic areas), hepatitis B virus (liver cancer), and Epstein-Barr virus (Burkitt lymphoma and nasopharyngeal carcinoma). The fraction of human cancers attributable to infection may now need to be revised in light of the fact that new viral associations have been discovered and other nonviral associations have been identified. This article addresses the increasingly recognized role of infectious agents as precipitants of human neoplasia and the possibility that novel diagnostic, therapeutic, and chemopreventive strategies may emanate directly from research directed at identifying and understanding these agents.

HPV positive bronchopulmonary carcinomas in women with previous high-grade cervical intraepithelial neoplasia (CIN III)

A significant higher incidence of some cancers, especially lung cancer, has been found in women with previous HPV-related (human papillomavirus) urogenital and anal neoplasias than in individuals without this particular clinical history. The aim of our study was to investigate whether HPV is present in both CIN III (cervical intraepithelial neoplasia) lesions and bronchopulmonary second primary cancers in women with a clinical history of both diseases. Paraffin-embedded tumour tissue from 75 patients with bronchopulmonary carcinomas was examined using the polymerase chain reaction (PCR) technique and in situ hybridization for the presence of human HPV. In total, 51 primary tumours without metastases, 11 primary tumours with metastases and 13 lymph node metastases without available tissue from primary tumours were analysed. In our study 37/75 primary bronchopulmonary tumours (49%) were identified as HPV positive by the PCR method: 18 cases were purely HPV 16 positive (49%), 12 were purely HPV 6 positive (32%), 5 cases were HPV 16/6 positive (14%), 1 case was HPV 16/11 positive (2%) and 1 case was HPV 16/18 positive (2%). Fourteen metastases were HPV positive, and HPV 16, 11 and 6 were detected in both regional and distant metastases. Two of the HPV 16-positive metastases were brain metastases from two separate HPV 16-positive primary tumours; 35% of the HPV-positive cases were adenocarcinomas, 30% squamous cell carcinomas, 22% oat cell carcinomas, 5% large cell carcinomas, 3% anaplastic carcinoma, 3% low-differentiated carcinoma, and 3% malignant cylindroma. The CIN III lesions from 34 of the 37 HPV-positive bronchopulmonary carcinomas were analysed by PCR. The overall HPV positivity in the CIN III lesions was 74% (25/34 cases): 48% were purely HPV 16 positive, 24% purely HPV 6 positive, 24% HPV 16/6 positive and 4% were HPV 18 positive. Our results indicate that HPV is also involved in the development of bronchopulmonary cancers in women with a history of CIN III lesions.

Expression of human papillomavirus E7 mRNA in human oral and cervical neoplasia and cell lines

Human papillomaviruses (HPVs) have been strongly linked to progression of human cancers, such as cervical and oral cancers. Two HPV oncoproteins, E6 and E7, can inhibit the tumor suppressor proteins, p53 and pRB, respectively, resulting in a deregulation of the cell cycle. In order to further test the significance of HPV expression in oral and cervical carcinogenesis, we analyzed HPV E7 mRNA in oral and cervical neoplasia and cell lines by reverse transcriptase-polymerase chain reaction (RT-PCR). We found that HPV E7 mRNA was present in 90% of patients with oral neoplasia and 100% of patients with cervical neoplasia. Quantitative RT-PCR and western blot analysis on both transformed cervical and oral epithelial cell lines demonstrated that the mRNA level of HPV-16 E7 corresponded to E7 protein level, suggesting that HPV oncogene expression is primarily regulated at the transcriptional or post-transcription level. The potential clinical application of quantitative RT-PCR for HPV E7 mRNA expression in cancer screening and treatment evaluation requires further investigation.

Components of human papillomavirus that activate transcription and support plasmid replication in human airway cells

Human papillomaviruses (HPVs) such as types 6 and 11 can establish lifelong infections in airway epithelial cells in patients, and long-term infection can lead to pulmonary involvement and death. The mechanisms underlying this persistence depend on both the transcriptional activity of the viral enhancers and promoters and the ability of this virus to maintain its double-stranded circular DNA genome in infected tissues. We investigated the transcription and replication properties of HPV sequence elements and protein products in a human airway cell line. We showed that incorporation of the upstream regulatory region and cotransfection with expression vectors of two virus-encoded proteins, E1 and E2, conferred approximately 5,000-fold stimulation of reporter gene expression. Transient plasmid replication in transfected human airway cells and lungs of FVB/N-C57BL/6 mice was demonstrated by a modified transient replication assay. These results have important implications for viral pathogenesis in airway cells and the potential of HPV-based replicons for gene transfer into airway epithelium.

Human papillomavirus DNA in adenosquamous carcinoma of the lung

AIM

To investigate the presence of human papillomavirus (HPV) DNA in adenosquamous carcinoma of the lung--which is relatively common in Okinawa but not in mainland Japan--and examine its histological features.

METHODS

Of 207 cases where primary lung cancers were surgically removed between January 1995 and June 1997 in Okinawa, 23 were adenosquamous carcinoma. HPV was detected by non-isotopic in situ hybridisation (NISH) and polymerase chain reaction (PCR) amplification with primers specific for E6 and E7 regions of the HPV genome. PCR products were analysed by Southern blotting. Immunohistochemical determination of high molecular weight cytokeratin (HMC) and involucrin was also carried out.

RESULTS

18 cases were positive for HPV DNA by PCR and NISH. HPV types 6, 11, 16, and 18 were found. Seven cases were dual positive for different types of HPV. Using NISH, HPV was also found in the squamous cell components and in neighbouring enlarged adenocarcinoma cells. The HMC and involucrin were demonstrated immunohistochemically in the same areas.

CONCLUSIONS

HPV DNA was found in a high proportion (78.3%) of adenosquamous carcinomas in Okinawa, a region where HPV has previously been shown to be prevalent in squamous cell carcinoma of the lung. The adenocarcinoma cells adjacent to the squamous cell carcinoma component were enlarged and positive for HPV, HMC, and involucrin. This is thought to indicate the transition from adenocarcinoma to squamous cell carcinoma.

Detection of human papillomavirus in squamous cell carcinomas of the lung by polymerase chain reaction

Existing evidence supports the hypothesis that human papillomavirus (HPV) may play an etiologic role in the malignant transformation of squamous epithelial cells. Although HPV DNA has been identified in a high proportion of squamous cell carcinomas (SCC) of the cervix, anorectum, skin, and upper airways, few studies have tested for HPV in SCC of the lung. To confirm the presence of HPV in lung SCC, we tested for HPV DNA extracted from formalin-fixed tissues of 34 patients by polymerase chain reaction (PCR). DNA amplification was performed using HPV L1 consensus sequence primers (MY11 and MY09; Perkin-Elmer Cetus, Norwalk, CT) which recognize a broad spectrum of HPV types including 6, 11, 16, 18, 31, and 33, among many other known types, as well as at least 20 other unidentified types. PCR products were analyzed by agarose gel electrophoresis and Southern blot hybridization with [32P]-labeled generic HPV probes. HPV DNA positive cases were subsequently analyzed by slot-blot hybridization of the PCR products with specific probes for HPV types 6, 11, 16, 18, and 33. HPV type 18 was detected in two cases, including one case from a 44-year-old female and one from a 64-year-old male, with the remaining 32 cases negative. In situ hybridization for HPV DNA failed to detect HPV types 6/11, 16/18, or 31/33/35 in any of the cases. We conclude that a small proportion of cases of primary pulmonary SCC test positive for HPV type 18 but that the great majority of cases are not associated with HPV.

Carcinoma of the lung in Okinawa, Japan: with special reference to squamous cell carcinoma and squamous metaplasia

In Okinawa, a subtropical island in southern Japan, squamous cell carcinoma (SCC), especially the well-differentiated form, is prevalent, while this form is relatively rare in both the mainland and other countries (e.g. United States of America). More patients with SCC from Okinawa, moreover, were positive for human papillomavirus (HPV) DNA by polymerase chain reaction (PCR) (79%), and harbored HPV types 6, 16 and 18, in combination. On the other hand, less than 30% of the mainland patients were positive for HPV DNA by PCR. Those patients who were positive all harbored only one HPV type. Furthermore, in Okinawa, there were a significant number of cases with adenosquamous carcinoma, and they too were positive for HPV DNA. The SCC and the adenocarcinoma cells adjacent to the SCC component in these cases were also positive for HPV DNA, and such adenocarcinoma cells were enlarged in size with relatively wide cytoplasm. The authors postulate that HPV infects adenocarcinoma cells and changes them to enlarged cells, followed by squamous metaplasia. In this report, HPV DNA was transfected to adenocarcinoma cells (cultured cell lines) and this showed that HPV causes squamous metaplasia. In addition, aberrant expression of p53 was demonstrated in a large number of the SCC cases in Okinawa. The enlarged adenocarcinoma cells adjacent to the SCC components in adenosquamous carcinomas also showed aberrant expression of p53. The recent advances in the studies of anti-oncogenes, p53, etc. and oncogenes are outlined. It is to be noted that the molecular mechanisms of carcinogenesis in the lung have been studied in general, classifying lung tumors into two groups, namely, small cell carcinoma (SCLC) and non-small cell carcinoma (NSCLC). However, because human lung cancer is represented by a wide variety of histologic types, molecular genetic studies according to a more detailed histological subclassification is needed.

Genetic factors in lung disease. Part II: Lung cancer and angiotensin converting enzyme gene

The recent progress in molecular biology has led to the elucidation of pathogenesis of lung cancer. The development of a lung cancer requires multiple genetic changes, consisting of the activation of oncogenes, including the K-ras and myc genes, and of inactivation of tumour suppressor genes, including the Rb, p53 and CDKN2 genes. Knowing the specific genes undergoing such changes should be useful as biomarkers for the early detection of cells destined to become malignant. Moreover, such genetic changes could be targets of newly designed drugs and gene-based therapy. Although the angiotensin I-converting enzyme was originally discovered in equine plasma, it has been recognized in various organs and cells other than vascular endothelial cells. This enzyme is also known to have wide substrate specificity to many peptides. The definite roles of angiotensin converting enzyme (ACE) in the respiratory system are largely unknown. Recent progress in molecular biology of the ACE, however, gives us a good chance to look over the significance of ACE in respiratory diseases as well as cardiovascular disorders. In this review, we show the recent advances in the basic studies of the ACE and refer to its clinical application.

High prevalence of human papillomavirus types 16 and 18 in middle-ear carcinomas

Chronic suppurative otitis media, averaging 20 or more years of duration, has been associated with cancer in this region in 40%-80% of cases. Although human papillomaviruses (HPV) have been implicated in many human squamous-cell neoplasms, their role in the pathogenesis of middle-ear malignancies remains unexplored. In this study, we investigated the presence and subtypes of HPV in middle-ear carcinomas. Formalin-fixed and paraffin-embedded tumor tissues were sampled for DNA extraction. PCR was done with consensus primers, capable of detecting HPV 16, 18, 31, 33, 52b and 58. Typing of the products generated by consensus primers was performed with restriction enzyme digestion. It was found that a resulting 89% (8/9) of the middle-ear carcinomas contained HPV DNA. Coexistence of HPV 16 and 18 was detected in 3 squamous-cell carcinomas. HPV 16 was detected in 4 squamous-cell carcinomas and 1 adenocarcinoma. The high prevalence of high-risk-type HPV in carcinomas of the middle ear suggests that viral infection may be an important etiologic component in the carcinogenic process.

Human papillomavirus infection is not associated with bronchial carcinoma: evaluation by in situ hybridization and the polymerase chain reaction

While a strong association between human papillomaviruses (HPVs) and squamous cell cancers of the female genital tract is known to exist, there is substantial controversy regarding the relationship of HPV with other non-genital carcinomas. Recently there have been some reports focusing on a possible association of HPVs with bronchial carcinomas. These studies mostly used either in situ hybridization (ISH) or the polymerase chain reaction (PCR). In view of these reports, 32 squamous cell carcinomas (SCCs) and six small cell carcinomas of the bronchus were examined for the presence of HPV DNA by both techniques: ISH using 35S-labelled, type-specific probes (HPV 6, 11, 16, 18), and PCR with consensus primers coding for more than 25 different HPV subtypes performed on formalin-fixed, paraffin-embedded material. None of the 38 bronchial carcinomas analysed was positive for HPV DNA, either by ISH or by PCR. On the other hand, additionally examined specimens of 15 cervical carcinomas were positive for HPV 16 DNA in at least three cases by ISH (20 per cent) and in 12 cases by PCR (80 per cent). We conclude that common HPV types do not play an important role in the pathogenesis of bronchial carcinoma.

Presence of human papillomavirus DNA and abnormal p53 protein accumulation in lung carcinoma

BACKGROUND

In some carcinomas inactivation of the tumour suppressor gene product p53, either by point mutation or indirectly by the human papillomavirus (HPV), has been suggested as two alternative routes to malignant transformation. To test this hypothesis in lung tumours, 43 lung carcinomas were analysed by in situ hybridisation and polymerase chain reaction (PCR) for the presence of HPV DNA, and the results were compared with p53 protein immunohistochemical analysis.

METHODS

The presence of HPV DNA in lung carcinoma was detected by nucleic acid in situ hybridisation for HPV types 6, 11, 16, 18, 31, and 33 using nonradioactively labelled DNA probes. Polymerase chain reaction (PCR) analysis was performed on all cases showing positive HPV DNA labelling by in situ hybridisation and in an additional 13 negative cases. Abnormal nuclear accumulation of the p53 protein was revealed by immunohistochemistry using the avidin-biotin-peroxidase complex method and a CM-1 polyclonal anti-human p53 antibody and a monoclonal mutation-specific Pab 240 p53 antibody.

RESULTS

HPV DNA was found by in situ hybridisation in 13 lung carcinomas (30%). In all these cases subtype-specific HPV DNA could also be detected by PCR. Abnormal p53 protein accumulation was seen in 21 of the 43 carcinomas (49%), of which 18 were HPV negative. Twelve (57%) of the CM-1 positive cases were also positive for the mutation-specific antibody Pab 240. There was an obvious inverse relationship between the presence of papilloma viral DNA and abnormal p53 protein accumulation.

CONCLUSIONS

p53 plays an important part in the development of lung carcinomas and, in some cases, HPV may contribute to it by binding and inactivating the p53 protein.