Human papillomavirus DNA in squamous cell carcinoma of the lung

HPV and Lung Cancer: A Systematic Review

This systematic review aims to explore the diagnostic criteria, epidemiology, etiology, and prognosis of Human Papillomavirus (HPV) infection in lung cancer. This PRISMA-guided review searched the PubMed® and EmbaseTM databases for "lung cancer AND HPV" on 10 June 2023, filtering human subject papers. A total of 97 studies encompassing 9098 patients worldwide, revealing varied HPV infection rates in lung cancer, ranging from 0% to 69%, were analyzed. While HPV16/18 was predominant in some regions, its association with lung cancer remained inconclusive due to conflicting findings. Studies from Asia reported lower HPV infection rates compared to Western populations. Some studies suggested a limited role of HPV in lung carcinogenesis, particularly in non-smokers. However, intriguing associations were noted, including HPV's potential role in lung adenocarcinoma and squamous cell carcinoma. Discrepancies in HPV detection methods and sample sources highlight the need for further research with standardized methodologies to elucidate HPV's role in lung carcinogenesis and its clinical implications. Overall, this systematic review offers insights into HPV's role in lung cancer epidemiology and clinical characteristics. Despite inconclusive evidence, intriguing associations between HPV and lung adenocarcinoma and squamous cell carcinoma have emerged. Further research with standardized methodologies and larger cohorts is needed for clarity.

The emerging role of human papillomavirus in lung cancer

Lung cancer stands as one of the most lethal diseases and is the foremost cause of cancer-related mortalities worldwide. The pathophysiology of lung cancer is multifaceted, and it includes multiple cell signaling pathways and other complex factors such as oxidative stress and genetics. The association of HPV with lung carcinogenesis was first proposed in 1979, and since then, scientists worldwide have been putting forward several hypotheses to establish a relationship between this virus and lung cancer. Although studies have reported the presence of HPV in lung cancer, the exact mechanism of entry and the route of transmission have not been elucidated clearly till date. Numerous studies across the globe have detected differentially expressed HPV oncoproteins in lung cancer patients and found their association with the critical cell signaling pathways that leads to the development and progression of lung cancer. Many reports have also provided evidence stating the involvement of HPV in determining the survival status of lung cancer patients. The present review recapitulates the studies evincing the association of HPV and lung cancer, its route of transmission and mechanism of action; the detection of the virus and treatment opportunities for HPV-positive lung cancer; and the severity associated with this disease. Therefore, this will provide an explicit idea and would help to develop preventive measures and specific as well as effective treatment for HPV-associated lung carcinogenesis.

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.

Extracellular domain of semaphorin 5A serves a tumor‑suppressing role by activating interferon signaling pathways in lung adenocarcinoma cells

Semaphorin 5A (SEMA5A), which was originally identified as an axon guidance molecule in the nervous system, has been subsequently identified as a prognostic biomarker for lung cancer in nonsmoking women. SEMA5A acts as a tumor suppressor by inhibiting the proliferation and migration of lung cancer cells. However, the regulatory mechanism of SEMA5A is not clear. Therefore, the purpose of the present study was to explore the roles of different domains of SEMA5A in its tumor‑suppressive effects in lung adenocarcinoma cell lines. First, it was revealed that overexpression of full length SEMA5A or its extracellular domain significantly inhibited the proliferation and migration of both A549 and H1299 cells using MTT, colony formation and gap closure assays. Next, microarray analyses were performed to identify genes regulated by different domains of SEMA5A. Among the differentially expressed genes, the most significant function of these genes that were enriched was the 'Interferon Signaling' pathway according to Ingenuity Pathway Analysis. The activation of the 'Interferon Signaling' pathway was validated by reverse transcription‑quantitative PCR and western blotting. In summary, the present study demonstrated that the extracellular domain of SEMA5A could upregulate genes in interferon signaling pathways, resulting in suppressive effects in lung adenocarcinoma cells.

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.

Expression and Significance of HPV16 E6/E7 mRNAs in the Bronchial Brush and TBNA Cells of Patients With Small Cell Lung Cancer

BACKGROUND AND OBJECTIVE

Small cell lung cancer (SCLC) is characterized by rapid growth, strong invasion, and early metastasis. However, the cause of its occurrence remains unclear. High-risk HPV infection is closely related to the occurrence of non-small cell lung cancer and cervical small cell neuroendocrine carcinoma.

METHODS

The expression levels of E6 mRNA and E7 mRNA in HPV16 were detected by qRT-PCR in the bronchial brushing and transbronchial needle aspiration (TBNA) of 310 patients with lung cancer and with benign lung diseases. To make the design of this experiment scientific and reasonable, the expression levels in lung squamous cell carcinoma were taken as positive controls, while those in benign cells were taken as negative controls.

RESULTS

The expression levels of E6 mRNA and E7 mRNA in SCLC group were significantly higher than those in benign cell group and slight higher than those in squamous cell carcinoma group. The expression levels of E6 mRNA and E7 mRNA in the central type of SCLC were significantly higher than those in the peripheral type of SCLC.

CONCLUSIONS

We speculate that the occurrence of some small cell carcinoma is the same as that of some squamous cell carcinoma, which is closely related to HPV16 infection. The overexpression of E6 mRNA and E7 mRNA is in some benign lesion cells, which may be related to HPV transient infection.

Use tumor suppressor genes as biomarkers for diagnosis of non-small cell lung cancer

Lung cancer is the leading cause of death worldwide. Especially, non-small cell lung cancer (NSCLC) has higher mortality rate than the other cancers. The high mortality rate is partially due to lack of efficient biomarkers for detection, diagnosis and prognosis. To find high efficient biomarkers for clinical diagnosis of NSCLC patients, we used gene differential expression and gene ontology (GO) to define a set of 26 tumor suppressor (TS) genes. The 26 TS genes were down-expressed in tumor samples in cohorts GSE18842, GSE40419, and GSE21933 and at stages 2 and 3 in GSE19804, and 15 TS genes were significantly down-expressed in tumor samples of stage 1. We used S-scores and N-scores defined in correlation networks to evaluate positive and negative influences of these 26 TS genes on expression of other functional genes in the four independent cohorts and found that SASH1, STARD13, CBFA2T3 and RECK were strong TS genes that have strong accordant/discordant effects and network effects globally impacting the other genes in expression and hence can be used as specific biomarkers for diagnosis of NSCLC cancer. Weak TS genes EXT1, PTCH1, KLK10 and APC that are associated with a few genes in function or work in a special pathway were not detected to be differentially expressed and had very small S-scores and N-scores in all collected datasets and can be used as sensitive biomarkers for diagnosis of early cancer. Our findings are well consistent with functions of these TS genes. GSEA analysis found that these 26 TS genes as a gene set had high enrichment scores at stages 1, 2, 3 and all stages.

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.

Identification of Methylation-Driven, Differentially Expressed STXBP6 as a Novel Biomarker in Lung Adenocarcinoma

DNA methylation is an essential epigenetic marker associated with the silencing of gene expression. Although various genome-wide studies revealed aberrantly methylated gene targets as molecular biomarkers for early detection, the survival rate of lung cancer patients is still poor. In order to identify methylation-driven biomarkers, genome-wide changes in DNA methylation and differential expression in 32 pairs of lung adenocarcinoma and adjacent normal lung tissue in non-smoking women were examined. This concurrent analysis identified 21 negatively correlated probes (r ≤ −0.5), corresponding to 17 genes. Examining the endogenous expression in lung cancer cell lines, five of the genes were found to be significantly down-regulated. Furthermore, in tumor cells alone, 5-aza-2′-deoxycytidine treatment increased the expression levels of STXBP6 in a dose dependent manner and pyrosequencing showed higher percentage of methylation in STXBP6 promoter. Functional analysis revealed that overexpressed STXBP6 in A549 and H1299 cells significantly decreased cell proliferation, colony formation, and migration, and increased apoptosis. Finally, significantly lower survival rates (P < 0.05) were observed when expression levels of STXBP6 were low. Our results provide a basis for the genetic etiology of lung adenocarcinoma by demonstrating the possible role of hypermethylation of STXBP6 in poor clinical outcomes in lung cancer patients.

Human Papillomavirus, Smoking, and Cancer

Background:

The effect of smoking on human papillomavirus (HPV) activity and subsequent dysplasia and neoplasia remains controversial

Objective:

To determine any reported effects of smoking on either HPV activity or HPV-related dysplasia/cancer using retrospective analysis of the literature from 1966 through 1998 via Toxline and PubMed to search for “smoking,” “papillomavirus,” and “cancer.”

Conclusion:

Several recent large studies demonstrated that smoking was associated with a greater incidence of cervical, vulvar, penile, anal, oral, and head and neck cancer in a dose-dependent fashion, while other studies did not show any correlation between smoking and cervical dysplasia after multivariate adjustment. Recent studies have also indicated that smoking may be more closely related to high-grade lesions of the cervix and vulva. These data provide evidence of an association between HPV, smoking, and cancer. Progression of dysplasia likewise seems to be associated with smoking. Several groups have attempted to discern whether the connection between smoking and cervical cancer is from local immunosuppression and/or from direct carcinogenic effects.

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.

Differential diagnosis between primary lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma

Differentiation between lung squamous cell carcinoma and pulmonary metastasis of head and neck squamous cell carcinoma is clinically important because the prognoses and therapeutic options are considerably different. However, the clinical, pathological, and immunohistochemical diagnostic methods have not yet been fully established. Although various molecular methods have been developed, they have not yet been practically applied. A combined approach involving molecular and immunohistochemical analysis, such as one that uses antibodies selected on the basis of comprehensive genetic analysis results, may be effective. We suggest a new diagnostic criteria using the clinical characteristics and the result of immunohistochemical analysis. However, there are two underlying problems in the development of new diagnostic methods: tumor heterogeneity and determination of the diagnostic accuracy.

Human papilloma virus detection and typing in 334 lung cancer patients

BACKGROUND

Unlike cervical, anogenital and oropharyngeal cancers, where high-risk human papillomavirus (hrHPV) has long been known to play a major role, a causative link between HPV and lung cancer has been investigated for decades with discrepant results.

METHODS

Lung cancer patients eligible for surgical treatment were tested for the presence of HPV-DNA in excised, fresh frozen lung tumor tissue. Patients that tested positive were further examined for the presence of HPV-DNA in adjacent normal lung parenchyma. HPV detection and genotyping was performed using a polymerase chain reaction (PCR)-based approach and allowed the typing of 13 "high-risk"-HPV-types and 2 "low-risk"-HPV-types.

RESULTS

Of the 334 tumor-DNA samples tested, 13 (3.9%) showed presence of HPV-DNA, of which 12 were of a high-risk HPV type (16, 33, 66). In those tested positive, HPV-DNA was not found in adjacent normal lung tissue. No correlation with smoking or EGFR/KRAS mutation status was seen, and only one of 84 squamous cell carcinomas was HPV-positive.

CONCLUSION

We conclude that HPV is rarely associated with lung cancer in a Northern European population and in those tested positive, more functional studies are required to determine the role HPV plays in lung cancer oncogenesis.

SNP rs10248565 in HDAC9 as a novel genomic aberration biomarker of lung adenocarcinoma in non-smoking women

BACKGROUND

Numerous efforts have been made to elucidate the etiology and improve the treatment of lung cancer, but the overall five-year survival rate is still only 15%. Although cigarette smoking is the primary risk factor for lung cancer, only 7% of female lung cancer patients in Taiwan have a history of smoking. Since cancer results from progressive accumulation of genetic aberrations, genomic rearrangements may be early events in carcinogenesis.

RESULTS

In order to identify biomarkers of early-stage adenocarcinoma, the genome-wide DNA aberrations of 60 pairs of lung adenocarcinoma and adjacent normal lung tissue in non-smoking women were examined using Affymetrix Genome-Wide Human SNP 6.0 arrays. Common copy number variation (CNV) regions were identified by ≥30% of patients with copy number beyond 2 ± 0.5 of copy numbers for each single nucleotide polymorphism (SNP) and at least 100 continuous SNP variant loci. SNPs associated with lung adenocarcinoma were identified by McNemar's test. Loss of heterozygosity (LOH) SNPs were identified in ≥18% of patients with LOH in the locus. Aberration of SNP rs10248565 at HDAC9 in chromosome 7p21.1 was identified from concurrent analyses of CNVs, SNPs, and LOH.

CONCLUSION

The results elucidate the genetic etiology of lung adenocarcinoma by demonstrating that SNP rs10248565 may be a potential biomarker of cancer susceptibility.

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.

Detection and genotype analysis of human papillomavirus in non-small cell lung cancer patients

Although the role of human papillomavirus (HPV) in the development of uterine cervical cancer is well established, the role of HPV in lung carcinogenesis remains controversial. The detection rates of HPV DNA are subject to a wide variation from 0 to 100%. This is partly influenced by the detection techniques employed. To elucidate the impact of HPV infection on lung parenchyma, we analyzed 100 non-small cell lung cancer (NSCLC) specimens (39 squamous cell carcinomas, 50 adenocarcinomas, 5 samples with characteristics of both squamous cell and adenocarcinoma, 5 undifferentiated and 1 large cell carcinoma) from the region of Crete, Greece. Sixteen non-cancerous samples served as the negative controls. DNA was extracted from 100 paraffin-embedded tissue sections obtained from NSCLC patients. The specimens were examined for the detection of HPV DNA by Real-Time PCR using GP5+/GP6+ primers. Furthermore, the HPV-positive samples were subjected to genotyping. In contrast to the absence of viral genomes in the control samples, HPV DNA was detected in 19 NSCLC specimens (19%). In particular, 4 squamous cell carcinomas, 12 adenocarcinomas, 1 sample with characteristics of both squamous cell and adenocarcinoma, and 2 undifferentiated samples were HPV-positive. The distribution of HPV genotypes was as follows: HPV 16: eight cases (42.1%); HPV 11: three cases (15.8%); HPV 6: one case (5.2%); HPV 59: one case (5.2%); HPV 33: two cases (10.5%); HPV 31: two cases (10.5%) and HPV 18: two cases (10.5%). The presence of HPV in the tumor samples provides evidence of the potential role of HPV in NSCLC and strongly argues for additional research on this issue.

Human papillomavirus and non-small cell lung cancer

Lung cancer is the most common cause of cancer-related deaths in the world, causing more than one million deaths worldwide each year. Human papillomavirus (HPV) are small non-enveloped DNA viruses that infect squamous epithelial cells. Relevant studies have reported lung cancer-related HPV infection rates that fluctuate between 10% and 80%, depending on the various research methods and geographical factors. Various scholars gathered statistics from global research reports and found that 22.4% of the patients with lung cancer presented with an HPV infection, which suggested that HPV infection may relate to the tumorigenesis of non-small cell lung cancer. This article will review the history and discovery of HPV, the correlation between HPV and lung cancer development, and carcinogenesis caused by HPV regulatory genes, such as p53, p21, p16INK4a, and genes related to hypermethylation and genome instability in lung cancer patients with HPV infection. In addition, because studies have highlighted the difference in clinical prognosis for HPV-positive and HPV-negative patients, articles demonstrating the correlation between HPV infection and prognosis for lung cancer patients will be reviewed.

HPV in exhaled breath condensate of lung cancer patients

BACKGROUND

A recent intriguing carcinogenetic hypothesis for lung cancer foresees its viral aetiology. The human papilloma virus (HPV) is the main virus actually recognised in the pathogenesis of lung cancer. The aim of this study was to investigate, for the first time to our knowledge, the presence of HPV in the exhaled breath condensate (EBC) of lung cancer patients.

MATERIALS AND METHOD

We enrolled 89 patients affected by lung cancer and 68 controls. HPV infections were investigated in their EBC, paired bronchial brushing and neoplastic lung tissue through genotyping.

RESULTS

We were able to detect HPV in the EBC, bronchial brushing and neoplastic lung tissue. We described the presence of an HPV infection in 16.4% of the subjects affected by non-small cell lung cancer, but in none of the controls. HPV 16 and 31 turned out to be the most widespread genotypes. The HPV positivity in airways as well as in the smoking habit was seen to independently increase the individual's susceptibility to developing lung cancer.

CONCLUSION

When summing up, we demonstrated the possibility to identify an HPV infection in the EBC of lung cancer patients; further, we supported the notion that the EBC is a suitable tool to study airway colonisation. That being said, although further studies are needed to confirm our results, we retain the study of HPV in EBC to be very interesting in terms of future programmes involving lung-cancer screening.

Human papillomavirus infection in lung and esophageal cancers: analysis of 485 Asian cases

The role of human papillomavirus (HPV) in the development of lung and esophageal cancer remains inconclusive, which is in contrast to the established role HPV plays in the development of uterine cervical cancer. One of the reasons for this is the difference among reported HPV infection rates in these cancers. An analysis of 485 lung and esophageal cancers (176 lung squamous cell carcinoma, 128 lung adenocarcinoma, 181 esophageal carcinoma) in eight institutions in Asia (Tokyo, Kochi, Kagoshima, and Okinawa, Japan; Seoul and Daegu, Korea; Changhua, Republic of China (Taiwan); Singapore, Singapore) was carried out in order to clarify infection rates with HPV. Samples were examined in one laboratory of the Department of Pathology, the University of Tokyo, Japan in order to avoid inter-laboratory variation using a combination of polymerase chain reaction and in situ hybridization (ISH). HPV was found in 6.3%, 7%, and 9.4% of patients with lung squamous cell carcinoma, lung adenocarcinoma, and esophageal cancer, respectively. Among the geographic areas surveyed, Kagoshima exhibited a significantly higher prevalence of HPV infection in cases of esophageal carcinoma (24.1%). There was no geographical difference in the infection rates of HPV in lung carcinomas. Subtype-specific ISH was also performed, which identified the high-risk HPV types 16/18 in the majority (75.7%) of the patients with lung and esophageal cancer positive for HPV.

Identification of a novel biomarker, SEMA5A, for non-small cell lung carcinoma in nonsmoking women

BACKGROUND

Although cigarette smoking is the major risk factor for lung cancer, only 7% of female lung cancer patients in Taiwan have a history of smoking. The genetic mechanisms of carcinogenesis in nonsmokers are unclear, but semaphorins have been suggested to play a role as lung tumor suppressors. This report is a comprehensive analysis of the molecular signature of nonsmoking female lung cancer patients in Taiwan, with a particular focus on the semaphorin gene family.

METHODS

Sixty pairs of tumor and adjacent normal lung tissue specimens were analyzed by using Affymetrix U133plus2.0 expression arrays. Differentially expressed genes in tumor tissues were identified by a paired t test and validated by reverse transcriptase-PCR and immunohistochemistry. Functional analysis was conducted by using Ingenuity Pathway Analysis as well as gene set enrichment analysis and sigPathway algorithms. Kaplan-Meier survival analyses were used to evaluate the association of SEMA5A expression and clinical outcome.

RESULTS

We identified 687 differentially expressed genes in non-small cell lung carcinoma (NSCLC). Many of these genes, most notably the semaphorin family, were participants in the axon guidance signaling pathway. The downregulation of SEMA5A in tumor tissue, both at the transcriptional and translational levels, was associated with poor survival among nonsmoking women with NSCLC.

CONCLUSIONS

In summary, several semaphorin gene family members were identified as potential therapeutic targets, and SEMA5A may be useful as a prognostic biomarker for NSCLC, which may also be gender specific in Taiwanese patients.

IMPACT

A novel biomarker for NSCLC is identified.

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.

Population-based trends in lung cancer incidence in women

Lung cancer is the leading cause of cancer mortality in women worldwide. Although the rise and growing epidemic status of lung cancer are overwhelmingly attributed to tobacco use, its rank in nonsmokers as the seventh most common cause of cancer worldwide suggests that other factors contribute to this disease. The majority of lung cancers among nonsmokers occur in women. Aside from geographic, cultural, and genetic differences, hormonal and possibly infectious factors also may play etiologic roles. This review aims to discuss the epidemiology of lung cancer in women, as well as the incidence of second primaries, and presents current opinions on the myriad of causes.

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.

Usefulness of p16 for differentiating primary pulmonary squamous cell carcinoma from cervical squamous cell carcinoma metastatic to the lung

To date, there is no reliable immunohistochemical marker that discriminates between primary pulmonary squamous cell carcinoma (SCC) and cervical SCC metastatic to the lung. In this study, immunohistochemical staining of p16 was performed on 33 primary pulmonary SCCs, 48 primary cervical SCCs, and 17 cases of cervical SCC with pulmonary metastasis. Expression of p16 was noted in 47 cases of cervical SCC (47/48 [98%]), and all were strongly stained. Of the 7 cases of primary pulmonary SCC (7/33 [21%]) in which p16 expression was detected, 3 were weakly positive, 1 was moderately positive, and 3 were strongly positive. Among these p16+ pulmonary SCCs, only 1 showed detectable human papillomavirus DNA. Of the 17 cases of cervical SCC with pulmonary metastasis, all of the pulmonary and cervical tumors were positive for p16. p16 is a useful marker for the discrimination between cervical and pulmonary SCCs. The performance of p16 staining at different cutoff values was also compared.

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.

Differences in epidemiology, histology, and survival between cigarette smokers and never-smokers who develop non-small cell lung cancer

BACKGROUND

The impact that smoking cigarettes has on the characteristics and survival of patients with non-small cell lung cancer (NSCLC) is disputed.

METHODS

A retrospective cohort study using a prospective database of patients with NSCLC over a 6-year period. Clinical and histologic characteristics and survival rates were compared between smokers and never-smokers.

RESULTS

There were 730 patients; 562 patients (77%) were smokers and 168 patients (23%) were never-smokers. The overall 5-year survival rate was greater in never-smokers (64%) compared to smokers (56%; p = 0.031). Never-smokers were more likely to be younger (p = 0.04), female (p = 0.01), symptomatic at the time of presentation (p < 0.001), have poorly differentiated tumors (p = 0.04), and have a higher maximum standardized uptake value (maxSUV) on positron emission tomography (PET) (p = 0.026) than smokers. The stage-specific 5-year survival rate was greater for never-smokers compared to smokers for stage I disease (62% vs 75%, respectively; p = 0.02), stage II disease (46% vs 53%, respectively; p = 0.09), and stage III disease (36% vs 41%, respectively; p = 0.13). The 5-year survival rate was significantly lower in patients who had a smoking history of > 20 pack-years.

CONCLUSIONS

Never-smokers in whom NSCLC develops are more likely to be young, female, and have poorly differentiated tumors with higher maxSUV values on PET scans. Never-smokers with early-stage cancer have a significantly better survival rate than smokers. Patients with a smoking history of > or = 20 pack-years have worse survival. Thus, smoking not only causes lung cancer, but once NSCLC is diagnosed, the prognosis becomes worse. A biological, hormonal, and genetic explanation is currently lacking to explain these findings, and these data may help to improve treatment and surveillance.

The prevalence of human papillomavirus infection in Korean non-small cell lung cancer patients

Human papillomavirus (HPV) infection is a co-carcinogen of lung cancer and contributes to its pathogenesis. To evaluate the prevalence of HPV infection, polymerase chain reaction (PCR) was employed to detect HPV 16, 18, and 33 DNA in tumor tissues of 112 patients with non-small cell lung cancer (NSCLC) who underwent curative surgery from Jan. 1995 to Dec. 1998 at Severance Hospital, Seoul, Korea. The patients consisted of 90 men and 22 women. Nineteen patients were under 50 years old (17%), and 92 patients (82%) were smokers. Fifty-three patients had adenocarcinomas, while 59 patients had non-adenocarcinomas. Early stage (I and II) cancer was found in 64 patients (57.1%) and advanced stage (III and IV) found in 48 (42.9%). The prevalence of HPV 16, 18, and 33 were 12 (10.7%), 11 (9.8%), and 37 (33.0%), respectively. Smoking status, sex, and histologic type were not statistically different in the presence of HPV DNA. The presence of HPV 16 was more common in younger patients and HPV 18 was more common in advanced stage patients. This study showed that the prevalence rate of HPV 16 and 18 infections in NSCLC tissue was low, suggesting HPV 16 and 18 infections played a limited role in lung carcinogenesis of Koreans. However, the higher prevalence of HPV 33 infections in Korean lung cancer patients compared to other Asian and Western countries may be important and warrants further investigation.

A potent replicative delta-24 adenoviral vector driven by the promoter of human papillomavirus 16 that is highly selective for associated neoplasms

BACKGROUND

Several human epithelial neoplasms are associated with high-risk strains of human papillomavirus (HPV) such as cervical, anorectal, and other carcinomas. For some tumor types the current therapeutic tools are only palliative. Conditionally replicative adenoviruses (CRAds) are promising antineoplastic agents, which also can trigger confined antitumor effects.

METHODS

We constructed a series of CRAds driven by the upstream regulatory promoter region (URR) of an Asian-American variant of HPV-16, which contained different mutations at the E1A region (dl1015 and/or Delta24) and wild-type. All vectors were tested in vitro for viral replication and cytotoxicity. Viral DNA replication and E1A expression were also assessed by quantitative PCR. Finally, we confirmed the antitumoral efficacy of this vector in injected and non-injected xenotransplanted cervical tumors in a murine model for tumor regression and survival studies.

RESULTS

A vector denominated Ad-URR/E1ADelta24 displayed a potent cytopathic effect associated with high selectivity for HPV+ cell lines. We found that the oncolytic effect of this CRAd was comparable to Ad-wt or Ad-Delta24, but this efficacy was significantly attenuated in HPV- cell lines, an effect that was contributed by the URR promoter. Ad-URR/E1ADelta24 was very effective to control tumor growth, in both, injected and non-injected tumors generated with two different HPV+ cell lines.

CONCLUSIONS

CRAd Ad-URR/E1ADelta24 is a highly selective vector for HPV+ cell lines and tumors that preserves the oncolytic efficacy of Ad-wt and Ad-Delta24. Our preclinical data suggest that this vector may be useful and safe for the treatment of tumors induced by HPV, like cervical cancers.

Women With Pathologic Stage I, II, and III Non-small Cell Lung Cancer Have Better Survival Than Men

OBJECTIVE

Bronchogenic malignancy is the number one cause of cancer deaths in both men and women worldwide. National registry-based studies have shown gender disparity in clinicopathologic characteristics and in survival. This study evaluates the risk factors and trends of lung cancer between genders.

METHODS

A prospective cohort of consecutive patients with non-small cell lung cancer (NSCLC) who were carefully clinically (all underwent dedicated positron emission tomography scans) and pathologically staged with stage I, II, or III disease underwent homogenous treatment algorithms and were followed up over a period of 7 years. Primary outcomes were 5-year survival and response to neoadjuvant therapy.

RESULTS

There were 1,085 patients (671 men and 414 women). Groups were similar for race, pulmonary function, smoking history, comorbidities, neoadjuvant therapy, histology, and resection rates. Women were younger (p = 0.014), had a higher incidence of adenocarcinoma (p = 0.01), and presented at an earlier pathologic stage (p = 0.01) than men. The overall age-adjusted and stage-adjusted 5-year survival rate favored women (60% vs 50%, respectively; p < 0.001). Women had better stage-specific 5-year survival rates (stage I disease, 69% vs 64%, respectively [p = 0.034]; stage II disease, 60% vs 50%, respectively [p = 0.042]; and stage III disease, 46% vs 37%, respectively [p = 0.024]). Women who received neoadjuvant chemotherapy alone (n = 76) were more likely to be a complete or partial responder than men (n = 142; p = 0.025).

CONCLUSIONS

Despite uniform staging and treatment, the 5-year survival rate of women with stage I to III NSCLC was better than men overall and at each stage. Women are more likely to have adenocarcinoma, to present with earlier stage disease, and to be younger. Interestingly, women respond better to neoadjuvant chemotherapy.

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.

Lung cancer in women: emerging differences in epidemiology, biology, and therapy

Lung cancer is the major cause of cancer-related death in both men and women in the United States. Emerging evidence indicates that there are differences in the pathogenesis and possibly increased susceptibility to lung cancer in women. In addition, considerable data support small, but important differences favoring women in terms of response to therapy and long-term survival after the diagnosis of lung cancer, regardless of histology or stage. These differences in both biology and outcome will be important considerations in the design of future trials of screening and therapy for lung cancer.

Lung cancer in Asian women-the environment and genes*

The mortality rate of lung cancer in Asian women has increased significantly in the past few decades. Environmental factors include tobacco smoke (active and environmental), other indoor pollutions (cooking oil vapours, coal burning, fungus spores), diet, and infections. Active tobacco smoking is not the major factor. The relative risk of lung cancer among non-smoking women ever exposed to environmental smoke from their husbands was 1.20 from a meta-analysis. Cooking oil vapours associated with high temperature wok cooking and indoor coal burning for heating and cooking in unvented homes, particularly in rural areas, are risk factors for Chinese women. Chronic benign respiratory diseases due to the fungus Microsporum canis probably accounts for the high incidence of lung cancer in northern Thai women at Sarapee. Diets rich in fruits, leafy green vegetables, and vitamin A are protective, while cured meat (Chinese sausage, pressed duck and cured pork), deep-fried cooking, and chili increased the risk. Tuberculosis is associated with lung cancer. Also, a Taiwanese study showed that the odds ratio of papillomavirus (HPV) 16/18 infection in non-smoking female lung cancer patients was 10.1, strongly suggesting a causative role. Genetic factors have also been studied in Chinese women, including human leucocyte antigens, K-ras oncogene activation, p53 mutation, polymorphisms of phase I activating enzymes (cytochrome P450, N-acetyltransferase slow acetylator status), and phase II detoxifying enzymes (glutathione-S-transferases, N-acetyltransferase rapid acetylator status). New molecular screening technology would facilitate identification of molecular targets for future studies. The interaction between environmental and genetic factors should also be further elucidated.

Epstein-Barr virus (EBV)-related oral squamous cell carcinoma in Okinawa, a subtropical island, in southern Japan--simultaneously infected with human papillomavirus (HPV)

Up to now, many authors have reported on the EBV infection and its carcinogenic importance in undifferentiated nasopharyngeal carcinoma (WHO classification, type III), but the infection of the virus in well differentiated oral squamous cell carcinoma has not been well described. We introduce the EBV-related well differentiated oral squamous cell carcinomas in Okinawa, a subtropical island in the southernmost part of Japan. This study aimed to clarify the pathogenesis of this malignancy in this area by carrying out analysis of the histology and the Epstein-Barr (EBV) and human papillomavirus (HPV) infection. In the Department of Oral Surgery, Ryukyu University Hospital Okinawa, 188 cases of oral malignant tumours were encountered from 1996 to 2000. The histopathological examination and the sequence analysis of LMP-1 carboxy terminal region and EBNA2 region of EBV were carried out, as were the analysis of virus subtypes, A and B, BamHI-F and f, and C and D. Additionally, HPV infection in the squamous cell carcinomas were demonstrated using E6 and E7 region primer sets by PCR method. In Okinawa, 94% (177/188) of the cases were squamous cell carcinomas. A surprisingly large number of EBV (72%) and HPV (78%) infections in the oral squamous cell carcinomas were demonstrated. EBV type B virus infection was found in 36% of EBV-related oral squamous cell carcinoma in Okinawa, but in only 2-5% of the mainland cases. In both regions the incidence of the BamHI- f variant infection was very low. The infected virus in 79 out of 80 (39 Okinawan and 41 mainland) cases was BamHI- F type. In Okinawa, the numbers of C and D variants were almost equal, whereas in the mainland the D variant was rare. Further, a 30 bp deletion in LMP-1 gene was frequently demonstrated in Okinawan and mainland cases of type A virus, but not in type B virus. Lastly, single nucleotide mutations in EBNA2 region of type A virus when compared with B95-8 strain were demonstrated in Okinawan cases. The prognosis for (mostly EBV/HPV infected) squamous cell carcinomas in Okinawa was better than that in the mainland where most cases were negative for EBV and/or HPV.

Environmental exposure and lung cancer among nonsmokers: an example of Taiwanese female lung cancer

Lung cancer is the leading cause of cancer death worldwide and in Taiwan. Cigarette smoking is considered to be the most important risk factor, since about 90% of lung cancer can be related to cigarette smoking. Despite the recent decrease of cigarette smoking, lung cancer is still the leading cause of cancer death in the United States. In Taiwan, only around 50% of lung cancer incidence could be associated with cigarette smoking, particularly less than 10% of Taiwanese women are smokers. Thus, the aetiology of lung cancer for nonsmokers remains unknown. DNA damages including bulky and oxidative damage may be related with mutation of tumor suppressor genes, such as p53 gene. The high DNA adduct levels in female may be associated with frequent exposure to indoor cooking oil fumes (COF) and outdoor heavy air pollution. Oxidative stress induced by COF was also discussed. Different p53 mutation spectra and mutation frequency between genders reflected that different environmental factors may be involved in nonsmoking male and female lung cancer development. Most importantly, our recent report has demonstrated that human papillomavirus (HPV) infection was associated with nonsmoking female lung cancer. Based on our studies with Taiwanese nonsmoking lung cancer as the model, the possible aetiological factors of lung cancer incidence in Taiwanese nonsmokers were elucidated.

Squamous metaplasia induced by transfection of human papillomavirus DNA into cultured adenocarcinoma cells

BACKGROUND/AIM

It has been reported previously in cases of adenosquamous carcinoma of the lung in Okinawa, a subtropical island 2000 km south of mainland Japan, that the squamous cell carcinoma components were positive for human papillomavirus (HPV) by non-isotopic in situ hybridisation (NISH). The adenocarcinoma cells adjacent to the squamous cell carcinoma components were enlarged and also positive for HPV. This is thought to indicate that after adenocarcinoma cells are infected with HPV, they undergo morphological changes, and that "squamous metaplasia" follows. In this present study, the effects of HPV transfection into adenocarcinoma cells were examined. The relation between the region expressing the HPV gene and squamous metaplasia was also studied.

METHODS

Plasmid pBR322 containing HPV type 16 (HPV-16) was transfected into cultured colonic adenocarcinoma (DLD-1) and lung adenocarcinoma (PC-14) cells using the calcium phosphate method. Neomycin was used as a selection marker. The presence of HPV E1, E2, E4, E5, E6, E7, L1, and L2 mRNAs and also transglutaminase 1, involucrin, cyclin dependent kinases (CDKs), cyclins, caspases, apoptosis inducing factor, DNase gamma, Fas, and Fas ligand mRNAs in HPV transfected cells was investigated by means of reverse transcription polymerase chain reaction (RT-PCR). The G0-G1 cell population was analysed by flow cytometry. Morphological examination under light and electron microscopes was also carried out.

RESULTS

The virus transfected cells showed squamous metaplasia when they were injected into severe combined immunodeficient mice, expressing the high molecular weight keratin (Moll's number 1 keratin) and involucrin molecules immunohistochemically, and involucrin and transglutaminase I mRNAs by RT-PCR. The squamous metaplasia was most conspicuous in the HPV transfected DLD-1 cell when compared with HPV transfected PC-14 cells. Squamous metaplasia was most clearly demonstrated in one HPV transfected DLD-1 cell clone, which expressed not only E2 but also E6-E7 fusion gene mRNA. Viral L1 mRNA expression was absent in HPV transfected cell clones, and was not related to squamous metaplasia. The growth rate of HPV transfected cells was reduced. Transfection of the virus into the cultured adenocarcinoma cells increased the G0-G1 cell population greatly, as assessed by flow cytometer analysis. Furthermore, in the virus transfected cells, apoptosis was also observed by means of the terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labelling method.

CONCLUSION

HPV transfection into adenocarcinoma cells induced clear squamous metaplasia. One of the HPV transfected cell clones that expressed E2 and E6-E7 fusion gene mRNA showed the squamous metaplasia particularly clearly, and apoptosis was also demonstrated.

The presence of human papillomavirus type 16/18 DNA in blood circulation may act as a risk marker of lung cancer in Taiwan

BACKGROUND

Lung cancer is the leading cause of cancer death in Taiwan, and the paucity of dependable risk markers has impeded the early management of lung cancer. An association of human papillomavirus (HPV) 16/18 infection with lung cancer among nonsmoking Taiwanese women was revealed in our previous study.

METHODS

Nested PCR was employed to detect HPV 16/18 DNA in the blood circulation of 149 lung cancer patients and 174 noncancer controls. In addition, correlation of prevalence of HPV DNA between the blood circulation and lung tumor tissue was compared from 70 sets of paired tumor tissues and peripheral blood samples available.

RESULTS

The results showed that the prevalence rate of HPV 16/18 in the blood circulation of lung cancer cases was significantly higher than that of noncancer controls (47.7% vs. 12.6% for HPV 16, P < 0.0001; 30.9% vs. 5.2% for HPV 18, P < 0.0001). A significantly higher HPV 16 prevalence was detected in female lung cancer patients than that of male (57.6% vs. 41.1%, P = 0.048), as well as in cases with tumor Stages III/IV than those with tumor Stages I/II (54.6% vs. 29.3%, P = 0.006). After adjusting the effects of age, gender, and smoking status, a 6.5-fold greater risk of lung cancer was demonstrated for those subjects with HPV Type 16 positive (95% CI 3.7-11.3, P < 0.0001), a 9.2-fold for HPV Type 18 positive (95% CI 4.2-20.2, P < 0.0001), and a 75.7-fold greatest risk for those with both HPV Type 16 and 18 positive (95% CI 9.8-582.1, P < 0.0001).

CONCLUSIONS

These results suggested that the presence of HPV DNA in the blood circulation may serve as a feasible risk marker of lung cancer.

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.

Thymic hyperplasia and lung carcinomas in a line of mice transgenic for keratin 5-driven HPV16 E6/E7 oncogenes

Human Papillomavirus type 16 (HPV-16) is the cause of both benign lesions and ano-genital cancers. In HPV-associated cancers the transforming properties of the expressed viral E6 and E7 proteins have been revealed by a number of different assays. We have generated transgenic mice expressing HPV-16 E6/E7 genes under the control of the murine keratin 5 gene promoter, which should confer cell-type specific expression in the basal cells of squamous stratified epithelia. Transgenic mice developed thymic hyperplasia and lung neoplasia with 100% frequency, the thymus showing a size increase at 2 months and reaching the maximum dimension at 6 months, when lung carcinomas appeared. After this time the size of hyperplastic thymi decreased, while malignant formations invaded the mediastinal area. Hepatic metastasis could be also observed in some of the animals at the autopsy and death invariably occurred around 10-11 months of age.

Extremely high Langerhans cell infiltration contributes to the favourable prognosis of HPV-infected squamous cell carcinoma and adenocarcinoma of the lung

AIMS

The infiltration of Langerhans cells in adenocarcinomas and squamous cell carcinomas of the lung was examined in relation to prognostic implications and human papillomavirus (HPV) infection.

METHODS AND RESULTS

Samples from 62 adenocarcinoma and 59 squamous cell carcinoma patients in 1995-97, the prognosis of which had been followed up, were used. The Langerhans cells were demonstrated immunohistochemically using anti S100a and CD1 antibodies. Human papillomavirus (HPV) infection was examined by polymerase chain reaction (PCR) and nonisotopic in-situ hybridization (NISH) methods. Statistical analysis was carried out using the Kaplan-Meier method (Wilcoxon analysis) and multiple regression analysis. HPV infection was demonstrated in 12 cases (19.4%) of adenocarcinoma. The HPV-infected adenocarcinomas had abundant faintly eosinophilic cytoplasm, and were immunohistochemically positive for the surfactant apoprotein A. In the 59 cases of squamous cell carcinomas 19 were of the well differentiated form, and 29 and 11 were moderately and poorly differentiated cases, respectively. HPV was detected in 29 cases (49.2%) (13 well and 16 moderately differentiated cases). In all HPV-infected adenocarcinoma and squamous cell carcinoma cases, extremely large numbers of Langerhans cells (more than 100 per high-power field) were demonstrated in the tumour nests. In contrast, in the non-HPV-infected adenocarcinomas and squamous cell carcinomas, only a few (less than about 10 per high-power field) Langerhans cells were observed. The squamous cell carcinoma cases with high Langerhans cell infiltration, which were also infected with HPV, showed a significantly good prognosis (P = 0.007). The adenocarcinoma cases with high Langerhans cell infiltration tended to have a better prognosis than the cases with low Langerhans cell infiltration, but the difference was not statistically significant. The low number of highly infiltrated cases was insufficient for an adequate statistical analysis. Furthermore, there was no significant correlation between either Langerhans cell infiltration and smoking, or HPV infection and smoking, in either squamous cell carcinoma or adenocarcinoma cases.

CONCLUSIONS

It was considered that the extremely high Langerhans cell infiltration in the tumours was caused by HPV infection. The extremely large number of Langerhans cells in the tumours contributes to the favourable prognosis for HPV-infected lung cancer.

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.