Association of epidermal growth factor receptor mutations with human papillomavirus 16/18 E6 oncoprotein expression in non-small cell lung cancer

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.

Infection with human cytomegalovirus, Epstein-Barr virus, and high-risk types 16 and 18 of human papillomavirus in EGFR-mutated lung adenocarcinoma

AIM

To assess the frequency of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), and high-risk types of human papillomavirus (HPV16 and HPV18) infections in lung adenocarcinoma samples.

METHODS

Lung adenocarcinoma cytological smears and their DNA isolates were obtained from patients hospitalized at the Department for Lung Diseases Jordanovac, Zagreb, in 2016 and 2017. Overall, 67 lung adenocarcinoma samples were examined: 34 with epidermal growth factor receptor gene (EGFR) mutations and 33 without EGFR mutations. The EGFR mutation status and virus presence were assessed with a polymerase chain reaction, and random samples were additionally tested for EBV with Sanger sequencing. HCMV, EBV, HPV16, and HPV18 infections were evaluated in relation to EGFR mutation, smoking status, and sex. A meta-analysis of available data about HPV infection in non-small cell lung cancer was performed.

RESULTS

More frequent HCMV, EBV, HPV16, and HPV18 infections were observed in lung adenocarcinoma samples with EGFR mutations than in samples without these mutations. Coinfection of the investigated viruses was observed only in lung adenocarcinoma samples with mutated EGFR. In the group with EGFR mutations, smoking was significantly associated with HPV16 infection. The meta-analysis showed that non-small cell lung cancer patients with EGFR mutations had a higher odds of HPV infection.

CONCLUSION

HCMV, EBV, and high-risk HPV infections are more frequent in EGFR-mutated lung adenocarcinomas, which indicates a possible viral impact on the etiology of this lung cancer subtype.

Association of hOGG1-Cys variants with occurrence of p53 and EGFR deletion mutations in non-small cell lung cancer

Background

The human 8‐oxoguanine DNA glycosylase 1 (hOGG1) gene encodes a DNA glycosylase that removes 8‐hydroxy‐2‐deoxyguanine (8‐OH‐dG) DNA damage to protect against gene mutations. The association of hOGG1 Ser326Cys polymorphism with lung cancer risk has predicted that hOGG1‐Cys variants are less effective at removing 8‐OH‐dG damage from DNA; therefore, these variants might show an increased occurrence of tumor suppressor gene and oncogene mutations. However, no evidence has yet supported this hypothesis.

Methods

Direct sequencing was performed to examine the mutations of p53 and EGFR genes in lung tumors from patients with non‐small cell lung cancer (NSCLC). Polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) was used to examine hOGG1 Ser326Cys polymorphism in this study population.

Results

A total of 99 p53‐mutated and 99 EGFR‐mutated patients with NSCLC were selected to explore the possible associations of these mutations with hOGG1 Ser326Cys polymorphism. The p53‐mutated and EGFR‐mutated patients were divided into nondeletion and deletion subgroups. P53 deletion mutations were more commonly observed in male than in female patients (P = 0.030). However, EGFR exon 19 deletion mutations were more prevalent in female and adenocarcinoma patients than in male and squamous cell carcinoma patients (P = 0.028 for genders, P = 0.017 for tumor histology). Interestingly, p53 and EGFR exon 19 deletion mutations were more frequent in patients with hOGG1 Ser/Cys + Cys/Cys hOGG1‐Cys variants than with the hOGG1 Ser/Ser genotype (P = 0.010 for p53, P = 0.032 for EGFR).

Conclusions

We suggest that the association of hOGG1 Ser326Cys polymorphism with lung cancer risk could be partially explained by increases in p53 and EGFR deletion mutations.

Key points

Significant findings of the study

NSCLC patients with hOGG1‐Cys variants may have a higher risk of p53 and EGFR deletion mutations than with hOGG1 Ser/Ser genotype.

What this study adds

NSCLC patients with hOGG1‐Cys variants might be helpful to predict patients having higher risk of EGFR exon 19 deletion mutations and these patients who were treated with gefitinib or erlotinib could be a higher risk to occur EGFR T790M mutation.

NSCLC patients with hOGG1‐Cys variants may have higher risk of p53 and EGFR deletion mutations than with hOGG1 Ser/Ser genotype. NSCLC patients with hOGG1‐Cys variants might be helpful to predict patients with higher risk of EGFR exon 19 deletion mutations and these patients who were treated with gefitinib and erlotinib were more common to occur EGFR T790M mutation.

Possible Oncogenic Viruses Associated with Lung Cancer

Lung cancer is the most common cause of cancer death worldwide. Tobacco smoking is the most predominant etiology for lung cancer. However, only a small percentage of heavy smokers develop lung cancer, which suggests that other cofactors are required for lung carcinogenesis. Viruses have been central to modern cancer research and provide profound insights into cancer causes. Nevertheless, the role of virus in lung cancer is still unclear. In this article, we reviewed the possible oncogenic viruses associated with lung cancer.

The association between human papillomavirus presence and epidermal growth factor receptor mutations in Asian patients with non-small cell lung cancer

Background

The etiology of non-small cell lung cancer (NSCLC) in non-smoker patients remains largely unknown. It has been widely proved that human papillomavirus (HPV) participates in the development of various cancers. Epidermal growth factor receptor (EGFR) mutation patients represent a large portion of non-smokers with NSCLC. We performed this meta-analysis to determine whether HPV infection in NSCLC tissue is associated with EGFR mutations compared with HPV negative controls.

Methods

Online databases were searched up to June 30th 2017. We included studies in which HPV detection was based on polymerase chain reaction (PCR) methods. Random effects model was used in data synthesis and the relative effects were presented as odds ratio (OR) with 95% confidence intervals (CIs).

Results

Finally, four eligible studies with a total of 498 patients from Asian countries were identified and included. The general EFGR mutation positive rate was 38.2% among all patients, and the HPV DNA detection rate (HPV subtype being involved: 16, 18, 33 and 58) was 35.3%. The presence of EGFR mutation was significantly higher in HPV-positive patients compared with HPV-negative controls (52% vs. 31%; OR =2.41, 95% CI: 1.21 to 4.77; P=0.012), with moderate heterogeneity among studies (I²=59%; P=0.062).

Conclusions

Our results suggest that HPV infection is associated with EGFR mutations in NSCLC, at least in Asian populations. Further efforts should be made on exploring the potential mechanism and the prognostic character of HPV/EGFR positive NSCLC patient.

Association between human papillomavirus and EGFR mutations in advanced lung adenocarcinoma

Previous studies have demonstrated an association between human papillomavirus (HPV) and mutations in the epidermal growth factor receptor (EGFR) gene in lung cancer patients; however, few studies have investigated this association in advanced lung adenocarcinoma patients undergoing gefitinib treatment. The present study investigated the association between HPV and EGFR mutations in advanced lung adenocarcinoma patients. A total of 95 advanced lung adenocarcinoma patients were enrolled in the study. The HPV infection status and presence of EGFR mutations in tumor tissue was evaluated. Patient clinical characteristics were also determined and compared with HPV infection and EGFR mutation status to analyze their impact on progression-free survival. HPV DNA was identified in 27/95 (28.4%) lung adenocarcinoma tumors and was most common in patients with lymph node metastasis (P=0.016). A total of 44/95 (46.3%) cases exhibited EGFR mutations, which were predominantly observed in female patients and non-smokers. The presence of HPV DNA was significantly associated with EGFR mutations (P=0.012) and multivariate analysis also revealed that HPV DNA was significantly associated with EGFR mutations (odds ratio=3.971) in advanced lung adenocarcinoma. Patients with both HPV infections and EGFR mutations exhibit a marked decrease in the risk of lung cancer progression when compared with those without HPV infection or EGFR mutations (adjusted HR=0.640; 95% confidence interval: 0.488-0.840; P=0.001). HPV infection was significantly associated with EGFR mutations in advanced lung adenocarcinoma patients. Furthermore, patients with HPV infections exhibited the longest progression-free survival times, which may be due to good response to tyrosine kinase inhibitor- or platinum-based-adjuvant therapy in these patients. Patients with EGFR mutations exhibited a better prognosis when compared with those exhibiting wild-type EGFR, regardless of HPV status.

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.

Environmental exposure and HPV infection may act synergistically to induce lung tumorigenesis in nonsmokers

Most studies of lung tumorigenesis have focused on smokers rather than nonsmokers. In this study, we used human papillomavirus (HPV)-positive and HPV-negative lung cancer cells to test the hypothesis that HPV infection synergistically increases DNA damage induced by exposure to the carcinogen benzo[a]pyrene (B[a]P), and contributes to lung tumorigenesis in nonsmokers. DNA adduct levels induced by B[a]P in HPV-positive cells were significantly higher than in HPV-negative cells. The DNA adduct formation was dependent on HPV E6 oncoprotein expression. Gene and protein expression of two DNA repair genes, XRCC3 and XRCC5, were lower in B[a]P-treated E6-positive cells than in E6-negative lung cancer cells. The reduced expression was also detected immunohistochemically and was caused by increased promoter hypermethylation. Moreover, mutations of p53 and epidermal growth factor receptor (EGFR) genes in lung cancer patients were associated with XRCC5 inactivation. In sum, our study indicates that HPV E6-induced promoter hypermethylation of the XRCC3 and XRCC5 DNA repair genes and the resultant decrease in their expression increases B[a]P-induced DNA adducts and contributes to lung tumorigenesis in nonsmokers.

Overexpression of HPV16 E6/E7 mediated HIF-1α upregulation of GLUT1 expression in lung cancer cells

High-risk human papillomavirus (HPV) infection may play an important role in non-small cell lung carcinoma (NSCLC) development. However, some recent studies have proved that it was not directly associated with lung cancer. The aim of this study was to evaluate the underlying molecular mechanism that HPV16 regulate the expression of GLUT1 and may promote the development of lung cancer. HPV16, HIF-1α, and GLUT1 were detected in pleural effusions of patients with lung cancer (n = 95) and with benign lung disease (n = 55) by immunocytochemistry. Western blotting and qRT-PCR were used to detect the expression chances of HPV16 E6/E7, HIF-1α, and GLUT1 in lung cancer cells. HPV16, HIF-1α, and GLUT1 were significantly more likely to be expressed in the malignant group than in the benign group as detected by immunocytochemistry (ICC), and HIF-1α was significantly correlated with HPV16 or GLUT1 in the malignant group (P < 0.01). Expression changes of E6 and E7 significantly promoted the protein expression of HIF-1α, the expression of both protein and mRNA of GLUT1, but had no effect on the expression of HIF-1α mRNA in lung cancer cells. After inhibition of HIF-1α, it obviously downregulated the expression of both protein and mRNA of GLUT1 in lung cancer cells. E6 and E7 regulated the expression of GLUT1 may be due to the mediation of HIF-1α in lung cancer cells. These results suggest that both E6 and E7 play the important role in the regulation of Warburg effect and may be a valuable therapeutic target for HPV-related cancer.

Nickel may contribute to EGFR mutation and synergistically promotes tumor invasion in EGFR-mutated lung cancer via nickel-induced microRNA-21 expression

We recently reported that nickel accumulation in lung tissues may be associated with an increased in p53 mutation risk via reduced DNA repair activity. Here, we hypothesized that nickel accumulation in lung tissues could contribute to EGFR mutations in never-smokers with lung cancer. We enrolled 76 never-smoking patients to evaluate nickel level in adjacent normal lung tissues by ICP-MS. The prevalence of EGFR mutations was significantly higher in the high-nickel subgroup than in the low-nickel subgroup. Intriguingly, the OR for the occurrence of EGFR mutations in female, adenocarcinoma, and female adenocarcinoma patients was higher than that of all patients. Mechanistically, SPRY2 and RECK expressions were decreased by nickel-induced miR-21 via activation of the EGFR/NF-κB signaling pathway, which promoted invasiveness in lung cancer cells, and particularly in the cells with EGFR L858R expression vector transfection. The patients' nickel levels were associated with miR-21 expression levels. Kaplan-Meier analysis revealed poorer overall survival (OS) and shorter relapse free survival (RFS) in the high-nickel subgroup than in low-nickel subgroup. The high-nickel/high-miR-21 subgroup had shorter OS and RFS periods when compared to the low-nickel/low-miR-21 subgroup. Our findings support previous epidemiological studies indicating that nickel exposure may not only contribute to cancer incidence but also promote tumor invasion in lung cancer.

Up-regulation of FOXM1 by E6 oncoprotein through the MZF1/NKX2-1 axis is required for human papillomavirus-associated tumorigenesis

PURPOSE

Foxhead box M1 (FOXM1) expression has been shown to be linked with human papillomavirus (HPV) 16/18-infected cervical cancer. However, the mechanism underlying the induction of FOXM1 in HPV 16/18-infected cancers remains elusive.

EXPERIMENTAL DESIGN

The mechanistic actions of FOXM1 induced by the E6/NKX2-1 axis in tumor aggressiveness were elucidated in cellular and animal models. The prognostic value of FOXM1 for overall survival (OS) and relapse-free survival (RFS) in HPV-positive oral and lung cancers was assessed using Kaplan-Meier and Cox regression models.

RESULTS

Herein, FOXM1 expression is upregulated by E6-mediated NKX2-1 in HPV-positive cervical, oral, and lung cancer cells. Induction of FOXM1 by E6 through the MZF1/NKX2-1 axis is responsible for HPV-mediated soft agar growth, invasiveness, and stemness through activating Wnt/β-catenin signaling pathway. In a nude mice model, metastatic lung tumor nodules in HPV 18 E6-positive GNM or HPV 16 E6-positive TL-1-injected nude mice were markedly decreased in both cell types with E6 knockdown, FOXM1 knockdown, or treatment with FOXM1 inhibitor (thiostrepton). Among the four subgroup patients, the worst FOXM1 prognostic value for OS and RFS was observed in HPV 16/18-positive patients with tumors with high-expressing FOXM1.

CONCLUSIONS

Induction of FOXM1 by E6 oncoprotein through the MZF1/NKX2-1 axis may be responsible for HPV 16/18-mediated tumor progression and poor outcomes in HPV-positive patients.

Serum 25-hydroxyvitamin D levels correlate with EGFR mutational status in pulmonary adenocarcinoma

There have been several epidemiological studies of the association between 25-hydroxyvitamin D (25(OH)D) level and lung cancer risk. We explored the potential association between serum 25(OH)D levels and mutations in epidermal growth factor receptor (EGFR) in patients with pulmonary adenocarcinoma. We analyzed clinical data from 135 patients whose serum 25(OH)D levels were measured and EGFR mutational status was tested at the time of diagnosis. The relationship between 25(OH)D and clinical factors such as EGFR mutational status and sex was examined. The median serum 25(OH)D level in patients with pulmonary adenocarcinoma was 16.8 ng/ml (range: 3.0-84.3 ng/ml). The level of 25(OH)D was lower in female patients than in male patients (P=0.03). Interestingly, 25(OH)D levels of patients with EGFR-mutated tumors were low compared with those with wild-type tumors (median 18.2 vs 14.7 ng/ml, P=0.011). After a dose-response relationship between EGFR mutations and 25(OH)D levels (as a continuous variable) was observed (OR=0.96, P=0.036), we categorized 25(OH)D levels as low (≤16.8 ng/ml) and high (>16.8 ng/ml). Multivariate analysis revealed the association between low 25(OH)D levels and a high incidence of EGFR mutations (adjusted OR=2.42, 95% CI: 1.11-5.26, P=0.026). The results from this study indicate that low 25(OH)D levels are associated with EGFR mutations in pulmonary adenocarcinoma.

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.