P53 Mutations In Lung Cancer Research Articles

Smoking, p53 mutation, and lung cancer.

This issue marks the 50th anniversary of the release of the U.S. Surgeon General's Report on Smoking and Health. Perhaps no other singular event has done more to highlight the effects of smoking on the development of cancer. Tobacco exposure is the leading cause of cancers involving the oral cavity, conductive airways, and the lung. Owing to the many carcinogens in tobacco smoke, smoking-related malignancies have a high genome-wide burden of mutations, including in the gene encoding for p53. The p53 protein is the most frequently mutated tumor suppressor in cancer, responsible for a range of critical cellular functions that are compromised by the presence of a mutation. Herein, we review the epidemiologic connection between tobacco exposure and cancer, the molecular basis of p53 mutation in lung cancer, and the normal molecular and cellular roles of p53 that are abrogated during lung tumor development and progression as defined by in vitro and in vivo studies. We also consider the therapeutic potential of targeting mutant p53 in a clinical setting based upon the cellular role of mutant p53 and data from genetic murine models.

Association between Smoking and p53 Mutation in Lung Cancer: A Meta-analysis

AimsTo carry out a meta-analysis on the relationship between smoking and p53 gene mutation in lung cancer patients. Materials and methodsPubMed, Web of Science, ProQest and Medline were searched by using the key words: ‘lung cancer or lung neoplasm or lung carcinoma’, ‘p53 mutation’ and ‘smoking’. According to the selection criteria, 15 articles were identified and methodologically analysed by stata 12.0 software package. Crude odds ratios with 95% confidence intervals calculated using the fixed-effects model were used to assess the strength of association between smoking and p53 mutation in lung cancer. ResultsIn total, 15 articles with 1770 lung cancer patients were identified; 69.6% of the patients were smokers, 30.4% were non-smokers. Overall, smokers with lung cancer had a 2.70-fold (95% confidence interval 2.04–3.59) higher risk for mutation than the non-smokers with lung cancer. In subgroup analyses, the increased risk of p53 mutation in smokers than in non-smokers was found in the non-small cell lung cancer (NSCLC) group (odds ratio = 2.38, 95% confidence interval = 1.71–3.32) and in the NSCLC and SCLC group (odds ratio = 3.82, 95% confidence interval = 2.19–6.69). ConclusionsThis meta-analysis strongly suggests that p53 mutation is associated with smoking-induced lung cancer. Smokers with lung cancer had a higher risk for p53 mutation than non-smokers.

Analysis of EGFR, KRAS and P53 mutations in lung cancer using cells in the curette lavage fluid obtained by bronchoscopy

Histopathological samples are commonly used for molecular testing to detect both oncogenes and tumor-suppressor genes in lung cancer. The purpose of this study was to determine the efficacy of using curette lavage fluid for molecular testing to detect EGFR, KRAS and P53 mutations in lung cancer patients. Samples were obtained from 77 lung cancer patients by bronchoscopy at the time of diagnosis, collected by scraping the site of the primary tumor lesion with a curette. DNA was extracted from cells in the curette lavage fluid, and PCRs were performed to amplify mutation hot spot regions in the EGFR, KRAS and P53 genes. The PCR products were direct-sequenced to detect mutations of each gene. The reference sequence of each gene was obtained from GenBank. Overall, 27% (21 of 77) were found with EGFR mutations, 1% (1 of 77) with KRAS mutations, and 36% (28 of 77) with P53 mutations. KRAS mutations were not detected in patients harboring mutations in either EGFR or P53. P53 mutations were identified in 38% (8 of 21) of the patients with EGFR mutations, all of who had advanced lung cancer. Of these patients, a 62-year-old female current smoker was given EGFR-TKI as third-line therapy, with no improvement in clinical symptoms or results of radiographic examination. Multivariate analysis indicated that P53 mutation rates in advanced-stage lung cancer were significantly higher than those in early-stage lung cancer (P=.017). In contrast, EGFR mutation rates were not significantly associated with staging. L747S in EGFR, described as a mutation associated with secondary resistance to EGFR-TKI, was detected in three patients who had never received EGFR-TKI, including one SCLC patient. It is possible to analyze EGFR, KRAS and P53 mutations using curette lavage fluid collected from lung cancer patients. This is useful when sufficient amounts of tumor samples cannot be obtained. Data from the current study suggest that EGFR mutations in concert with P53 mutations accelerate cancer development and lead to evolution of therapeutic resistance.

The APE1 Asp/Asp Genotype and the Combination of APE1 Asp/Asp and hOGG1-Cys Variants Are Associated With Increased p53 Mutation in Non^|^ndash;Small Cell Lung Cancer

BackgroundThe hOGG1 Ser326Cys polymorphism is associated with lung cancer risk, but there are limited data regarding an association between the APE1 Asp148Glu polymorphism and lung cancer. Biological evidence shows that the hOGG1-Cys allele results in less DNA repair activity; however, this is not associated with p53 mutation in lung cancer. Therefore, we investigated whether an interaction between hOGG1 and APE1 is associated with the frequency of p53 mutation in lung cancer.MethodsWe studied 217 Taiwanese adults with primary lung cancer. DNA polymorphisms of hOGG1 and APE1 were determined by polymerase chain reaction (PCR)-based restriction fragment length polymorphism. Mutations in p53 exons 5–8 were detected by direct sequencing. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% CIs for the risk of p53 mutation associated with polymorphisms of hOGG1 and APE1 in lung cancer.ResultsAs expected, no association between hOGG1 polymorphism and p53 mutation was observed in this population. However, a higher risk of p53 mutation was found in participants with the APE1 Asp/Asp genotype than in those with the APE1-Glu allele (OR, 2.15; 95% CI, 1.19–3.87; P = 0.011). The risk of p53 mutation was also higher in participants with APE1 Asp/Asp plus hOGG1-Cys than in those with APE1-Glu plus hOGG1 Ser/Ser (OR, 3.72; 95% CI, 1.33–10.40; P = 0.012).ConclusionsThese results suggest that the APE1 Asp/Asp genotype and the combination of the APE1 Asp/Asp and hOGG1-Cys variants are associated with increased risk of p53 mutation in non–small cell lung cancer.

P53 Dysfunction by Xeroderma Pigmentosum Group C Defects Enhance Lung Adenocarcinoma Metastasis via Increased Mmp1 Expression

Xeroderma pigmentosum group C (XPC) interacts with hHR23B to recognize DNA damage in global genomic repair. We previously showed that XPC is predominantly affected by its hypermethylation and is associated with an increased occurrence of p53 mutation in lung cancer. Tumors with low XPC mRNA levels had a poorer prognosis than those with high XPC mRNA levels, suggesting that XPC defects may enhance tumor metastasis. However, the underlying mechanism is unclear. Here, we show that p53 transcriptional activity is modulated by XPC, whereby XPC stabilizes hHR23B to form an hHR23B-p53 complex that prevents p53 degradation. In addition, in lung cancer cells and xenograft tumors in nude mice, overexpression of XPC suppresses cell/tumor metastatic ability via repression of matrix metalloproteinase-1 (MMP1) transcription by p53. Among tumors from lung cancer patients, those with low XPC mRNA also tended to have low expression of MMP1 mRNA compared with those with high XPC mRNA. Patients with low XPC mRNA levels also more commonly had tumors with late-stage, distant metastasis (M1), nodal metastasis, and T value (P < 0.001 for tumor stage, distant metastasis, and nodal metastasis; P = 0.006 for t value). In conclusion, p53 dysfunction caused by XPC defects in lung cancers may enhance tumor metastasis via increased MMP1 expression.

P53 immunostaining is correlated with reduced survival and is not correlated with gene mutations in resected pulmonary large cell carcinomas

Malignancy of pulmonary large cell carcinomas (LCC) increases from classic LCC through LCC with neuroendocrine morphology (LCCNM) to large cell neuroendocrine carcinomas (LCNEC). However, the histological classification has sometimes proved to be difficult. Because the malignancy of LCC is highly dependent on proteins with functions in the cell cycle, DNA repair, and apoptosis, p53 has been targeted as a potentially useful biological marker. p53 mutations in lung cancers have been shown to result in expression and protein expression also occurs in the absence of mutations. To validate the importance of both p53 protein expression (by immunostaining) and p53 gene mutations in lung LCC (by PCR-single strand conformational polymorphism analysis of exons 5, 6, 7, and 8) and to study their relationships with clinical factors and sub-classification we investigated the correlation of p53 abnormalities in 15 patients with LCC (5 classic LCC, 5 LCNEC, and 5 LCCNM) who had undergone resection with curative intent. Of these patients, 5/15 expressed p53 and none had mutant p53 sequences. There was a negative survival correlation with positive p53 immunostaining (P = 0.05). After adjustment for stage, age, gender, chemotherapy, radiotherapy, and histological subtypes by multivariate analysis, p53 expression had an independent impact on survival. The present study indicates that p53 assessment may provide an objective marker for the prognosis of LCC irrespective of morphological variants and suggests that p53 expression is important for outcome prediction in patients with the early stages of LCC. The results reported here should be considered to be initial results because tumors from only 15 patients were studied: 5 each from LCC, LCNEC and LCCNM. This was due to the rarity of these specific diseases.

Clinical implications of p53 mutations in lung cancer.

The process of bronchial carcinogenesis is characterized by accumulated genetic abnormalities which ultimately lead to malignant transformation of bronchial epithelial cells, followed by invasion and metastasis. One of the most common and consistent of these genetic lesions is inactivation of the p53 tumor suppressor gene by mutation or deletion. The frequency of p53 alterations in lung cancer is highest in those subtypes of bronchial carcinomas that are most consistently associated with smoking, especially SCLC and squamous cell carcinomas. The frequency is lower in adenocarcinomas, in which the association with smoking, although present, is not as strong. The frequency of p53 abnormalities is higher in patients with greater cumulative tobacco exposure. Tobacco-specific carcinogens, in particular BPDE, cause a unique spectrum of p53 mutations, quite distinct from those found in cancers that are not associated with smoking. This characteristic genetic "signature" may persist even decades following smoking cessation. The prognostic significance of p53 mutations in lung cancer is not entirely clear despite the multitude of clinical studies that have been carried out. Nevertheless, the majority of clinical studies suggest that lung cancers with p53 alterations carry a worse prognosis. Furthermore, those tumors with mutant p53 may be relatively more resistant to chemotherapy and radiation. An understanding of the role of p53 in human lung cancer may lead to more rational targeted approaches for treating this disease. For example, the observation that the introduction of wild-type p53 into lung cancer cells with mutant or deleted p53 may reverse the malignant phenotype despite the presence of multiple other genetic abnormalities (14) suggests that replacement of this gene may be an effective clinical strategy. Preclinical and early clinical studies indicate that this is a promising approach, but clearly more effective means of gene delivery to the tumor cells are required (127-129), as discussed elsewhere in this volume.

Clinical implication of p53 mutation in lung cancer.

Lung cancer development involves multiple genetic abnormalities leading to malignant transformation of the bronchial epithelial cells, followed by invasion and metastasis. One of the most common changes is mutation of the p53 tumor suppressor gene. The frequency of p53 alterations in lung cancer is highest in small cell and squamous cell carcinomas. A genetic "signature" of the type of p53 mutations has been associated with carcinogens in cigarette smoke. The majority of clinical studies suggest that lung cancers with p53 alterations carry a worse prognosis, and may be relatively more resistant to chemotherapy and radiation. An understanding of the role of p53 in human lung cancer may lead to more rational targeted approaches for treating this disease. P53 gene replacement is currently under clinical investigation but clearly more effective means of gene deliver to the tumor cells are required. Novel approaches to lung cancer therapy are needed to improve the observed poor patient survival despite current therapies.

Tobacco smoke carcinogens, DNA damage and p53 mutations in smoking-associated cancers.

It is estimated that cigarette smoking kills over 1 000 000 people each year by causing lung cancer as well as many other neoplasmas. p53 mutations are frequent in tobacco-related cancers and the mutation load is often higher in cancers from smokers than from nonsmokers. In lung cancers, the p53 mutational patterns are different between smokers and nonsmokers with an excess of G to T transversions in smoking-associated cancers. The prevalence of G to T transversions is 30% in smokers' lung cancer but only 12% in lung cancers of nonsmokers. A similar trend exists, albeit less marked, in laryngeal cancers and in head and neck cancers. This type of mutation is infrequent in most other tumors aside from hepatocellular carcinoma. At several p53 mutational hotspots common to all cancers, such as codons 248 and 273, a large fraction of the mutations are G to T events in lung cancers but are almost exclusively G to A transitions in non-tobacco-related cancers. Two important classes of tobacco smoke carcinogens are the polycyclic aromatic hydrocarbons (PAH) and the nicotine-derived nitrosamines. Recent studies have indicated that there is a strong coincidence of G to T transversion hotspots in lung cancers and sites of preferential formation of PAH adducts along the p53 gene. Endogenously methylated CpG dinucleotides are the preferred sites for G to T transversions, accounting for more than 50% of such mutations in lung tumors. The same dinucleotide, when present within CpG-methylated mutational reporter genes, is the target of G to T transversion hotspots in cells exposed to the model PAH compound benzo[a]pyrene-7,8-diol-9,10-epoxide. As summarized here, a number of other tobacco smoke carcinogens also can cause G to T transversion mutations. The available data suggest that p53 mutations in lung cancers can be attributed to direct DNA damage from cigarette smoke carcinogens rather than to selection of pre-existing endogenous mutations.

Patterns of p53 G-->T transversions in lung cancers reflect the primary mutagenic signature of DNA-damage by tobacco smoke.

It is unquestionable that the major cause of lung cancer is cigarette smoking. p53 mutations are common in lung cancers from smokers but less common in non-smokers. A large fraction of the p53 mutations in lung cancers are G-->T transversions, a type of mutation that is infrequent in other tumors aside from hepatocellular carcinoma. Previous studies have indicated that there is a good correlation between G-->T transversion hotspots in lung cancers and sites of preferential formation of polycyclic aromatic hydrocarbon (PAH) adducts along the p53 gene. The origin of p53 mutations in lung cancer has been questioned by recent reports suggesting that there are no significant differences in p53 mutation spectra between smokers and non-smokers and between lung cancers and non-lung cancers [S.N. Rodin and A.S. Rodin (2000) Human lung cancer and p53: The interplay between mutagenesis and selection. P:roc. Natl Acad. Sci. USA, 97, 12244-12249]. We have re-assessed these issues by using the latest update of the p53 mutation database of the International Agency for Research on Cancer (14 051 entries) as well as recent data from the primary literature on non-smokers. We come to the conclusion that the p53 mutation spectra are different between smokers and non-smokers and that this difference is highly statistically significant (G-->T transversions are 30 versus 10%; P < 0.0001, chi2 test). A similar difference is seen between lung cancers and non-lung cancers. At a number of mutational hotspots common to all cancers, a large fraction of the mutations are G-->T transversions in lung cancers but are almost exclusively G-->A transitions in non-lung cancers. Our data reinforce the notion that p53 mutations in lung cancers can be attributed to direct DNA damage from cigarette smoke carcinogens rather than to selection of pre-existing endogenous mutations.

Screening of p53 mutations in lung cancers using a yeast functional assay: Investigation of relationship between p53 mutations and pulmonary fibrosis or clinical parameters

Screening of p53 mutations in lung cancers using a yeast functional assay: Investigation of relationship between p53 mutations and pulmonary fibrosis or clinical parameters

A specific spectrum of p53 mutations in lung cancer from smokers: review of mutations compiled in the IARC p53 database.

Mutations in the p53 gene are common in lung cancer. Using data from the the International Agency for Research on Cancer p53 mutation database (R1), we have analyzed the distribution and nature of p53 mutations in 876 lung tumors described in the literature. These analyses confirm that G to T transitions are the predominant type of p53 mutation in lung cancer from smokers. The most frequently mutated codons include 157, 158, 179, 248, 249, and 273, and several of them (157, 248, and 273) have been shown to correspond to sites of in vitro DNA adduct formation by metabolites of polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene. Furthermore, most of the base changes at codons 248, 249, and 273 in lung cancer differ from those commonly observed at these codons in other cancers reported in the database. Thus, lung cancer from smokers shows a distinct, unique p53 mutation spectrum that is not observed in lung cancer from nonsmokers. These results further strengthen the association between active smoking, exposure to PAHs, and lung cancer. They also indicate that a different pattern of mutations occurs in nonsmokers, and this observation may help to identify other agents causally involved in lung cancer in nonsmokers.

A Specific Spectrum of p53 Mutations in Lung Cancer from Smokers: Review of Mutations Compiled in the IARC p53 Database

A Specific Spectrum of p53 Mutations in Lung Cancer from Smokers: Review of Mutations Compiled in the IARC p53 Database

1067 - p53 mutations in lung cancers of former german uranium miners

1067 - p53 mutations in lung cancers of former german uranium miners

Cigarette smoking and p53 mutations in lung cancer and bladder cancer.

We report here a compilation of p53 mutation results from two smoking-related cancers, lung cancer and bladder cancer. The overall mutation frequencies reported for these two types of cancer were relatively similar--50% in lung cancer and 40% in bladder cancer. The compiled data from lung cancer and bladder cancer suggest an increasing proportion of patients with p53 mutations in nonsmokers, former smokers, and current smokers, in that order, in both cancer groups. Taken together, more than half (55% and 56% for lung cancer and bladder cancer, respectively) of the patients who continued smoking (CS), less than 40% (38% and 38%) of those who had stopped smoking before > or = 1 or > or = 5 years) clinical diagnosis (ES), and less than 30% (25% and 29%) of those who were nonsmokers (NS) had a p53 mutation. The differences seen in the mutation frequencies between the three smoking groups did not, however, reach statistical significance (lung cancer--CS vs ES: odds ratio [OR] = 2.0, 95% CI 0.7-5.4; CS vs NS: OR = 3.7, 95% CI 0.4-37; bladder cancer--CS vs ES: OR = 2.1, 95% CI 0.6-7.9; CS vs NS: OR = 3.1, 95% CI 0.7-13). Guanine to thymine transversions were the most common type in lung cancer followed by guanine to adenine transitions. In bladder cancer, on the contrary, G:C to A:T transitions at cytosine-guanine dinucleotide sites were the most frequently detected base substitutions. Analysis of the compiled p53 mutation data suggest that, in addition to lifetime cumulative exposure to cigarette smoke, also stopping smoking for years prior to clinical manifestation of the disease may affect the incidence of p53 mutations. The differences in the mutation profiles appear to support the view that the main genotoxic agents from cigarette smoke exposure may be different in bladder cancer as compared to lung cancer, as suggested previously by DNA adduct studies.

Cigarette Smoking and p53 Mutations in Lung Cancer and Bladder Cancer

Cigarette Smoking and p53 Mutations in Lung Cancer and Bladder Cancer

P53 Immunostaining Positivity Is Associated With Reduced Survival and Is Imperfectly Correlated With Gene Mutations in Resected Non-small Cell Lung Cancer: A Preliminary Report of LCSG 871

We investigated the correlation of p53 abnormalities with survival in 85 patients with non-small cell lung cancer (NSCLC) who had undergone resection with curative intent as part of Lung Cancer Study Group (LCSG) 871. Our previous studies showed that only a subset of p53 mutations in lung cancers result in overexpression. In addition, protein overexpression has been described in the absence of mutation. Therefore, we determined both p53 protein overexpression (by immunostaining) and p53 and ras gene mutations (by single-strand conformation polymorphism and DNA sequencing) in this set of resected tumor specimens. Clinical follow-up data were available for 75 cases. Of the studied patients, 64% showed p53 overexpression and 51% had mutant p53 sequences; however, the concordance rate was only 67%. There was a negative survival correlation with positive p53 immunostaining (p = 0.05), but not with the presence of gene mutations (p = 0.62) in this group of patients. Overexpression of p53 protein determined by immunostaining may contribute to adverse outcome due to the ability of p53 to act as a dominant oncogene, or alternatively, overexpression may reflect ongoing DNA damage in the tumor as a marker for a more aggressive behavior. When adjusted for stage, age, and gender by multivariate analysis, however, there was no independent impact of p53 overexpression on survival.

P53 Mutations in lung cancer from non-smoking atomic-bomb survivors : Takeshima Y, Soyama T, Bennett WP, Akiyama M, Tokuoka S, Inai K et al. National Cancer Institute, Bethesda, MD 20892. Lancet 1993;342:1520–1521

p53 Mutations in lung cancer from non-smoking atomic-bomb survivors : Takeshima Y, Soyama T, Bennett WP, Akiyama M, Tokuoka S, Inai K et al. National Cancer Institute, Bethesda, MD 20892. Lancet 1993;342:1520–1521

P53 mutation hotspot in radon-associated lung cancer

Mutations in gene p53 are the most common defects in lung cancer and may be a pathway through which environmental carcinogens initiate cancer. We investigated p53 mutations in lung cancers from uranium miners with high radon exposure. 16 (31%) of 52 large-cell and squamous-cell cancers from miners contained the same AGG to ATG transversion at codon 249, including cancers from 3 or 5 miners who had never smoked. This specific mutation has been reported in only 1 of 241 published p53 mutations from lung cancers. The codon 249 mutation may be a marker for radon-induced lung cancer.

P53 mutations in lung cancers from Japanese mustard gas workers.

Mustard gas (MG) is a mutagenic and carcinogenic alkylating agent, and is a known risk factor for occupational lung cancer. Our hypothesis is that lung cancers from MG workers contain mutations (G:C to A:T transitions) as the result of MG-produced DNA promutagenic adducts in the p53 tumor suppressor gene. We analyzed 12 primary lung cancers from Japanese MG factory workers and 12 lung cancers from non-exposed individuals. Genomic DNA was isolated from archival paraffin-embedded tissues. Exons 5-8 were amplified by polymerase chain reaction using p53-specific primers, and sequenced by dideoxy termination methods. Six out of 12 lung cancers from MG workers contained a total of eight somatic point mutations: two cases had double G:C to A:T transitions; one had a G:C to T:A transversion; one case had an A:T to G:C transition; and two cases had single base deletions. Four of the six mutated purines occurred on the non-transcribed, DNA-coding strand. Out of 12 unexposed cases, there were six single base mutations in six cancers, and no double mutations. The p53 mutational frequency in the MG-exposed cases is similar to the non-exposed controls and the usual smoking-related lung cancers reported previously. However, the distinctive double mutations (G:C to A:T transition) observed in two cases are unusual and may be related to MG exposure.