Gender comparisons in human lung cancer: analysis of p53 mutations, anti-p53 serum antibodies and C-erbB-2 expression

The emerging role of estrogen related receptorα in complications of non-small cell lung cancers

Approximately 85% of lung cancer cases are recognized as non-small cell lung cancer (NSCLC) with a perilous (13–17%) 5-year survival in Europe and the USA. Although tobacco smoking has consistently emerged as the leading cause of NSCLC complications, its consequences are distinctly manifest with respect to sex bias, due to differential gene and sex hormone expression. Estrogen related receptor α (ERRα), a member of the nuclear orphan receptor superfamily is normally expressed in the lungs, and activates various nuclear genes without binding to the ligands, such as estrogens. In NSCLC ERRα expression is significantly higher compared with healthy individuals. It is well established ERα and ERβ‚ have 93% and 60% identity in the DNA and ligand binding domains, respectively. ERα and ERRα have 69% (70% with ERRα-1) and 34% (35% with ERRα-1) identity, respectively; ERRα and ERRβ‚ have 92 and 61% identity, respectively. However, whether there is distinctive ERRα interaction with mammalian estrogens or concurrent involvement in non-ER signalling pathway activation is not known. Relevant to NSCLC, ERRα promotes proliferation, invasion and migration by silencing the tumor suppressor proteins p53 and pRB, and accelerates G₂-M transition during cell division. Epithelial to mesenchymal transition (EMT) and activation of Slug (an EMT associated transcription factor) are the prominent mechanisms by which ERRα activates NSCLC metastasis. Based on these observations, the present article focuses on the feasibility of antiERRα therapy alone and in combination with antiER as a therapeutic strategy for NSCLC complications.

Genome-Wide Sex and Gender Differences in Cancer

Despite their known importance in clinical medicine, differences based on sex and gender are among the least studied factors affecting cancer susceptibility, progression, survival, and therapeutic response. In particular, the molecular mechanisms driving sex differences are poorly understood and so most approaches to precision medicine use mutational or other genomic data to assign therapy without considering how the sex of the individual might influence therapeutic efficacy. The mandate by the National Institutes of Health that research studies include sex as a biological variable has begun to expand our understanding on its importance. Sex differences in cancer may arise due to a combination of environmental, genetic, and epigenetic factors, as well as differences in gene regulation, and expression. Extensive sex differences occur genome-wide, and ultimately influence cancer biology and outcomes. In this review, we summarize the current state of knowledge about sex-specific genetic and genome-wide influences in cancer, describe how differences in response to environmental exposures and genetic and epigenetic alterations alter the trajectory of the disease, and provide insights into the importance of integrative analyses in understanding the interplay of sex and genomics in cancer. In particular, we will explore some of the emerging analytical approaches, such as the use of network methods, that are providing a deeper understanding of the drivers of differences based on sex and gender. Better understanding these complex factors and their interactions will improve cancer prevention, treatment, and outcomes for all individuals.

Influence of Estrogen on the NSCLC Microenvironment: A Comprehensive Picture and Clinical Implications

Lung cancer mortality represents the leading cause of cancer related deaths in the United States and worldwide. Almost half of these deaths occur in female patients, making lung cancer the most common cause of cancer mortality in women with a higher annual mortality rate than breast, uterine, and ovarian cancers combined. The distinct epidemiological, histological and biological presentation of non-small cell lung cancer (NSCLC) in women combined with extensive preclinical data have demonstrated that the female sex hormone β-estradiol (E2) plays an important role in NSCLC tumorigenesis, prognosis, and treatment response. Estrogen receptors are widely expressed on stromal and immune cells, and estrogen-linked signaling pathways are known to be involved in regulating the response of both the innate and adaptive immune system. Immune evasion has been recognized as a “hallmark” of cancer and immunotherapy has re-defined standard of care treatment for NSCLC. Despite these advancements, the low response rates observed in patients treated with immune checkpoint inhibitors has led to a search for mediators of immunosuppression and ways to augment the action of these agents. We focus on emerging data describing sex differences that modulate immunotherapy efficacy in NSCLC, immunosuppressive properties of E2 that lead to a pro-tumor microenvironment (TME), and the translational potential of altering the immune microenvironment by targeting the estrogen signaling pathway. E2-induced modulation affects multiple cell types within the TME, including cancer-associated fibroblasts, tumor infiltrating myeloid cells, and tumor infiltrating lymphocytes, all of which interplay with lung tumor cells via E2 and estrogen receptor engagement, ultimately shaping the TME that may, in part, be responsible for the sex-based disparities observed in NSCLC. An improved understanding of the role of the estrogen pathway in NSCLC anti-cancer immunity may lead to novel therapeutic approaches for altering the TME to improve the efficacy of immunotherapy agents.

Lung Cancer in Women: A Modern Epidemic

Lung cancer in women is a modern epidemic and a major health crisis. Cigarette smoking remains the most important risk factor for lung cancer, and unfortunately smoking rates are either stabilized or continue to increase among women. Women may not be more susceptible to the carcinogenic effects of tobacco, but the biology of lung cancer differs between the sexes. This paper summarizes the biological sex differences in lung cancer, including molecular abnormalities, growth factor receptors, hormonal influences, DNA repair capacity, as well as differences in the histology and treatment outcomes of lung cancer in women.

The estrogen pathway as a modulator of response to immunotherapy

Lung cancer is the leading cause of cancer deaths worldwide, with a 5-year survival rate of about 18%. Thus, there is a great need for novel therapeutic approaches to treat non-small-cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICIs) have improved outcomes for a subset of patients, especially those with high programmed death-ligand 1 expression and/or high tumor mutational burden, but have failed in the majority of patients. Increasing evidence suggests that the estrogen signaling pathway may be a therapeutic target in metastatic NSCLC and that the estrogen pathway may play a role in sex-based responses to ICIs. This report will review the epidemiologic, preclinical and clinical data on the estrogen pathway in NSCLC, its implications in sex-based responses to ICIs and the potential use of antiestrogen therapy in combination with ICIs.

Synchronous Multiple Lung Adenocarcinomas: Estrogen Concentration in Peripheral Lung

BACKGROUND

The detection rate of synchronous multiple lung adenocarcinomas (SMLA), which display multiple ground glass opacity nodules in the peripheral lung, is increasing due to advances in high resolution computed tomography. The backgrounds of multicentric development of adenocarcinoma are unknown. In this study, we quantitated estrogen concentration in the peripheral lungs of postmenopausal female patients with SMLA.

METHODS

The tissue concentration of estrogens (estrone [E1] and estdadiol [E2]) in the noncancerous peripheral lung were measured with liquid chromatography/electrospray tandem mass spectrometry in postmenopausal female patients with lung adenocarcinoma. The expression levels of CYP19A1 in the normal lung were also quantitated with real-time PCR. Thirty patients with SMLA and 79 cases of control patients with single lung adenocarcinoma were analyzed.

RESULTS

The concentrations of E1 and E2 in the noncancerous tissue were significantly higher in SMLA cases than control cases (P = 0.004 and P = 0.02, respectively). The minor allele (A) of single nucleotide polymorphism rs3764221 were significantly associated with higher concentration of E1 and E2 (P = 0.002 and P = 0.01, respectively) and higher CYP19A1 mRNA expression (P = 0.03).

CONCLUSION

The tissue estrogen concentration of peripheral lung was significantly higher in SMLA than control cases. The high concentration of estrogen may be one of the causes of multicentric development of peripheral lung adenocarcinomas.

Do smoking habits differ between women and men in contemporary Western populations? Evidence from half a million people in the UK Biobank study

OBJECTIVES

Several studies have shown that smoking may confer a greater excess risk for chronic diseases in women compared with men. The reasons for this excess risk of smoking in women are unclear, yet sex differences in smoking habits may play a role. We, thus, characterised sex differences in smoking habits in a contemporary Western population.

DESIGN

Cross-sectional population-based study.

SETTING

UK Biobank Resource.

PARTICIPANTS

499,797 (54% women) individuals with data on smoking habits.

MAIN OUTCOME MEASURES

Women-to-men prevalence ratios in smoking status, and the women-minus-men mean difference in age at smoking initiation, number of cigarettes smoked daily and age at smoking cessation in 5-year birth cohort bands.

RESULTS

The women-to-men ever-smoking ratio ranged from 0.57 in the oldest to 0.87 in the youngest birth cohort. In the oldest cohort, born 1935-1939, women started smoking 1.9 years (95% CI 1.7 to 2.1) later than did men, but in those born after 1959 there was no difference in the age at initiation. The oldest women smoked 5.3 (95% CI 4.7 to 5.9) cigarettes per day fewer than did the oldest men, compared with 2.0 (95% CI 1.7 to 2.3) fewer cigarettes smoked per day in the youngest, born 1965-1969. Among quitters, women born before 1945 were, on average, 1.5 years older than their male contemporaries, but this differential was 1 year or less among people born after 1949.

CONCLUSIONS

Differences in smoking behaviour between women and men have decreased over time. Even past differentials are unlikely to explain the increased susceptibility to smoking-related chronic disease in women compared with men that has previously been observed. Future studies are required to determine whether sex differences in the physiological and biological effects of smoking are responsible for the differential impact of smoking on health in women and men.

Worldwide trend of increasing primary adenocarcinoma of the lung

The four major histological types of lung cancer are adenocarcinoma, squamous cell carcinoma (SQ), large cell carcinoma and small cell carcinoma. Over the past few decades, the incidence of lung adenocarcinoma has increased gradually in most countries as the most frequently occurring histological type, displacing SQ. Adenocarcinoma is the predominant type of lung cancer among lifelong non-smokers and among females. Especially in East Asian countries, the cause(s) of the increase in adenocarcinomas are not clear. Several genetic mutations specific to lung adenocarcinomas have been found, representing attractive targets for molecular therapy. Recently, the pathological classification of lung adenocarcinoma was revised by integrating the newer clinical and biological knowledge concerning this prevailing type. Additional epidemiological, pathological and genetic studies are required to better understand this type of lung cancer.

EGFR exon 19 in-frame deletion and polymorphisms of DNA repair genes in never-smoking female lung adenocarcinoma patients

We explored potential associations between genetic polymorphisms in genes related to DNA repair and detoxification metabolism and epidermal growth factor receptor (EGFR) mutations in a cohort of 410 never-smoking patients with lung adenocarcinoma. Multivariate-adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CI) of EGFR mutation status in association with the genotypes of DNA repair and detoxification metabolism genes were evaluated using logistic regression analysis. We found an association between in-frame deletion in EGFR exon 19 and a single nucleotide polymorphism (SNP) rs1800566C/T located in NQO1 (aOR, 2.2 with 95% CI, 1.0-4.8) in female never-smokers. The SNP rs744154C/G in ERCC4 was also associated with the EGFR exon 19 in-frame deletion both in never-smokers (aOR, 1.7 with 95% CI, 1.0-3.0) and female never-smokers (aOR, 1.9 with 95% CI, 1.0-3.6). Although the association was marginally significant in multivariate logistic regression analysis, the A/A genotype of rs1047840 in EXO1 was associated with a 7.6-fold increase in the occurrence of the EGFR exon 19 in-frame deletion in female never-smokers. Moreover, risk alleles in NQO1, ERCC4 and EXO1 were associated with an increasing aOR of the EGFR exon 19 in-frame deletion both in never-smokers (p = 0.007 for trend) and female never-smokers (p = 0.002 for trend). Our findings suggest that the in-frame deletion in EGFR exon 19 is associated with polymorphisms in DNA repair and detoxification metabolism genes in never-smoking lung adenocarcinoma patients, especially in females.

Usefulness of serum anti-p53 antibody assay for lung cancer diagnosis

CONTEXT

Some tumor markers, including carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1), are used for the detection of lung cancer; however, their use is limited because of low sensitivities and high false-positive rates.

OBJECTIVES

To investigate the usefulness of an anti-p53 assay in detecting lung cancer and to compare the anti-p53 to CEA and CYFRA 21-1 tumor markers.

DESIGN

Serum samples were collected from 82 patients with lung cancer. Sera were also collected from 79 patients with or without benign pulmonary disease for the control group. All 161 specimens were assayed for CEA, CYFRA 21-1, and anti-p53. The diagnostic performances of these markers were compared using receiver operating characteristic analysis.

RESULTS

The receiver operating characteristic area under the curve values of CYFRA 21-1, CEA, and anti-p53 for discriminating lung cancers from benign or healthy conditions were 0.79, 0.81, and 0.79, respectively. Area under the curve for the 3 markers in combination was 0.90. The sensitivities of those markers for lung cancer detection were respectively 39.0%, 53.7%, and 34.1% at 94.9% specificity, and the cutoff levels at those sensitivities and specificities were 4.5 ng/mL for CYFRA 21-1, 5.4 ng/mL for CEA, and 2.7 U/mL for anti-p53. We found 79.3% positive results for patients with lung cancer by any of the 3 markers, and 12.2% were positive only for anti-p53. All patients without cancer had negative results for 2 or all 3 markers.

CONCLUSIONS

Anti-p53 combined with other conventional markers is helpful in increasing the sensitivity and specificity for detecting lung cancer.

Gender is a risk factor for lung cancer

Results of epidemiological studies suggest that, after one controls for the number of cigarettes smoked, women have a three times higher risk of getting lung cancer than men. Although the mechanism(s) explaining this gender-dependent difference in lung cancer risk is not known, it is thought that endocrine factors may play an important role. Normal human bronchial epithelial cells contain estrogen receptors and synthesize 17β-estradiol (E(2)) and estrone (E(1)), which can undergo further metabolism into the catechol estrogens, 4-hydroxyestradiol (4-OHE(2)) and 4-hydroxyestrone (4-OHE(1)), respectively. Catechol estrogens are formed from E(2) by the actions of cytochrome p450 1B1 (CYP1B1). CYP1B1 is present in normal human bronchial epithelial) cells, and its activity is increased by cigarette smoking. Both 4-OHE(1) and 4-OHE(2) are mutagenic and carcinogenic and may exert their biological effects by inducing DNA adducts in cancer-related genes, including the tumor suppressor gene p53 and the proto-oncogene K-ras. Women with lung cancer have a different p53 mutational spectrum and a higher frequency of K-ras mutations than do men with lung cancer. Both clinical and basic research studies support the hypothesis that E(2) and cigarette smoking are cofactors in lung carcinogenesis in women. More specifically, cigarette smoke stimulates metabolism of E(2) into the genotoxic metabolites, 4-OHE(1) and 4-OHE(2,) which interact with DNA in cancer-related genes, including the tumor suppressor gene, p53, and the proto-oncogene K-ras, two genes frequently mutated in patients with lung cancer. E(2) may stimulate cellular proliferation and enhance tumor growth.

The influence of gender, race, and marital status on survival in lung cancer patients: analysis of Radiation Therapy Oncology Group trials

OBJECTIVE

A meta-analysis was conducted to determine the influence of gender, race, and marital status on overall survival (OS) in Radiation Therapy Oncology Group nonoperative non-small cell lung cancer trials.

MATERIALS AND METHODS

Data from 1365 patients treated on nine prospective Radiation Therapy Oncology Group studies activated during the 1990s were analyzed. Impact of gender, marital status, and race was considered in the Cox proportional hazards models. Age, Karnofsky performance status, weight loss, stage, histology, location of primary tumor, biologic equivalent dose, deviation from protocol dose, and education level were adjusted in the model. A two-sided p value <0.05 was considered statistically significant.

RESULTS

Males had significantly higher mortality than females adjusted for other covariates (hazard ratio [HR] 1.22, 95% confidence interval 1.08 -1.38). Race and marital status were not independently predictive for OS. Single females had significantly better OS than single males (HR 0.72), and married males had lower OS than single females (HR 1.36).

CONCLUSIONS

These results suggest that although certain subgroups of gender, race, and/or marital status have better outcomes with respect to OS; gender seems to be the most significant factor influencing survival results among nonoperative non-small cell lung cancer patients.

Gender-related differences in response to mutagens and carcinogens

The incidences of many cancers can be very different in men and women. Besides differences in exposures to putative causative agents, it is plausible that both genetic and epigenetic effects play roles in these differences. In addition, gender-specific lifestyle and behavioural factors may modulate the effects of exposure to genotoxins. This commentary focuses on several aspects of gender-related differences in responses to mutagens and carcinogens, including sensitivity to chromosome damage, the contribution of genotypic variation and the role of DNA methylation. It is concluded that the reasons for gender differences in cancer susceptibility remain largely unknown in many cases, and the subject deserves more attention and study.

Differential expression of biomarkers in men and women

Lung cancer is one of the most common cancers in the world. While historically, more men than women have died from lung cancer as a result of higher numbers of male smokers, the sex mortality ratio is now showing signs of narrowing. Tumors in women with lung cancer may be slightly different to those in men with lung cancer. This review focuses on biomarkers differentially expressed between female and male patients with lung cancer. There is variation in gene expression between men and women in some genes that encode carcinogen-metabolizing enzymes (CYP1A1, GSTM). Gastrin-releasing peptide (GRP), a bombesin-like peptide, is present in two actively transcribed alleles in women compared with men. Higher prevalence of infection with oncogenic variants human papilloma viruses (HPVs) HPV16 and HPV18 has been suggested in women. A higher frequency of G to T transversion was found in the p53 gene in lung tumors of women. KRAS mutation was found to be more frequent in women with resected non-small cell lung cancer (NSCLC) than in men with resected NSCLC. Epidermal growth factor receptor (EGFR) mutation is more frequently found in lung tumors from women, but the confounding effect of tobacco exposure may explain this difference. Lower levels of ERCC1 and BRCA1 have been reported in women with NSCLC. Lung tumors from women are more likely to express estrogen receptors than those from men. An in silico analysis of transcriptome datasets from lung cancer patients demonstrated that only seven genes (in at least two studies) had significantly different expression patterns in male versus female patients. All of these genes are localized on the sex chromosomes: one on chromosome X and six on chromosome Y. Many areas remain under debate and there are still significant gaps in our understanding, particularly how sex-linked factors relate to lung cancer risk, and to biological and clinical behaviors. Future research into lung cancer needs to address these gender differences more specifically.

Differences in the tumor microenvironment between African-American and European-American breast cancer patients

Background

African-American breast cancer patients experience higher mortality rates than European-American patients despite having a lower incidence of the disease. We tested the hypothesis that intrinsic differences in the tumor biology may contribute to this cancer health disparity.

Methods and Results

Using laser capture microdissection, we examined genome-wide mRNA expression specific to tumor epithelium and tumor stroma in 18 African-American and 17 European-American patients. Numerous genes were differentially expressed between these two patient groups and a two-gene signature in the tumor epithelium distinguished between them. To identify the biological processes in tumors that are different by race/ethnicity, Gene Ontology and disease association analyses were performed. Several biological processes were identified which may contribute to enhanced disease aggressiveness in African-American patients, including angiogenesis and chemotaxis. African-American tumors also contained a prominent interferon signature. The role of angiogenesis in the tumor biology of African-Americans was further investigated by examining the extent of vascularization and macrophage infiltration in an expanded set of 248 breast tumors. Immunohistochemistry revealed that microvessel density and macrophage infiltration is higher in tumors of African-Americans than in tumors of European-Americans. Lastly, using an in silico approach, we explored the potential of tailored treatment options for African-American patients based on their gene expression profile. This exploratory approach generated lists of therapeutics that may have specific antagonistic activity against tumors of African-American patients, e.g., sirolimus, resveratrol, and chlorpromazine in estrogen receptor-negative tumors.

Conclusions

The gene expression profiles of breast tumors indicate that differences in tumor biology may exist between African-American and European-American patients beyond the knowledge of current markers. Notably, pathways related to tumor angiogenesis and chemotaxis could be functionally different in these two patient groups.

Cigarette smoking, body mass index, gastro-esophageal reflux disease, and non-steroidal anti-inflammatory drug use and risk of subtypes of esophageal and gastric cancers by P53 overexpression

A number of risk factors for esophageal and gastric cancers have emerged, yet little is known whether risk factors map to molecular tumor markers such as overexpression of the tumor suppressor TP53. Using a US multicenter, population-based case-control study (170 cases of esophageal adenocarcinomas, 147 gastric cardia adenocarcinomas, 220 non-cardia gastric adenocarcinomas, and 112 esophageal squamous cell carcinomas), we examined whether the risk associated with cigarette smoking, body mass index (BMI), gastroesophageal reflux disease (GERD), and non-steroidal anti-inflammatory drug (NSAID) use varied by P53 overexpression. We defined P53 overexpression through immunohistochemistry of paraffin-embedded tumor tissues, using cutpoints based on percent of cells positive. Polytomous logistic regression was used to assess differences between each case group (defined by tumor subtype and P53 expression) and the control group by risk factors. The proportion of cases overexpressing P53 by tumor subtype was 72% for esophageal adenocarcinoma, 69% for gastric cardia adenocarcinoma, 52% for non-cardia gastric adenocarcinoma, and 67% for esophageal squamous cell carcinoma. For most tumor subtypes, we found little difference in risk factors by tumor P53 overexpression. For non-cardia gastric cancer however, an association with cigarette smoking was suggested for tumors that do not overexpress P53, whereas larger BMI was related to adenocarcinomas that overexpress P53 versus no overexpression. Overall, this study did not find a clear relationship between P53 protein overexpression and the known risk factors for subtypes of esophageal and gastric cancers. Further research on these tumors is needed to identify molecular markers associated with variations in the risk factor profiles.

Genetic susceptibility to renal cell carcinoma: the role of DNA double-strand break repair pathway

Alterations in DNA repair genes have been shown to cause a reduction in host DNA repair capacity and may influence host susceptibility to carcinogenesis. The double-strand break repair is a major DNA-repair pathway. This study tested the hypothesis that common sequence variants of the double-strand break pathway genes predispose susceptible individuals to an increased risk for renal cell carcinoma. Toward this end, we evaluated the associations of 13 single-nucleotide polymorphisms in 10 candidate genes involved in the double-strand break pathway with renal cell carcinoma risk in a population-based case-control study that included 326 Caucasian renal cell carcinoma patients and 335 controls. Using the homozygous wild type as the reference group, we observed a significantly increased renal cell carcinoma risk associated with the homozygous variant genotype of NBS1 (rs1805794; odds ratio, 2.13; 95% confidence interval (95% CI), 1.17-3.86). Carrying of at least one copy of the variant XRCC4 allele was also associated with a significantly increased risk (rs1805377; odds ratio, 1.56; 95% CI, 1.08-2.26). Importantly, in pathway analysis, compared with the reference group (1 or less adverse alleles), individuals with two (odds ratio, 1.26; 95% CI, 0.83-1.91), three (odds ratio, 1.00; 95% CI, 0.64-1.56), and more than three adverse alleles (odds ratio, 1.75; 95% CI, 1.03-2.98) were at increased risk for renal cell carcinoma with significant association in subjects carrying more than 3 adverse alleles. Results from this study provide evidence that individuals with a higher number of genetic variations in the DBS repair pathway are at an increased risk for renal cell carcinoma. These findings require further validation in independent populations.

Molecular and genetic changes in asbestos-related lung cancer

Asbestos-exposure is associated with an increased risk of lung cancer, one of the leading causes of cancer deaths worldwide. Asbestos is known to induce DNA and chromosomal damage as well as aberrations in signalling pathways, such as the MAPK and NF-kappaB cascades, crucial for cellular homeostasis. The alterations result from both indirect effects through e.g. reactive oxygen/nitrogen species and direct mechanical disturbances of cellular constituents. This review describes the current knowledge on genomic and pathway aberrations characterizing asbestos-related lung cancer. Specific asbestos-associated molecular signatures can assist the development of early biomarkers, molecular diagnosis, and molecular targeted treatments for asbestos-exposed lung cancer patients.

Single base instability is promoted in vulvar lichen sclerosus

Single base substitution mutations in codons 248 and 273 of TP53 and codon 12 Kirsten-ras (KRAS) are commonly found in human carcinomas. To determine whether these mutations also occur in normal and inflamed tissues from which carcinomas arise, we utilized the ultra-sensitive polymerase chain reaction/restriction endonuclease/ligase chain reaction mutation assay. Ninety samples of genital skin, including lichen sclerosus (LS) affected skin, adjacent normal and non-adjacent normal, were assayed. Mutations were detected in 103 of 349 assays and consisted of KRAS G34A, G34T, G35A, and TP53 C742T, G818C, C817T, and G818A mutations. Mutant prevalence varied from 1 to 20 per 10(6) wild-type cells. Mutations occurred significantly more frequently in LS (78/224 (35%)) than adjacent normal (20/88 (23%)) and non-adjacent normal genital skin (5/38 (13%)). KRAS G34A mutation was relatively common to all classes of specimen, whereas TP53 gene C742T and G818C mutations were significantly more frequent in LS than normal genital skin. In matched samples, immunohistochemistry evaluation of p53 protein expression revealed the presence of epidermal p53 clones in LS whose presence and number significantly correlated with the presence of TP53 C742T and G818C mutations. Based on these results, it appears oncogenic point mutations occur in normal genital skin, and are selected for in LS.

Women and lung cancer: Epidemiology, tumor biology, and emerging trends in clinical research

Lung cancer is the leading cause of cancer-related death in both men and women. Environmental carcinogens, particularly tobacco smoke, play a dominant role in the development of lung cancer, although 10-15% of all patients diagnosed are non-smokers. In addition, emerging data demonstrate sex-specific differences in lung cancer susceptibility and prognosis. This implies that the development of lung cancer is modulated by complex interactions between genetic, hormonal, behavioral, and environmental factors. A better understanding of the differences between men and women and their impact on the prevention, diagnosis, and treatment of lung cancer requires continued basic and clinical research. Recent data on the epidemiological aspects of lung cancer in women, lung tumor biology, and emerging trends in clinical research were presented at a thought leaders' roundtable hosted by the Society for Women's Health Research. The panel concluded that as the patient population in lung cancer is changing from mostly male smokers to include women and non-smokers, an urgent need exists to increase awareness and research funding to improve lung cancer care, particularly in women. To further improve survival in this disease, both clinical characteristics and tumor biology should be considered in the development of new treatment options.

Polymorphisms in the DNA repair genes XRCC1, APEX1, XRCC3 and NBS1, and the risk for lung cancer in never- and ever-smokers

This case-control study examines the association between lung cancer and genetic polymorphisms in two base excision repair (BER) genes, XRCC1 and APEX1 and two genes involved in homologous recombination repair (HR), XRCC3 and NBS1. Never-smoking lung cancer patients were recruited, and also the next diagnosed ever-smoking case of the same gender and age group. Controls were recruited from the regional population register, frequency matched to cases by hospital catchment area, gender, age group and smoking category. As a result more than 70% of the study population were women. A total of 331 individuals were analysed. Presence of the XRCC1 399Gln allele was associated with a significantly decreased risk for lung cancer among non-smoking women (odds ratio (OR) 0.4, 95% confidence interval (CI) 0.2-0.9). No significant effect was seen with the APEX1 polymorphism. Women smokers carrying the XRCC3 241Met allele showed a significantly decreased risk for lung cancer (OR 0.3, CI 0.2-0.7). The NBS1 185Gln allele was significantly associated with an increased risk for lung cancer among non-smoking women (OR 2.2, CI 1.0-4.8) and low-dose smoking women (OR 4.8, CI 1.5-15.7). The protective effect of the variant XRCC3 241Met allele was strengthened when combined with the low-risk Glu185 allele of the NBS1 gene. Smokers (OR 0.38, CI 0.16-0.90) and women (OR 0.42, CI 0.21-0.85) with at least three low-risk alleles in these two HR genes showed a significantly decreased risk for lung cancer. Thus, in spite of a relatively small study population, this study, including a comparatively large number of never-smokers and women, presents several novel aspects on genetic susceptibility to lung cancer. Our results show that the genetic variation in XRCC1, XRCC3 and NBS1 influence lung cancer susceptibility among women, and that combinations of risk alleles in the two HR genes can enhance the effects.

Association of breast cancer outcome with status of p53 and MDM2 SNP309

BACKGROUND

A common single-nucleotide polymorphism (SNP) in the promoter region of the MDM2 gene, known as T-309G and referred to as SNP309 for this study, leads to increased expression of Mdm2 protein and attenuated function of the p53 tumor suppressor protein. We investigated whether genetic variants in MDM2 were associated with breast cancer incidence and survival and whether the variant status could interact with the tumor p53 status to modify breast cancer survival.

METHODS

We used multivariable logistic and Cox regression analyses to study the relationship of SNP309 status and the status of a second MDM2 SNP in exon 12 at codon 354 (SNP354) with breast cancer incidence and with disease-specific survival among 293 case patients and 317 cancer-free control subjects. Survival analysis included 248 of the 293 case patients who had known tumor p53 status. All statistical tests were two-sided.

RESULTS

We did not observe an association between SNP309 status and breast cancer incidence in the unstratified analysis, but we did find a statistically significant association between SNP354 status and breast cancer incidence (odds ratio = 3.34, 95% confidence interval [CI] = 1.88 to 5.93). We also discovered a statistically significant interaction between SNP309 status and tumor p53 expression for breast cancer survival (P(interaction) = .002). Among homozygous carriers of the common MDM2 SNP309 allele (T/T), a mutant p53 status (risk ratio [RR] of death = 2.33, 95% CI = 1.08 to 5.03) and aberrant p53 protein expression (RR = 2.61, 95% CI = 1.22 to 5.57) in breast tumors were associated with poor survival. Tumor p53 status was not associated with breast cancer survival among carriers of the variant MDM2 SNP309 allele (G/T or G/G), which is consistent with a dominant effect of the variant allele.

CONCLUSION

A strong interaction between SNP309 status and tumor p53 status appears to modify the association between p53 status and breast cancer survival.

Evaluation of two phosphorylation sites improves the prognostic significance of Akt activation in non-small-cell lung cancer tumors

PURPOSE

Akt is a serine/threonine kinase that has been implicated in lung tumorigenesis and lung cancer therapeutic resistance. Full activation of Akt requires two phosphorylation events, but only one site of phosphorylation (S473) has been evaluated thus far in clinical non-small-cell lung cancer (NSCLC) specimens, which has resulted in conflicting results regarding the prognostic significance of Akt activation in NSCLC. In this study, we sought to determine whether evaluation of Akt phosphorylation at T308 would improve prognostic accuracy.

PATIENTS AND METHODS

Phosphospecific antibodies against T308 and S473 were validated and used in an immunohistochemical analysis of tissue microarray slides containing NSCLC specimens (n = 300) and surrounding lung tissue specimens (n = 100).

RESULTS

Phosphorylation of either S473 or T308 was positive in most NSCSLC specimens, but was detected rarely in surrounding normal tissues. When Akt activation was defined by using both sites of phosphorylation, Akt activation was specific for NSCLC tumors versus surrounding tissue (73.4% v 0%; P < .05), was higher in adenocarcinoma than in squamous cell carcinoma (78.1% v 68.5%; P = .040), and was associated with shorter overall survival for all stages of disease (log-rank P = .041). In multivariate analyses, increased phosphorylation of T308 alone was a poor prognostic factor for stage I patients or for tumors < 5 cm (log-rank P = .011 and P = .015, respectively).

CONCLUSION

These results suggest that monitoring phosphorylation of Akt at T308 improves the assessment of Akt activation, and show that Akt activation is a poor prognostic factor for all stages of NSCLC.

DNA adducts as markers of exposure and risk

Many carcinogens exert their biological effects through the formation of DNA adducts by metabolically activated intermediates. Detecting the presence of DNA adducts in human tissues is, therefore, a tool for molecular epidemiological studies of cancer. A large body of evidence demonstrates that DNA adducts are useful markers of carcinogen exposure, providing an integrated measurement of carcinogen intake, metabolic activation, and delivery to the target macromolecule in target tissues. Monitoring accessible surrogate tissues, such as white blood cells, also provides a means of investigating occupational or environmental exposure in healthy individuals. Such exposure to carcinogens, e.g. to polycyclic aromatic hydrocarbons, has been demonstrated in several industries and in defined populations, respectively, by the detection of higher levels of adducts. Adducts detected in many tissues of smokers are at levels significantly higher than in non-smokers, although the magnitude of the elevation does not predict the magnitude of the risk. While such associations do not demonstrate causality, they do, importantly, lend plausibility to observed associations between smoking and cancer. However, there is still resistance to the notion that such monitoring can inform, rather than merely confirm, epidemiological investigations of cancer causation. Interestingly, smoking was recently causally linked to cervical cancer after years of being considered a confounding factor; yet smoking-related adducts have been known to be present in cervical epithelium for some time. In the few prospective studies thus far, elevated adduct levels have been found in individuals who subsequently developed cancer compared with individuals who did not. The potential for biomarker measurements, such as DNA adducts, to provide answers to the origin of many cases of human cancer for which an environmental cause is suspected, needs to be exploited more fully in future epidemiological studies.

TP53 and KRAS mutation load and types in lung cancers in relation to tobacco smoke: distinct patterns in never, former, and current smokers

TP53 mutations are common in lung cancers of smokers, with high prevalence of G:C-to-T:A transversions generally interpreted as mutagen fingerprints of tobacco smoke. In this study, TP53 (exons 5-9) and KRAS (codon 12) were analyzed in primary lung tumors of never (n = 40), former (n = 27), and current smokers (n = 64; mainly heavy smokers). Expression of p53, cyclooxygenase-2 (Cox-2), and nitrotyrosine (N-Tyr), a marker of protein damage by nitric oxide, were analyzed by immunohistochemistry. TP53 mutations were detected in 47.5% never, 55.6% former, and 77.4% current smokers. The relative risk for mutation increased with tobacco consumption (P(linear trend) < 0.0001). G:C-to-T:A transversions (P = 0.06, current versus never smokers) and A:T-to-G:C transitions (P = 0.03, former versus never smokers) were consistently associated with smoking. In contrast, G:C-to-A:T transitions were associated with never smoking (P = 0.02). About half of mutations in current smokers fell within a particular domain of p53 protein, suggesting a common structural effect. KRAS mutations, detected in 20 of 131 (15.3%) cases, were rare in squamous cell carcinoma compared with adenocarcinoma [relative risk (RR), 0.2; 95% confidence interval (95% CI), 0.07-1] and were more frequent in former smokers than in other categories. No significant differences in Cox-2 expression were found between ever and never smokers. However, high levels of N-Tyr were more common in never than ever smokers (RR, 10; 95% CI, 1.6-50). These results support the notion that lung tumorigenesis proceeds through different molecular mechanisms according to smoking status. In never smokers, accumulation of N-Tyr suggests an etiology involving severe inflammation.

TP53 Mutation Spectrum in Lung Cancer Is Not Different in Women and Men

Whether women are more susceptible to lung cancer than men has been controversial. Several case-control studies suggested that women have greater risk of lung cancer compared with men at similar levels of cigarette smoking, whereas some large cohort studies failed to observe this association. Other studies indicated that lung cancer may have biological characteristics and mechanisms of carcinogenesis that are gender specific. Therefore, we hypothesized that women are more susceptible to the carcinogenic effects of tobacco smoke exposure, as evidenced by a higher frequency of G:C-to-T:A somatic mutations in tumors from women in comparison with men at similar levels of tobacco smoke exposure. To investigate our hypothesis, we examined the TP53 mutational spectrum in a case-only (102 women and 201 men) series study where complete smoking information was available. A similar frequency and type of somatic TP53 mutations were observed in women and men. In conclusion, our study indicates that the TP53 mutation spectrum is similar in women and men. Our results are consistent with a recent large cohort study and summary of previous cohort studies, suggesting that women likely have equivalent susceptibility to lung cancer as men.

p53 autoantibodies predict subsequent development of cancer

Because TP53 mutations can induce an immune response and can occur early in the carcinogenic process for some tumors, p53 autoantibodies may be useful biomarkers for risk of development of cancer. Using banked serum samples from an asbestosis cohort at high risk for cancer, we demonstrate for the first time a statistically significant relationship between p53 autoantibodies and the subsequent development of malignancy (hazard ratio [HR] = 5.5, 95% confidence interval [CI] = 2.8-10.9) with a positive predictive value of 0.76 and an average lead time to diagnosis of 3.5 years. p53 autoantibodies were also significantly associated with p53 alterations in the resultant tumors (kappa = 0.78, p = 0.01).

Chromatin remodeling factors and BRM/BRG1 expression as prognostic indicators in non-small cell lung cancer

We immunohistochemically examined 12 core proteins involved in the chromatin remodeling machinery using a tissue microarray composed of 150 lung adenocarcinoma (AD) and 150 squamous cell carcinoma (SCC) cases. Most of the proteins showed nuclear staining, whereas some also showed cytoplasmic or membranous staining. When the expression patterns of all tested antigens were considered, proteins with nuclear staining clustered into two major groups. Nuclear signals of BRM, Ini-1, retinoblastoma, mSin3A, HDAC1, and HAT1 clustered together, whereas nuclear signals of BRG1, BAF155, HDAC2, BAF170, and RbAP48 formed a second cluster. Additionally, two thirds of the cases on the lung tissue array had follow-up information, and survival analysis was performed for each of the tested proteins. Positive nuclear BRM (N-BRM) staining correlated with a favorable prognosis in SCC and AD patients with a 5 year-survival of 53.5% compared with 32.3% for those whose tumors were negative for N-BRM (P = 0.015). Furthermore, patients whose tumors stained positive for both N-BRM and nuclear BRG1 had a 5 year-survival of 72% compared with 33.6% (P = 0.013) for those whose tumors were positive for either or negative for both markers. In contrast, membranous BRM (M-BRM) staining correlated with a poorer prognosis in AD patients with a 5 year-survival of 16.7% compared with those without M-BRM staining (38.1%; P = 0.016). These results support the notion that BRM and BRG1 participate in two distinct chromosome remodeling complexes that are functionally complementary and that the nuclear presence of BRM, its coexpression with nuclear BRG1, and the altered cellular localization of BRM (M-BRM) are useful markers for non-small cell lung cancer prognosis.

Prognostic Implications of Molecular and Immunohistochemical Profiles of the Rb and p53 Cell Cycle Regulatory Pathways in Primary Non–Small Cell Lung Carcinoma

Purpose: Many studies have highlighted the aberrant expression and prognostic significance of individual proteins in either the Rb (particularly cyclin D1, p16INK4A, and pRb) or the p53 (p53 and p21Waf1) pathways in non–small cell lung cancer. We hypothesize that cumulative abnormalities within each and between these pathways would have significant prognostic potential regarding survival.

Experimental Design: Our study population consisted of 106 consecutive surgically resected cases of predominantly early-stage non–small cell lung cancer from the National Cancer Institute-Mayo Clinic series, and assessment of proteins involved both immunohistochemical (cyclin D1, p21Waf1, pRb, p16INK4A, and p53) and mutational analysis (p53) in relationship to staging and survival.

Results: Cyclin D1 overexpression was noted in 48% of the tumors, p16INK4A negative in 53%, pRb negative in 17%, p53 immunopositive in 50%, p53 mutation frequency in 48%, and p21Waf1 overexpression in 47%, none with prognostic significance. Cyclin D1 overexpression in pRb-negative tumors revealed a significantly worse prognosis with a mean survival of 2.3 years (P = 0.004). A simultaneous p53 mutation dramatically reduced the mean survival time to 0.9 years (P = 0.007). Cyclin D1 overexpression with either a p53 mutation or a p53 overexpression was also associated with a significantly poorer prognosis (P = 0.0033 and 0.0063, respectively).

Conclusions: Some cumulative abnormalities in the Rb and p53 pathways (e.g., cyclin D1 overexpression and p53 mutations) significantly cooperate to predict a poor prognosis; however, the complexity of the cell cycle protein interaction in any given tumor warrants caution in interpreting survival results when specific protein abnormalities are taken in isolation.

Molecular epidemiology of lung cancer in female passive smokers

To clarify etiology of lung cancer in nonsmoker females, various studies have been done. Particularly, host factors and environmental tobacco smoking (ETS) of females have been emphasized. However, traditional epidemiological data showed controversial results of sex or gender differences in lung cancer susceptibility and suggest presence of some confounders. One of them is that most of epidemiology studies are based on self-reports for ETS. To prevent misestimate effects of ETS via the self-report, exposure monitoring of ETS is required. On the other hand, focusing on genetic polymorphisms in metabolic enzymes and DNA repair, molecular epidemiological studies have been done in nonsmoker females. Therefore, this review considered: 1. gender differences in lung cancer; 2. effects of passive smoking on lung cancer; 3. exposure monitoring of ETS including genetic risks of lung cancer to clarify etiology of lung cancer in the nonsmoker females with molecular epidemiological discussion.

Alteration of autoantibodies against p53 in Taiwanese lung cancer patients undergoing chemotherapy

BACKGROUND

Correlation between p53 autoantibodies (p53 Abs) titers and the efficacy of Taiwanese lung cancer patients undergoing chemotherapy has never been investigated. Our present study aimed at evaluating putative possibility of using p53 Abs levels as a model system to monitor effect of chemotherapy and prognosis prediction of lung cancer.

METHODS

The prevalence of p53 Abs in lung cancer patients and temporal alteration of p53 Abs titers in lung cancer patients carrying p53 Abs were investigated by using ELISA and Western blot analysis.

RESULTS

p53 Abs was detected in 17 of 277 (6.14%) lung cancer patients, the positivity of p53 Abs in patients with small cell lung carcinoma and non-small cell lung carcinoma was 4.88% and 6.36%, respectively. No significant association between p53 Abs and patients' clinical manifestations was found. Titer of p53 Abs was decreased in 6 of 17 p53 Abs-carrying patients after chemotherapy. However, the decreasing p53 Abs titers were not correlated with patients' survival or chemotherapeutic efficacy.

CONCLUSIONS

The prevalence of p53 Abs in Taiwanese lung cancer is much lower than that in Caucasians. It is unlikely that p53 Abs titer could be a monitoring indicator for the chemotherapeutic efficacy or a prognosis indicator of lung cancer.

Gender and lung cancer

Although lung cancer is the leading cause of cancer death among men and women in the United States, female smokers appear to be at increased risk. After controlling for the number of cigarettes smoked, female sex imparts a significant, independent risk for most histologic types of lung cancer. Cigarette smoking, genetics, and endocrine factors may interact to contribute to the disparity in lung cancer risk between the sexes. Estrogens have direct and indirect actions in the lung, and estrogen has been implicated in lung carcinogenesis in female smokers. This review of the literature will focus on endocrine factors and tobacco carcinogens as risk factors for lung cancer in women.

Estrogen receptor pathways in lung cancer

Lung cancer is the leading cause of death from neoplasia in men and women in the United States. Some studies suggest that women are more susceptible than men to tobacco-induced carcinogenesis and may show higher risk than men for lung cancer development from smoking. More recently, increasing biochemical and genetic data have supported this male-female difference in response to tobacco. Estrogens may be involved in lung carcinogenesis, and estrogen receptors (ERs), mainly ERb, are present and functional in normal lung and tumor cell lines and tissues. Estrogen can directly stimulate the transcription of estrogen-responsive genes in the nucleus of lung cells, and it can also transactivate growth factor signaling pathways, in particular the epidermal growth factor pathway. Lung cancer patients currently have few effective therapeutic options. An understanding of these new developments in estrogen signaling and cross-talk pathways may pave the way for innovative combinatorial approaches for treatment of lung cancer and possibly chemoprevention.

Gender and lung cancer

Accumulating data suggest that the risks for development of lung cancer are different in women compared with men. An increased susceptibility in women to the adverse effects of tobacco may be due to higher levels of DNA adducts, decreased DNA repair capacity, increased frequency of mutations in tumor suppressor genes, and hormonal differences. There are many sex and gender differences in lung cancer presentation, including a greater proportion of adenocarcinoma among women, a greater representation of women in cohorts of younger patients who have lung cancer, and women who do not smoke are more likely to be diagnosed with lung cancer than men. When guidelines for screening, preventive therapies, and treatment options for lung cancer are outlined these differences should be considered.

Making sense of sex and supplements: differences in the anticarcinogenic effects of selenium in men and women

The role of the essential trace mineral selenium in human health and disease is currently a subject of intense interest. In particular, the possible cancer preventive effects of dietary selenium supplementation are now being investigated in several large, randomized trials. The association between selenium status, genotoxic damage, and cancer risk remains enigmatic because epidemiologic studies have failed to consistently link low selenium status with increased cancer risk in men and women. In this paper, we considered the evidence that there are sex-based differences in the anticarcinogenic effects of selenium in humans. We focused our review on prospective human studies in which the relationship between selenium status and cancer risk in men and women was directly compared. Results from cohort studies conducted in seven countries (Belgium, China, Finland, Japan, Netherlands, Norway, and United States) were used to assess the strength of association between low selenium status and the incidence of all cancers, sex-specific cancers, and cancers at particular anatomic sites. In general, the available data support the hypothesis that cancer risk in men is more profoundly influenced by selenium status than cancer risk in women. Factors contributing to the apparent difference in the effects of selenium on cancer incidence in men and women may include sex-based differences in the metabolism and/or tissue distribution of selenium, as well as sex- or gender-related factors that influence tumor biology. Studies are needed to further define the dose-response relationship between selenium and cancer risk in men and women. A more complete understanding of the mechanisms by which selenium modulates cancer initiation and progression is needed to optimize dietary selenium supplementation as a practical cancer preventive strategy. Ultimately, achieving the ambitious goal of cancer prevention may require sex- and gender-specific approaches.

Molecular classification and molecular genetics of human lung cancers

Recent advances in the molecular classification of lung carcinomas and the identification of causative genetic alterations will likely lead to improvements in the diagnosis and treatment of patients with lung cancer. It is now possible to identify gene expression profiles that associate with patient outcome in lung carcinomas, in particular adenocarcinoma. Furthermore, patient survival has been shown to correlate with lung cancer oligonucleotide microarray expression profiles. Large-scale microarray technology may allow for the identification of useful biomarkers for early cancer detection. Oligonucleotide microarray data can be optimized by relating them to protein expression levels in tissue microarrays, by annotation with mutational data, and with results of testing for post-translational modification of cellular proteins. These data may be useful in tailoring chemotherapeutic protocols to individual tumors and identifying new targets for therapeutic intervention.

Serum p53 antibodies in correlation to other biological parameters of breast cancer

Breast cancer is the second most frequent cancer of Thai women. Mutation of p53 is a common event in breast cancer. This alteration can result in cellular accumulation of p53 and may also found in serum p53 antibodies (p53-Abs). To clarify prognostic significance of these antibodies, we evaluated p53-Abs in 158 sera of patients with breast cancer. Thirty (19%) patients were found to have p53-Abs. The incidence of p53-Abs tended to be higher in patients with advanced disease group (stages III and IV) than patients with early disease group (stages I and II) (P=0.055). Strong correlations were found between the presence of p53-Abs and p53 protein expression (P<0.001) and lymph node status (P=0.021). The presence of p53-Abs was associated with lack of estrogen (ER) receptor expression (P=0.035) but was not related to progesterone receptor (PR) (P=0.567). In addition, there was a statistically significant correlation between p53-Abs and proliferation associated antigen Ki-67 (P=0.006), but no relation between c-erbB2 oncoprotein and p53-Abs was observed (P=0.112). Additionally, no correlation was noted between the presence of p53-Abs and serum carcinoembryonic antigen (CEA) or carbohydrate antigen (CA15-3). Our findings indicate that p53-Abs appears to be a promising new parameter to evaluate the cellular biology and prognosis of breast cancer.

The TP53 gene, tobacco exposure, and lung cancer

Of the various genetic alterations in lung cancer, the abnormalities of the TP53 gene (p53) are among the most frequent and important events. Because of its importance, many aspects of TP53 have been studied, including preneoplastic lesions and TP53as a marker for early detection and prognosis and as a therapeutic option. We summarize recent knowledge of TP53 in lung cancer with a special emphasis on the relationship between smoking exposure (e.g, cigarette, etc.) and specific mutational pattern of TP53by analyzing the latest version of the International Agency for Research on Cancer (IARC) database on TP53 mutations in human cancer. Our analysis confirmed several other studies showing significant differences in the frequencies of G:C to T:A transversions between ever-smokers and never-smokers. Furthermore, when comparing the mutational spectrum by gender, important differences were noted between male and female never-smokers. We concluded that the previously noted G:C to T:A transversions were mainly due to female smokers having a high frequency of these changes compared to female never-smokers. There was no relationship between adenocarcinomas and squamous cell carcinomas independent of gender. We also examined the seven codons which have been previously identified as hot spots, that is, the sites of frequent G:C to T:A transversions in smoking-related lung cancers. However, there was no specific codon which was strongly related to smoke exposure despite a moderate relationship. We considered the term "warmspot" may be more appropriate. While mutations of TP53 are frequent in lung cancers, further investigation is necessary to understand their role for lung carcinogenesis, especially as they relate to gender differences, and to translate our laboratory knowledge to clinical applications.

Effect of genotype on steady-state CYP1A1 gene expression in human peripheral lymphocytes

We have analyzed the steady-state levels of cytochrome P-450 1A1 (CYP1A1) mRNA in peripheral blood lymphocytes of 177 individuals with various CYP1A1 genotypes using a quantitative reverse transcriptase-polymerase chain reaction technique that makes use of a homologous internal standard for accurate quantitation. We found no effects of ethnicity, age, or smoking status on CYP1A1 gene expression in this population. We did see a significant 2-fold increase in the mean level of CYP1A1 mRNA in women compared with men for both Caucasians and African Americans. We observed no effect of the African American-specific polymorphism (CYP1A1(*)3) on expression of the gene. However, we found a significant 3-fold decrease in expression associated with the homozygous MspI restriction fragment length polymorphism (CYP1A1(*)2A/(*)2A).

c-erbB-2 protein in serum of primary lung cancer patients

We determined c-erbB-2 protein level in serum of 86 primary lung cancer patients (78 non-small cell lung carcinomas (NSCLC), 3 small cell carcinomas, 5 not histologically defined) and in 61 controls. Aim of this study was to evaluate the clinical usefulness of c-erbB-2 as marker for lung cancer diagnosis. The protein was measured with a commercially available sandwich enzyme immunoassay. Mean levels of c-erbB-2 were 72.8 +/- 122.3 fmol/ml in lung cancers and 64.6 +/- 17.5 fmol/ml in controls (P = 0.2). No association was found between c-erbB-2 levels and histotype, tumor stage, sex and smoking habits. Among NSCLC, only four patients showed a c-erbB-2 concentration higher than the selected cut-off value of 99.6 fmol/ml. Subjects with levels higher than the 75th percentile in tumors (73 fmol/ml) had a shorter median survival than those with lower levels (6.3 months versus 10.0 months, P = 0.003). Our results indicated that serum c-erbB-2 protein is not a reliable diagnostic marker. There is, however, a suggestion of a possible clinical usefulness in terms of survival prediction.

Clinical relevance of molecular markers in lung cancer

The last two decades have seen an exponential growth of our knowledge on the molecular biology of cellular processes and neoplastic transformation. There is high expectation that these advances will be translated into further improvement in the care of cancer patients, especially in the areas of prevention, diagnosis and treatment. Realizing that the histopathological classification of lung cancer has reached its limit in providing additional critical information to further improve treatment strategy, numerous molecular aberrations occurring in lung cancers have been explored as potential new diagnostic markers and markers for molecular sub-staging. Despite extensive studies, most results remain largely controversial. This manuscript will briefly review molecular/genetic changes that have been investigated as candidate diagnostic, prognostic and predictive markers and as biomarkers for early detection in lung cancer. A more concerted and global approach to study the clinical relevance of molecular changes in lung cancers is required in the future.

Mutational spectral analysis at the HPRT locus in healthy children

There is growing evidence linking somatic mutational events during fetal development and childhood to an increasing number of multifactorial human diseases. Despite this, little is known about the relationship between endogenous and environmentally induced exogenous mutations during human development. Here we describe a comparative spectral analysis of somatic mutations at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) reporter gene locus in healthy children. We observed an age-specific decrease in the proportion of large alterations and a corresponding increase in the proportion of small alterations with increasing age following birth (P<0.001). The age specific decrease in the proportion of large alterations (67-30%) was mainly due to a decrease in the proportion of aberrant variable (V), diversity (D) and joining (J) (V(D)J) recombinase mediated HPRT deletions (P<0.001). The increase in the proportion of small alterations with age (28-64%) was associated with an increase in transversions from 8% in children at the late stages of fetal development to 31% in children 12-16 years old (P=0.003). Transitions decreased with age, especially at CpG dinucleotides (P=0.010), as transversions increased (P=0.009). These patterns of mutations provide insight into important spontaneous, genotoxic, and site-specific recombinational somatic mutational events associated with the age-specific development of human disease in children as well as adults.

Expression of estrogen receptors alpha and beta in human lung tissue and cell lines

Epidemiological studies have indicated that females may be at greater risk of smoking associated lung cancer compared with males. Several lines of biochemical evidence support these observations. A possible role of circulating steroid hormones in the etiology of lung cancer has been hypothesized. In the present paper, we have studied the expression of the estrogen receptors (ER)-alpha and ER beta in histologically normal human lung tissue and lung tumor cell lines. Relative ER mRNA levels were measured by reverse transcriptase-PCR and normalized to the level of expression of the glyceraldehyde 3-phosphate dehydrogenase gene (GAPDH). In lung tissue, an ER alpha transcript was found at various levels in 38 out of 46 cases (83%). ER beta was expressed in all cases. The ERs were expressed at similar levels in females and males, and the levels of ER alpha and ER beta mRNA were significantly related (P<0.0001). Compared with the lung tissue, ER expression levels were lower in 16 human lung tumor cell lines and two immortalized human bronchial epithelial cell lines. Five of the tumor cell lines (31%) expressed detectable levels of ER alpha and both of the immortalized cell lines showed a weak ER alpha expression level. All cell lines expressed the ER beta. The lung cell lines BEAS-2B and DB354 showed significantly reduced cell proliferation in response to tamoxifen and a minor increased growth in response to 17 beta-estradiol. In conclusion, ER genes are abundantly expressed in both histologically normal human lung and lung tumor cell lines. This indicates a possible role of ERs in lung carcinogenesis.

Analysis of mutational spectra: locating hotspots and clusters of mutations using recursive segmentation

Mutations within different regions of disease-causing genes can vary in their impact on disease initiation and progression. Determining how individual mutations within such genes affect disease risk and progression can improve the accuracy of prognoses and help guide treatment selection. Estimates of mutation-specific risks can be poor, however, when genes have a large number of distinct mutations, and data for any given mutation is sparse. To address this problem, we present here a method of analysing the spectrum of mutations observed across a gene that pools together mutations that appear to have similar effects on disease. One of the assumptions underlying the analysis of mutational spectra created in this manner is that the frequency of the mutation in the sample reflects the degree of its effect on disease development. Additionally, mutations that disrupt the same functionally important region of the gene are expected to have a similar impact on disease development. These mutations tend to form a cluster within the spectrum. Therefore, we developed an algorithm that segments a spectrum into regions containing sites with similar mutational frequencies, and have derived by simulation equations that allow one to evaluate whether segmentation is needed. We used this approach to investigate the spectrum of mutations observed in the p53 tumour suppressor gene in colorectal cancer tumours. Here, recursive segmentation identified the boundaries of apparent clusters better than did other methods, and this approach could identify clusters of mutations which corresponded to biologically important regions of the p53 protein.

Immunohistochemical study of thyroid transcription factor-1 and HER2/neu in non-small cell lung cancer: strong thyroid transcription factor-1 expression predicts better survival

The relationship of thyroid transcription factor-1 (TTF-1) and HER2/neu expression in non-small cell lung cancer (NSCLC) with multiple parameters including survival were examined. Patients with primary NSCLC who had surgical resection and follow-up of at least 5 years were included in the study. There were 57 patients (38 men and 19 women), 44 to 75 years old (median age, 61 years); 28 patients had adenocarcinoma (AD) and 29 had squamous cell carcinoma. Tumors were examined for TTF-1 and HER2/neu expression using formalin-fixed, paraffin-embedded tissue. Clinical and follow-up data were obtained from the hospital records and Cancer Center database. Representative tumor sections were stained using standard immunohistochemical technique and commercial antibodies for TTF-1 (clone 8G7G3/1, Dako) and HER2/neu (polyclonal, Dako). Tumors were graded as negative (<5%), weak positive (5-49%), and strong positive (>50%), based on the percentage of positively stained tumor cells. Statistical analyses were performed using log-rank test, Pearson and Spearman correlations, and Kaplan-Meier survival curves. TTF-1 expression was seen in 45.6% of all tumors (80% of ADs and 14% of squamous cell carcinomas). Eighteen patients with tumors showing strong TTF-1 expression had significantly better survival compared with the 39 patients whose tumors showed negative or weak TTF-1 expression, although many more of the higher stage AD had strong TTF-1 staining than stage I AD. The TTF-1 expression did not correlate with tumor differentiation and was considered an independent predictor of survival. Seventeen of the 18 tumors with strong TTF-1 expression were ADs. Only eight of 57 (17%) tumors showed HER2/neu expression; seven of these eight were ADs. Although HER2/neu expression and survival did not show correlation, the majority of those ADs with weak or strong HER2/neu staining also had strong TTF-1 staining, were mostly stage I tumors. and had overall longer survival. All patients with stage I disease showed better 5-year survival compared with those with stages II and III. Hispanic patients had significantly worse survival compared with Caucasians and African Americans. The results of this study suggest that strong expression of TTF-1 is an independent predictor of better survival and may be a useful prognostic tool for evaluation of patients with NSCLC.