Population sepsis incidence, mortality, and trends in Hong Kong between 2009-2018 using clinical and administrative data

BACKGROUND

Sepsis surveillance using electronic health record (EHR)-based data may provide more accurate epidemiologic estimates than administrative data, but experience with this approach to estimate population-level sepsis burden is lacking.

METHODS

This was a retrospective cohort study including all adults admitted to publicly-funded hospitals in Hong Kong between 2009-2018. Sepsis was defined as clinical evidence of presumed infection (clinical cultures and treatment with antibiotics) and concurrent acute organ dysfunction (≥2 point increase in baseline SOFA score). Trends in incidence, mortality, and case fatality risk (CFR) were modelled by exponential regression. Performance of the EHR-based definition was compared with 4 administrative definitions using 500 medical record reviews.

RESULTS

Among 13,550,168 hospital episodes during the study period, 485,057 (3.6%) had sepsis by EHR-based criteria with 21.5% CFR. In 2018, age- and sex-adjusted standardized sepsis incidence was 759 per 100,000 (relative +2.9%/year [95%CI 2.0, 3.8%] between 2009-2018) and standardized sepsis mortality was 156 per 100,000 (relative +1.9%/year [95%CI 0.9,2.9%]). Despite decreasing CFR (relative -0.5%/year [95%CI -1.0, -0.1%]), sepsis accounted for an increasing proportion of all deaths (relative +3.9%/year [95%CI 2.9, 4.9%]). Medical record reviews demonstrated that the EHR-based definition more accurately identified sepsis than administrative definitions (AUC 0.91 vs 0.52-0.55, p < 0.001).

CONCLUSIONS

An objective EHR-based surveillance definition demonstrated an increase in population-level standardized sepsis incidence and mortality in Hong Kong between 2009-2018 and was much more accurate than administrative definitions. These findings demonstrate the feasibility and advantages of an EHR-based approach for widescale sepsis surveillance.

Comparison of COVID-19 with influenza A in the ICU: a territory-wide, retrospective, propensity matched cohort on mortality and length of stay

OBJECTIVES

Direct comparisons between COVID-19 and influenza A in the critical care setting are limited. The objective of this study was to compare their outcomes and identify risk factors for hospital mortality.

DESIGN AND SETTING

This was a territory-wide, retrospective study on all adult (≥18 years old) patients admitted to public hospital intensive care units in Hong Kong. We compared COVID-19 patients admitted between 27 January 2020 and 26 January 2021 with a propensity-matched historical cohort of influenza A patients admitted between 27 January 2015 and 26 January 2020. We reported outcomes of hospital mortality and time to death or discharge. Multivariate analysis using Poisson regression and relative risk (RR) was used to identify risk factors for hospital mortality.

RESULTS

After propensity matching, 373 COVID-19 and 373 influenza A patients were evenly matched for baseline characteristics. COVID-19 patients had higher unadjusted hospital mortality than influenza A patients (17.5% vs 7.5%, p<0.001). The Acute Physiology and Chronic Health Evaluation IV (APACHE IV) adjusted standardised mortality ratio was also higher for COVID-19 than influenza A patients ((0.79 (95% CI 0.61 to 1.00) vs 0.42 (95% CI 0.28 to 0.60)), p<0.001). Adjusting for age, P_aO₂/F_iO₂, Charlson Comorbidity Index and APACHE IV, COVID-19 (adjusted RR 2.26 (95% CI 1.52 to 3.36)) and early bacterial-viral coinfection (adjusted RR 1.66 (95% CI 1.17 to 2.37)) were directly associated with hospital mortality.

CONCLUSIONS

Critically ill patients with COVID-19 had substantially higher hospital mortality when compared with propensity-matched patients with influenza A.

Bleeding, thrombosis and transfusion in patients on ECMO: A retrospective study in a tertiary center in Hong Kong

Purpose:

Use of anticoagulation in patients on ECMO, especially in Chinese, has always been difficult. This study aimed to review the incidence of bleeding, thrombosis, and transfusion requirement in Chinese ECMO patients and to identify risk factors for bleeding complications.

Materials and Methods:

This was a retrospective observational study of a tertiary hospital from 2010 to 2018. Patients aged ⩾18 years who received ECMO were included. The primary outcome was incidence of bleeding. Secondary outcomes included ICU mortality, hospital mortality, and length of the ICU and hospital stay.

Results:

Of the 130 patients, 55(42.3%) had at least one bleeding events and thrombosis occurred in 37(28.5%). A lower fibrinogen level (adjusted OR 0.56 (0.36–0.86), p = 0.009), bloodstream infection (adjusted OR 2.76 (1.01–7.53), p = 0.047) and longer duration on ECMO (adjusted OR 1.14 (1.02–1.27), p = 0.018) were independently associated with occurrence of bleeding. APTT (adjusted OR 0.99 (0.97–1.01), p = 0.370) and platelet count (adjusted OR 1.00 (0.98–1.01), p = 0.632) were not statistically significant risk factors for bleeding events.

Conclusions:

Bleeding and thrombosis were common complications in Chinese patients receiving ECMO. Hypofibrinogenemia and bloodstream infection, but not APTT nor platelet counts, were independent risk factors for bleeding events.

Enhanced vascular assessment by ultrasound using microbubble contrast after percutaneous decannulation of peripheral veno-arterial extracorporeal membrane oxygenation

Termination of peripheral veno-arterial extracorporeal membrane oxygenation support by managing the arteriotomy wound using a percutaneous closure device was reported successful and effective. However, careful assessment by clinical examination and also ultrasound Doppler assessment of the lower limb vasculature after closure is of paramount importance. Complications including pseudoaneurysm, arterial stenosis, and acute thrombosis are not uncommon. In this case report, commercial microbubbles were used as ultrasound contrast to enhance the image quality for better vascular ultrasound and Doppler assessment after veno-arterial extracorporeal membrane oxygenation percutaneous decannulation. A peudoaneurysm was revealed after microbubble injection, which would otherwise be missed.

Simulation training on bedside veno-arterial extracorporeal membrane oxygenation decannulation

Veno-arterial extracorporeal membrane oxygenation is a form of mechanical circulatory support for patients with refractory decompensated heart failure. Blood is drawn from a large vein and pumped back to a large artery, usually a femoral artery through large bore catheters. When the heart recovers, the extracorporeal membrane oxygenation support can be terminated and the catheters are decannulated. The bleeding at the venous side can be controlled by prolonged compression; however, the arteriotomy wound needs to be repaired. Conventionally, the arteriotomy wounds require open vascular repair in the operating theater. The novel application of percutaneous vascular closure devices, which have been commonly used in vascular operations and percutaneous structural heart interventions, could be applied for closure of arteriotomy wounds at the bedside after extracorporeal membrane oxygenation support. The post-close ProGlide (Abbott Vascular) technique was shown to be safe and could potentially save time and manpower. The wounds are much smaller as compared with the conventional open repair and potentially, the chance of wound infection can be reduced. However, the success of percutaneous bedside closure requires careful prior planning and technique training. Backup plans with vascular surgeons' standby are essential in case of failure of closure. Staffs in the extracorporeal membrane oxygenation centers need to be familiar with the preparation, the procedure as well as the device application technique for successful percutaneous closure. The long learning curve and the limited case load mean that such skills are best trained by simulation scenarios. This article described how this new technique and the team logistics can be trained by simulation.

Preoxygenation before intubation in adult patients with acute hypoxemic respiratory failure: a network meta-analysis of randomized trials

Background

Patients with acute hypoxemic respiratory failure are at risk for life-threatening complications during endotracheal intubation. Preoxygenation might help reduce the risk of hypoxemia and intubation-related complications. This network meta-analysis summarizes the efficacy and safety of preoxygenation methods in adult patients with acute hypoxemic respiratory failure.

Methods

We searched PubMed, EMBASE, and the Cochrane Library Central Register of Controlled Trials through April 2019 for randomized controlled trials (RCT) that studied the use of conventional oxygen therapy (COT), high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), and HFNC and NIV as preoxygenation before intubation in patients with acute hypoxemic respiratory failure. Citations’ screening, study selection, data extraction, and risk of bias assessment were independently performed by two authors. The primary outcome was the lowest SpO₂ during the intubation procedure.

Results

We included 7 RCTs (959 patients). Patients preoxygenated with NIV had significantly less desaturation than patients treated with COT (mean difference, MD 5.53, 95% CI 2.71, 8.34) and HFNC (MD 3.58, 95% CI 0.59, 6.57). Both NIV (odds ratio, OR 0.43, 95% CI 0.21, 0.87) and HFNC (OR 0.49, 95% CI 0.28, 0.88) resulted in a lower risk of intubation-related complications than COT. There were no significant mortality differences among the use of NIV, HFNC, COT, and HFNC and NIV during preoxygenation.

Conclusions

In adult patients with acute hypoxemic respiratory failure, NIV is a safe and probably the most effective preoxygenation method.

Positive fluid balance and mortality in adult patients treated with extracorporeal membrane oxygenation: A retrospective study

Background

Intravenous fluid is important for resuscitation and maintenance of circuit flow in patients with extracorporeal membrane oxygenation, but fluid overload is widely recognized as detrimental in critically ill patients. This study aimed to evaluate the association between positive fluid balance and outcomes in adult patients treated with extracorporeal membrane oxygenation.

Methods

This was a retrospective observational study of a tertiary hospital from October 2010 to January 2018. Patients aged ≥18 years who received extracorporeal membrane oxygenation for ≥48 h were included. The fluid balance was determined as the difference between fluid intake and fluid output, and the cumulative fluid balance was calculated as the sum of these values on the preceding days. The primary outcome was hospital mortality.

Results

Of the 123 included extracorporeal membrane oxygenation episodes, 79 were venovenous extracorporeal membrane oxygenation. The hospital mortality rate was 31.7%. Seventy-eight patients underwent continuous renal replacement therapy during their extracorporeal membrane oxygenation course. Non-survivors had a greater cumulative fluid balance (p≤0.001) and a lower cumulative fluid output (p = 0.006) than survivors on day 7. Fluid intake was not significantly different between survivors and non-survivors (p = 0.583). In the multivariate analysis, the cumulative fluid balance (per litre) on day 7, but not on day 3, was associated with increased hospital mortality (adjusted OR: 1.17, 95% CI: 1.06-1.29, p = 0.001).

Conclusions

In adult patients treated with extracorporeal membrane oxygenation, a higher positive cumulative fluid balance on day 7 was associated with increased hospital mortality. The association between positive fluid balance and mortality was mainly influenced by lower fluid output rather than an increase in fluid intake.

A survey of lung cancer in rural and remote Aboriginal and Torres Strait Islander communities in Queensland: health views that impact on early diagnosis and treatment

BACKGROUND

Lung cancer incidence, mortality and hospitalisation rates are higher for Indigenous Australians compared with non-Indigenous Australians and increase again when living in more remote areas. If Indigenous Australians are made more aware of lung cancer through better access to health services and programmes, lung cancer outcomes might improve.

AIM

We aimed to survey the level of lung cancer awareness in rural and remote Aboriginal and Torres Strait Islander communities and discover perceived barriers to timely diagnosis and treatment of lung cancer.

METHODS

Interviews were conducted in three discrete outer regional and remote Aboriginal communities and one urban setting in Queensland. Participants included Aboriginal and Torres Strait Islander peoples from three target population groups: patients referred for medical treatment with symptoms suspicious of lung cancer or confirmed lung cancer; Indigenous health workers; community members aged 18 years and over. Participants gave written, informed consent.

RESULTS

Of 51 community members and 14 Indigenous health workers, 32 reflected they knew very little about lung cancer, 60 cited smoking as the cause of lung cancer and 54 recognised warning symptoms as a prompt to seek healthcare. Indigenous health workers were not able to describe a healthcare pathway that would apply to a patient with suspected lung cancer.

CONCLUSION

The two main barriers identified as impacting on quality healthcare were communication and follow-up processes. These could be addressed by service improvement activities.

Realising opportunities for evidence-based cancer service delivery and research: linking cancer registry and administrative data in Australia

The traditional roles of Australian cancer registries have been incidence, mortality and survival surveillance although increasingly, roles are being broadened to include data support for health-service management and evaluation. In some Australian jurisdictions, cancer stage and other prognostic data are being included in registry databases and this is being facilitated by an increase in structured pathology reporting by pathology and haematology laboratories. Data linkage facilities are being extended across the country at national and jurisdictional level, facilitating data linkage between registry data and data extracts from administrative databases that include treatment, screening and vaccination data, and self-reported data from large population cohorts. Well-established linkage protocols exist to protect privacy. The aim is to gain better data on patterns of care, service outcomes and related performance indicators for health-service management and population health and health-services research, at a time of increasing cost pressures. Barriers include wariness among some data custodians towards releasing data and the need for clearance for data release from large numbers of research ethics committees. Progress is being made though, and proof of concept is being established.

Queensland Lung Cancer Screening Study: rationale, design and methods

BACKGROUND

Lung cancer is the leading cause of cancer-related mortality in Australia. Screening using low-dose computed tomography (LDCT) can reduce lung cancer mortality. The feasibility of screening in Australia is unknown. This paper describes the rationale, design and methods of the Queensland Lung Cancer Screening Study.

AIMS

The aim of the study is to describe the methodology for a feasibility study of lung cancer screening by LDCT in Australia.

METHODS

The Queensland Lung Cancer Screening Study is an ongoing, prospective observational study of screening by LDCT at a single tertiary institution. Healthy volunteers at high risk of lung cancer (age 60-74 years; smoking history ≥30 pack years, current or quit within 15 years; forced expiratory volume in 1s ≥50% predicted) are recruited from the general public through newspaper advertisement and press release. Participants receive a LDCT scan of the chest at baseline, year 1 and year 2 using a multidetector helical computed tomography scanner and are followed up for a total of 5 years. Feasibility of screening will be assessed by cancer detection rates, lung nodule prevalence, optimal management strategies for lung nodules, economic costs, healthcare utilisation and participant quality of life.

CONCLUSIONS

Studying LDCT screening in the Australian setting will help us understand how differences in populations, background diseases and healthcare structures modulate screening effectiveness. This information, together with results from overseas randomised studies, will inform and facilitate local policymaking.

Exploratory study of the 'weekend effect' for acute medical admissions to public hospitals in Queensland, Australia

AIMS

To determine whether in-hospital deaths of patients admitted through emergency departments with acute exacerbations of chronic obstructive pulmonary disease (COPD), acute myocardial infarction, intracerebral haemorrhage and acute hip fracture are increased by weekend versus weekday admission (the 'weekend effect').

METHODS

We performed a retrospective analysis of statewide administrative data from public hospitals in Queensland, Australia, during the 2002/2003-2006/2007 financial years. The primary outcome was 30-day in-hospital mortality. The secondary outcome of 2-day in-hospital mortality helped determine whether increased mortality of weekend admissions was closely linked to weekend medical care.

RESULTS

During the study period, there were 30 522 COPD, 17 910 acute myocardial infarction, 4183 acute hip fracture and 1781 intracerebral haemorrhage admissions. There was no significant weekend effect on 30-day in-hospital mortality for COPD (adjusted risk ratio = 0.92, 95% CI: 0.81-1.04, P= 0.222), intracerebral haemorrhage (adjusted risk ratio = 1.01, 95% CI: 0.86-1.16, P= 0.935) or acute hip fracture (adjusted risk ratio = 0.78, 95% CI: 0.54-1.03, P= 0.13). There was a significant weekend effect for acute myocardial infarction (adjusted risk ratio = 1.15, 95% CI: 1.03-1.26, P= 0.007). Two-day in-hospital mortality showed similar results.

CONCLUSION

This is the first Australian study on the 'weekend effect' (in a cohort other than neonates), and the first study worldwide to assess specifically the weekend effect among COPD patients. Observed patterns were consistent with overseas research. There was a significant weekend effect for myocardial infarction. Further research is needed to determine whether location (e.g. rural), clinical (e.g. disease severity) and service provision factors (e.g. access to invasive procedures) influence the weekend effect for acute medical conditions in Australia.

Screening for activating EGFR mutations in surgically resected nonsmall cell lung cancer

The clinical applicability of screening surgically resected nonsmall cell lung cancer (NSCLC) tumour tissue and serum for activating epidermal growth factor receptor (EGFR) mutation is unknown. Furthermore, the comparative accuracy of inexpensive EGFR mutation tests, mutant-enriched (ME)-PCR and high-resolution melt (HRM) has not been determined. Lung tumour DNA from 522 surgically resected stage I-IV NSCLC and matched serum DNA from a subset of 64 subjects was analysed for EGFR mutations in exons 19 and 21 using ME-PCR and HRM. Additionally, 97 subjects had previous EGFR DNA sequencing data available for comparison. ME-PCR and HRM detected EGFR mutations in 5% (27 out of 522) of tumour samples. Compared to DNA sequencing, ME-PCR had a sensitivity of 100% and specificity of 99%, while HRM had 100% sensitivity and specificity. Six subjects with EGFR mutation tumours had matched serum, where ME-PCR detected mutations in three samples and HRM in two samples. In the cohort of never-smoker subjects, those with EGFR mutated tumours had worse survival compared with wild-type tumours (30 versus 49 months; p=0.017). ME-PCR and HRM have similar accuracy in detecting EGFR mutations but the prognostic implications of the mutations in resected NSCLC warrants further study.

Genetic susceptibility to the respiratory effects of air pollution

There is large variation between individuals in their response to air pollutants. This review summarises the existing evidence that genetic factors influence the mechanisms of lung injury caused by air pollutants. Genetic association studies have compared the adverse effects of air pollutants between subjects with specific genotypes in biologically relevant genes. In human studies of ozone exposure, polymorphisms in oxidative stress genes (NQO1, GSTM1, GSTP1) modify respiratory symptoms, lung function, biomarkers and risk of asthma. Inflammatory gene polymorphisms (TNF) influence the lung function response to ozone, and the effect of different levels of ozone on the development of asthma. Polymorphisms in oxidative stress genes (GSTM1, GSTP1) alter the response to combined exposure to ragweed pollen and diesel exhaust particles. Importantly, polymorphisms in an oxidative stress gene (GSTM1) have predicted patients with asthma who benefit from antioxidant supplementation in Mexico City, which has chronically high ozone exposure. Genetic linkage studies of families have not been feasible for studying the effects of air pollution in humans, but some progress has been made with pedigrees of specially bred mice, in identifying chromosomal regions linked to effects of ozone or particles. A high priority now, in addition to avoiding exposure in the most susceptible people, is to clearly identify the most effective and safe chemopreventive agents for individuals who are genetically susceptible to the adverse effects of air pollution (eg, antioxidants to be taken during high ozone levels).

Systematic review of multidisciplinary teams in the management of lung cancer

BACKGROUND

In several countries, clinical practice guidelines for lung cancer recommend that multidisciplinary (MD) teams should be used to plan the management of all lung cancer patients. We conducted a systematic review to evaluate and critically appraise the effectiveness of multidisciplinary teams for lung cancer.

MATERIALS AND METHODS

Medline searches were carried out for the period 1984 to July 2007. We included any study that mentioned team working among specialists with diagnostic and curative therapeutic intent, where members of the team met at a specified time, either in person or by video or teleconferencing, to discuss the diagnosis and management of patients with suspected lung cancer. All study designs were included. We were particularly interested in whether multidisciplinary working improved survival but also considered other outcomes such as practice patterns and waiting times.

RESULTS

Sixteen studies met the criteria for inclusion. Statistical pooling was not possible due to clinical heterogeneity. Only two of the primary studies reported an improvement in survival. Both were before-and-after designs, providing weak evidence of a causal association. Evidence of the effect of MD teams was stronger for changing patient management than for affecting survival. Six of the studies reported an increase in the percentage of patients undergoing surgical resection or an increase in the percentage of patients undergoing chemotherapy or radiotherapy with curative intent.

CONCLUSION

This systematic review shows limited evidence linking MD teams with improved lung cancer survival. This does not mean that MD teams do not improve survival, merely that currently available evidence of this is limited. It seems intuitively obvious that MD teams should improve outcomes for lung cancer patients, but there are difficulties in conducting randomised trials to show this. The best way forward would be prospective evaluation of the effectiveness of MD teams as they are implemented, paying particular attention to collecting data on potential confounders.

Gene expression of lung squamous cell carcinoma reflects mode of lymph node involvement

Tumour, node, metastasis staging is essential for lung cancer management. However, similarly staged cancers may have markedly different prognoses, indicating that stage cannot completely explain tumour behaviour. While ipsilateral hilar node involvement is designated N1, the current authors hypothesised that primary tumours involving nodes by direct extension are biologically distinct from those involving nodes through lymphatic metastasis. Microarrays were used to investigate the gene expression profiles of 59 primary lung squamous cell carcinomas, comparing N0 tumours (n = 35), N1 tumours by direct extension (N1d; n = 8), and N1/N2 tumours by lymphatic metastasis (N1/N2m; n = 16). Hierarchical clustering using 125 genes differentially expressed between N0 and N1/N2m tumours found N1d tumours clustered with N0 tumours. Class prediction modelling found the expression profiles of all eight N1d tumours were more similar to N0 than to N1/N2m tumours. The present study demonstrates for the first time that N1 tumours directly invading hilar nodes are genomically different to those that metastasise via lymphatics. Independent reports suggest that tumours with direct, rather than metastatic node involvement have better outcomes. Consequently, the data suggest that there is a need to re-evaluate the N1 staging definition in lung cancer. This is relevant for prognosis prediction and also for clinical management, particularly in selecting those patients most likely to benefit from adjuvant chemotherapy.

Inhaled corticosteroids for stable chronic obstructive pulmonary disease

BACKGROUND

The role of inhaled corticosteroids (ICS) in chronic obstructive pulmonary disease (COPD) has been the subject of much controversy. Major international guidelines recommend selective use of ICS. Recently published meta-analyses have reported conflicting findings on the effects of inhaled steroid therapy in COPD.

OBJECTIVES

The objective of the review is to determine the efficacy of regular use of inhaled corticosteroids in patients with stable COPD.

SEARCH STRATEGY

A pre-defined search strategy was used to search the Cochrane Airways Group specialised register for relevant literature. Searches are current as of October 2006.

SELECTION CRITERIA

We selected randomised trials comparing any dose of any type of inhaled steroid with a placebo control in patients with COPD. Acute bronchodilator reversibility to short term beta2-agonists and bronchial hyperresponsiveness were not exclusion criteria. The a priori primary outcome was change in lung function. Data on mortality, exacerbations, quality of life and symptoms, rescue bronchodilator use, exercise capacity, biomarkers and safety were also analysed.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

Forty-seven primary studies with 13,139 participants met the inclusion criteria. Medium term use of ICS (> two months and up to six months) resulted in a small improvement in FEV1 in some studies. Long term use of ICS (> six months) did not significantly reduce the rate of decline in FEV1 in COPD patients (weighted mean difference (WMD) 5.80 ml/year with ICS over placebo, 95% CI -0.28 to 11.88, 2333 participants). There was no statistically significant effect on mortality in COPD patients (OR 0.98, 95% CI 0.83 to 1.16, 8390 participants). Long term use of ICS reduced the mean rate of exacerbations in those studies where pooling of data was possible (WMD -0.26 exacerbations per patient per year, 95% CI -0.37 to -0.14, 2586 participants). ICS slowed the rate of decline in quality of life, as measured by the St George's Respiratory Questionnaire (WMD -1.22 units/year, 95% CI -1.83 to -0.60, 2507 participants). Response to ICS was not predicted by oral steroid response, bronchodilator reversibility or bronchial hyper-responsiveness in COPD patients. There was an increased risk of oropharyngeal candidiasis (OR 2.49, 95% CI 1.78 to 3.49, 4380 participants) and hoarseness. The few long term studies that measured bone effects generally showed no major effect on fractures and bone mineral density over 3 years.

AUTHORS' CONCLUSIONS

Patients and clinicians should balance the potential benefits of inhaled steroids in COPD (reduced rate of exacerbations, reduced rate of decline in quality of life), against the known increase in local side effects (oropharyngeal candidiasis and hoarseness). The risk of long term adverse effects is unknown.

Cochrane systematic reviews of treatments for lung cancer

Morbidity and mortality from lung cancer is a major burden to global health. The integration of expert clinical experience, patient preference and high-quality evidence, including Cochrane systematic reviews, can only help improve outcomes from this highly lethal condition.

Cytokine gene polymorphisms in idiopathic pulmonary fibrosis

Pro- and anti-fibrotic cytokine gene polymorphisms may affect expression of idiopathic pulmonary fibrosis (IPF). The aims of the present case-control study were to examine polymorphisms in the IL-6, transforming growth factor (TGF)-beta 1, tumour necrosis factor (TNF)-alpha and interleukin-1 (IL-1)Ra genes in patients with IPF (n = 22) -compared to healthy controls (n = 140). Genotyping was performed on DNA extracted from peripheral blood lymphocytes, using polymerase chain reaction - restriction fragment length polymorphism with gene polymorphisms determined according to -published techniques. The following sites were examined: (i) IL-1Ra*1-5 (86 bp variable tandem repeat intron 2), (ii) IL-6 (-174G > C), (iii) TNF-alpha (-308G > A) and (iv) TGF-beta 1 (Arg25Pro). The TNF-alpha (-308 A) allele was over-represented in the IPF (p(corr) = 0.004) group compared to controls. Risk of IPF was significant for heterozygotes for: (i) the TNF-alpha (-308 A) allele (A/G) (odds ratio (OR) 2.9; 95% confidence interval (CI) 1.2-7.2; P = 0.02), (ii) homozygotes (A/A) (OR 13.9; 95%CI 1.2-160; P = 0.04) and (iii) carriage of the allele (A/A + A/G) (OR 4; 95%CI 1.6-10.2; P = 0.003). The distribution of alleles and genotypes for IL-6, TGF-beta 1 and IL-1Ra between the two groups was not significantly different. This is the third study to independently confirm that there is a significant association of the TNF-alpha (-308 A) allele with IPF. Further research is needed to assess the utility of cytokine gene polymorphisms as markers of disease -susceptibility.

Lung cancer. 9: Molecular biology of lung cancer: clinical implications

It has been hypothesised that clinically evident lung cancers have accumulated many different genetic or epigenetic abnormalities in oncogenes and/or tumour suppressor genes. This notion has important clinical ramifications. Recent developments in our knowledge of the molecular biology of lung cancer are reviewed, with particular reference to genetic abnormalities in tumour suppressor gene inactivation and overactivity of growth promoting oncogenes. These changes lead to the "hallmarks of lung cancer". These hallmarks are the new rational targets for early detection, prevention, and treatment of lung cancer.

Mannose-binding lectin gene polymorphism predicts hospital admissions for COPD infections

Infection frequently causes exacerbations of chronic obstructive pulmonary disease (COPD). Mannose-binding lectin (MBL) is a pattern-recognition receptor that assists in clearing microorganisms. Polymorphisms in the MBL2 gene reduce serum MBL levels and are associated with risk of infection. We studied whether the MBL2 codon 54 B allele affected serum MBL levels, admissions for infective exacerbation in COPD and disease susceptibility. Polymorphism frequency was determined by PCR-RFLP in 200 COPD patients and 104 smokers with normal lung function. Serum MBL was measured as mannan-binding activity in a subgroup of 82 stable COPD patients. Frequency of COPD admissions for infective exacerbation was ascertained for a 2-year period. The MBL2 codon 54 B allele reduced serum MBL in COPD patients. In keeping, patients carrying the low MBL-producing B allele had increased risk of admission for infective exacerbation (OR 4.9, P(corrected)=0.011). No association of MBL2 genotype with susceptibility to COPD was detected. In COPD, serum MBL is regulated by polymorphism at codon 54 in its encoding gene. Low MBL-producing genotypes were associated with more frequent admissions to hospital with respiratory infection, suggesting that the MBL2 gene is disease-modifying in COPD. MBL2 genotype should be explored prospectively as a prognostic marker for infection risk in COPD.

5' CpG island methylation of the FHIT gene is correlated with loss of gene expression in lung and breast cancer

Allele loss and loss of expression of fragile histidine triad (FHIT), a putative tumor suppressor gene located in chromosome region 3p14.2, are frequent in several types of cancers. Tumor-acquired methylation of promoter region CpG islands is one method for silencing tumor suppressor genes. We investigated 5' CpG island methylation of the FHIT gene in 107 primary non-small cell lung cancer (NSCLC) samples and corresponding nonmalignant lung tissues, 39 primary breast carcinomas, as well as in 49 lung and 22 breast cancer cell lines by a methylation-specific PCR assay. In addition, we analyzed brushes from the bronchial epithelium of 35 heavy smokers without cancer. FHIT methylation was detected in 37% of primary NSCLCs, 31% of primary breast cancers, and 65% of lung and 86% of breast cancer cell lines. The frequency of methylation in small cell and NSCLC cell lines were identical. Methylation was found in 9% of the corresponding nonmalignant lung tissues and in 17% of bronchial brushes from heavy cigarette smokers. FHIT methylation was significantly correlated with loss of FHIT mRNA expression by Northern blot analysis in lung cancer cell lines and with loss of Fhit expression in NSCLC and breast tumors by immunostaining. We conclude that methylation of FHIT is a frequent event in NSCLC and breast cancers and is an important mechanism for loss of expression of this gene. Methylation of FHIT commences during lung cancer pathogenesis and may represent a marker for risk assessment.

Aberrant promoter methylation of multiple genes in non-small cell lung cancers

Aberrant methylation of CpG islands acquired in tumor cells in promoter regions is one method for loss of gene function. We determined the frequency of aberrant promoter methylation (referred to as methylation) of the genes retinoic acid receptor beta-2 (RARbeta), tissue inhibitor of metalloproteinase 3 (TIMP-3), p16INK4a, O6-methylguanine-DNA-methyltransferase (MGMT), death-associated protein kinase (DAPK), E-cadherin (ECAD), p14ARF, and glutathione S-transferase P1 (GSTP1) in 107 resected primary non-small cell lung cancers (NSCLCs) and in 104 corresponding nonmalignant lung tissues by methylation-specific PCR. Methylation in the tumor samples was detected in 40% for RARbeta, 26% for TIMP-3, 25% for p16INK4a, 21% for MGMT, 19% for DAPK, 18% for ECAD, 8% for p14ARF, and 7% for GSTP1, whereas it was not seen in the vast majority of the corresponding nonmalignant tissues. Moreover, p16INK4a methylation was correlated with loss of p16INK4a expression by immunohistochemistry. A total of 82% of the NSCLCs had methylation of at least one of these genes; 37% of the NSCLCs had one gene methylated, 22% of the NSCLCs had two genes methylated, 13% of the NSCLCs had three genes methylated, 8% of the NSCLCs had four genes methylated, and 2% of the NSCLCs had five genes methylated. Methylation of these genes was correlated with some clinicopathological characteristics of the patients. In comparing the methylation patterns of tumors and nonmalignant lung tissues from the same patients, there were many discordancies where the genes methylated in nonmalignant tissues were not methylated in the corresponding tumors. This suggests that the methylation was occurring as a preneoplastic change. We conclude that these findings confirm in a large sample that methylation is a frequent event in NSCLC, can also occur in smoking-damaged nonmalignant lung tissues, and may be the most common mechanism to inactivate cancer-related genes in NSCLC.

Promoter methylation and silencing of the retinoic acid receptor-beta gene in lung carcinomas

BACKGROUND

Retinoic acid plays an important role in lung development and differentiation, acting primarily via nuclear receptors encoded by the retinoic acid receptor-beta (RARbeta) gene. Because receptor isoforms RARbeta2 and RARbeta4 are repressed in human lung cancers, we investigated whether methylation of their promoter, P2, might lead to silencing of the RARbeta gene in human lung tumors and cell lines.

METHODS

Methylation of the P2 promoter from small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) cell lines and tumor samples was analyzed by the methylation-specific polymerase chain reaction (PCR). Expression of RARbeta2 and RARbeta4 was analyzed by reverse transcription-PCR. Loss of heterozygosity (LOH) was analyzed by PCR amplification followed by electrophoretic separation of PCR products. Statistical differences were analyzed by Fisher's exact test with continuity correction.

RESULTS

The P2 promoter was methylated in 72% (63 of 87) of SCLC and in 41% (52 of 127) of NSCLC tumors and cell lines, and the difference was statistically significant (two-sided P:<.001). By contrast, in 57 of 58 control samples, we observed only the unmethylated form of the gene. Four tumor cell lines with unmethylated promoter regions expressed both RARbeta2 and RARbeta4. Four tumor lines with methylated promoter regions lacked expression of these isoforms, but demethylation by exposure to 5-aza-2'-deoxycytidine restored their expression. LOH at chromosome 3p24 was observed in 100% (13 of 13) of SCLC lines and 67% (12 of 18) of NSCLC cell lines, and the difference was statistically significant (two-sided P: =.028).

CONCLUSIONS

Methylation of the RARbeta P2 promoter is one mechanism that silences RARbeta2 and RARbeta4 expression in many lung cancers, particularly SCLC. Chemical demethylation is a potential approach to lung cancer therapy.

Loss of Fhit expression in non-small-cell lung cancer: correlation with molecular genetic abnormalities and clinicopathological features

The FHIT gene is located at a chromosomal site (3p14.2) which is commonly affected by translocations and deletions in human neoplasia. Although FHIT alterations at the DNA and RNA level are frequent in many types of tumours, the biological and clinical significance of these changes is not clear. In this study we aimed at correlating loss of Fhit protein expression with a large number of molecular genetic and clinical parameters in a well-characterized cohort of non-small-cell lung cancers (NSCLCs). Paraffin sections of 99 non-small-cell carcinomas were reacted with an anti-Fhit polyclonal antibody in a standard immunohistochemical reaction. Abnormal cases were characterized by complete loss of cytoplasmic Fhit staining. The Fhit staining results were then correlated with previously obtained clinical and molecular data. Fifty-two of 99 tumours lacked cytoplasmic Fhit staining, with preserved reactivity in adjacent normal cells. Lack of Fhit staining correlated with: loss of heterozygosity (LOH) at the FHIT 3p14.2 locus, but not at other loci on 3p; squamous histology; LOH at 17p13 and 5q but not with LOH at multiple other suspected tumour suppressor gene loci; and was inversely correlated with codon 12 mutations in K-ras. Fhit expression was not correlated overall with a variety of clinical parameters including survival and was not associated with abnormalities of immunohistochemical expression of p53, RB, and p16. All of these findings are consistent with loss of Fhit protein expression being as frequent an abnormality in lung cancer pathogenesis as are p53 and p16 protein abnormalities and that such loss occurs independently of the commitment to the metastatic state and of most other molecular abnormalities.

Molecular pathogenesis of lung cancer

Lung cancer is the largest cancer killer of men and women in the united states. In addition to the progress made from antismoking primary prevention measures, new tools to help treat patients with lung cancer are emerging from the rapid advances in knowledge of the molecular pathogenesis of lung cancer. These tools include molecular and cellular biology and are starting to provide an insight into how the tumor cell, by altering oncogenes and tumor suppressor genes, achieves growth advantage, uncontrolled proliferation and metastatic behavior via disruption of key cell-cycle regulators and signal transduction cascades. Moreover, new knowledge is being developed in terms of the molecular definition of individual susceptibility to tobacco smoke carcinogens. These tools are being translated into clinical strategies to complement surgery, radiotherapy, and chemotherapy and also to assist in primary and secondary prevention efforts. This review summarizes current knowledge of the molecular pathogenesis of lung cancer. From this we know that respiratory epithelial cells require many genetic alterations to become invasive and metastatic cancer. We can detect cells with a few such changes in current and former smokers, offering the opportunity to intercede with a biomarker-monitored prevention and early detection effort. This will be coupled with new advances in computed tomography-based screening. Finally, because the molecular alterations are known, new mechanism-based therapies are being developed and brought to the clinic, including new drugs, vaccines, and gene therapy, which also must be integrated with standard therapies.

Role of TSG101 in uterine cervix cancer

OBJECTIVE

TSG101 was first described as a possible tumor suppressor gene in breast cancer. To determine whether TSG101 might play a role in cervical carcinogenesis, we examined a panel of cervical cancer cell lines and primary tumor specimens for transcript abnormalities and mutations in TSG101.

METHODS

Total RNA was derived from cell line cultures or primary tumor specimens. We performed nested reverse transcription polymerase chain reaction (RT-PCR) with eight overlapping primer sets, followed by single-strand conformational polymorphism (SSCP) analysis, to screen for mutations in the TSG101 open reading frame. Representative normal and shifted SSCP bands were sequenced. To identify abnormal-sized transcripts, we performed RT-PCR with primers flanking the open reading frame followed by gel electrophoresis.

RESULTS

Mutational analysis was performed on cDNAs from 20 primary cervical tumors and 8 cervical carcinoma cell lines. Two polymorphisms were identified, neither of which resulted in an altered amino acid sequence. Transcript analysis was performed on a subset of 16 primary cervix tumors and 6 cervix carcinoma cell lines. The wild-type transcript (1228 bp) was the dominant transcript expressed in all samples. A transcript measuring 330 bp was detected in 5 of 6 cell lines and 11 of 16 primary tumor specimens.

CONCLUSION

Our results suggest that mutations in TSG101 rarely occur in carcinomas of the uterine cervix. However, the presence of minor aberrant TSG101 transcripts is a common feature. The relationship between aberrant transcription and carcinogenesis should be further investigated.

Frequent loss of KAI1 expression in squamous and lymphoid neoplasms. An immunohistochemical study of archival tissues

The metastasis suppressor gene KAI1 was identified by its ability to inhibit the formation of pulmonary metastases in experimental models for prostatic carcinoma. Down-regulation of this gene may be correlated with the invasive phenotype in melanomas and colon and bladder carcinomas and with the metastatic phenotype in carcinomas of the lung, breast, prostate, and pancreas. The goal of our study was to establish an immunohistochemical method to detect KAI1 expression in archival tissues. Using cell lines with known KAI1 levels and paraffin-embedded KAI1 positive tissues as controls, we observed strong membrane staining in lymphoid follicular centers and squamous epithelia. We then demonstrated the utility of our assay by studying KAI1 expression in 34 lymphoid and 57 squamous lesions. All eight reactive lymph nodes were KAI1 positive. In contrast, three of 13 follicular small cleaved and five of 13 diffuse large cell lymphomas were KAI1 negative. Seventy-nine percent (37 of 47) of invasive squamous cell carcinomas from the lung (n = 15), head and neck (n = 18), and cervix (n = 14) showed extensive KAI1 down-regulation. Loss of KAI1 expression was also found in a subset of 10 high-grade cervical dysplasias. Our data show that (i) immunohistochemistry is a suitable technique for evaluating KAI1 expression in archival tissues; (ii) KAI1 was not expressed in a subset of both low-grade and high-grade lymphomas; and (iii) there was extensive down-regulation of KAI1 in squamous cell carcinomas, suggestive of an important role of the gene in the suppression of invasion in these malignancies.

Correlation of abnormal RB, p16ink4a, and p53 expression with 3p loss of heterozygosity, other genetic abnormalities, and clinical features in 103 primary non-small cell lung cancers

This study was performed to determine the frequency of inactivation and clinical correlates in non-small cell lung cancer (NSCLC) of three known tumor suppressor genes [TSGs; RB, MTS1/CDKN2 (p16), and p53] and various regions of 3p loss of heterozygosity (LOH) as other major potential TSG sites. Paraffin sections from 103 resected NSCLCs were analyzed for expression of pRB, p16, and p53 by immunohistochemistry, whereas DNA from tumor and normal tissue were tested for LOH at 3p25-26, 3p21, and 3p14. Previously published LOH data for 5q, 11p, 17q, and 18q were also available. Loss of pRB or p16 expression and overexpression of p53 were considered abnormal. The immunohistochemical and LOH data were correlated with a variety of clinical parameters including stage, age, sex, smoking history, and survival. With respect to pRB, p16, and p53, the tumors could be grouped into four categories: normal for all three proteins (21%); abnormal for pRB or p16 and normal for p53 (30%); normal for pRB and p16 and abnormal for p53 (20%); and abnormal in both pathways (28%). Aberrant expression of pRB, p16, p53, and 3p LOH, either individually or in combination, was not associated with survival differences or any other clinical parameters, with the exception that pRB/pl6 abnormalities were more common in older patients (P = 0.0005). pRB and p16 expression showed a strong inverse correlation (P = 0.002), whereas there was no correlation between expression of pRB, p16, and p53. Abnormal expression of any of the three genes inversely correlated with K-ras codon 12 mutations (P = 0.004), but not with 3p LOH or LOH at other TSG loci. We conclude that resectable NSCLCs show distinct patterns of TSG inactivation, but that no clear clinical correlates exist either alone or in combination for pRB, p16, p53, and 3p abnormalities.

TSG101 is not mutated in lung cancer but a shortened transcript is frequently expressed in small cell lung cancer

TSG101 is a candidate tumor suppressor gene whose deletion in NIH3T3 cells leads to spontaneous lung metastases in nude mice. Aberrant transcripts of TSG101 have been identified in 47% of primary breast carcinomas, without evidence of intragenic deletions at the TSG101 locus on 11p15. To investigate the possible role of TSG101 in lung cancer, which often shows 11p allele loss, we performed transcript analysis and mutational analysis of TSG101 in lung cancer cell lines. Reverse transcriptase RT-PCR and Northern analysis detected a common TSG101 transcript, shortened because of an internal deletion, which was expressed simultaneously with the wild-type transcript in 89% of small cell lung cancer (SCLC) lines. In contrast, the wild-type transcript was expressed alone in normal tissues, primary non-small cell lung cancer (NSCLC) specimens, and the majority of NSCLC cell lines. Sequence of the shortened SCLC transcript was identical to that of the most common aberrant transcript identified in breast cancer, consisting of a deletion of exons 2-4 and part of 1 and 5. Southern analysis of SCLC lines expressing the shortened transcript did not detect any intragenic deletions. Single strand conformational polymorphism (SSCP) analysis and direct sequencing of TSG101 cDNAs also identified no mutations or deletions. These results suggest that TSG101 is not mutated in lung cancer but that aberrant splicing of TSG101 occurs in SCLC.

Progress in understanding the molecular pathogenesis of human lung cancer

We review the molecular pathogenesis of lung cancer including alterations in dominant oncogenes, recessive oncogenes/tumor suppressor genes, alterations in growth regulatory signaling pathways, abnormalities in other pathways, such as apoptosis, autocrine and paracrine growth stimulatory loops, angiogenesis, and host immune responses, other mechanisms of genetic changes, such as microsatellite and methylation alterations, and the potential for inherited predisposition to lung cancer. These changes are related to multistage carcinogenesis involving preneoplastic lesions, and lung development and differentiation. The translational applications of these findings for developing new ways of early detection, prevention, treatment, and prognosis of lung cancer are discussed.

KRAS codon 12 mutations in Australian non-small cell lung cancer

BACKGROUND

In certain non-small cell lung cancer (NSCLC) populations, codon 12 mutations of the KRAS oncogene comprising mostly G-T transversions have diagnostic and prognostic value. However, it is not known if these findings are applicable to all populations of lung cancer patients.

AIMS

To examine for KRAS codon 12 mutations in Australian NSCLC patients.

METHODS

Tumour samples and corresponding normal lung tissue from 108 Australian patients with NSCLC undergoing curative resection were studied for mutations of KRAS codon 12 using a sensitive PCR assay. Mutations were confirmed by DNA sequencing and correlated with histological subtype, tumour stage, the presence of nodal metastases and survival.

RESULTS

Eleven KRAS codon 12 mutations were detected in 108 NSCLCs, with most (8/11) occurring in the adenocarcinoma subtype (17% prevalence), but were not associated with adverse outcome or clinico-pathological features. G-T transversions were surprisingly infrequent (37% of adenocarcinoma mutations).

CONCLUSIONS

These data add to the evidence suggesting geographical differences in the spectrum and significance of KRAS codon 12 mutational genotypes in NSCLC. While these may be due to genetic variation and/or differences in carcinogen exposure, there is a need for larger population based studies before this potentially important biomarker can be recommended universally for optimising lung cancer management.

Allelotyping demonstrates common and distinct patterns of chromosomal loss in human lung cancer types

Allelic loss is a hallmark of tumor suppressor gene (TSG) inactivation. We have allelotyped 29 paired lymphoblastoid and lung cancer cell lines derived from 11 patients with small cell (SCLC) and 18 patients with non-small cell lung carcinomas (NSCLC). Statistical analysis indicated that a threshold of 30% separated non-random allelic loss from the random genetic deletions of malignancy. We have identified non-random allelic loss at 42 of 54 (78%) specific chromosomal regions examined, with 22 regions (52%) common between the two major lung cancer histologic types. There were 3 regions (7%) with allelic loss specific for SCLC and 17 regions (41%) specific for NSCLC. Furthermore, there were significant differences in loss of heterozygosity (LOH) frequencies between NSCLC and SCLC at 13 regions on eight chromosome arms (3p, 5q, 6q, 9p, 10q, 11p, 13q, and 19p). Eight homozygous deletions were present in seven cell lines at four regions, 3p12, 3p14.2, 9p21, and 10q23-25. We have also identified novel sites of chromosomal deletions. In particular, there was frequent loss at 11p13 in SCLC and loss at 6p21.3 and 13q12.3 in NSCLC. In this study, we demonstrate that a) non-random allelic losses in lung cancer involve multiple regions; b) some losses are common to both NSCLC and SCLC subtypes, whereas others are subtype specific; c) there are genetic deletions at novel chromosomal regions; and d) several homozygous deletions have been noted. Our studies demonstrate the usefulness of continuous cell lines for detailed allelotyping, for comparing genetic abnormalities between SCLC and NSCLC, and for identifying homozygous deletions.

Abnormalities of fragile histidine triad genomic and complementary DNAs in cervical cancer: association with human papillomavirus type

BACKGROUND

Chromosome 3p14.2 contains FRA3B, the most active chromosome breakage site in the human genome. The fragile histidine triad (FHIT) gene, a putative tumor suppressor gene, overlaps FRA3B. Human papillomavirus (HPV), a known cofactor in cervical carcinogenesis, can integrate into FRA3B. We examined abnormalities in FHIT and its RNA transcripts in cervical cancer cell lines and tumors. We also investigated the relationship between loss of heterozygosity (LOH) in FHIT/FRA3B and the presence of oncogenic HPV types.

METHODS

Eleven cell lines, 40 tumors (20 fresh and 20 archival), and 10 normal cervical epithelia were examined. Two intragenic polymorphic markers (D3S1300 and D3S4103) and the polymerase chain reaction (PCR) were used to examine FHIT LOH. Reverse transcription-PCR (RT-PCR) analysis and single-strand conformation polymorphism analysis of RT-PCR products were used to characterize FHIT transcripts. Oncogenic HPV types were identified by PCR, using general and type-specific primers.

RESULTS

All normal epithelia, 19 of 20 fresh tumors and nine of 11 cell lines expressed wild-type and, occasionally, exon 8-deleted FHIT transcripts. Additional aberrant FHIT transcripts were seen in nine of 20 fresh tumors and in seven of 11 cell lines. DNA sequencing of the aberrant transcripts revealed a variety of insertions and deletions but no point mutations. Three cell lines also had homozygous FHIT deletions. Oncogenic HPV types (i.e., 16, 18, 31, and 33) were detected in 18 of 20 archival tumors, and, in these tumors, LOH within FHIT was identified in nine of 16 informative cases. HPV 16 was found to be associated with LOH in the FHIT/FRA3B region (P = .041).

CONCLUSION

FHIT/FRA3B is frequently altered in cervical cancer, demonstrating LOH, occasional homozygous deletions, and frequent aberrant transcripts not found in normal epithelia. However, the presence of wild-type transcripts and the lack of protein-altering point mutations raise questions about FHIT's function as a classic tumor suppressor gene in cervical tissue.

Association of chromosome 11 locus D11S12 with histology, stage, and metastases in lung cancer

We have reported frequent allele loss for the marker D11S12 on chromosome band 11p15.5 in human lung cancer. The smallest common region of allele loss has been refined to approximately 500 kb and is confined between D11S1758 and D11S860. Here, we investigated the association of D11S12 allele loss with epidemiologic, pathologic, and clinical parameters. Analysis of allele loss was performed by Southern blotting on a cohort of 156 patients with lung cancer, and data were interpreted with the use of a phosphorimager. Results were statistically compared with retrospectively collected variables. D11S12 allele loss was found in 88% of small cell carcinomas, 57% of squamous cell carcinomas, and 40% of adenocarcinomas. Allele loss was associated with tumor stage (p = 0.04) and was more frequent in tumors that had already metastasized. These results suggest that a gene in the D11S12 region may be responsible for the metastatic potential of lung cancer. The functional status of this gene may thus be of future value in guiding clinicians on decisions regarding adjuvant and neoadjuvant therapies for patients with lung cancer.

Analysis of the FHIT gene and FRA3B region in sporadic breast cancer, preneoplastic lesions, and familial breast cancer probands

The FHIT gene, which spans the FRA3B fragile site at chromosome 3p14.2, is a candidate tumor suppressor gene in breast and other cancers. We investigated FHIT and FRA3B for loss of heterozygosity (LOH); homozygous deletions; abnormal transcripts; and acquired/germ-line point mutations in breast cancer cell lines (n = 32), breast epithelial and stromal cell cultures (n = 18), microdissected invasive (n = 16) and ductal in situ carcinomas (n = 6), and their accompanying normal and abnormal epithelial foci (n = 14). LOH at 3p14.2, especially at FHIT intragenic marker D3S1300, was found in 6 of 16 microdissected invasive tumors and 3 of 6 ductal in situ carcinomas. In accompanying preneoplastic foci, LOH occurred in two of eight intraductal hyperplasias but not in histologically normal ductal epithelium (n = 6). Three of 32 (9%) breast cancer cell lines demonstrated homozygous deletions of FHIT exon 4 (two cases) and exon 5 (one case), which correlated with exon 4-deleted transcripts and loss of the cDNA transcript containing the coding exons 5-9, respectively. Normal mammary cultures and 31 of 32 tumor cell lines (97%) expressed wild-type coding transcripts as well as a minor exon 8-deleted message. Single-strand conformation polymorphism analysis of the coding exons in the 32 tumor and 18 normal breast cell lines and their sequencing revealed four silent polymorphisms and a germ-line histidine triad point mutation (651 G-->T) in a tumor arising in a 70-year-old woman. This mutation was also present in one of her two thus far unaffected daughters. Analysis of additional DNAs from 280 probands of high-risk breast cancer families for other FHIT exon 8 mutations detected an intronic point mutation 13 bases upstream of exon 8. Thus, we have demonstrated relatively early abnormalities of the FHIT/FRA3B region in breast cancer and discovered two rare FHIT germ-line mutations. The expression of a transcript containing the coding exons in nearly all cell lines, including those with germ-line mutations, suggests the possibility that another gene in the FRA3B region may be involved in the pathogenesis of breast cancer.

Precise localization of the FHIT gene to the common fragile site at 3p14.2 (FRA3B) and characterization of homozygous deletions within FRA3B that affect FHIT transcription in tumor cell lines

Chromosomal or allelic losses at 3p14 are common in a variety of human tumors, including those of the lung, breast, kidney, and head and neck. This suggests the existence of a tumor suppressor gene in this band. A promising candidate is the recently cloned FHIT gene, which spans the common fragile site, FRA3B, at 3p14.2. We previously identified a region of fragility at 3p14.2 (FRA3B) of > 85 kb by cloning DNA flanking pSV2neo integrations and constructed a partial genomic contig of the region. Using probes from the contig, we tested for deletions within this region in DNA from 105 human tumor cell lines, predominantly derived from lung cancers. We identified one gastric and four lung cancer cell lines with homozygous interstitial deletions involving the FRA3B region. The deletion in one lung cancer cell line lies entirely within our contig and is < 65 kb. We have identified, cloned, and sequenced this breakpoint junction. We have also shown that our probes lie within intron S of the FHIT gene and, furthermore, that exon 5 is located approximately 1 kb from one of our probes and, thus, lies within the region of fragility. Two lines with entirely intronic deletions yield FHIT transcripts of normal size. In one of these, this was the sole transcript identified. In the other line, an FHIT transcript completely normal in sequence was accompanied by two larger abnormal transcripts. These results leave open the possibility that some homozygous deletions within the FHIT gene are without phenotypic effect and result from genetic instability of this region. However, taken together, our results provide evidence that breakage and rearrangement within the FRA3B fragile site sequences result in alterations of FHIT and are likely to be involved in carcinogenesis.

FHIT and FRA3B 3p14.2 allele loss are common in lung cancer and preneoplastic bronchial lesions and are associated with cancer-related FHIT cDNA splicing aberrations

We evaluated primary lung cancers, tumor cell lines, and preneoplastic bronchial lesions for molecular genetic abnormalities in the candidate tumor suppressor gene FHIT, which spans the FRA3B fragile site at 3p14.2. 3p14.2 allele loss was very frequent in 32 lung cancer cell lines [100% of small cell lung cancer and 88% of non-small cell lung cancer (NSCLC)] and 108 primary NSCLC cancers (45%), with numerous breakpoints indicating involvement of several distinct regions in the FRA3B site. 3p14 allele loss was least frequent in the adenocarcinoma subtype and occurred at the relatively late carcinoma in situ stage of preneoplastic bronchial lesions found in NSCLC patients. Homozygous deletions within the FHIT/FRA3B region were found in 6 of 135 (4.4%) thoracic cancer cell lines. Northern blot showed low or absent FHIT expression in most thoracic cancer cell lines tested, whereas reverse transcription-PCR showed that 59-62% exhibited aberrant FHIT transcripts but nearly always (93-100%) also expressing the wild-type transcripts. Aberrant transcripts included precise deletions of FHIT exons, insertion of non-FHIT sequences between exons and insertions replacing exons. Complete open reading frame single-strand conformational polymorphism analysis of 102 lung cancer cDNAs revealed only one nonsplicing mutation. Normal cells including bronchial epithelium, lung, and trachea expressed wild-type FHIT transcript and a variant transcript deleted for exon 8 but not the other aberrant transcripts, arguing against exon 8-deleted FHIT transcripts being tumor specific. Our findings support the conclusion that FHIT/FRA3B abnormalities are associated with lung cancer pathogenesis but that FHIT abnormalities differ from the types of mutations and lack of wild-type transcript found in classic tumor suppressor genes, and functional studies are needed to define the role of FHIT in thoracic tumorigenesis.

Smoking, gender, and survival association with allele loss for the LOH11B lung cancer region on chromosome 11

We have reported frequent allele loss for the marker HRAS on chromosome 11p in human lung cancer and defined the smallest common region of deletion (designated LOH11B) to approximately 500 kb. Here, we investigated the association of allele loss for LOH11B with epidemiological, pathological, and clinical parameters. Analysis of allele loss was performed using Southern blotting on a cohort of 200 patients with lung cancer, and data were interpreted with the use of a phosphorimager. Results were statistically compared with retrospectively collected variables. LOH11B allele loss was significantly associated with cigarette consumption (P = 0.009), gender (P = 0.02), and survival (P = 0.04). None of the nonsmokers had allele loss as compared with 28% of the patients with low and 43% with high cigarette consumption. Allele loss was more frequent in men (43%) than in women (11%). The median survival of patients without allele loss was 42 months compared with 25 months for patients with allele loss. These results suggest that the LOH11B region contains a gene responsible for a more malignant phenotype independent of the metastatic potential of lung cancer. They also suggest that alterations in this gene are associated with cigarette consumption and are more frequent in men than in women.

Identification of three distinct tumor suppressor loci on the short arm of chromosome 9 in small cell lung cancer

Deletion at 9p21 is frequent in many tumor types. A candidate tumor suppressor gene, p16INK4a, was mapped to this region and is frequently inactivated by several different mechanisms in many tumor types, including non-small cell lung cancer, but not in small cell lung cancer (SCLC). p16 functions as a cyclin/CDK inhibitor to prevent phosphorylation of pRB. It has been demonstrated that most SCLCs have lost pRB but retained p16, and the inactivation of pRB excludes the inactivation of p16 and vice versa. To determine the potential existence of other tumor suppressor genes on the short arm of chromosome 9 in SCLC, we tested 46 primary SCLCs by microsatellite analysis. We found that more than 89% of the tumors exhibited loss of heterozygosity (LOH) at 9p with three distinct minimal deleted areas. Among those areas, LOH at 9p21 was most frequent (86%), with a peak at a marker 150 kb telomeric to p16INK4a. LOH was also observed in more than 50% of the tumors at two other regions, 9p22 and 9p13. Our data strongly suggest the presence of at least three novel tumor suppressor loci on 9p in SCLC, and further investigations to clone candidate tumor suppressor genes are warranted.

MYCL genotypes and loss of heterozygosity in non-small-cell lung cancer

Some studies have suggested that the S allele of the MYCL oncogene, which results from an intragenic EcoRI restriction fragment length polymorphism (RFLP), may be associated with cancer susceptibility. In addition, this allele has also been linked to metastases and adverse survival in certain cancers, although studies of lung cancer patients from different populations have yielded controversial results. We studied 108 cases of surgical resected non-small-cell lung cancer (NSCLC) and found no evidence that MYCL genotypes were associated with tumour progression or a worse prognosis. However, the presence of loss of heterozygosity (LOH) at this chromosome 1p32 locus correlated significantly with regional lymph node involvement, as well as advanced TNM stage. These data indicate the existence of a chromosome 1p candidate tumour-suppressor gene(s), possibly in linkage disequilibrium with the EcoRI RFLP in specific populations, which appears to play a role in determining tumour progression in NSCLC. Refined mapping of the critical region of loss should help attempts to identify and clone the candidate gene.