(1/530) Alterations of Rb pathway (Rb-p16INK4-cyclin D1) in preinvasive bronchial lesions.
Lung cancer results from a stepwise accumulation of genetic and molecular abnormalities with unknown temporal relationships to precursor bronchial lesions. In a search for biomarkers of malignant progression, we analyzed the expression of the tumor suppressor gene Rb and of the proteins regulating its phosphorylation and function in G1 arrest, p16INK4A and cyclin D1, in preinvasive bronchial lesions accompanying cancer in 75 patients, in comparison with similar lesions in 22 patients with no cancer history. Rb was constantly expressed in preinvasive lesions, including carcinoma in situ (CIS). In contrast, p16 expression was lost in moderate dysplasia (12%) and in CIS (30%) in patients with lung cancer. p16 loss occurred exclusively in patients who displayed loss of p16 expression in their related invasive carcinoma. Loss of p16 expression was not seen in nine patients with dysplasia but no cancer progression. Cyclin D1 overexpression was seen in hyperplasia and metaplasia (6%), mild dysplasia (17%), moderate dysplasia (46%), and CIS (38%) in patients with cancer but was lost in 5% of the patients during the process of invasion; it was also observed in patients with no cancer progression (14%). Our results indicate that Rb protein function can be invalidated before invasion through alteration of the Rb phosphorylation pathway, by p16 inhibition, and/or by cyclin D1 overexpression and suggest a role for p16 and cyclin D1 deregulation in progression of preinvasive bronchial lesions to invasive carcinoma. (+info)
(2/530) Differential responses of normal, premalignant, and malignant human bronchial epithelial cells to receptor-selective retinoids.
Using an in vitro lung carcinogenesis model consisting of normal, premalignant, and malignant human bronchial epithelial (HBE) cells, we analyzed the growth inhibitory effects of 26 novel synthetic retinoic acid receptor (RAR)- and retinoid X receptor (RXR)-selective retinoids. RAR-selective retinoids such as CD271, CD437, CD2325, and SR11364 showed potent activity in inhibiting the growth of either normal or premalignant and malignant HBE cells (IC50s mostly <1 microM) and were much more potent than RXR-selective retinoids. Nonetheless, the combination of RAR- and RXR-selective retinoids exhibited additive effects in HBE cells. As the HBE cells became progressively more malignant, they exhibited decreased or lost sensitivity to many retinoids. The activity of the RAR-selective retinoids, with the exception of the most potent retinoid, CD437, could be suppressed by an RAR panantagonist. These results suggest that: (a) RAR/RXR heterodimers play an important role in mediating the growth inhibitory effects of most retinoids in HBE cells; (b) CD437 may act through an RAR-independent pathway; (c) some of the RAR-selective retinoids may have the potential to be used in the clinic as chemopreventive and chemotherapeutic agents for lung cancer; and (d) early stages of lung carcinogenesis may be responsive targets for chemoprevention by retinoids, as opposed to later stages. (+info)
(3/530) Cyclin D1 proteolysis: a retinoid chemoprevention signal in normal, immortalized, and transformed human bronchial epithelial cells.
BACKGROUND: Retinoids (derivatives of vitamin A) are reported to reduce the occurrence of some second primary cancers, including aerodigestive tract tumors. In contrast, beta-carotene does not reduce the occurrence of primary aerodigestive tract cancers. Mechanisms explaining these effective retinoid and ineffective carotenoid chemoprevention results are poorly defined. Recently, the all-trans-retinoic acid (RA)-induced proteolysis of cyclin D1 that leads to the arrest of cells in G1 phase of the cell cycle was described in human bronchial epithelial cells and is a promising candidate for such a mechanism. In this study, we have investigated this proteolysis as a common signal used by carotenoids or receptor-selective and receptor-nonselective retinoids. METHODS: We treated cultured normal human bronchial epithelial cells, immortalized human bronchial epithelial cells (BEAS-2B), and transformed human bronchial epithelial cells (BEAS-2BNNK) with receptor-selective or receptor-nonselective retinoids or with carotenoids and studied the effects on cell proliferation by means of tritiated thymidine incorporation and on cyclin D1 expression by means of immunoblot analysis. We also examined whether calpain inhibitor I, an inhibitor of the 26S proteasome degradation pathway, affected the decline (i.e., proteolysis) of cyclin D1. RESULTS: Receptor-nonselective retinoids were superior to the carotenoids studied in mediating the decline in cyclin D1 expression and in suppressing the growth of bronchial epithelial cells. Retinoids that activated retinoic acid receptor beta or retinoid X receptor pathways preferentially led to a decrease in the amount of cyclin D1 protein and a corresponding decline in growth. The retinoid-mediated degradation of cyclin D1 was blocked by cotreatment with calpain inhibitor I. CONCLUSIONS: Retinoid-dependent cyclin D1 proteolysis is a common chemoprevention signal in normal and neoplastic human bronchial epithelial cells. In contrast, carotenoids did not affect cyclin D1 expression. Thus, the degradation of cyclin D1 is a candidate intermediate marker for effective retinoid-mediated cancer chemoprevention in the aerodigestive tract. (+info)
(4/530) Survey of outpatient sputum cytology: influence of written instructions on sample quality and who benefits from investigation.
OBJECTIVES: To evaluated quality of outpatient sputum cytology and whether written instructions to patients improve sample quality and to identify variables that predict satisfactory samples. DESIGN: Prospective randomised study. SETTING: Outpatient department of a district general hospital. PATIENTS: 224 patients recruited over 18 months whenever their clinicians requested sputum cytology, randomized to receive oral or oral and written advice. INTERVENTIONS: Oral advice from nurse on producing a sputum sample (114 patients); oral advice plus written instructions (110). MAIN MEASURES: Percentages of satisfactory sputum samples and of patients who produced more than one satisfactory sample; clinical or radiological features identified from subsequent review of patients' notes and radiographs associated with satisfactory samples; final diagnosis of bronchial cancer. RESULTS: 588 sputum samples were requested and 477 received. Patients in the group receiving additional written instructions produced 75(34%) satisfactory samples and 43(39%) of them one or more sets of satisfactory samples. Corresponding figures for the group receiving only oral advice (80(31%) and 46(40%) respectively)were not significantly different. Logistic regression showed that radiological evidence of collapse or consolidation (p<0.01) and hilar mass (p<0.05) were significant predictors of the production of satisfactory samples. Sputum cytology confirmed the diagnosis in only 9(17%) patients with bronchial carcinoma. CONCLUSIONS: The quality of outpatients' sputum samples was poor and was not improved by written instructions. Sputum cytology should be limited to patients with probable bronchial cancer unsuitable for surgery. IMPLICATIONS: Collection of samples and requests for sputum cytology should be reviewed in other hospitals. (+info)
(5/530) Sex-related differences in bronchial epithelial changes associated with tobacco smoking.
BACKGROUND: Lung cancer is the most common cause of cancer death in North American women. Because smoking-related changes in the bronchial epithelium and in lung function have not been studied in detail in women, we used fluorescence bronchoscopy-directed biopsy to determine the prevalence of high-grade preinvasive lesions in former and current smokers of both sexes. METHODS: Spirometry, white-light bronchoscopy, and fluorescence bronchoscopy were performed in 189 women and 212 men older than 40 years of age who had smoked 20 pack-years or more (pack-years = number of packs of cigarettes smoked per day x number of years of smoking). RESULTS: Carcinoma in situ was found in 1.8% of the subjects, severe dysplasia was found in 6.5%, and moderate dysplasia was found in 14% (all preinvasive lesions). Compared with men, women had a lower prevalence of high-grade preinvasive lesions in the observed airways (14% versus 31%; odds ratio = 0.18; 95% confidence interval = 0.04-0.88), and women with preinvasive lesions had fewer such lesions (two-sided P = .048). The prevalence of preinvasive lesions did not change substantially for more than 10 years after cessation of smoking. Lung function was associated with the prevalence of preinvasive lesions, but the association was weaker in women than in men. If the presence of airflow obstruction was defined by an FEV1/FVC (forced expiratory volume in 1 second/forced vital capacity) value of 70% or less, only 56% of the men and 44% of the women with preinvasive lesions had abnormal lung function. CONCLUSION: In developing strategies for chemoprevention or early detection of lung cancer in high-risk populations, it is important to consider the effect of sex and arbitrarily chosen lung function values on the prevalence of preinvasive airway lesions. (+info)
(6/530) Malignant tumors of the liver and lungs in an area with a PVC industry.
The incidence of malignant tumors of the lung and bronchus and of cytologically confirmed primary malignant tumor of the liver was analyzed for a 4-yr period in a city with several factories, including a PVC industry. Prior to the study two cases of angio-sarcoma of the liver were diagnosed in workers employed in PVC production. The total incidence of analyzed tumors was only slightly higher than predicted. The tumors of the liver recorded did not show any dependence on place of work or residence. During the period of observation, malignant tumors of the bronchus (lung) were not recorded in the PVC industry. Their rate in the area in which the PVC industry is situated was approximately the same as that for the entire city area. The study does not indicate that the occurrence of malignant tumors other than angiosarcoma is associated with exposure to vinyl chloride. (+info)
(7/530) Overexpression of cyclins D1 and E is frequent in bronchial preneoplasia and precedes squamous cell carcinoma development.
Increased protein expression of the G1 cyclins D1 and E is reported in invasive non-small cell lung carcinoma. However, during transformation of the bronchial epithelium, overexpression of these species occurs, and their relationship to aberrant expression of p53 and retinoblastoma (Rb) has not been described previously. To determine the expression of these cell cycle regulators during the development of invasive squamous cell carcinoma (SCC) of the lung, the immunohistochemical expression patterns in normal bronchial epithelium (n = 36), squamous metaplasia (SM; n = 28), and epithelial atypia (n = 34) were compared with that in low-grade dysplasia (LGD; n = 17), high-grade bronchial dysplasia (HGD; n = 30), and SCC (n = 36). Monoclonal anti-p53 Pab1801, polyclonal anti-cyclin D1 DCS6, monoclonal anti-cyclin E HE12, and monoclonal anti-Rb OP-66 antibodies were used. Cyclin D1 was not expressed in normal bronchial epithelium but was detected in 7% of SMs, 15% of atypias; 18% of LGDs, 47% of HGDs, and 42% of SCCs. Cyclin E was not detected in normal epithelium (n = 24), SM (n = 16), or LGD (n = 12), but it was found in 9% of atypias (2 of 22), 33% of HGDs (7 of 21), and 54% of SCCs (13 of 24). p53 was not expressed in normal epithelium, SM, and LGD, but it was overexpressed in 6% of atypias, 53% of HGDs, and 61% of SCCs. Abnormal Rb expression was found only in 2 of 36 cases of SCC. A total of 91% of HGDs and 92% of SCCs exhibited overexpression of at least one of the p53, cyclin D1, or cyclin E species. However, no link was observed between overexpression of p53 and the overexpressed G1 cyclins in preneoplastic lesions. Overexpression of cyclin D1, cyclin E, and p53 occurs frequently and independently in pulmonary SCC and is detected in lesions before the development of invasive carcinoma. In contrast, altered Rb expression is a late and infrequent event in squamous cell carcinogenesis. (+info)
(8/530) Bronchial capillary hemangioma in adults.
Two cases with capillary hemangioma of the trachea and the left upper lobe bronchus are presented. The adult patients were referred to the hospital because of hemoptysis and cough. The chest radiographs were normal in both cases. The bronchoscopic examination revealed circumscribed lesions with a capillarized surface protruding into the lumen of the trachea and the left upper lobe bronchus, respectively. The lesions were excised in toto with flexible bronchoscopic forceps. The specimens contained typical capillary hemangiomas without any signs of malignancy. Capillary hemangioma in the bronchial tree is an extremely rare benign lesion in adults. Nevertheless, it should be considered as a possible cause of hemoptysis and cough. (+info)