Distinctive gene expression of human lung adenocarcinomas carrying LKB1 mutations.

LKB1, a tumor-suppressor gene that codifies for a serine/threonine kinase, is mutated in the germ-line of patients affected with the Peutz-Jeghers syndrome (PJS), which have an increased incidence of several cancers including gastrointestinal, pancreatic and lung carcinomas. Regarding tumors arising in non-PJS patients, we recently observed that at least one-third of lung adenocarcinomas (LADs) harbor somatic LKB1 gene mutations, supporting a role for LKB1 in the origin of some sporadic tumors. To characterize the pattern of LKB1 mutations in LADs further, we first screened for LKB1 gene alterations (gene mutations, promoter hypermethylation and homozygous deletions) in 19 LADs and, in agreement with our previous data, five of them (26%) were shown to harbor mutations, all of which gave rise to a truncated protein. Recent reports demonstrate that LKB1 is able to suppress cell growth, but little is known about the specific mechanism by which it functions. To further our understanding of LKB1 function, we analysed global expression in lung primary tumors using cDNA microarrays to identify LKB1-specific variations in gene expression. In all, 34 transcripts, 24 of which corresponded to known genes, differed significantly between tumors with and without LKB1 gene alterations. Among the most remarkable findings was deregulation of transcripts involved in signal transduction (e.g. FRAP1/mTOR, ARAF1 and ROCK2), cytoskeleton (e.g. MPP1), transcription factors (e.g. MEIS2, ATF5), metabolism of AMP (AMPD3 and APRT) and ubiquitinization (e.g. USP16 and UBE2L3). Real-time quantitative RT-PCR on 15 tumors confirmed the upregulation of the homeobox MEIS2 and of the AMP-metabolism AMPD3 transcripts in LKB1-mutant tumors. In addition, immunohistochemistry in 10 of the lung tumors showed the absence of phosphorylated FRAP1/mTOR protein in LKB1-mutant tumors, indicating that LKB1 mutations do not lead to FRAP1/mTOR protein kinase activation. In conclusion, our results reveal that several important factors contribute to LKB1-mediated carcinogenesis in LADs, confirming previous observations and identifying new putative pathways that should help to elucidate the biological role of LKB1.

Pulmonary vascular remodeling in pulmonary hypertension due to chronic heart failure.

UNLABELLED: Pulmonary hypertension (PHT) associated with chronic heart failure (CHF) is a risk factor of right ventricular failure after heart transplantation (HT). Our aim was to study pulmonary vascular changes in patients with CHF and to assess any correlation with haemodynamic data. METHODS: We studied 17 HT recipients with preoperative CHF who died shortly after HT. Preoperative haemodynamic information was obtained immediately before HT. Vascular lesions in muscular arteries were assessed by linear morphometry. Haemodynamic data were correlated with the morphologic changes. RESULTS: Mean transpulmonary gradient (TPG) was 8.9+/-4.5 mm Hg and pulmonary vascular resistance (PVR) was 2.25+/-1.34 Wu. According to the threshold for at-risk PHT (TPG>12 mm Hg or PVR>2.5 Wu), six patients had at-risk PHT. Medial thickness was 23.82+/-7.23% in patients with at-risk PHT and 17.16+/-3.24% in patients without at-risk PHT (p=0.018). CONCLUSIONS: Medial hypertrophy of muscular pulmonary arteries is more common and severe than expected in patients with CHF, even in patients without at-risk PHT. This structural change could explain why PHT, even in range of values not excluding HT, is a risk factor for right ventricular failure after HT and influences post-HT haemodynamic behaviour.

Assessment of cardiac viability by thallium 201 redistribution and dobutamine echocardiography.

OBJECTIVE: Dobutamine echocardiography and thalium 201 are useful in the assessment of myocardial viability, but both techniques frequently yield conflicting results. The objective of this study was to determine the minimum mass of viable myocardium that each test could detect and compare the agreement of dobutamine echocardiography and thallium 201 to detect viability. METHODS: Dobutamine echocardiography and thallium 201 were performed in 10 patients scheduled for cardiac transplantation. In each patient, 15 segments were studied. After transplantation these segments were analyzed by the pathologist measuring by a computer system the total area of each segment, the necrotic + fatty mass, and area (%) of viable myocytes per segment. The percentage of viable tissue was estimated ([Total mass - (Necrotic + Fatty tissue)]/Total mass x 100) on each segment, which was compared with the result (viable or not viable) obtained by echocardiography or thallium 201. RESULTS: Dobutamine echocardiography defined 90 segments (60%) as viable versus 117 (78%) in thallium (kappa 0.49, 95% CI 0.36-0.63). The minimum percent of viable tissue per segment defined as viable by thallium was 43% versus 49% by echocardiography. With use of thallium, the highest accuracy of the test to detect viability was when the percent of necrotic tissue of the segment analyzed was 40% (positive and negative likelihood ratio 2.2 and 3.6, respectively). By use of echocardiography, the highest accuracy of the test was observed when the percent of necrotic tissue of the segment analyzed was 31% (positive and negative likelihood ratio 5.5 and 7.7, respectively). CONCLUSION: The discrepant results of dobutamine echocardiography and thallium 201 are due to differences in the minimum mass of live myocytes required by each technique to detect viability.

Endobronchial hamartoma.

OBJECTIVES: To describe clinical, endoscopic, radiographic, and follow-up characteristics of a series of patients in whom endobronchial hamartoma (EH) had been diagnosed. METHODS: Retrospective study of all cases of hamartoma diagnosed by bronchial biopsy between 1974 and 1997 in a tertiary referral hospital in Madrid, Spain. RESULTS: EH was diagnosed 47 patients during the study period. Four patients were excluded from the study because no clinical history was available. We analyzed the cases of 43 patients (37 men and 6 women), with a mean (+/- SD) age of 62 +/- 12 years. Seven patients had a concurrent lung neoplasm, and the EH was an incidental endoscopic finding. Among the other 36 patients, 31 had a new onset of respiratory symptoms, most commonly, recurrent respiratory infections in 16 patients (44%) and hemoptysis in a further 12 patients (33.4%). Chest radiograph findings were abnormal in 38 of 43 patients. At bronchoscopy, the lesions were equally distributed throughout the right and left lungs with no clear lobar predilection. Endobronchial obstruction was evident in 26 patients (72.2%) without concurrent neoplasm, 17 of whom underwent resection with a rigid bronchoscope and laser, with total resolution in 13 patients. Partial resolution was achieved in four patients, two of whom needed a second endoscopic procedure. Five patients were treated with open lung surgery. Clinical and endoscopic follow-up was performed in 23 patients at 1 to 73 months (mean, 17 months), and recurrence was found in 4 patients. CONCLUSION: EH frequently produces respiratory complaints and radiographic abnormalities. Patients with endobronchial obstructions had satisfactory responses to endoscopic therapy.

Tumor cytosol carcinoembryonic antigen as prognostic parameter in non-small cell lung cancer.

AIMS AND BACKGROUND: Carcinoembryonic antigen (CEA) belongs to a family of cell surface glycoproteins. Its level in serum has a significant value for the follow-up and treatment of patients with malignancies. The aim of this study was to correlate the concentration of tumor cytosol CEA (cCEA) with tumor size, patient age and sex, clinical stage, lymph node metastases, and overall survival rate in primary non-small cell lung carcinoma (NSCLC). METHODS AND STUDY DESIGN: The cCEA levels were determined in 76 NSCLC patients by luminescence assay (LIA) and radioimmunoassay (RIA). RESULTS: A strong correlation between LIA and RIA assay results was found (r = 0.992). No correlation was observed between serum CEA and cCEA levels. Tumors smaller than 3 cm had significantly higher cCEA levels than larger tumors, but when a logistic modeling process was applied this difference was not significant (P = 0.038). Histologically well-differentiated tumors also showed a significantly higher expression of cCEA (P <0.05). In addition, patients without lymph node involvement had higher cCEA levels than patients with tumor-positive lymph nodes (P < 0.05). Univariate statistical analysis revealed that the risk of lymph node metastases was 1.8-fold higher in patients with low cCEA levels than in patients with higher levels, taking the median value as cutoff (P = 0.04, Kruskal-Wallis test). CONCLUSIONS: According to the results of our study, patients with overexpression of cCEA may have a better prognosis than those with low cCEA expression. cCEA might therefore be considered a good prognostic parameter as well as a prognostic factor independent of the traditional parameters for lymph node metastases.

Impact of diltiazem administration and cyclosporine levels on the incidence of acute rejection in heart transplant patients.

To identify the clinical factors associated with acute rejection (AR) in the first year after heart transplantation (HT), we analysed 112 patients. All patients received OKT3 and standard triple-drug therapy. We analysed the following variables to determine their relationship with AR: age and gender, panel-reactive antibodies, HLA-DR mismatch, use of Sandimmune vs Neoral, diltiazem administration, and cyclosporine levels in week 2 and months 1, 2, and 3 after HT. Fifty-two patients had no AR and 49 had at least one episode. The variables independently associated with absence of AR were diltiazem administration (odds ratio 0.306, confidence limit 0.102-0.921) and cyclosporine level in the first month after HT (odds ratio 0.996, confidence limit 0.992-0.999). Furthermore, a cyclosporine level greater than 362 ng/ml in the first month predicted the absence of AR. In conclusion, a cyclosporine level greater than 362 ng/ml and diltiazem administration in the first month after HT reduce AR during the first year. Both cyclosporine level and diltiazem show a large and independent protective effect.