This study shows that higher levels of free circulating DNA can be detected in patients with lung cancer compared with disease-free heavy smokers by a PCR assay, and suggests a new, noninvasive approach for early detection of lung cancer. Levels of plasma DNA could also identify higher-risk individuals for lung cancer screening and chemoprevention trials.

Purpose: Spiral computed tomography (CT) can detect lung cancer at an early stage, but the malignant potential is unknown. The question is, as follows: do these small lesions have the same lethal potential as do symptomatic tumors?Experimental Design: We used a cDNA microarray platform and compared the gene expression profile of spiral CT-detected lung carcinomas with a matched case-control population of patients presenting with symptomatic lung cancer.Results: CT-detected and symptomatic tumors have shown a comparable gene expression profile. Correspondence analysis has demonstrated that nine genes were differentially expressed, although with a high variability across the samples that prevented distinguishing the two groups of tumors. Analysis of these nine genes has suggested that early-detected tumors have higher levels of retinoic acid production and higher expression levels of caveolin 2, matrix Gla, and cystatin A, which are already known to be lost during tumor progression.Conclusions: All of the tumors observed are histologically malignant according to the WHO Classification. Early lung cancers that are detected by screening have a gene expression pattern similar to, but not identical to, that of symptomatic lung carcinomas.

We evaluated the aberrant promoter methylation profile of a panel of 3 genes in DNA from tumor and sputum samples, in view of a complementary approach to spiral computed tomography (CT) for early diagnosis of lung cancer. The aberrant promoter methylation of RARb2, p16 INK4A and RASSF1A genes was evaluated by methylation-specific PCR in tumor samples of 29 CTdetected lung cancer patients, of which 18 had tumor-sputum pairs available for the analysis, and in the sputum samples from 112 cancer-free heavy smokers enrolled in a spiral CT trial. In tumor samples from 29 spiral CT-detected patients, promoter hypermethylation was identified in 19/29 (65.5%) cases for RARb2, 12/29 (41.4%) for p16 INK4A and 15/29 (51.7%) for RASSF1A. Twenty-three of twenty-nine (79.3%) samples of the tumors exhibited methylation in at least 1 gene. In the sputum samples of 18 patients, methylation was detected in 8/18 (44.4%) for RARb2 and 1/18 (5%) for both RASSF1A and p16 INK4A . At least 1 gene was methylated in 9/18 (50%) sputum samples. Promoter hypermethylation in sputum from 112 cancer-free smokers was observed in 58/112 (51.7%) for RARb2 and 20/112 (17.8%) for p16, whereas methylation of the RASSF1A gene was found in only 1/112 (0.9%) sputum sample. Our study indicates that a high frequency of hypermethylation for RARb2, p16 INK4A and RASSF1A promoters is present in spiral CT-detected tumors, whereas promoter hypermethylation of this panel of genes in uninduced sputum has a limited diagnostic value in early lung cancer detection. ' 2005 Wiley-Liss, Inc.Key words: lung cancer; methylation; sputum; spiral CT Lung cancer is the leading cause of cancer deaths in the world. Although surgical resection still represents the best curative approach for this neoplasm, its efficacy strictly depends on the stage of disease presentation. Earlier diagnosis of patients with lung cancer is expected to increase the number of potentially resectable tumors. 1 Several large prospective randomized trials have demonstrated that conventional sputum cytology and chest radiography are not effective in detecting early lung cancer and reducing lung cancer mortality. 2 In this respect, over the last decade, spiral computed tomography (CT) has been tested as a powerful and fast imaging technique to detect tumors of less than 1 cm in diameter, with a proportion of detection of Stage I tumors greater than 80%, opening new possibilities for the early detection of lung cancer. 3,4 However, because of the complex algorithm of high-resolution CT employed in order to achieve the maximal performance of this approach 3 and to achieve the background noise created by the high detection rate of noncalcified nodules, 5 questions have been raised about the challenge of differential diagnosis, efficacy and costs of spiral CT screening. 6 In 2000, a prospective trial of early lung cancer detection was launched in Milan, using repeated yearly low-dose spiral CT, selective use of positron emission tomography and analysis of molecular markers in a large cohort of 1,035 high-...

It was previously reported that 8701-BC breast cancer cells express the gene for parathyroid hormone-related peptide (PTHrP) and its cognate receptor (PTHrP-R), and release immunoreactive PTHrP in the extracellular medium; it was also found that PTHrP, in turn, exerts a role on the proliferative and invasive behavior in vitro of the same cell line. On the other hand, evidence has been produced that adhesion of 8701-BC cells onto different collagen substrates influences in various ways a number of phenotypic expressions, such as cell growth, motility, invasion of reconstituted basement membrane and production of lytic enzymes of the extracellular matrix (ECM). In light of these previous data, we have examined whether substrates of either reconstituted basement membrane or representative collagen components of the breast tumor stroma (type I, V and OF/LB) might (i) regulate the PTHrP promoter usage and mRNA splicing patterns, (ii) modulate quantitatively the extracellular release of immunoreactive PTHrP (iPTHrP), and (iii) affect the expression of PTHrP-R. The results obtained give evidence that (i) 8701-BC cells are able to utilize different start sites and mRNA splicing patterns for PTHrP transcription; (ii)`structural' components of the stroma, such as collagens, are by themselves capable of controlling both the expression pattern of the PTHrP gene and the extent of extracellular release of iPTHrP, and (iii) PTHrP-R expression can be up-or downregulated in response to the ECM substrate present. These data demonstrate that PTHrP and PTHrP-R expression by 8701-BC neoplastic cells can be modulated by ECM molecules, indirectly supporting the active participation of stromal collagen composition in the regulation of PTHrP-controlled circuits which may play a role in carcinogenesis.z 1999 Federation of European Biochemical Societies.

Our results indicate that telomerase is repressed in most lung carcinoids and that hTERT transcription and alternative splicing play a role in such a negative regulation. Moreover, the absence of any telomerase maintenance mechanism may contribute to the favorable prognosis of this malignancy.