Lung cancers detected by screening with spiral computed tomography have a malignant phenotype when analyzed by cDNA microarray

Towards novel anti-cancer strategies based on cystatin function

Cystatins have recently emerged as important players in a multitude of physiological and patho-physiological settings that range from cell survival and proliferation, to differentiation, cell signaling and immunomodulation. This group of cysteine protease inhibitors forms a large super-family of proteins composed of one, two, three, and, in some species, more than three cystatin domains. Over the last 20 years or so, members of the cystatin super-family have been primarily explored with respect to their capacity to inhibit intracellular cysteine proteases. Yet, this classical mode of action does not fully explain their remarkably diverse biological functions. Due to the space limitations, the author will discuss here the most recent findings that suggest that some of the single-domain, cytoplasmic and cell-secreted cystatins may play important roles in the promotion or suppression of tumor growth, invasion and metastasis. Based on the present understanding of cystatin function, novel avenues for anti-cancer strategies are proposed.

Molecular Profiling of Computed Tomography Screen-Detected Lung Nodules Shows Multiple Malignant Features

RATIONALE AND PURPOSE

Low-dose spiral computerized axial tomography (spiral CT) is effective for the detection of small early lung cancers. Although published data seem promising, there has been a significant degree of discussion concerning the potential of overdiagnosis in the context of spiral CT-based screening. The objective of the current study was to analyze the phenotypic and genetic alterations in the small pulmonary malignancies resected after detection in the University of Navarra/International Early Lung Cancer Action Project spiral CT screening trial and to determine whether their malignant molecular features are similar to those of resected lung tumors diagnosed conventionally.

EXPERIMENTAL DESIGN

We analyzed 17 biomarkers of lung epithelial malignancy in a series of 11 tumors resected at our institution during the last 4 years (1,004 high-risk individuals screened), using immunohistochemistry and fluorescence in situ hybridization (FISH). A parallel series of 11 gender-, stage-, and histology-matched lung cancers diagnosed by other means except screening was used as control.

RESULTS

The molecular alterations and the frequency of phenotypic or genetic aberrations were very similar when screen-detected and nonscreen-detected lung cancers were compared. Furthermore, most of the alterations found in the screen-detected cancers from this study were concordant with what has been described previously for stage I-II lung cancer.

CONCLUSIONS

Small early-stage lung cancers resected after detection in a spiral CT-based screening trial reveal malignant molecular features similar to those found in conventionally diagnosed lung cancers, suggesting that the screen-detected cancers are not overdiagnosed.

Analysis of gene and protein expression in healthy and carious tooth pulp with cDNA microarray and two-dimensional gel electrophoresis

Complementary DNA (cDNA) microarray and two-dimensional (2-D) gel electrophoresis, combined with mass spectrometry, enable simultaneous analysis of expression patterns of thousands of genes, but their use in pulp biology has been limited. Here we compared gene and protein expression of pulp tissues from sound and carious human teeth using cDNA microarray and 2-D gel electrophoresis to evaluate their usefulness in pulp biology research and to identify the genes with changes in carious teeth. The cDNA microarray revealed several differentially expressed genes and genes with a high expression in both tissues. These genes have various functions, e.g. effects on vascular and nerve structures, inflammation, and cell differentiation. Variability between cDNA hybridizations indicates that the overall gene expression pattern may vary significantly between individual teeth. The 2-D gel electrophoresis revealed no change between healthy and diseased tissue. The identification of 96 proteins in the pulp tissue revealed none of the gene products with corresponding high/different mRNA expression in cDNA microarray. Interestingly, we detected also a hypothetical protein (putative nucleoside diphosphate kinase), and present therefore the first evidence for the existence of this protein. Even though the methods reveal potentially important gene expression, they may currently have only limited value in in vivo pulp biology research.

Emerging role of KLF4 in human gastrointestinal cancer

Recent analyses revealed that Krüppel-like factors (KLFs) play important roles in both normal development and carcinogenesis. Of the 16 known KLFs, KLF4 has been shown to be involved in the regulation of proliferation, differentiation and tumorigenesis of gastrointestinal tract epithelium. Clinical, experimental and mechanistic findings indicate that KLF4 is a bona fide tumor suppressor for both gastric and colorectal cancers. In this review, we summarize how this growing area of research has formed and the challenging new frontiers for better understanding of the oncogenic potential of the KLFs.

Methylation profile in tumor and sputum samples of lung cancer patients detected by spiral computed tomography: A nested case-control study

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 RARbeta2, p16(INK4A) and RASSF1A genes was evaluated by methylation-specific PCR in tumor samples of 29 CT-detected 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 RARbeta2, 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 RARbeta2 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 RARbeta2 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 RARbeta2, 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.

New Developments in Lung Cancer Screening

Lung cancer is the most lethal cancer in our society. Late diagnosis of this disease is a major problem and so recent favorable reports with spiral computed tomography screening of high-risk populations have rekindled interest in improving early lung cancer detections. The process of lung cancer screening is a complicated process that involves many component activities. Interest to date has heavily focused on the initial case identification, but more recent reports have suggested that the issues with case work-up and surgical management also bear closer consideration. Given the dynamic nature of spiral computed tomography scan development and the remarkable improvements in imaging resolution over the last decade, there is an urgent need for research to establish optimal clinical management of early lung cancer detected in a screening setting.