Survival, classifications, and desmosomal plaque genes in non-small cell lung cancer.

Novel biomarkers are required to improve prognostic predictions obtained with lung cancer staging systems. This study of 62 surgically-treated Non-Small Cell Lung Cancer (NSCLC) patients had two objectives: i) to compare the predictive value of T-stage classifications between the 6(th) and 7(th) editions of the Tumor, Node, and Metastasis staging system (TNM); and ii) to examine the association of Pkp1 and/or Krt15 gene expression with survival and outcomes. Multivariate and Kaplan-Meier survival analyses were performed, examining the relationship of survival with T-stage, recurrence, and TNM-stage (by each TNM edition) and with the single/combined expression of Pkp1 and/or Krt15 genes. Five-year survival rates only significantly differed as a function of T-stage in patients without recurrence when estimated using the 6(th) edition of the TNM classification and only in patients in pathologic TNM-stage IA using the 7(th). Overall survival for patients with elevated expression of both genes was 13.5 months in those with adenocarcinoma and 34.6 months in those with squamous cell carcinoma. Overall survival was 30.4 months in patients with Pkp1 gene upregulation and 30.9 months in those with Krt15 gene upregulation. In conclusion, survival estimations as a function of T-staging differed between the 6(th) and 7(th) editions of TNM. Overall survival differed according to the expression of Pkp1 and/or Krt15 genes, although this relationship did not reach statistical significance.

Differential immunohistochemical localization of desmosomal plaque-related proteins in non-small-cell lung cancer.

AIMS: Immunohistochemistry is a highly valuable and widely used tool in the subtyping of lung carcinomas. The aim of this study was to identify markers for the differential diagnosis of non-small-cell carcinomas. METHODS AND RESULTS: We report on the immunohistochemical localization of plakophilin-1 (PKP1), keratin-15 (KRT15) and desmoglein-3 (DSG3) intercellular adhesion proteins in samples from 75 primary non-small-cell lung cancers in non-treated patients. The staining pattern of these proteins differed between squamous cell carcinomas and adenocarcinomas, with no membrane staining in the latter. Membrane staining for all three proteins was characteristic of squamous cell carcinomas. We observed a relationship between the presence/absence of these proteins in the membranes of squamous cell carcinomas and the differentiation grade, with more intense staining in better differentiated areas. CONCLUSIONS: Staining for these proteins marked intercellular junctions that are characteristic of stratified squamous epithelium and of neoplasias with this type of differentiation, and can be useful in the diagnosis of patients with squamous cell carcinoma of the lung. The high specificity of membrane staining for PKP1 and DSG3 and high sensitivity of cytoplasmic and membrane staining for KRT15 for the diagnosis of squamous cell carcinoma may be useful for the differential diagnosis of non-small-cell carcinomas.

Multiplex primer extension reaction and capillary electrophoresis to study the frequency of thrombophilia-related mutations in a spanish population.

BACKGROUND: Thrombophilia is defined as an inherited or acquired abnormality of hemostasis predisposing to thrombosis. While the most common thrombophilia has a genetic origin and is manifested by elevated circulating antiphospholipid antibodies, about 40% of cases presenting with thrombosis are acquired. Factor V Leiden G1691A, prothrombin G20210A, MTHFR C677T, and Factor XII C46T mutations are associated with the risk of developing thrombophilia. METHODS: In this study, a method using single base extension assay coupled with fluorescent detection and capillary electrophoresis was applied to simultaneously detect G1691A, G20210A, C677T and C46T mutations in 1499 patients from Spain with suspicion of thrombotic disease. RESULTS: Out of these individuals, 5.4% were heterozygous for G20210A mutation, 9.21% were heterozygous and 0.20% homozygous for G1691A mutation, 46.36% were heterozygous and 20.71% homozygous for MTHFR mutation, and 30.41% were heterozygous and 3.4% homozygous for C46T mutation. CONCLUSION: We applied an accurate, simple, semi-automatic, and cost-effective method to simultaneously detect the main thrombophilia-related mutations, allowing us to determine the frequency of these mutations in a Spanish population.

Gene expression profiling reveals novel biomarkers in nonsmall cell lung cancer.

The development of reliable gene expression profiling technology is having an increasing impact on our understanding of lung cancer biology. Our study aimed to determine any correlation between the phenotypic heterogeneity and genetic diversity of lung cancer. Microarray analysis was performed on a set of 46 tumor samples and 45 paired nontumor samples of nonsmall cell lung cancer (NSCLC) samples to establish gene signatures in primary adenocarcinomas and squamous-cell carcinomas, determine differentially expressed gene sequences at different stages of the disease and identify sequences with biological significance for tumor progression. After the microarray analysis, the expression level of 92 selected genes was validated by qPCR and the robust Bonferroni test in an independent set of 70 samples composed of 48 tumor samples and 22 nontumor samples. Gene sequences were differentially expressed as a function of tumor type, stage and differentiation grade. High upregulation was observed for KRT15 and PKP1, which may be good markers to distinguish squamous-cell carcinoma samples. High downregulation was observed for DSG3 in stage IA adenocarcinomas.

Multi-mutational analysis of fifteen common mutations of the glucose 6-phosphate dehydrogenase gene in the Mediterrranean population.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) is a cytosolic enzyme encoded by a housekeeping X-linked gene whose main function is to produce NADPH, a key electron donor in the defence against oxidizing agents and in reductive biosynthetic reactions. Many variants of G6PD have been described, mostly produced from missense mutations, with wide ranging levels of enzyme activity and associated clinical symptoms. METHOD: A single base extension assay is used, yielding a single base difference of the extended products. Primers are designed to amplify products of different sizes with distinct fluorescent dyes in order to accurately distinguish all possible combinations of genotypes (homozygous and heterozygous for each mutation) in a multiplex PCR analysis. RESULTS: We present the first application of a multiplex multicolour assay to detect 15 of the most frequent G6PD-related mutations in Spain, which are studied in three multiplex reactions. Capillary electrophoresis analysis of the amplified products enables easy, rapid, unambiguous and high-resolution discrimination between wild-type and mutant alleles, even though various mutations may be present in the multiplex analysis. CONCLUSION: The analytical method described herein offers greater diagnostic power in Spanish and Mediterranean populations and would facilitate automated genotyping in routine molecular diagnostics and large-scale genetic studies (e.g., newborn screening programs).

Use of capillary electrophoresis for accurate determination of CAG repeats causing Huntington disease. An oligonucleotide design avoiding shadow bands.

Huntington disease (HD) is a neurodegenerative disorder associated with the expansion of a polymorphic trinucleotide CAG repeat in the HD gene. We have developed an assay to accurately determine CAG repeats that combines a novel oligonucleotide design and the resolution of capillary electrophoresis. A mismatch in the second nucleotide from the 3' end enhanced specificity by avoiding mispriming and diminishing shadow bands and artifactual PCR products. The coupling of capillary electrophoresis analysis with the assay added the advantages of accuracy, high resolution, semi-automation, rapid analysis and low sample consumption. Analysis of 200 chromosomes in the Spanish population sample studied (control group) gave a peak frequency for 16 CAG repeats and of 7 triplets for CCG repeats. Diagnosis of HD was confirmed in 22 of 34 individuals with a range of CAG repeats from 39 to 52. Predictive testing was also carried out for 19 relatives of the HD families diagnosed at our laboratory. The method proposed in this article provides an accurate sizing of DNA repeats that can be applied to the analysis of DNA size-related disorders.

A family with atypical cystic fibrosis: brother and sister with heterozygosity for both G542X and R117H.

Clinical manifestations of cystic fibrosis (CF) are variable. Genetic and environmental factors that determine whether an individual will develop associated complications are still under investigation. The present study reports the genetic analysis of a family with different clinical forms of CF and addresses the difficulty of CF diagnosis in an individual with mutant alleles G542X and R117H because of the variable phenotype associated with R117H mutation. Both children in this family were heterozygous for G542X/R117H with the same thymine sequence (7T/9T) in intron 8 of CF transmembrane conductance regulator. The girl was diagnosed with CF, whereas the boy was diagnosed with azoospermia as the sole clinical manifestation. The possible implication of the hemochromatosis gene as a CF modifier locus was analyzed because the 2 children had the same genotype. No genetic differences were detected between brother and sister that explained the different clinical manifestations of CF.

Frequency and clinical expression of HFE gene mutations in a Spanish population of subjects with abnormal iron metabolism.

Three HFE gene mutations (HFE 845 G-->A, 187 C-->G and 193 A-->T) are the most common mutations related to hereditary haemochromatosis (HH). The genotype for these mutations was analysed in 359 Spanish individuals with altered iron metabolism and iron overload. Various biochemical parameters were measured in serum samples from 96 of these individuals, and the effect of the genotype on these parameters was studied. Allele frequencies were 12.95% for the HFE C282Y variant, 28.97% for the HFE H63D variant and 0.69% for the HFE S65C variant, calculated in a total of 718 chromosomes. Multiple comparisons analysis showed very significant differences (p=0.001) in transferrin saturation index (TSI) between the HFE C282Y variant homozygous and control (ten healthy volunteers) groups. Highly significant (p=0.0001) and significant (p=0.005) differences in serum ferritin values were found between the HFE C282Y variant homozygous and control groups and between compound (HFE C282Y/H63D variant) heterozygous and control groups, respectively. Very significant differences (p=0.001) in serum iron values were observed between the HFE C282Y variant homozygous and control groups. TSI and serum ferritin values detected most HFE C282Y variant homozygotes and are recommended to facilitate the clinical diagnosis of HH.

Multiplex analysis of the most common mutations related to hereditary haemochromatosis: two methods combining specific amplification with capillary electrophoresis.

We present the first application of a multiplex multicolour assay for the simultaneous detection of three of the most frequent mutations related to hereditary haemochromatosis (C282Y, H63D and S65C), using fluorescent detection and capillary electrophoresis. We describe two methods: the first is based on a single base extension assay, resulting in a single base difference of the extended products; and the second is a competitive allele-specific polymerase chain reaction (PCR), based on competition between allele-specific primers. Specificity of the latter primers is enhanced with a mismatch at the antepenultimate nucleotide. Primers are designed to amplify products of different sizes and with different fluorescent dyes in order to accurately distinguish all possible combinations of genotypes (homozygous and heterozygous for each mutation) in a multiplex PCR analysis. An advantage of the present approach is that capillary electrophoresis analysis of the amplified products enables easy, rapid, unambiguous and high resolution discrimination between wild-type and mutant alleles, although different mutations may be present in the multiplex analysis. This will facilitate automated genotyping for routine molecular diagnostics and large-scale genetic studies.

Dietary nucleotide supplementation reduces thioacetamide-induced liver fibrosis in rats.

Dietary nucleotides reportedly promote functionality and repair in fibrotic liver. Liver fibrosis is characterized by an excessive accumulation of extracellular matrix components, which lead to the impairment of the hepatic function. The aim of this work was to evaluate the influence of dietary nucleotides on liver fibrosis induced by thioacetamide and to elucidate the mechanism by which nucleotides exert their protective effects. Rats consumed ad libitum 300 mg/L thioacetamide in drinking water and were pair-fed diets with (group TN) or without nucleotides (group TS) for 4 mo. Liver histology and extracellular matrix components, liver collagenase and prolyl 4-hydroxylase activities, and tissue inhibitor of metalloproteinases-1 were assessed. The degree of fibrosis was lower in group TN than in group TS. Group TN had lower hepatic concentration of hydroxyproline (P < 0.05), collagen type I (P = 0.12) and type III (P = 0.20), fibronectin (P = 0.05), laminin (P = 0.11) and desmin (P = 0.07), higher collagenolytic activity (P < 0.05), lower prolyl 4-hydroxylase activity (P < 0.05) and lower prolyl 4-hydroxylase (P = 0.10) and tissue inhibitor of metalloproteinase-1 (P = 0.06) expression than group TS. Moreover, expression of tissue inhibitor of the metalloproteinases-1 gene was lower in group TN than in group TS (P < 0.05). These data indicate that the reduction of liver fibrosis in nucleotide-supplemented rats may rely on the enhancement of collagenase activity and the reduction of collagen content and maturation.