Polymorphism of p16 INK4A and cyclin D1 in adenocarcinomas of the upper gastrointestinal tract.

Purpose: We investigated the prevalence of single nucleotide polymorphisms in the p16 gene (C540G) and the cyclin D1 gene (G870A), both known to regulate function in G1 arrest and therefore, may play an important role in carcinogenesis.

Methods: Using PCR based restriction fragment length polymorphism and single strand conformational polymorphism, we determined single nucleotide exchanges in the p16 and cyclin D1 genes among 56 esophageal adenocarcinomas (ADC) arising in Barrett's esophagus, 95 cardiac gastric ADC, and in 191 distal gastric ADC. The allelic frequencies were compared to a control group of 253 healthy blood donors.

Decreased agonist, but not antagonist, binding to the naturally occurring Thr92Lys variant of the h5-HT7(a) receptor.

In the present study on transfected human embryonic kidney (HEK)293 cells, we aimed at establishing whether expression of the naturally occurring Thr92Lys variation of the Gs-coupled h5-HT7(a) receptor leads to changes of ligand binding properties, of agonist-evoked cAMP formation and/or of antagonist-mediated blockade of the latter. Binding of [3H]5-carboxamidotryptamine ([3H]5-CT) to membranes and stimulated [3H]cAMP accumulation in whole cells were determined. Saturation binding experiments in membranes of transiently transfected cells expressing either the wild-type or the variant receptor revealed a single binding site in both cases and no difference in Bmax between both receptor isoforms.

Aberrant methylation of the adenomatous polyposis coli promoter 1A in bronchial aspirates from patients with suspected lung cancer.

Promoter hypermethylation is a major mechanism for gene silencing and offers a promising starting point for developing molecular biomarkers. The purpose of our study was to determine aberrant methylation of the adenomatous polyposis coli (APC) gene promoter 1A with respect to its prevalence and quantitative level in bronchial aspirates from patients with suspected lung cancer. Applying quantitative methylation-specific PCR, 155 bronchial aspirates from patients with non-small cell cancer (NSCLC) and small cell cancer (SCLC) of the lung as well as 67 bronchial aspirates from patients diagnosed for nonneoplastic lung disease were examined in a retrospective case-control study.

Correlation of hMLH1 and HPP1 hypermethylation in gastric, but not in esophageal and cardiac adenocarcinoma.

Using methylation-specific real-time PCR, we determined the prevalence of aberrant methylation in the mismatch repair gene hMLH1 and in the recently described HPP1 gene among 50 esophageal, 50 cardiac and 50 gastric ADCs. Additionally, expression of hMLH1 protein was detected immunohistochemically and correlated with DNA MSI. Hypermethylation of hMLH1 was found in 14% of esophageal, 28% of cardiac and 32% of gastric ADCs, whereas HPP1 hypermethylation was found more frequently in the 3 tumor types (64% vs.

The role of p63 and deltaNp63 (p40) protein expression and gene amplification in esophageal carcinogenesis.

p63, a member of the p53 gene family, is known to encode functionally antagonistic protein isoforms. Although transactivating protein isoforms display p53-like functions, deltaNp63 isoforms act toward p53 in a dominant negative way. Using immunohistochemistry, we examined the expression of pan-p63 and deltaNp63 in 50 esophageal squamous cell carcinomas (SCCs) as well as in squamous low-grade intraepithelial neoplasias (S-LGINs; n = 4) and high-grade intraepithelial neoplasias (S-HGINs; n = 18).

Impairment of signal transduction in response to stimulation of the naturally occurring Pro279Leu variant of the h5-HT7(a) receptor.

The aim of this study, performed in stably transfected HEK293 cells, was to investigate whether expression of the naturally occurring Pro279Leu variant of the h5-HT7(a) receptor (located in the third intracellular loop) is associated with changes in the pharmacological properties and/or second messenger formation compared to the wild-type receptor. Radioligand binding of [3H]5-carboxamidotryptamine ([3H]5-CT) to membranes and stimulation of [3H]cAMP formation in whole cells evoked by 5-HT receptor agonists were determined. Maximum binding (B(max)) to, and affinity (K(D)) of [3H]5-CT for, the variant receptor and the wild-type receptor were equal.