Intestinal-type Samples Research Articles

Interrelationship between TP53gene deletion, protein expression and chromosome 17 aneusomy in gastric adenocarcinoma

BackgroundThis study evaluates the existence of numerical alterations of chromosome 17 and TP53 gene deletion in gastric adenocarcinoma. The p53 protein expression was also evaluated, as well as, possible associations with clinicopathological characteristics.MethodsDual-color fluorescence in situ hybridization and immunostaining were performed in twenty gastric cancer samples of individuals from Northern Brazil.ResultsDeletion of TP53 was found in all samples. TP53 was inactivated mainly by single allelic deletion, varying to 7–39% of cells/case. Aneusomy of chromosome 17 was observed in 85% of cases. Chromosome 17 monosomy and gain were both observed in about half of cases. Cells with gain of chromosome 17 frequently presented TP53 deletion. The frequency of cells with two chr17 and one TP53 signals observed was higher in diffuse than in intestinal-type GC. Immunoreactivity of p53 was found only in intestinal-type samples. The frequency of cells with two chr17 and two TP53 signals found was higher in samples with positive p53 expression than in negative cases in intestinal-type GC.ConclusionWe suggest that TP53 deletion and chromosome 17 aneusomy is a common event in GC and other TP53 alterations, as mutation, may be implicated in the distinct carcinogenesis process of diffuse and intestinal types.

Polyamine levels and ODC activity in intestinal-type and diffuse-type gastric carcinoma.

Gastric carcinomas are divided into two types according to Lauren's classification: intestinal and diffuse types. Polyamines (putrescine, spermidine, and spermine) are polycations involved in neoplastic growth of gastrointestinal mucosa. A key role is also played by ornithine decarboxylase, the rate limiting enzyme in polyamine metabolism. Our aim was to investigate whether there were differences between the two types of tumor in polyamine metabolism. Twenty-seven patients with gastric carcinoma entered the study. Seventeen carcinomas were classified as diffuse type and 10 as intestinal type. Polyamine levels were evaluated by high-performance liquid chromatography. Ornithine decarboxylase activity was measured by a radiometric technique. Polyamine levels and ornithine decarboxylase activity were significantly higher in intestinal type samples than diffuse type samples. A similarity of polyamine levels in intestinal type samples with levels previously observed in patients with colorectal adenocarcinoma was also found. These findings show a different proliferative behavior of these two types of tumor, and therefore different therapeutic strategies can be hypothesized.