Melanoma antigen genes 1 and 2 are differentially expressed in human gastric and cardial carcinomas.

BACKGROUND: MAGE genes encode for tumor-rejection antigens and are expressed in tumors of different histologic types but not in normal tissues, with the exception of testis and placenta. The aim of this study was to evaluate the frequency of MAGE-1 and -2 expression in gastric and in cardial carcinomas; these conditions have been described as two distinct diseases, having different etiologies, epidemiologic patterns, and gene mutations. METHODS: Two groups of patients were studied: patients with distal gastric carcinoma and patients with carcinoma of the cardia. A group of patients with intestinal metaplasia in the gastric mucosa and controls were also included. All of them underwent upper GI endoscopy. Paired biopsy specimens were taken for routine histology and for RNA extraction, to study the expression of MAGE-1 and -2 genes. RESULTS: None of the intestinal metaplastic samples or controls expressed MAGE-1 and -2 at detectable levels. Whereas 40% of the gastric cancer patients expressed either MAGE-1 or -2, 26.6% transcribed both. In the cardial cancer group, 20% of the cases expressed at least one MAGE, and only 6.6% expressed both genes. These results might reinforce the concept that cancer of the cardia is a distinct neoplastic disease with regard to esophageal and gastric (distal) carcinomas. CONCLUSIONS: Here we show that MAGE gene expression occurs in advanced stages of gastric and cardial cancer and therefore appears to be a late event. This might point to a reconsideration of their potential role in cancer immunotherapy.

Expression of the epidermal growth factor receptor gene in human intestinal metaplasia: a preliminary report.

BACKGROUND: The role of growth factors/receptors in the etiopathology and/or development of gastric cancer has recently come under scrutiny, since overexpression or amplification of the EGF system has been found in many intestinal type gastric cancers and related to a more aggressive behavior. Since these gastric carcinomas appear to develop from intestinal metaplasia, a study was planned to investigate whether overexpression of the EGF-receptor gene also occurred in intestinal metaplastic mucosa. METHODS: Patients underwent upper GL endoscopy. Gastric biopsies for routine histology, Helicobacter pylori detection, quantification of intestinal metaplasia and EGF-R expression analysis were performed. A 30mer EGF-R specific oligonucleotide was end-labeled and used to probe a dot blot filter containing the RNA from the bioptic samples. RESULTS: Though all the gastric samples transcribed the EGF-R gene to a detectable level, overexpression of the EGF-R gene was found in the metaplastic mucosa in a minority of patients. CONCLUSIONS: These preliminary findings suggest that overexpression of the EGF-R gene is infrequent in the metaplastic gastric mucosa.

Differential diagnosis of Crohn's disease of the colon from ulcerative colitis: ultrastructure study with the scanning electron microscope.

Mucosal biopsies from patients with Crohn's disease and with ulcerative colitis were studied by scanning electron microscopy. Important abnormalities of the mucosal surface were found in both diseases. For Crohn's disease, the characteristic abnormality was loss of the regularity of the polygonal units, but with preservation of the mucosal integrity and of the normal mucosal design. For ulcerative colitis, the abnormalities were disorganization of the cells, signs of sloughing, and superficial erosions. Patients with Crohn's disease always had a significantly increased number of muciparous cells, while those with ulcerative colitis had obvious signs of decreased mucus production. The lesions of ulcerative colitis could be seen under the scanning electron microscope in mucosal areas that appeared normal endoscopically. We feel therefore that scanning electron microscopy of biopsy specimens from patients with inflammatory bowel diseases can be of great help in differential diagnosis.