[Expression of p53 in gallbladder carcinoma and in dysplastic and metaplastic lesions of the surrounding mucosa]. / Espressione di p53 nei carcinomi della colecisti e nelle lesioni displastiche e metaplastiche della mucosa circostante.

We studied the expression of p53 in 80 gallbladder carcinomas, 43 peritumoral mucosae, 5 adenomas and 20 mucosae of non tumoral gallbladders. Gallbladder cancers were classified according to WHO criteria. We found p53 overexpression in 51 out of the 80 gallbladder cancers (64%). p53 expression was variable in different histologic subtypes: 100% of intestinal type, 66% of papillary type, 83% of adenosquamous carcinomas and 66% of giant cells cancers showed immunoreactive cells. In well and moderately differentiated conventional gallbladder adenocarcinomas we found 60% of positive cases, while, among poorly differentiated conventional cancers, 83% were immunoreactive. All mucinous adenocarcinomas were p53-negative. In peritumoral dysplastic mucosae, p53 was expressed in 23 out 38 cases (60%), 22 (96%) of which were associated to a p53-positive adenocarcinoma. On the contrary, only 5 of the 15 p53-negative dysplastic lesions (33%) were associated to an p53-immunoreactive adenocarcinoma. Metaplastic lesions, of gastric and intestinal type, and adenomas were completely p53-negative. In conclusion, our data suggest that p53 expression is an early event, frequently involved in gallbladder carcinogenesis, and related to different histologic subtypes of gallbladder adenocarcinomas.

Mixed endocrine-exocrine tumors of the gastrointestinal tract.

Mixed endocrine-exocrine tumors of the gastrointestinal tract are rare neoplasms, which have been reported in the literature mainly as case reports and have been designated with a various and rather confusing terminology. In this review, on the basis of personally studied cases and of the analysis of cases reported in the literature, we have tried to identify types of mixed endocrine-exocrine tumors showing different clinicopathologic and biological characteristics. We have also tried to group the different clinicopathologic entities in prognostic classes which include: benign, low-grade, intermediate grade, and high-grade malignant mixed endocrine-exocrine tumors. The criteria for identifying the various types of mixed endocrine-exocrine tumors are extensively discussed.

Immunohistochemical localization of alpha- and betaA-subunits of inhibin/activin in human normal endocrine cells and related tumors of the digestive system.

Activin A and inhibin A, first isolated from the ovary, are dimeric proteins able to modulate pituitary FSH secretion. Inhibin A is a heterodimer composed of one alpha-subunit and one betaA-subunit (alpha-betaA), while activin A is a homodimer of the betaA-subunit (betaA-betaA). Their identification in several tissues has suggested that they have numerous physiological functions, acting as either paracrine or autocrine factors. The aim of this study was to evaluate the expression of activin A and inhibin A in normal endocrine cells and in 70 endocrine tumours from different sites in the gastro-entero-pancreatic system, using specific monoclonal antibodies directed against the alpha- and betaA-subunits of inhibin/activin. Immunoreactivity for the betaA-subunit, but not for the alpha-subunit, was observed in normal G, EC, and GIP cells of the antrum and duodenum, and in pancreatic A cells. BetaA-subunit expression was observed in G cell and A cell tumours, and in a few insulinomas and ileal EC cell carcinoids. The alpha-subunit was found in rare cells in 7 of the 70 tumours and was colocalized with the betaA-subunit in only 1 tumor. Specific types of endocrine cells from the gut and pancreas appear to produce only activin A, a possible paracrine or autocrine modulator. Activin A is mainly produced by tumours derived from endocrine cells that normally express it.