Gastric hamartomatous tumours in a transgenic mouse model expressing an activated dioxin/Ah receptor

The dioxin/Aryl hydrocarbon (Ah) receptor is a ligand-activated transcription factor known to mediate the toxic effects of the environmental pollutants dioxins.

Transgenic mice expressing a constitutively active Ah receptor were found to develop gastric tumours.

Segments of the normal gastric glands of the corpus region (lined by foveolar, parietal and cardio-pyloral cells) developed cystic tumours. Tumours in the submucosa and muscularis propria consisted of large cysts surrounded by organized lymphocytic, connective, squamous and adipose tissues and vessels. Those tumours were obviously hamartomatous in nature. Despite the fact that the tumours had an inward growth and penetrated all stomach layers, no metastases developed.

The model here described may open new vistas into the investigation of the role of environmental pollutants in the development of gastric hamartomas.