title: Pathological features of N-methyl-N'-nitro-N-nitrosoguanidine induced neoplastic and preneoplastic lesions of rat stomach.
abstract: Malignant transformation of rat stomach was studied after oral administration of MNNG. The lesions were investigated with cytomorphological and histochemical methods, while the alkaline phosphatase (ALP) isoenzyme pattern was investigated by means of gel electrophoresis. Hyperdiploid-aneuploid DNA values were observed in dysplasias, as well as in carcinomas. The liver type ALP isoenzyme could be detected in intact and regenerative gastric mucosa. It also occurred in atypical hyperplasia and carcinoma. Placental type ALP isoenzyme was absent in all intact or regenerating gastric mucosa, but present in atypical hyperplasias and carcinomas. It can be concluded that DNA aneuploidy and the presence of placental type ALP are indicative of malignant transformations. The MNNG-induced adenomatous hyperplasia associated with atypia behaved like cancer and can thus be regarded as an obligatory preneoplastic lesion.
mesh_terms: D000236:Adenoma / Q000139:chemically induced; D000818:Animals; D002277:Carcinoma / Q000139:chemically induced; D006965:Hyperplasia; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D011230:Precancerous Conditions / Q000139:chemically induced*; D051381:Rats; D013270:Stomach / Q000187:drug effects / Q000473:pathology*; D013274:Stomach Neoplasms / Q000139:chemically induced*; D013997:Time Factors
chemical_list: D008769:Methylnitronitrosoguanidine