title: Phenotypic alterations of 7,12-dimethylbenz(a)anthracene and N-methyl-N-nitrosourea induced rat mammary tumors during repeated transplantations.
abstract: New transplantable rat mammary tumor lines derived from 7,12-dimethylbenz(a)anthracence (DMBA)- and N-methyl-N-nitrosourea (MNU)-induced carcinogenesis were established and characterized for biological and morphological criteria in the course of multiple tumor generations growing in female or male Wistar rats. DMBA-derived tumors RMT-1, RMT-2 and RMT-3 converted from adenocarcinoma to fibrosarcoma in the early passages. Conversion proceeded earlier in tumors with a well differentiated epithelial component compared to less differentiated ones, providing evidence for clonal spindle cell selection as the most probable mechanism responsible. On the other hand, MNU-derived tumor lines--RMT-4 and RMT-5--maintained histological patterns of parent tumors for a long time, exceeding 20 passages. Analysis of stromal cell tumor component and its interference with developmental sequences of transplantable tumor progression contributes to the explanation of some recent divergent findings (1, 2, 3, 4, 5).
authors.affiliation: Research Institute of Clinical and Experimental Oncology, Ol Brno, CSSR.
authors.forename: V
authors.initials: V
authors.lastname: Dolezalová
authors.forename: R
authors.initials: R
authors.lastname: Nĕmecek
authors.forename: J
authors.initials: J
authors.lastname: Tóth
authors.forename: J
authors.initials: J
authors.lastname: Sugár
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002460:Cell Line; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology*; D008770:Methylnitrosourea; D009368:Neoplasm Transplantation; D010641:Phenotype; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene; D008770:Methylnitrosourea