title: Effects of 12-O-tetradecanoylphorbol-13-acetate on carcinogenesis in the heterotopically transplanted rat urinary bladder.
abstract: 12-O-Tetradecanoylphorbol-13-acetate (TPA), a potent promoter of mouse skin carcinogenesis, was tested for possible tumor-enhancing effects on urinary bladder carcinogenesis using the heterotopically transplanted bladder (HTB) model. Weekly administration of TPA at 1.0 microgram/week to N-methyl-N-nitrosourea-initiated HTBs did not increase tumor incidence, but instead, resulted in a significantly high incidence of nodulopapillary hyperplasia, an early neoplastic lesion, suggesting possible tumor enhancement by TPA. In addition, administration of a high dose of TPA with or without a carcinogen treatment led to the development of numerous finger-like epithelial projections on the luminal surface of the HTBs. Evidence indicates that epithelial projections are formed as a result of proliferation of intermediate cells. Whether these structures evolve into true neoplastic lesions is at present unknown.
mesh_terms: D000818:Animals; D002455:Cell Division; D008297:Male; D008770:Methylnitrosourea; D010704:Phorbols; D051381:Rats; D011916:Rats, Inbred F344; D013755:Tetradecanoylphorbol Acetate; D001743:Urinary Bladder / Q000473:pathology / Q000637:transplantation; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced* / Q000473:pathology / Q000648:ultrastructure
chemical_list: D010704:Phorbols; D008770:Methylnitrosourea; D013755:Tetradecanoylphorbol Acetate