title: Immunohistochemical demonstration of p73 protein in the early stages of DMBA-induced squamous-cell carcinogenesis in hamster buccal pouch.
abstract: The identification of a new protein, p73, with structural and functional similarities to p53 protein suggests that a family of p53-like proteins is likely to exist. This study investigated the status of p73 protein in the early stages of 7,12-dimethyl benz[a]anthracene (DMBA)-induced carcinogenesis. Outbred young (6-week-old) male Syrian golden hamsters (Mesocricatus auratus; 40 animals) were randomly divided into four equal groups: a 3-week DMBA-treated experimental group, a 6-week DMBA-treated experimental group, a mineral oil-treated control group, and a non-treated control group. Following this, a total of 80 specimens of pouch mucosa were obtained from the 40 animals in the four groups. Positive nuclear staining for p73 protein was randomly distributed throughout the whole epithelial layer of the DMBA-treated specimens and was absent in controls. Positive p73 staining was observed in 8 of the 20 (40%) 3-week, and 14 of the 20 (70%) 6-week DMBA-treated specimens. None of the 3-week DMBA-treated specimens revealed more than 25% p73-positive keratinocytes, but, in 12 (60%) of the 6-week-treated specimens, more than 25% of the keratinocytes examined were p73-positive. This suggests that the longer the DMBA painting period, the higher the proportion of p73-stained pouch keratinocytes. Furthermore, a p73-dependent mechanism may be associated with the early stages of oral carcinogenesis. Such a mechanism could be very important to an understanding of the participation of p73 in the development of oral squamous-cell carcinomas.
authors.affiliation: Oral Pathology Department, School of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung, Taiwan.
authors.forename: Yuk-Kwan
authors.initials: YK
authors.lastname: Chen
authors.forename: Shui-Sang
authors.initials: SS
authors.lastname: Hsue
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Lin
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D002273:Carcinogens; D002294:Carcinoma, Squamous Cell / Q000737:chemistry*; D002610:Cheek; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000032:analysis*; D016147:Genes, Tumor Suppressor; D007150:Immunohistochemistry / Q000379:methods; D015603:Keratinocytes / Q000737:chemistry; D008297:Male; D008647:Mesocricetus; D009062:Mouth Neoplasms / Q000737:chemistry*; D009374:Neoplasms, Experimental / Q000737:chemistry; D009687:Nuclear Proteins / Q000032:analysis*; D011897:Random Allocation; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins
chemical_list: D014408:Biomarkers, Tumor; D002273:Carcinogens; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D015127:9,10-Dimethyl-1,2-benzanthracene