N,N' -dinitrosopiperazine (DNP), a carcinogen with specificity for nasopharyngeal epithelium, facilitates NPC metastasis.
Dose-related nuclear staining was observed 24 hr after application of the carcinogen but specificity in terms of sites of tumor development was lacking.
This is the first time that mutagenicity of D. alata extract was investigated using Salmonella (Ames test) assay, which has 58% sensitivity to rodent carcinogens, and 73% specificity for noncarcinogens [ 28].
The transformation assay complemented the Salmonella mutagenesis assay in the identification of nonmutagenic carcinogens; thus, the two assays had a combined 83% sensitivity for all carcinogens and a 75% specificity for nonmutagenic noncarcinogens.
Model systems involving three direct-acting alkylating carcinogens, two organ sites, and two species have been employed to elucidate the relationships between carcinogenic etiology, tissue specificity, and activation of known and novel oncogenes.
In this review, a comprehensive summary of the carcinogen-activating role of CYP1A1 is presented, in terms of substrate specificity, mechanisms of carcinogen activation, polymorphisms and extrahepatic expression.
A well-characterized case of apparent mutational origin of hotspots is the preponderance of G>T transitions in the TP53 gene in lung cancers which is usually perceived as a reflection of the mutagenesis specificity of polycyclic carcinogens [ 18, 19].
