PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 8142011-1 1994 Distinct differences have been described in the development of C3H/He mouse liver tumors induced by the genotoxic carcinogen diethylnitrosamine (DEN) and by the nongenotoxic agent phenobarbitone (PB) in terms of pathology and the frequency of mutation at codon 61 of the Ha-ras oncogene. Phenobarbital 180-194 Harvey rat sarcoma virus oncogene Mus musculus 271-277