Higher frequency of point mutations in the c-K-ras 2 gene in human colorectal adenomas with severe atypia than in carcinomas.
Human colorectal carcinomas may be induced from adenomas or they may occur de novo. To examine which is the main pathway, we analyzed point mutations at codon 12 in the c-K-ras 2 gene in 73 colorectal carcinomas, 13 metastatic tumors, 72 adenomas and 30 normal tissues. The c-K-ras 2 codon 12 mutation frequency was 0/30 in normal tissues, 0/17 in adenomas with mild atypia, 3/37 (8.1%) in adenomas with moderate atypia, 15/18 (83.3%) in adenomas with severe atypia, 19/73 (26.0%) in primary carcinomas and 3/13 (23.1%) in metastatic tumors. The mutation frequency in adenomas with severe atypia was much higher than that in carcinomas. These results indicate that many colorectal carcinomas may not be induced through adenomas with severe atypia.
Ando
M
M
Department of Hygiene and Oncology, Tokyo Medical and Dental University School of Medicine.
Maruyama
M
M
Oto
M
M
Takemura
K
K
Endo
M
M
Yuasa
Y
Y
D000236:Adenoma / Q000235:genetics*; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics*; D003062:Codon / Q000235:genetics; D003110:Colonic Neoplasms / Q000235:genetics*; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; D011905:Genes, ras; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000473:pathology; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D012004:Rectal Neoplasms / Q000235:genetics*; D012016:Reference Values
D003062:Codon; D015345:Oligonucleotide Probes; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific