Genetic events in sporadic colorectal adenomas: K-ras and p53 heterozygous mutations are not sufficient for malignant progression.
Twenty-four sporadic colorectal adenomas were analysed for the presence of allelic loss on the short arm of chromosome 17 as well as mutations in the K-ras and p53 genes. Chromosome 17p13 allelic loss was not present in 14 out of 14 informative cases. K-ras mutations were observed in 15 out of 24 cases. A p53 gene mutation (GGC-->GAC at codon 245) was detected in two biopsies taken at a four year interval from a recurrent rectal villous adenoma. Both biopsies also contained the same K-ras gene mutation (GGT-->GTT at codon 12). The data from the recurrent rectal adenoma provide in vivo evidence that K-ras and p53 heterozygous mutations confer a proliferative advantage but together are not sufficient for malignant transformation.
De Benedetti
L
L
IST, National Cancer Institute, Genova, Italy.
Varesco
L
L
Pellegata
N S
NS
Losi
L
L
Gismondi
V
V
Casarino
L
L
Sciallero
S
S
Bonelli
L
L
Biticchi
R
R
Bafico
A
A
D000236:Adenoma / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002872:Chromosome Deletion; D002886:Chromosomes, Human, Pair 17; D003062:Codon / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics*; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017354:Point Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods
D003062:Codon