Characterization of p53 gene mutations in colorectal carcinomas from an Asian population.
A series of colorectal carcinomas from an Asian population in Singapore were analyzed for mutations in the tumor suppressor gene p53. Based on single-strand conformation polymorphism (PCR-SSCP) analysis and direct DNA sequencing, 15 of 38 tumors (39%) were found to contain mutations in exons 5-8 of the p53 gene. The point mutations were predominantly base transitions. Among the 10 transitions, 5 were at CpG dinucleotide sites. One-third (5/15) of the mutations were found at previously identified hotspot codons 175, 248 and 282. In one case, an insertion of a 6-base pair sequence was found. p53 mutations did not correlate with tumor histological grade, Dukes' stage, or metastases. However, tumors at the distal site showed a higher proportion of mutations than the proximal site. Further, no mutation was found in the normal mucosa adjacent to tumor site, suggesting that no germ-line mutations were present. The results were compared with those from other studies and are discussed in connection to possible etiological factors that are specific to the local population.
Shi
C Y
CY
Department of Community, Occupational and Family Medicine, National University of Singapore, Kent Ridge.
Phang
T W
TW
Ngoi
S S
SS
Wee
A
A
Li
B
B
Lin
Y
Y
Lee
H P
HP
Ong
C N
CN
D000595:Amino Acid Sequence; D001208:Asia; D001483:Base Sequence; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000737:chemistry / Q000302:isolation & purification; D005091:Exons; D016158:Genes, p53; D006801:Humans; D008969:Molecular Sequence Data; D009367:Neoplasm Staging; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D012846:Singapore
D003062:Codon; D017931:DNA Primers; D004273:DNA, Neoplasm