K-ras gene mutation is a useful predictor of the survival of early stage colorectal cancers.
Mutations in the K-ras gene were found to be of predictive value in the clinical outcome of non-small cell lung cancers, but its role in predicting the survival of colorectal cancer patients is still inconclusive. Point mutations in codon 12 or 13 of K-ras gene were analyzed in 64 colorectal cancers composing 4 Dukes' stage. A, 34 stage B, 21 stage C and 5 stage D. DNA extracted from the paraffin-embedded tissues of the 64 patients was amplified with the polymerase chain reaction and subsequently analyzed by direct cycle sequencing. Thirteen of sixty-four (20%) resected colorectal cancer specimens were found to have K-ras gene mutation at either codon 12 or 13. Log rank tests found that K-ras gene mutation and Dukes' stage were associated with patients' survival. When stratified by Dukes' stage, the patients with mutated K-ras genes in the stratum of stage A or B were found to have shorter survival times than those without mutated K-ras genes (P = 0.003), but this was not the case in the stratum of stages C and D. The relative risk of mortality in the stratum of stage A or B was 7.74 (95% confidence interval: 1.72-34.89) by Cox regression analysis. We thereby conclude that K-ras gene mutation is a usefull predictor of the survival of early stage colorectal cancers.
Lee
J C
JC
Department of Surgery, National Cheng-Kung University Hospital, Tainan, Taiwan, Republic of China.
Wang
S T
ST
Lai
M D
MD
Lin
Y J
YJ
Yang
H B
HB
D000328:Adult; D000368:Aged; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017354:Point Mutation / Q000235:genetics*; D011379:Prognosis; D012004:Rectal Neoplasms / Q000235:genetics* / Q000473:pathology