N. Urosevic et al., PREVALENCE OF G-TO-T TRANSVERSIONS AMONG K-RAS ONCOGENE MUTATIONS IN HUMAN COLORECTAL TUMORS IN YUGOSLAVIA, International journal of cancer, 54(2), 1993, pp. 249-254
Human colorectal carcinoma tissue sampled from 37 patients, routinely
graded into Dukes' stages A, B and C and histologically examined for t
he level of differentiation, were analyzed for the presence of point m
utations in the K-ras oncogene. Seventeen cases out of the 37 analyzed
were found to have a mutation in either the 12th or the 13th codon of
the K-ras gene, giving an overall frequency of mutation of 46%. The i
ncidence of mutations in Dukes' stages A, B and C was 33, 46 and SB% r
espectively. Although the frequency of mutation appears to be similar
to that reported for the USA population, the spectrum of point mutatio
ns in codons 12 and 13 of the K-ras gene in the Yugoslav population ap
pears to differ significantly. G-to-T transversions make up 77% of all
mutations present, with the distribution as follows: 18% at the first
base and 59% at the second base of codons 12 and 13. G-to-A transitio
ns at the second base is the only other mutation identified, occurring
mainly in codon 13 in colorectal tumors of all 3 stages.