M. Sato et al., FAR LESS FREQUENT MUTATIONS IN RAS GENES THAN IN THE P53 GENE IN SKINTUMORS OF XERODERMA-PIGMENTOSUM PATIENTS, Molecular carcinogenesis, 11(2), 1994, pp. 98-105
Mutations in Ha-ras, Ki-ras, and N-ras genes in squamous and basal cel
l carcinomas in patients with xeroderma pigmentosum (XP) were examined
by the polymerase chain reaction followed by single-strand conformati
on polymorphism analysis and direct base sequencing. No mutation was d
etected in codons 12, 13, and 61 of the ras genes in XP skin tumors. T
his was in contrast with previous findings of a high frequency of muta
tion in the p53 gene in skin tumors in XP patients. A novel mutation i
n codon 6 of the Ki-ras gene was detected in a squamous cell carcinoma
. The mutation was a C-->T transition at a dipyrimidine (5'-CT) sequen
ce and could have been produced by solar ultraviolet light. The mutate
d ras gene did not have the ability to transform NIH/ 3T3 cells. In th
ree tumors, multiple base substitutions were detected in exon 1 of the
Ki-ras and N-ras genes. These results and our previous work on p53 ge
ne mutations suggest that mutations in ras genes are far less frequent
than in the p53 gene in the skin tumors in XP patients and that ras g
enes are less important in skin tumorigenesis in XP patients than is t
he p53 gene. (C) 1994 Wiley-Liss, Inc.