p53 mutations in colorectal cancers in the patients of Metropolitan New York.

An unselected series of 19 colorectal adenocarcinomas obtained from patients treated by surgery at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, USA was investigated for mutations in exons 5, 6, 7 and 8 of the p53 gene. Ten of the tumors revealed at least one somatic mutation either in the exon 5 or 8. Two of them were found to carry two somatic mutations each. The DGGE pattern of one of these two tumors indicated that it contained two different clonal cell populations; a similar assessment was not possible in the other tumor. Sequence analysis of all the observed variants showed that eighty percent of the mutations were due to transitions and that half of them were at mutational hot spot codons, 175 and 273.