OBJECTIVE: To detect and analyse ki-ras point mutations in colorectal adenomas and carcinomas in patients from Greece, where mortality rate from colorectal cancer is lower than that in other European countries and the USA.
PATIENTS AND METHODS: As a method we used PCR-RFLP technique, to examine ki-ras codons 12 and 13 mutations in 450 paraffin embedded tissues, consisting of 141 normal mucosas, 165 adenomas and 144 sporadic colorectal cancers taken from 141 patients.
RESULTS: Frequency of ki-ras mutations was 3.2% (3/93) in small adenomas, 5.2% (3/57) in greater than 1 cm adenomas, 20% (3/15) in tissues where adenoma and cancer coexisted and 39.5% (57/144) in colorectal cancer.
CONCLUSION: These data showed that the frequency of ki-ras mutations was low in all sizes of polyps and high in carcinomas in a sample of a population, characterized by a low mortality rate from colorectal cancer. Ki-ras mutations were not an early event of colon carcinogenesis in these patients and the low frequency of ki-ras mutations in adenomas may probably have some relevance to the low mortality rate. Our findings could be explained, not by the dietary habits of this population, but by the presence of other hitherto unknown environmental factors.
- Colorectal Neoplasms/genetics
- Genes, ras/genetics
- Point Mutation/genetics