Ki-ras mutations in adenomas from cancer-bearing and cancer-freee bowel

✍ Scribed by Zauber, N. Peter; Sabbath-Solitaire, Marlene; Bishop, D. Timothy

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 19 KB
• Volume: 184
• Category: Article
• ISSN: 0022-3417
• DOI: 10.1002/(sici)1096-9896(199803)184:3<340::aid-path14>3.0.co;2-y

✦ Synopsis

We read with interest the paper by Morris et al. 1 reporting a higher incidence of Ki-ras oncogene mutations in villous or tubulovillous adenomas removed from cancer-bearing bowel as opposed to cancer-free bowel. Our calculation of the odds ratio for their data is 3•125. They found the higher percentage of mutations in adenomas from cancer-bearing bowel to be largely attributable to adenomas recovered from patients over 70 years of age.

We have evaluated a cohort of patients with sporadic colorectal polyps and cancer. All patients had had complete colonoscopies, thus ensuring proper identification as to cancer-bearing or cancer-free bowel. We analysed 188 adenomas and 52 carcinomas for mutations in codons 12/13 of the Ki-ras gene using singlestrand conformational polymorphism polyacrylamide electrophoresis. We derived the odds ratio and 95 per cent confidence intervals and used a two-sided chi-square test for the level of significance. This is a more conservative test than the one-sided test used by Morris et al.

For all adenomas, we found a 2•6-fold increased risk for a mutation in adenomas from cancer-bearing bowel compared with adenomas from cancer-free bowel, when adjusted for histology, P<0•02 (Table I). When we controlled for age less than or greater than 70 years, we found a 3•2-fold increased risk for Ki-ras mutation in