Kirsten ras Mutations in Patients With Colorectal Cancer: the Multicenter ‘‘RASCAL’ ’ Study

Background: Kirsten ras (Ki-ras) gene mutations occur early in the progression of colorectal adenoma to carcinoma. The aim of this collaborative study was to clarify the association between Ki-ras mutations, patient outcome, and tumor char-acteristics by use of data from colorectal cancer patients worldwide. Methods: Investigators who had published data on Ki-ras and colorectal cancer were invited to complete a questionnaire for each patient entered into a database. Two-sided statistical tests were used to analyze data. Results: Patients (n = 2721) were recruited from 22 groups in 13 countries. Mutations of Ki-ras codon 12 (wild type = GGT = glycine) or codon 13 (wild type = GGC = glycine) were de-tected in 37.7 % of the tumors; 80.8 % (584 of 723) of all the specified mutations occurred in codon 12, and 78.1 % (565 of 723) of all the specified mutations were at the second base o