The analysis of primary tumours revealed K-Ras mutations in 43% of cases, BRAF mutations in 6% of cases and PTEN loss of expression in 21% of cases, in agreement with the earlier data concerning sporadic colorectal cancers (Rajagopalan et al, 2002; Frattini et al, 2005, 2007). This evidence concerns the gene BRAF and colorectal cancer.