It has been reported that mutations in K-Ras and PIK3CA frequently occur in colorectal cancer, ~35–45% and 20%, respectively.22,23 Since IGF-1R governs PI3K/AKT and Ras/ERK signaling pathways,1 we next to test whether induction of p70S6K1 phosphorylation is dependent on K-Ras or PIK3CA mutation. Here, PIK3CA is linked to colorectal cancer.