KRAS and colorectal cancer: In colorectal cancer, exon 9 PIK3CA mutations showed a trend towards increased frequency in patients with KRAS mutations (9/45; 20%) compared to patients with wtKRAS (3/46; 6%) (p = 0.07), whereas the frequency of exon 20 PIK3CA mutations did not significantly differ (4/40 [10%] in KRAS mutant vs. 2/45 [4%] in wtKRAS; p = 0.4).